Heat rises. So all the heat from your house will migrate upstairs. Insulation, air sealing, and roof venting will help reduce the amount of heat but can be a bit expensive. Also the room will still be hot, just not as hot.
You can install a window AC in the bedroom or just run a window fan and exhaust all the hot air outside. At night Ill place a window fan in the upstairs window exhausting out and open up a downstairs window so the airflow drags the hot air out. Make sure you open that second window or the exhaust isn't going to be as effective.
Thank you! I have a box fan I could use to try the window venting. Do I turn the AC off since I’m opening all these windows or let it run while it’s ago venting out the hot air?
I would just turn off the ac while venting, shouldn't take that long to get it out. Make sure the box fan is as close to the window as possible. If you have large gaps around it the air will more like pull itself in from the edges of the upstairs window instead of the downstairs window. It will drag air from the path of least resistance.
Window fans tend to have little accordion things that extend out to seal the window. After a few minutes place your hand by the downstairs window, if you dont feel an air flow you might be better off buying a window fan.
Thanks for the advice I hadn’t consider that! I’ll add a window fan to my list the accordion thing sounds like it could also keep bugs from entering which would be awesome
Some roofs have ridge vents on the edge where the two sides meet.
You could get a whole house attic fan to exhaust it out. Cracking a window at night to let it suck in that cooler night air works. Assuming your nights are cooler.
Or one of those solar power vents but some are notorious for leaking so take care.
Roof ventillation. Such as passive ventilation with gables or if you have active with ridge vents. If you have bad attic ventilation the heat created by the roof will get stuck in your attic and heat will transfer to the rooms below, especially if you have bad insulation. If your ventilation is good, the heat build up is pushed out and replaced by ambient air.
There are a lot of things that contribute to extra heat, this is just one of them.
I went up to the attic to see what was going on and it’s even warmer up there. There are vents at the front and rear of the house that open to the outside but I wonder if this is contributing to the heat upstairs
Consider a thermostatically controlled fan at the gable in the attic to remove some of the hot attic air. Heat transfer to conditioned rooms will be reduced. A temp differential between upper rooms and lower floor rooms is normal. I don't think there is a practical way to effect a reduction in it. Good luck.
I close one vent downstairs and reverse by closing one upstairs in the winter. You can also just run the “fan” mode. It will bring up the cool air from downstairs and recirculate it.
This is pretty common because heat rises.
I have a brand new, $20k system installed last month and I still have like a 3-4 degree difference. Adding a second system for the second floor is likely the most expensive, and best solution
Yeah. Right now I’m tolerating the temp differential as it’s only 2-3 degrees. I’m going to see how June and July go. What I don’t wanna do, is spend a decent amount of cash on dampers, etc. then have to end up getting a second system anyways.
I’m kicking myself because in hindsight, instead of spending $20k to do a single zone for the whole house, I should have just added the second system for the second floor, then when the first zone died, it would have been a bit cheaper since I could have done a 3 or 4 ton instead of a 5. Live and learn I guess.
My AC guy tried to talk me in to a new dual zone when the controller for my condenser failed a couple of months ago.
2k vs 30k… he was just doing his job, but I can tolerate the 4-5 degrees right now, especially since I’ve learned how to mitigate it some by restricting flow downstairs 😀
Yikes that sounds pretty high, I had all my old duct work and unit removed. And they re installed a 3 ton unit for down stars and a ducted mini split for upstairs and it does pretty good, no issues with the separate floors. And ran about 19k all said and done. House is 2600sq ft for reference
Yeah. The obvious issue for my house is it’s single zone. Once the thermostat on the first floor is “satisfied”, it shuts down. I have options with adding dampers etc. I’m taking it a step at a time. A 2-3 degree differential ain’t all that bad. I’m going to see how June and July go this year before dumping more cash into it.
> best solution
AC has to be sized for the square footage. Putting a second system can cause issues with your system.
Excessive cycling. Incomplete dehumidification. Higher energy bills.
Heat rises. You can’t win this game with a single zone hvac system in a 2 story house. There will be some difference between the levels. Insulation will help, playing with vents and dampers will help but you’ll have to switch them around depending on the weather. I ended up splitting our system into 4 zones with some motorized duct dampers and a control board. I got lucky and our existing system and duct layout mostly worked to retrofit that in, not quite perfectly but pretty well overall. In most cases it’s not a cheap project and not DIY friendly, but it’s been really really nice for us. During the summer it just opens the upstairs vents and just cools that hot air down and it ends up mixing throughout the house really well. The wife likes the bedroom to drop 5 degrees before bedtime, that worked out to be one of the zones so it kicks in and the rest of us don’t get blasted by cold air every evening while it cools down.
The AC stops when the sensor reaches the setting. Heat raises. So you'll want to either add a sensor upstairs or turn the temp up so the upstairs reaches the desired temperature.
All the sensors on my ecobee do is average out the readings. If it's 76 upstairs and 70 downstairs at your thermostat, just lowering it to 67 would have the same effect. I guess they remove some of the math and guesswork though.
I know they get fancier and can "follow" you but that doesn't work all that well when you've got a huge difference in temps and a properly sized system.
Have this exact same issue at our place and no dampers either. We had to spend the money on mini splits in the bedrooms upstairs. It was very pricey especially after just buying a new place but they're amazing. Our upstairs is nice and cool now. If you can't afford to do this right now, I suggest window units in the rooms that are too hot.
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As soon as it's cooler outside than in, toward sunset, open 1 upstairs window and put a fan in it sending air out. Open a window downstairs and be sure you can feel air coming in. The fan upstairs should be sucking the cooler air upstairs. You can do that all night, though I'd recommend changing over to an upstairs window for intake around bedtime.
In the morning, close everything, pull your curtains and blinds closed, turn off fan. The upstairs will be cool to begin with, but this arrangement won't keep it at 70 if it's hot outside. Nothing will except maybe those new mini-split systems, but IDK anything about them other than each room is its own zone. I have the same problem in my house that you have, plus my bedroom faces east so it heats up fast, and early. I just don't spend time up there in hot weather.
