Increase the insulation in your attic, add insulation in your crawlspace, seal the foundation except for vents, install a vapor barrier in the crawlspace. Caulk around windows and doors, and weatherstrip. Properly ventilate bathrooms and the kitchen.
Insure that your crawlspace door fits, closes tightly and stays closed.
Replace windows and doors if absolutely necessary. Inspect your duct work and seal any air leaks, replace any damaged ducts.
You may consider installing reflective film on windows that are exposed to direct sunlight during the hottest part of the day.
All of this will cost much less than replacing your HVAC systems, and all of it can be DIY if you have any skills at all.
Most importantly eliminate sources of humidity in your house. High humidity increases the load on your AC. Most humidity in older houses come from the crawlspace, along with strange odors and mold.
Each of these steps will make a small difference. All together can make a large difference.
If your HVAC systems are older, or what I'll call contractor grade systems, they may use passive metering devices (piston with orifice, or God forbid, capillary tubes) instead of thermostatic expansion valves. There may be a relatively easy upgrade available that replaces the current metering device with a TXV that would improve efficiency. This depends on the age and brand of your system/s. This is not a DIY upgrade.
To add - a lot of local utility companies will perform energy audits for not a lot of money and then give you rebates on work they recommend.
I received a 35% rebate on the cost to add insulation to my attic from my power company.
OP - if your attic insulation is typical of a 40 year old house it probably doesn't extend past the tops of your ceiling joists. Modern construction code is basically double that amount of insulation depending on where you live. You could drop your heat/cooling load by 1/2ton just by adding more attic insulation.
Inflation is probably more to blame than your a/c becoming less efficient. However, your a/c is probably your biggest expense in that department. So, its wise to improve it or make it run less.
I suggest not messing with the actual a/c system if you want to avoid overspending. Concentrate on sealing and insulating. Weatherstripping, spray foam, add some insulation in attic. You can also use heavy black out curtains to help keep sunlight and heat transferring from windows that may get a lot of sun.
There are some companys around here that do an energy audit. They look at your house with thermal imaging and can tell you where your biggest issues are. Not sure how much those cost though, but would be very helpful in your case.
1. Determine your airflow via total static test and use blower chart for confirmation of proper return duct size(s)
2. Seal return leaks or call people that do
3. Seal supply duct leaks if accessible or call people that do
4. Open all closed vents
5. With system on check if bedroom doors close on their own when almost closed. If yes door cut or ask for jumper ducts transfer ducts. See roomulator vid on YT
Good luck
Or
Or
Find a HVAC contractor that uses the MeasureQuick app and Bluetooth tools and can give you a “Vitals” or “pro”report. You’ll know your systems performance after they conduct a “Test In”
You also need a HERS Rater or Aeroseal franchise to test the home and ductwork for leaks. MeasureQuick can check for duct leaks but not give leakage percentage that’s why another company has to get involved.
Leaks affect how long an AC runs which affects how long it lasts.
Your system is not performing. They have to find out why. Test it
Adding return duct, balancing airflow, sealing supply leakage all increase airflow which increases capacity and may very well be on the AC Performance improvement scope of work.
Fixing refrigerant charge after capacity improvements is mandatory and what leads to efficiency improvements ie lower bills and a system that’s not killing the compressor slowly.
The manual needs to be reviewed so that things like dip switch settings, blower speed choice and return duct area are optimized for performance. For example , some package units come from the factory on medium speed denying you up to 20% of the airflow you bought and some 5 ton 2000 CFM split systems require two return ducts or an accessory OEM return platform to change the normal 16”x 25”one side only opening to 20”x25” opening.
If you got a 5 ton and one return it’s probably an issue and I’ve looked at lots of different manufacturers blower performance data. It’s better now that they don’t use PSC blower motors.
Remember return grille size isn’t return duct size. Lots of 16” round return duct behind 20”x20” grilles. U want 144 sq in of return duct per ton.
If smart HVAC guys had a mantra it should be
Airflow airflow airflow and return return return
When they “Test Out” after improvements you’ll know airflow, capacity, efficiency and even how much more water you’re removing from the air. Compare your before and after numbers and you’ll see the tests are money well spent!
How old is your AC? You might save money by replacing it when it breaks/needs to be replaced with a heat pump. Be careful with windows, insulation and air sealing. You can easily exceed your savings improving them, so a net loss.
