HOW TO REDUCE A/C
Its summer again and utility costs for air conditioning are rising. You are HOPING to go as long as possible without turning on the air. However, if you are like me, you can’t sleep when you’re too warm. There’s only so much you can do; like lie on top of the covers, nude, with a fan on. Eventually even that won’t be enough. You could learn to love your home being warmer, or ….
We’ve already discussed and discarded ceiling fans as a method of saving energy and costs. They don’t work for a whole house (and only help dealing with a couple of degrees for a single room). We have also discussed and dismissed standard heat pump systems which exchange inside degrees with the outside air. The energy savings will never pay back the high cost of installation.
What are some viable options? (Things mentioned below are mostly how to plan for the future, your choices for this summer are probably cooked in, except #2.)
1. Upgrade roof. WHEN it is time to replace your roof you have a decision to make. Metal roof or “cool roof” type shingles. Of course, a lighter color shingle will reduce heat transfer to your attic. Base your roof on how long you plan to stay and so you won’t have to cough up the price of a new roof when you go to sell. Staying 10 years, go cheap with a lighter color (regular 25 year shingles maybe). Staying 20 years, install 30-35 year “cool roof-type” shingles which reduce the amount of solar energy they absorb into the attic. They come in multiple colors. Staying longer? … install a metal roof (40-60 year guaranteed). Installed correctly a metal roof can reduce summer heat absorbed by an amazing amount and allow snow to slide right off in winter.
2. Upgrade attic insulation. (BEST quick solution to the attic heat problem.) 3 to 4 inches of additional insulation won’t cost a lot, but will reduce energy used to heat and cool a home. It can pay for itself in just a few years. I recommend professional installation. At our home the difference was instantly noticeable. When we opened a closet door it no longer was like checking on a pie in the oven.
3. Add attic ventilation. If you are about to upgrade roofing and insulation you should, for a few more dollars, increase ventilation. If the summer heat and/or humidity can’t get out the insulation won’t be as efficient. I’ve been in attics which were being eaten alive by powder post beetles due to poor ventilation which was trapping humidity. Lowering attic temps by 5 degrees helps your AC’s efficiency. While you are at it, strengthen your vent covers. Raccoons and squirrels are master tin-benders. Flexible metal vents are wonderful, but should be reinforced, especially if your home is near a line of trees. I’ve seen raccoons rip off roof vents as well as gable vents (use screws instead of nails at least).
4. Your NEXT A/C should be built to last as long as you will be living in your home. Normal HVAC units last 15-20 years. Do your research. My study of reviews showed that some manufacturers and certain models have early failures. Get a product that is quality made and it will last 15-20 years. However, if you think you will be staying more than 20 more years you might want to invest in Geo-thermal. It will cost you up front, but you won’t have to replace the system for 35-50 years and the efficiency will pay you back.
5. Bulk up on tree shade. Be careful what kind of tree you plant and where. Some trees are known to damage foundations. Some buckle cement walks and driveways. Most attack septic and drain lines. And, of course, some are weak and drop branches in an ice storm or heavy wind. So, planting the right trees in the right places can help a bunch. Do your research. Hint: Stay away from fruit and nut trees. 100% “no” to Bradford Pear, Weeping Willow, or Black Gum.
6. Deck, parking, and window shade. Almost every deck leads to a windowed door. Almost every windowed door by a deck is unshaded. Think sails, pergola, or awning. A cooler deck also cools the house.
A car parked near the house can reflect heat as well. It is good to protect your car from harsh sunshine (and protect the house from reflected sunshine) with a carport or pergola.
If your window reflects sunshine on your siding or to another window (an inside angle situation) it could be valuable to place a lattice decorative panel between the window and its reflection. Some newer window systems’ reflectivity will melt siding if not controlled.
7. Basement to main level air circulation. This is not a replacement for A/C. But in spring and early fall it may be far more efficient than running A/C. For this you need a return air duct in the basement, and an inside stairwell. Open your basement duct, block your main level returns and turn on the furnace fan. Voila! You can reduce the temperature on your main level by up to 3 degrees. Unfortunately it won’t last long into the summer season.
8. Mini-Splits. If your house has a hard to heat/cool area you might be able to save money with a mini-split. Great for garage workshops, 4-season rooms, and porches which aren’t connected to the central air system. Cooling a 4-season room can help your central air keep up, especially if that room is on the south side of the home.
9. Other. Turn off AC at night and sleep in the basement or on a screen porch. Drink plenty of fluids. Take a couple cool showers. All the stuff your parents tried … and found didn’t work very well.
Copyright 2025 Donald Whelpley
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I have an instant reply, since this has been on our minds. The house we bought in the fall faces north/south; to the north is a large window and to the south there is CONSTANT HOT SUN coming down (ditto the long east side, most of the summer). Because it was built in 1948 I was anticipating issues with cooling. However we have found something that WORKS GREAT! I had intended actually to put in a mini-split system, since this is a very small house (about 700 sq ft). We have a small window a/c unit in the bedroom for sleeping on hot or humid nights, or just when it is needed. The back – south – part of the house accounts for about 1/3 of the square footage.
Typically simply keeping the house closed up until later in the day is enough. But on very hot and/or humid days we turn on the bedroom a/c (little unit – 5000BTU), keeping the single south-facing and single east-facing window back there covered, and closing the decorative curtain that blocks off that area. This counteracts the hot blast all morning and most of the afternoon. In addition, we close off the other 2 east-facing windows, and run a fan in the living room to keep the air moving. The living area rarely gets out of the 70s. And even on the hot days, if there’s no humidity, once the huge trees to the south of our yard reach the back of the house and the air temp naturally starts to cool – late afternoon or early evening – we open the back door, which is a steel door, and the front windows which are nicely shaded and cool by then, and turn on a fan in the hallway to draw the air from front to back. Within minutes the temp drops and the air inside is quickly replaced.
We do have one other window, which faces west, and is in the 2nd bedroom which is rarely used. The neighbor’s garage wall is just a few feet away, which reflects morning sun back to our house and allows evening sun to beat down for a short time. We have that window covered, and don’t even open the bedroom door. On hot days opening that door is like checking your cornbread in the oven!
On a personal note, I will look forward to any thoughts and suggestions that you may have when you actually see the house.
Thanks, owly.
Will do.
I recently noticed that a glass block window (west wall) gets seriously warm on a sunny day.
Today I will be looking at coatings for glass block windows. Who knows?