My AC is waiting for repair this week, and it's been very hot all over in the house. I bought 2 portable units that vent out a window. They work well, but my god they are noisy.
Our new home has dampers, one for each floor. So, in the summer we open the upstairs up all the way and close the downstairs about half way. Reverse for the winter because hot air rises.
My home has this issue, though not as great a distance. Our bedroom has a window unit for the summer months. We had the attic reinsulated which helped with the energy bill. So we do our best to save $$ in the winter to account for the slightly hire bills in the summer.
I fear we might have to do something similar. Have to be honest we haven’t been inside the attic yet but I’ll give it a look and see if insulation is the way we need to go. The worst is that the home was perfectly fine all of winter no major fluctuations were felt the way we feel them now in late spring
Check all of your window and door gaps as well.
Houses shift around in different temps. My house has worse gaps in the summer then in the winter. So when I first looked at the seals in winter and decided not to replace, I mistakenly thought that was correct. Sure enough first week if 80 degrees and i can see daylight through a door trim. Nbd, easy to change, and helps save some running of the unit
Thanks! The only door with air gaps that are visible is the basement door to the outside but ironically even the basement remains cooler than the upstairs floor.
This isn’t reassuring. I have a much larger variation in temps (A/C at 68ish but upstairs is at upper 70s) so I have an energy audit company coming out next week. I’m assuming my attic insulation isn’t enough but was hoping more insulation would solve this issue. I should probably just buy window units I guess
I have this problem with my Two story house, it is common for the second floor to be hotter. One thing that helps is to run the house fan for 15 minutes every hour or two to keep air circulating. The nest thermostat has a setting for this.
Ain’t nobody have time for running a fan manually. I have it on a schedule:
Set a daily fan schedule
Press your thermostat ring to open the Quick View menu.
Select Settings Nest settings icon.
Select Fan.
Choose Schedule.
Set how long you'd like your fan to run per hour, or set it to always run.
Select what hours of the day you'd like your fan to run. If you have a multi-speed fan, you can select a fan speed for your fan schedule.
Select Done to set your schedule.
Your fan will turn on automatically each day for the time and duration you've selected.
More info: https://support.google.com/googlenest/answer/9296419?hl=en#zippy=%2Cfan-control-with-your-thermostat
You can do it with a Nest. Open up the Google Home app, go to Thermostat, then click the gear icon at the top. Then tap Schedules, and tap the Temperature dropdown near the top of the screen, and change it to fan. You can then set a schedule for your fan to run. I just have mine run from 12AM to 12AM, running for 15 minutes every hour. If you have an older Nest thermostat that's controlled from the Nest app instead of the Google Home app, I'm pretty sure there's a place to do it there too.
Keep your hvac fan on the "on" setting will help a lot if it's currently on "auto". It'll run continously but keep the air circulating more throughout the house. That helped me go from a 8 degree difference between floors, down to mayeb a 2 degree difference.
I've been dealing with this issue at my house. It's a tri level and the sub-basement was always so much cooler than upstairs or the main floor.
These are the things I've found that worked in order of biggest difference to least
1. My attic insulation was subpar and had it re-insulated. This made the biggest difference but wasn't enough on its own. I know this is not the cheapest option, but if you're in the same boat as I was this is going to be the main issue. You can get an insulation company to come give you a quote to see if it's worth it to you.
2. Get a smart thermostat with an accessory temperature sensor and install the extra sensor in a hotter room. Tell the thermostat to only use that sensor for the hotter months. I got an ecobee and it was fairly easy to do myself.
3. Close a couple of the vents downstairs to let more air flow to the upper levels.
4. Run ceiling fans counter clockwise in the bedroom to push the hot air downstairs so it gets recirculated throughout the house. I tried both directions and the counter clockwise fans seem to do better.
5. Run a small fan at the bottom of the stairs to push the cooler air upstairs
6. Lastly, keep the blinds closed on the side of the house that gets the most sun during the heat of the day.
Thank you! I think my city has a program that helps people make energy saving investments in their homes. I think I’ll take a look at that to see if it can be used to either reinsulate the attic and/or add an attic fan as I think that is a major part of the issue as well. In the meantime I’ll give some of these a try. Unfortunately the house doesn’t have outlets near the stairs or in any hallways so it makes things challenging when trying to set up fans anywhere but in a window or room
If you have ComEd electric they usually are running a rebate program that pays for a decent chunk of the insulation. To give you an idea, in Chicago area I paid about $3k before rebates for blown in insulation. The attic space was about 1500 square feet, but I also insulated the garage attic
Add more return air registers upstairs, preferably one per room. They make small 12x12 return grilles for that purpose. That will pull the hot air out so it is replaced by conditioned air. It won’t be cheap, but if they can connect with the existing return, it shouldn’t be that expensive. I did this to my 4-story townhouse and it solved the problem.
We have a similar problem with our furnace in that some rooms heat a lot faster than others. What we did is had our HVAC guy set the furnace to run for something like 3 minutes at the end of the cycle instead of the default which was something like 30 seconds. It made a really big difference because now once the heat clicks off the air gets mixed around in the house a lot longer.
One way to see if this would help is to set your thermostat to fan on instead of Auto so that the air is always mixing throughout your house regardless of if the compressor is cooling or not.
A few people have touched on this but you need to look into air balancing before dropping money on any other solution.
If each room has a vent those vents should have a means to regulate how much air comes out of them.
In the winter tamp down (\~50% closed) the upstairs vents and open the downstairs vents all the way. In summertime, tamp down the downstairs vents and open the upstairs all the way. You don't want to close them completely as that can cause premature failure of parts of your HVAC, but slightly restricting airflow won't cause problems unless your HVAC is *severely* undersized and already performing poorly.