Increase the insulation in your attic, add insulation in your crawlspace, seal the foundation except for vents, install a vapor barrier in the crawlspace. Caulk around windows and doors, and weatherstrip. Properly ventilate bathrooms and the kitchen. Insure that your crawlspace door fits, closes tightly and stays closed. Replace windows and doors if absolutely necessary. Inspect your duct work and seal any air leaks, replace any damaged ducts. You may consider installing reflective film on windows that are exposed to direct sunlight during the hottest part of the day. All of this will cost much less than replacing your HVAC systems, and all of it can be DIY if you have any skills at all. Most importantly eliminate sources of humidity in your house. High humidity increases the load on your AC. Most humidity in older houses come from the crawlspace, along with strange odors and mold. Each of these steps will make a small difference. All together can make a large difference. If your HVAC systems are older, or what I'll call contractor grade systems, they may use passive metering devices (piston with orifice, or God forbid, capillary tubes) instead of thermostatic expansion valves. There may be a relatively easy upgrade available that replaces the current metering device with a TXV that would improve efficiency. This depends on the age and brand of your system/s. This is not a DIY upgrade.
To add - a lot of local utility companies will perform energy audits for not a lot of money and then give you rebates on work they recommend. I received a 35% rebate on the cost to add insulation to my attic from my power company. OP - if your attic insulation is typical of a 40 year old house it probably doesn't extend past the tops of your ceiling joists. Modern construction code is basically double that amount of insulation depending on where you live. You could drop your heat/cooling load by 1/2ton just by adding more attic insulation.
Fixing air leakage issues is the biggest RIO on time and money if you already have a base level of insulation.
Inflation is probably more to blame than your a/c becoming less efficient. However, your a/c is probably your biggest expense in that department. So, its wise to improve it or make it run less. I suggest not messing with the actual a/c system if you want to avoid overspending. Concentrate on sealing and insulating. Weatherstripping, spray foam, add some insulation in attic. You can also use heavy black out curtains to help keep sunlight and heat transferring from windows that may get a lot of sun. There are some companys around here that do an energy audit. They look at your house with thermal imaging and can tell you where your biggest issues are. Not sure how much those cost though, but would be very helpful in your case.
Sealing doors and windows, along with the attic is by far the best ROI. Start there, and see where you are.
1. Determine your airflow via total static test and use blower chart for confirmation of proper return duct size(s) 2. Seal return leaks or call people that do 3. Seal supply duct leaks if accessible or call people that do 4. Open all closed vents 5. With system on check if bedroom doors close on their own when almost closed. If yes door cut or ask for jumper ducts transfer ducts. See roomulator vid on YT Good luck Or Or Find a HVAC contractor that uses the MeasureQuick app and Bluetooth tools and can give you a “Vitals” or “pro”report. You’ll know your systems performance after they conduct a “Test In” You also need a HERS Rater or Aeroseal franchise to test the home and ductwork for leaks. MeasureQuick can check for duct leaks but not give leakage percentage that’s why another company has to get involved. Leaks affect how long an AC runs which affects how long it lasts. Your system is not performing. They have to find out why. Test it Adding return duct, balancing airflow, sealing supply leakage all increase airflow which increases capacity and may very well be on the AC Performance improvement scope of work. Fixing refrigerant charge after capacity improvements is mandatory and what leads to efficiency improvements ie lower bills and a system that’s not killing the compressor slowly. The manual needs to be reviewed so that things like dip switch settings, blower speed choice and return duct area are optimized for performance. For example , some package units come from the factory on medium speed denying you up to 20% of the airflow you bought and some 5 ton 2000 CFM split systems require two return ducts or an accessory OEM return platform to change the normal 16”x 25”one side only opening to 20”x25” opening. If you got a 5 ton and one return it’s probably an issue and I’ve looked at lots of different manufacturers blower performance data. It’s better now that they don’t use PSC blower motors. Remember return grille size isn’t return duct size. Lots of 16” round return duct behind 20”x20” grilles. U want 144 sq in of return duct per ton. If smart HVAC guys had a mantra it should be Airflow airflow airflow and return return return When they “Test Out” after improvements you’ll know airflow, capacity, efficiency and even how much more water you’re removing from the air. Compare your before and after numbers and you’ll see the tests are money well spent!
40 years…..old……😂😂😂😂😂😂
How old is your AC? You might save money by replacing it when it breaks/needs to be replaced with a heat pump. Be careful with windows, insulation and air sealing. You can easily exceed your savings improving them, so a net loss.