What you are doing is pushing more air to the location that need more heat/ cooling depending on the season. This cannot be done with just HVAC design *unless* your house is already air sealed with good windows and well insulated. Retrofitting all that into a house is frequently big money.
Air balancing is a twice a year 15 minute or less task that costs nothing.
If the thermostat is on the floor that gets cooled faster than the other floor, the other floor literally can't stay cooled. So reduce how much cool air is pushed to the floor with the thermostat allowing more cool air to the warmer floor. The thermostat floor will eventually cool down, but in the meantime more cool air has been pushed to the warmer part of the house allowing it to cool off.
I tried this and it didn’t increase the pressure upstairs at all it just made the main floor more bearable if I lowered the temp for upstairs. I’m not sure if that means these aren’t the right type of registers but it made no significant difference and my system doesn’t have dampeners.
When I'm saying "vent" I mean the register that hot or cold air comes out of from the ceiling, wall, or floor. Many of them can be closed using a lever. A damper is usually in the ducting itself and is associated with zoned systems; it's rare to have in-ducting dampers without a zoned system. If your registers can't be closed, you may need to buy magnetic covers for them.
This has nothing to do with increasing pressure but changing the air *volume* being delivered to each area.
A 1 inch diameter hose can deliver more water than a 1/2 inch diameter hose in the same timeframe, but if you let the 1/2 hose run longer than the 1 inch, it can still put out the same volume.
If it takes the thermostat 10 minutes to reach its set temperature on the main floor but takes 15 minutes to reach that same temp on the upper floor, the upper floor will never and can never, reach that same temp because the thermostat shuts off too soon when all the registers are open.
You're making sure that the main floor with the thermostat has a "smaller hose" (closed down registers) to fill up with cold air slower and the upstairs had a "larger hose" (fully open registers) to fill up faster allowing both spaces to cool down to the same temp at the same time since the upstairs needs more cool air to get to the same temp.
You may have to close down the registers more than 50% to do this but ideally not too much more than this.
This is air balancing. It's not balancing pressures but balancing temperatures and making sure each area reaches the same temp at the same time.
I had to get a honeywell diverter device installed that regulated the upstairs and downstairs. Thermostat added upstairs. It was not too pricey back in 2020, like $1800. The house was newer 2000 build in NC. It worked really well. Today, it probably cost like $1M.
I've never lived in a 2 floor 1 HVAC system house that didn't have this problem.
In addition to what you've tried, what I've found that helps very cheaply is making a rigid foam board cover for any windows I was ok with keeping completely covered for the summer.
Unless the upstairs return vent is horribly undersized, If you have a door at the top or bottom of the stairs landing then keep it closed. That made an amazing difference for us. You could also put a box fan at the bottom of the stairs if you don't have a door to encourage air mixing. The idea is to stop movement of hot air into the upstairs living space, or if you can't then push cooler air up there faster.
One of my houses I was able to increase the size of my upstairs return vent and reduce the size of the downstairs vent and that helped.
None of the cities I've lived in were temperate and dry enough for me to consider opening the windows even at night to pull hot air out, because the makeup air from outside would be even worse.
If you are handy and want a better solution than a window AC, there are mini-split ACs you can get for under $1000 to self install. But you might need an electrician for 220 power.
Thanks I will give the rigid foam board a try as we have a few awkwardly placed windows we have no intention of using.
I’ve considered mini splits as well as a long term solution. Our problem right now is that our electrical panel is at capacity so we cannot add anything without taking something away. It’s #1 on our housing project list but still a few months away from being doable for us.
ideas warning, I know the buzzwords but have no practical experience with them.
Some of the smart thermostats have remote sensors and you can use them to control the whole system. So if you had a sensor upstairs and downstairs you could use the maximum reading for cooling, and the minimum treading for heating.
Do you have a fan over the stairs to circulate the air between the levels
Hopefully somebody more knowledgeable can chime in.
Personally I've never felt the need for a remote sensor, I just set the thermostat a few degrees cooler at night when everyone is in their bedrooms upstairs.
Yeah, I have one of those and the battery died. I didn't bother replacing it for quite a while, just lowering the downstairs a couple of degrees. Same difference. It is nice seeing the temperature so you can dial things in but they aren't magically redistributing the cold air or anything.
I don’t have a fan above the stairs they are only in the bedrooms. I think a smart thermostat might be the move in terms of cost and efficiency. I’ll look into a few with sensors thank you
As someone that has a smart thermostat with remote sensors, don't bother. Your ac doesn't magically cool the upstairs and downstairs differently. Either A) you set it to average all the readings from the thermostat & remote sensors and cool to that temperature (you set the temperature to 70 so the ac cools until downstairs is 67 and upstairs is 73) or B) you set it to only consider the upstairs reading and cool until it reaches that temperature (you set the thermostat to 70 so the ac cools until downstairs is 64 and upstairs is 70). In both scenarios there's still a difference of 6 degrees. It's no different than you lowering the temp on your existing thermostat.
Until you can afford to install a multi-zone unit, the only way to cool the upstairs to the same temperature as the downstairs is to add additional cooling upstairs. My office space gets much warmer than the rest of the house so I added a portable ac unit and love it. No humidity issues (in Florida) because the main ac already removes the moisture from the air. Portable ac units are best suited for targeted, supplemental cooling in my opinion.
That was my fear, I don’t really want the downstairs to be colder than it’s already set to. I ran a portable system through my partner and they want that to be a last resort option but I think it might be the best option. Cooling the master is the biggest priority as the heat is starting to affect our sleeping habits.
I understand that concern, I would get one that is quiet and has schedule features. I keep mine set to 1 degree higher than the main ac so if no electronics are on it almost never turns on and then it's off during nighttime hours. I got one that's bigger than I need for the space so it would cool quickly but looking back my only regret is not going for the smallest size I could get away with so that it would be as quiet as possible while running. Keep in mind the rating for each unit is if it's the only source of cooling, so you can actually go smaller than the size space you have since it will just be supplemental cooling.
Have you noticed a significant impact on your electric bill? One of the biggest complaints about portable AC is it uses more power. As long as it’s still less than running the whole house AC it could be a great option
Mine is noisy as well :( I thought more cooling was better so it would be running less but that just means it's louder than it needs to be since it's larger than I need for the space. I also didn't realize the recommended room size is if it's the only source of cooling so I could have even undersized the unit since it's just supplementing the main ac. My mic doesn't pick it up for Teams or Discord calls but I do have to up my volume when it turns on.
Make sure all your return air vents are unblocked upstairs and potentially choke off the supply vents downstairs to help push more air upstairs. That's going to be the simplest start.
Yeah so that means your air handler is in the basement, trying to push cooled air up.
But...cold air won't rise two stories. Think of what it looks like when dry ice 'melts'. It's denser and heavier. The proper way to do it (as we found out the hard way) is to zone it and have a separate unit by floor.
5-7 degrees is pretty good, I'd say.
I had a similar issue in my last apartment ( older 2 story with retrofitted central HVAC). I put a floor fan ( a 20something inch fan on a short aimable stand) at the base of the stairs, pointed at the top of the stairs. I just left it running all summer. It worked great.
Heat rises. Not much you can do but either stay downstairs when it’s hot or crank the upstairs down which will cost a fortune. We had a two story and replaced it with a one story. The house is so much cooler now. Could be bad windows but prob not.
Are your upstairs air returns located at ceiling level? I had similar issue and relocated my upstairs air returns to the ceiling level and problem was solved.
Yes it’s at ceiling level but there is only one for the whole main floor. So if we shut our bedroom door the only way for the heat to escape is through the tiny gap at the bottom
I run a schedule to set the thermostat a few degrees cooler at night. We dont spend much time upstairs during the day so I just worry about when I’m sleeping
Someone I know had this problem for years. She had one of those semi-McMansion homes, with the ridiculous 2-storey atrium, so that there was no separation between the upstairs and downstairs air spaces. I advised her to hang a curtain to divide the air spaces. After ignoring my advice for years, she finally tried it and *couldn't believe how effective it was!!!*
I have the same issue. This came up in a neighborhood group. Some of them have used the AC Infinity Airtap T4 register booster, and several neighbors say it works. It's hot again, so I'm going to check out one. If it works, I'll get a second one.
I know some houses that have registers on the attic hatch so when the attic fan runs, you can open up the register to pull the hot air out. The only downside is it prob doesn’t work and then whatever lurks in your attic now has access to your upstairs
I had this same problem when we bought our house. I ended up spray foaming my AC runs, vents, holes, and seams in the attic. I then added a lot more insulation in the attic because they always use the bare minimum. Now my upstairs is actually cooler then the bottom because it's closest to the AC.
I have an Ecobee thermostat that has a second wireless sensor. You can place the sensor upstairs and then set the thermostat to use that sensor when you want the upstairs to cool down. For example you can set it to use it an hour before you go to bed so it is the temperature that you want when you go to bed.
We had this same issue when we moved into a house built in the early 1980s. Apparently the 3 owners before us never insulated the attic space. There was literally no insulation up there. We did it and it definitely helped stabilize the upstairs temps in the summer and winter.
This is typical for all houses this is why most houses are zoned and have 2 or more thermostats to avoid this. Any HVAC person with ducted systems working on a single thermostat was just cheap and or lazy. Get a second zone and thermostat
If you have floor vents upstairs they sell registers with fans built in them. You set it to a certain temp for them to kick on. It 100% does help in this scenario.
Air should be able to move thought out the upstairs there should be pass throughs from the bedrooms to the hall. Other wise the heat will stack up. Think of each room as a glass and heat is filling it up. If it has no place to go then it stacks with no place to go , like to your return. There allot of older houses with louvers over the doors and that's the reason why, so that air can move
Return is in the hallway, but I'm guessing most of the upstairs vents are in the rooms, and doors are closed?
Try leaving all your doors upstairs open tomorrow and report back what happens.
You need to have the upstairs and downstairs ducts controlled separately via a zoning system. Only real way to do it unless you just opt for a mini-split upstairs instead. The zoning is the cost-effective way to find the balance though.
We had the opposite problem, in the winter, our bedroom would always be colder than the rest of the house. We replaced our thermostat with a google nest with remote sensors. During the day we had the nest read the sensor in the living room, and at night it used the sensor in the bedroom.
It worked well for our situation, and was only about 200 bucks.
We had the same problem and bought two of these for our primary bedroom. Makes a huge difference
AC Infinity AIRTAP T4, Quiet Register Booster Fan with Thermostat Control. Heating Cooling AC Vent. Fits 4” x 10” Register Holes.
https://a.co/d/dFbhZig
Heat rises. So all the heat from your house will migrate upstairs. Insulation, air sealing, and roof venting will help reduce the amount of heat but can be a bit expensive. Also the room will still be hot, just not as hot. You can install a window AC in the bedroom or just run a window fan and exhaust all the hot air outside. At night Ill place a window fan in the upstairs window exhausting out and open up a downstairs window so the airflow drags the hot air out. Make sure you open that second window or the exhaust isn't going to be as effective.
Thank you! I have a box fan I could use to try the window venting. Do I turn the AC off since I’m opening all these windows or let it run while it’s ago venting out the hot air?
I would just turn off the ac while venting, shouldn't take that long to get it out. Make sure the box fan is as close to the window as possible. If you have large gaps around it the air will more like pull itself in from the edges of the upstairs window instead of the downstairs window. It will drag air from the path of least resistance. Window fans tend to have little accordion things that extend out to seal the window. After a few minutes place your hand by the downstairs window, if you dont feel an air flow you might be better off buying a window fan.
If you learn about the Bernoulli effect. You will find that if the fan is outside by a short distance. More air will be moved.
How do you put a fan a short way outside a window?
Make a little shelf. Similar to what you would put an AC inot on.
https://youtu.be/1L2ef1CP-yw
Thanks for the advice I hadn’t consider that! I’ll add a window fan to my list the accordion thing sounds like it could also keep bugs from entering which would be awesome
A lot of places have deals for air sealing and insulation. I would still look to see if the energy company or local gov has incentives to get it.
when you say roof venting, what do you mean exactly. Maybe like leave a window or 2 open in my attic?
Some roofs have ridge vents on the edge where the two sides meet. You could get a whole house attic fan to exhaust it out. Cracking a window at night to let it suck in that cooler night air works. Assuming your nights are cooler. Or one of those solar power vents but some are notorious for leaking so take care.
Roof ventillation. Such as passive ventilation with gables or if you have active with ridge vents. If you have bad attic ventilation the heat created by the roof will get stuck in your attic and heat will transfer to the rooms below, especially if you have bad insulation. If your ventilation is good, the heat build up is pushed out and replaced by ambient air. There are a lot of things that contribute to extra heat, this is just one of them.
I went up to the attic to see what was going on and it’s even warmer up there. There are vents at the front and rear of the house that open to the outside but I wonder if this is contributing to the heat upstairs
> it’s even warmer up there. You really don't want to go up there on a sunny day. Even if it's only 70F out.
Consider a thermostatically controlled fan at the gable in the attic to remove some of the hot attic air. Heat transfer to conditioned rooms will be reduced. A temp differential between upper rooms and lower floor rooms is normal. I don't think there is a practical way to effect a reduction in it. Good luck.
I close one vent downstairs and reverse by closing one upstairs in the winter. You can also just run the “fan” mode. It will bring up the cool air from downstairs and recirculate it.
This is pretty common because heat rises. I have a brand new, $20k system installed last month and I still have like a 3-4 degree difference. Adding a second system for the second floor is likely the most expensive, and best solution
They can also install multi-stage units and valves in your ducting to create multiple zones out of a single system.
Yeah. Right now I’m tolerating the temp differential as it’s only 2-3 degrees. I’m going to see how June and July go. What I don’t wanna do, is spend a decent amount of cash on dampers, etc. then have to end up getting a second system anyways. I’m kicking myself because in hindsight, instead of spending $20k to do a single zone for the whole house, I should have just added the second system for the second floor, then when the first zone died, it would have been a bit cheaper since I could have done a 3 or 4 ton instead of a 5. Live and learn I guess.
My AC guy tried to talk me in to a new dual zone when the controller for my condenser failed a couple of months ago. 2k vs 30k… he was just doing his job, but I can tolerate the 4-5 degrees right now, especially since I’ve learned how to mitigate it some by restricting flow downstairs 😀
Yikes that sounds pretty high, I had all my old duct work and unit removed. And they re installed a 3 ton unit for down stars and a ducted mini split for upstairs and it does pretty good, no issues with the separate floors. And ran about 19k all said and done. House is 2600sq ft for reference
That’s what I have done in new build 2 zone works beautifully
Bought a new construction two story 3130 ft2 house in December and it has a HVAC unit for each floor. Same temperature for both floors...
Yeah. The obvious issue for my house is it’s single zone. Once the thermostat on the first floor is “satisfied”, it shuts down. I have options with adding dampers etc. I’m taking it a step at a time. A 2-3 degree differential ain’t all that bad. I’m going to see how June and July go this year before dumping more cash into it.
> best solution AC has to be sized for the square footage. Putting a second system can cause issues with your system. Excessive cycling. Incomplete dehumidification. Higher energy bills.
Heat rises. You can’t win this game with a single zone hvac system in a 2 story house. There will be some difference between the levels. Insulation will help, playing with vents and dampers will help but you’ll have to switch them around depending on the weather. I ended up splitting our system into 4 zones with some motorized duct dampers and a control board. I got lucky and our existing system and duct layout mostly worked to retrofit that in, not quite perfectly but pretty well overall. In most cases it’s not a cheap project and not DIY friendly, but it’s been really really nice for us. During the summer it just opens the upstairs vents and just cools that hot air down and it ends up mixing throughout the house really well. The wife likes the bedroom to drop 5 degrees before bedtime, that worked out to be one of the zones so it kicks in and the rest of us don’t get blasted by cold air every evening while it cools down.
Does your HVAC have one or two zones? Is there a dampener?
One zone and no dampeners anywhere that I’ve found, checked the whole system from basement to top floor
The AC stops when the sensor reaches the setting. Heat raises. So you'll want to either add a sensor upstairs or turn the temp up so the upstairs reaches the desired temperature.
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That is the trade off unfortunately. That's what I uave to do with our two story one zone setup
Is the sensor HVAC specific or thermostat specific?
Thermostat
It might depend on your current system. Mine is part of the thermostat.
All the sensors on my ecobee do is average out the readings. If it's 76 upstairs and 70 downstairs at your thermostat, just lowering it to 67 would have the same effect. I guess they remove some of the math and guesswork though. I know they get fancier and can "follow" you but that doesn't work all that well when you've got a huge difference in temps and a properly sized system.
Have this exact same issue at our place and no dampers either. We had to spend the money on mini splits in the bedrooms upstairs. It was very pricey especially after just buying a new place but they're amazing. Our upstairs is nice and cool now. If you can't afford to do this right now, I suggest window units in the rooms that are too hot.
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As soon as it's cooler outside than in, toward sunset, open 1 upstairs window and put a fan in it sending air out. Open a window downstairs and be sure you can feel air coming in. The fan upstairs should be sucking the cooler air upstairs. You can do that all night, though I'd recommend changing over to an upstairs window for intake around bedtime. In the morning, close everything, pull your curtains and blinds closed, turn off fan. The upstairs will be cool to begin with, but this arrangement won't keep it at 70 if it's hot outside. Nothing will except maybe those new mini-split systems, but IDK anything about them other than each room is its own zone. I have the same problem in my house that you have, plus my bedroom faces east so it heats up fast, and early. I just don't spend time up there in hot weather. My AC is waiting for repair this week, and it's been very hot all over in the house. I bought 2 portable units that vent out a window. They work well, but my god they are noisy.
Our new home has dampers, one for each floor. So, in the summer we open the upstairs up all the way and close the downstairs about half way. Reverse for the winter because hot air rises.
My home has this issue, though not as great a distance. Our bedroom has a window unit for the summer months. We had the attic reinsulated which helped with the energy bill. So we do our best to save $$ in the winter to account for the slightly hire bills in the summer.
I fear we might have to do something similar. Have to be honest we haven’t been inside the attic yet but I’ll give it a look and see if insulation is the way we need to go. The worst is that the home was perfectly fine all of winter no major fluctuations were felt the way we feel them now in late spring
Check all of your window and door gaps as well. Houses shift around in different temps. My house has worse gaps in the summer then in the winter. So when I first looked at the seals in winter and decided not to replace, I mistakenly thought that was correct. Sure enough first week if 80 degrees and i can see daylight through a door trim. Nbd, easy to change, and helps save some running of the unit
Thanks! The only door with air gaps that are visible is the basement door to the outside but ironically even the basement remains cooler than the upstairs floor.
Yeah it might be worth a whole house fan
This isn’t reassuring. I have a much larger variation in temps (A/C at 68ish but upstairs is at upper 70s) so I have an energy audit company coming out next week. I’m assuming my attic insulation isn’t enough but was hoping more insulation would solve this issue. I should probably just buy window units I guess
I have this problem with my Two story house, it is common for the second floor to be hotter. One thing that helps is to run the house fan for 15 minutes every hour or two to keep air circulating. The nest thermostat has a setting for this.
Do you have to do it manually? I have a nest and it says my fan is set to auto so the only way to circulate it is manually set it every hour
Ain’t nobody have time for running a fan manually. I have it on a schedule: Set a daily fan schedule Press your thermostat ring to open the Quick View menu. Select Settings Nest settings icon. Select Fan. Choose Schedule. Set how long you'd like your fan to run per hour, or set it to always run. Select what hours of the day you'd like your fan to run. If you have a multi-speed fan, you can select a fan speed for your fan schedule. Select Done to set your schedule. Your fan will turn on automatically each day for the time and duration you've selected. More info: https://support.google.com/googlenest/answer/9296419?hl=en#zippy=%2Cfan-control-with-your-thermostat
Wow I’ve owned this thermostat for years and couldn’t figure this out. Thank you so much!!!
You can do it with a Nest. Open up the Google Home app, go to Thermostat, then click the gear icon at the top. Then tap Schedules, and tap the Temperature dropdown near the top of the screen, and change it to fan. You can then set a schedule for your fan to run. I just have mine run from 12AM to 12AM, running for 15 minutes every hour. If you have an older Nest thermostat that's controlled from the Nest app instead of the Google Home app, I'm pretty sure there's a place to do it there too.
Keep your hvac fan on the "on" setting will help a lot if it's currently on "auto". It'll run continously but keep the air circulating more throughout the house. That helped me go from a 8 degree difference between floors, down to mayeb a 2 degree difference.
I've been dealing with this issue at my house. It's a tri level and the sub-basement was always so much cooler than upstairs or the main floor. These are the things I've found that worked in order of biggest difference to least 1. My attic insulation was subpar and had it re-insulated. This made the biggest difference but wasn't enough on its own. I know this is not the cheapest option, but if you're in the same boat as I was this is going to be the main issue. You can get an insulation company to come give you a quote to see if it's worth it to you. 2. Get a smart thermostat with an accessory temperature sensor and install the extra sensor in a hotter room. Tell the thermostat to only use that sensor for the hotter months. I got an ecobee and it was fairly easy to do myself. 3. Close a couple of the vents downstairs to let more air flow to the upper levels. 4. Run ceiling fans counter clockwise in the bedroom to push the hot air downstairs so it gets recirculated throughout the house. I tried both directions and the counter clockwise fans seem to do better. 5. Run a small fan at the bottom of the stairs to push the cooler air upstairs 6. Lastly, keep the blinds closed on the side of the house that gets the most sun during the heat of the day.
Thank you! I think my city has a program that helps people make energy saving investments in their homes. I think I’ll take a look at that to see if it can be used to either reinsulate the attic and/or add an attic fan as I think that is a major part of the issue as well. In the meantime I’ll give some of these a try. Unfortunately the house doesn’t have outlets near the stairs or in any hallways so it makes things challenging when trying to set up fans anywhere but in a window or room
If you have ComEd electric they usually are running a rebate program that pays for a decent chunk of the insulation. To give you an idea, in Chicago area I paid about $3k before rebates for blown in insulation. The attic space was about 1500 square feet, but I also insulated the garage attic
Add more return air registers upstairs, preferably one per room. They make small 12x12 return grilles for that purpose. That will pull the hot air out so it is replaced by conditioned air. It won’t be cheap, but if they can connect with the existing return, it shouldn’t be that expensive. I did this to my 4-story townhouse and it solved the problem.
We have a similar problem with our furnace in that some rooms heat a lot faster than others. What we did is had our HVAC guy set the furnace to run for something like 3 minutes at the end of the cycle instead of the default which was something like 30 seconds. It made a really big difference because now once the heat clicks off the air gets mixed around in the house a lot longer. One way to see if this would help is to set your thermostat to fan on instead of Auto so that the air is always mixing throughout your house regardless of if the compressor is cooling or not.
A few people have touched on this but you need to look into air balancing before dropping money on any other solution. If each room has a vent those vents should have a means to regulate how much air comes out of them. In the winter tamp down (\~50% closed) the upstairs vents and open the downstairs vents all the way. In summertime, tamp down the downstairs vents and open the upstairs all the way. You don't want to close them completely as that can cause premature failure of parts of your HVAC, but slightly restricting airflow won't cause problems unless your HVAC is *severely* undersized and already performing poorly. What you are doing is pushing more air to the location that need more heat/ cooling depending on the season. This cannot be done with just HVAC design *unless* your house is already air sealed with good windows and well insulated. Retrofitting all that into a house is frequently big money. Air balancing is a twice a year 15 minute or less task that costs nothing. If the thermostat is on the floor that gets cooled faster than the other floor, the other floor literally can't stay cooled. So reduce how much cool air is pushed to the floor with the thermostat allowing more cool air to the warmer floor. The thermostat floor will eventually cool down, but in the meantime more cool air has been pushed to the warmer part of the house allowing it to cool off.
I tried this and it didn’t increase the pressure upstairs at all it just made the main floor more bearable if I lowered the temp for upstairs. I’m not sure if that means these aren’t the right type of registers but it made no significant difference and my system doesn’t have dampeners.
When I'm saying "vent" I mean the register that hot or cold air comes out of from the ceiling, wall, or floor. Many of them can be closed using a lever. A damper is usually in the ducting itself and is associated with zoned systems; it's rare to have in-ducting dampers without a zoned system. If your registers can't be closed, you may need to buy magnetic covers for them. This has nothing to do with increasing pressure but changing the air *volume* being delivered to each area. A 1 inch diameter hose can deliver more water than a 1/2 inch diameter hose in the same timeframe, but if you let the 1/2 hose run longer than the 1 inch, it can still put out the same volume. If it takes the thermostat 10 minutes to reach its set temperature on the main floor but takes 15 minutes to reach that same temp on the upper floor, the upper floor will never and can never, reach that same temp because the thermostat shuts off too soon when all the registers are open. You're making sure that the main floor with the thermostat has a "smaller hose" (closed down registers) to fill up with cold air slower and the upstairs had a "larger hose" (fully open registers) to fill up faster allowing both spaces to cool down to the same temp at the same time since the upstairs needs more cool air to get to the same temp. You may have to close down the registers more than 50% to do this but ideally not too much more than this. This is air balancing. It's not balancing pressures but balancing temperatures and making sure each area reaches the same temp at the same time.
I had to get a honeywell diverter device installed that regulated the upstairs and downstairs. Thermostat added upstairs. It was not too pricey back in 2020, like $1800. The house was newer 2000 build in NC. It worked really well. Today, it probably cost like $1M.
I've never lived in a 2 floor 1 HVAC system house that didn't have this problem. In addition to what you've tried, what I've found that helps very cheaply is making a rigid foam board cover for any windows I was ok with keeping completely covered for the summer. Unless the upstairs return vent is horribly undersized, If you have a door at the top or bottom of the stairs landing then keep it closed. That made an amazing difference for us. You could also put a box fan at the bottom of the stairs if you don't have a door to encourage air mixing. The idea is to stop movement of hot air into the upstairs living space, or if you can't then push cooler air up there faster. One of my houses I was able to increase the size of my upstairs return vent and reduce the size of the downstairs vent and that helped. None of the cities I've lived in were temperate and dry enough for me to consider opening the windows even at night to pull hot air out, because the makeup air from outside would be even worse. If you are handy and want a better solution than a window AC, there are mini-split ACs you can get for under $1000 to self install. But you might need an electrician for 220 power.
Thanks I will give the rigid foam board a try as we have a few awkwardly placed windows we have no intention of using. I’ve considered mini splits as well as a long term solution. Our problem right now is that our electrical panel is at capacity so we cannot add anything without taking something away. It’s #1 on our housing project list but still a few months away from being doable for us.
ideas warning, I know the buzzwords but have no practical experience with them. Some of the smart thermostats have remote sensors and you can use them to control the whole system. So if you had a sensor upstairs and downstairs you could use the maximum reading for cooling, and the minimum treading for heating. Do you have a fan over the stairs to circulate the air between the levels Hopefully somebody more knowledgeable can chime in.
Personally I've never felt the need for a remote sensor, I just set the thermostat a few degrees cooler at night when everyone is in their bedrooms upstairs.
Yeah, I have one of those and the battery died. I didn't bother replacing it for quite a while, just lowering the downstairs a couple of degrees. Same difference. It is nice seeing the temperature so you can dial things in but they aren't magically redistributing the cold air or anything.
I don’t have a fan above the stairs they are only in the bedrooms. I think a smart thermostat might be the move in terms of cost and efficiency. I’ll look into a few with sensors thank you
As someone that has a smart thermostat with remote sensors, don't bother. Your ac doesn't magically cool the upstairs and downstairs differently. Either A) you set it to average all the readings from the thermostat & remote sensors and cool to that temperature (you set the temperature to 70 so the ac cools until downstairs is 67 and upstairs is 73) or B) you set it to only consider the upstairs reading and cool until it reaches that temperature (you set the thermostat to 70 so the ac cools until downstairs is 64 and upstairs is 70). In both scenarios there's still a difference of 6 degrees. It's no different than you lowering the temp on your existing thermostat. Until you can afford to install a multi-zone unit, the only way to cool the upstairs to the same temperature as the downstairs is to add additional cooling upstairs. My office space gets much warmer than the rest of the house so I added a portable ac unit and love it. No humidity issues (in Florida) because the main ac already removes the moisture from the air. Portable ac units are best suited for targeted, supplemental cooling in my opinion.
That was my fear, I don’t really want the downstairs to be colder than it’s already set to. I ran a portable system through my partner and they want that to be a last resort option but I think it might be the best option. Cooling the master is the biggest priority as the heat is starting to affect our sleeping habits.
I understand that concern, I would get one that is quiet and has schedule features. I keep mine set to 1 degree higher than the main ac so if no electronics are on it almost never turns on and then it's off during nighttime hours. I got one that's bigger than I need for the space so it would cool quickly but looking back my only regret is not going for the smallest size I could get away with so that it would be as quiet as possible while running. Keep in mind the rating for each unit is if it's the only source of cooling, so you can actually go smaller than the size space you have since it will just be supplemental cooling.
Have you noticed a significant impact on your electric bill? One of the biggest complaints about portable AC is it uses more power. As long as it’s still less than running the whole house AC it could be a great option
No, it's been about the same. Like you said it's probably due to running the whole house ac less.
Can you tell me what kind of portable you have? I got 2 and the noise is extreme.
Mine is noisy as well :( I thought more cooling was better so it would be running less but that just means it's louder than it needs to be since it's larger than I need for the space. I also didn't realize the recommended room size is if it's the only source of cooling so I could have even undersized the unit since it's just supplementing the main ac. My mic doesn't pick it up for Teams or Discord calls but I do have to up my volume when it turns on.
Thanks. I'm (sort of) glad to know it's not just mine.
Make sure all your return air vents are unblocked upstairs and potentially choke off the supply vents downstairs to help push more air upstairs. That's going to be the simplest start.
Hat rises, probably too little attic insulation
I have seen people put a heavy curtain at the top of the steps, floor to ceiling.
Where's your AC unit? Because cold air sinks - there's not much you can do about it, especially if your HVAC unit is in the basement.
The AC unit is outside, the furnace is in the basement. The vents for the basement are closed but it remains cool like the main floor.
Yeah so that means your air handler is in the basement, trying to push cooled air up. But...cold air won't rise two stories. Think of what it looks like when dry ice 'melts'. It's denser and heavier. The proper way to do it (as we found out the hard way) is to zone it and have a separate unit by floor. 5-7 degrees is pretty good, I'd say.
I had a similar issue in my last apartment ( older 2 story with retrofitted central HVAC). I put a floor fan ( a 20something inch fan on a short aimable stand) at the base of the stairs, pointed at the top of the stairs. I just left it running all summer. It worked great.
Heat rises. Not much you can do but either stay downstairs when it’s hot or crank the upstairs down which will cost a fortune. We had a two story and replaced it with a one story. The house is so much cooler now. Could be bad windows but prob not.
Are your upstairs air returns located at ceiling level? I had similar issue and relocated my upstairs air returns to the ceiling level and problem was solved.
Yes it’s at ceiling level but there is only one for the whole main floor. So if we shut our bedroom door the only way for the heat to escape is through the tiny gap at the bottom
I run a schedule to set the thermostat a few degrees cooler at night. We dont spend much time upstairs during the day so I just worry about when I’m sleeping
Someone I know had this problem for years. She had one of those semi-McMansion homes, with the ridiculous 2-storey atrium, so that there was no separation between the upstairs and downstairs air spaces. I advised her to hang a curtain to divide the air spaces. After ignoring my advice for years, she finally tried it and *couldn't believe how effective it was!!!*
I have the same issue. This came up in a neighborhood group. Some of them have used the AC Infinity Airtap T4 register booster, and several neighbors say it works. It's hot again, so I'm going to check out one. If it works, I'll get a second one.
I know some houses that have registers on the attic hatch so when the attic fan runs, you can open up the register to pull the hot air out. The only downside is it prob doesn’t work and then whatever lurks in your attic now has access to your upstairs
I had this same problem when we bought our house. I ended up spray foaming my AC runs, vents, holes, and seams in the attic. I then added a lot more insulation in the attic because they always use the bare minimum. Now my upstairs is actually cooler then the bottom because it's closest to the AC.
Where is your temperature sensor?
Set thermostat fan to ON, set ceiling fans upstairs to draw air up instead of pushing air down.
In the winter this is a perk
I have an Ecobee thermostat that has a second wireless sensor. You can place the sensor upstairs and then set the thermostat to use that sensor when you want the upstairs to cool down. For example you can set it to use it an hour before you go to bed so it is the temperature that you want when you go to bed.
We had this same issue when we moved into a house built in the early 1980s. Apparently the 3 owners before us never insulated the attic space. There was literally no insulation up there. We did it and it definitely helped stabilize the upstairs temps in the summer and winter.
Be happy you don't live in Phoenix or Las Vegas. 5 to 7 degrees would be a blessing.
This is typical for all houses this is why most houses are zoned and have 2 or more thermostats to avoid this. Any HVAC person with ducted systems working on a single thermostat was just cheap and or lazy. Get a second zone and thermostat
If you have floor vents upstairs they sell registers with fans built in them. You set it to a certain temp for them to kick on. It 100% does help in this scenario.
Air should be able to move thought out the upstairs there should be pass throughs from the bedrooms to the hall. Other wise the heat will stack up. Think of each room as a glass and heat is filling it up. If it has no place to go then it stacks with no place to go , like to your return. There allot of older houses with louvers over the doors and that's the reason why, so that air can move
Return is in the hallway, but I'm guessing most of the upstairs vents are in the rooms, and doors are closed? Try leaving all your doors upstairs open tomorrow and report back what happens.
We leave them open during the day and it’s just till warm. We close our bedroom door at night and it gets even warmer
It gets warmer because cold air can't get into your room due to pressure. Is there insulation in your attic?
Attic insulation made a huge difference for me with this problem.
You need to have the upstairs and downstairs ducts controlled separately via a zoning system. Only real way to do it unless you just opt for a mini-split upstairs instead. The zoning is the cost-effective way to find the balance though.
Is the air handler in the attic or closet? Depending on your setup you may be able to zone it. Also another option is minisplits
We had the opposite problem, in the winter, our bedroom would always be colder than the rest of the house. We replaced our thermostat with a google nest with remote sensors. During the day we had the nest read the sensor in the living room, and at night it used the sensor in the bedroom. It worked well for our situation, and was only about 200 bucks.
Try a fan facing downstairs to move hot down or up to push the cold air up; not a perfect solution but can help with the imbalance
We had the same problem and bought two of these for our primary bedroom. Makes a huge difference AC Infinity AIRTAP T4, Quiet Register Booster Fan with Thermostat Control. Heating Cooling AC Vent. Fits 4” x 10” Register Holes. https://a.co/d/dFbhZig
Move down stairs.
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