How To Stay Efficiently Cool This Summer

Summertime is almost here, but hot weather doesn’t have to mean skyrocketing power bills and nonstop air conditioning. We’ve compiled these tips to help you maximize your summer comfort and energy efficiency.

Remember, It’s Summer

Listen up – your home isn’t an arctic retreat for polar testing, it simply needs to be a comfortable living space. Avoid using your AC when you don’t really need it, and set it at a reasonable temperature when it’s operating. HVAC experts suggest 78 degrees as an ideal level to ensure comfort without unnecessarily wasting power.

Also, don’t underestimate the power of a fan. Whether you use a portable room fan or a ceiling fan, it will consume far less energy than an air conditioner. A fan distributes cool air around a room, and the breeze on your skin can let you stay comfortable while relying less on the AC – or even skipping it altogether.

A portable fan can help reduce or eliminate your AC usage
A portable fan can help reduce or eliminate your AC usage

Make Your AC’s Job Easier

Summer heat is enough of a challenge for an air conditioner – don’t make it work even harder than it has to. Have your unit maintained regularly by a pro to make sure it’s operating at its peak efficiency. And you can do your part too, by regularly cleaning or replacing the air filter. A clean filter means less air resistance for the unit, and better air quality in your home.

Don’t Cool An Empty Room

Even though it seems obvious, this one gets ignored all too often: Turn off the air conditioning when you leave the house. If you absolutely must have a cool home waiting for you when you return, use a timed thermostat instead of running the AC all day. Remember that when you come back, turning the unit to its coldest setting won’t cool your house any faster, so set it at 78 and be patient. Also, while you’re at home, close the doors and vents in unused rooms, and consider using an efficient portable air conditioner that will only cool the living space you’re actually using.

An efficient portable air conditioner can be a good alternative to window units or central AC
An efficient portable air conditioner can be a good alternative to window units or central AC

Don’t Add Fuel To The Fire

Beware of unnecessary heat sources around the house that compete with your air conditioner. Still using incandescent light bulbs? The reason they use so much power is that only a fraction of the electricity they consume is used for light, while the rest gets wasted in the form of heat (which your air conditioner must then cool down). So that’s another reason to switch to compact fluorescent bulbs, or the even more efficient LED lights. Another common foe of your AC are long, hot showers that raise the surrounding air temperature inside your home, and also add humidity to the air which makes it feel even warmer.

Other appliances can be particularly tough for an AC to work against. Avoid using your dishwasher, oven, and clothes drier at peak heat times of the day, and use settings that minimize their heat output and energy usage (which you’re already doing anyway, right?) For example, disable the air-dry function on your dishwasher, and lower the temperature on your clothes drier – or even better, use a simple clothesline or laundry rack to let your clothes dry in the breeze.

Ironically, refrigerators can be one of the biggest heat sources in the home. Use a thermometer inside the refrigerator and freezer to make sure the temperature stays at the ideal levels, since going colder just wastes electricity and creates more wasted heat in the kitchen. And older models are especially inefficient – do you really need that old fridge you moved down to the basement for extra soda?

Shade Is Your Friend

Shade is nature’s air conditioning, and it doesn’t cost a penny. Low-e windows are great for keeping unnecessary heat out of the house, but a simple window shade will do the job too. On a bigger scale, shade trees can dramatically reduce interior temperatures when planted on the south and west sides of your home. Plus, lawn vegetation has the added advantage of transpiration cooling (the evaporative cooling effect from moisture in the leaves).

Properly placed shade trees can help keep your home substantially cooler (photo: Trint via Flickr)
Properly placed shade trees can help keep your home substantially cooler (photo: Trint via Flickr)

In addition to keeping direct sunlight out of your windows, try to locate AC units in shaded locations. An air conditioner basking in the sun all day has to work much harder to cool the air that passes through it. Just make sure that any screens or nearby plants don’t interfere with airflow to the unit.

Look Up

In freestanding homes, the roof and attic can be your best friend or your worst enemy when it comes to keeping the heat outside and cutting your energy consumption. Consider roof materials and colors that efficiently reflect heat from the sun’s rays, or even use them to provide solar power. Ensure that your roofline and attic are well insulated, and use an exhaust fan to draw collected heat out of your home.

And If You’re Shopping For A New AC…

It goes without saying that if you’re considering a new air conditioner, it’s worth investing in an energy efficient model. It will use less power, which means less pollution and lower energy bills. The new residential evaporative cooling models that use the same principle as skyscraper cooling towers can be extremely efficient, and they’re especially worth considering for residents of hot, dry climates. And though they may be more expensive initially, many high-efficiency models qualify for tax credits as well as rebates from local utility providers. Energy Star models are available everywhere, and remember that the higher the SEER/EER score, the better. Last, ensure that your model uses a non-flourocarbon refrigerant.

We all have better places to spend our hard-earned money than power bills, and summer is plenty hot already without needless pollution adding to global warming. Being smart about keeping cool in the summertime is a win-win scenario for everybody.

15 thoughts on “How To Stay Efficiently Cool This Summer”

  1. I remember my grandmother hanging the wet sheets in the windows (not soaking wet but damp). She would also use them to block off certain areas of the house to keep the living space cooler. I wanted to know how to save some money on my energy bill so I went online to They have a whole page on money-saving ideas to keep your heating/ac bills under control.

  2. @joy:

    Get a whole house fan from airscape. Also, install pull-down shades in doorways so that you can put a box-fan in the doorway and block the rest of the space to create more pull. Open windows at night, and use all the fans to get as much cold air as possible through the house ALL NIGHT, and then close all the windows before it starts to get hot in the early morning. Also, use awnings or shade-trees or whatever you can to shade the part of the house that gets the most sun.

  3. I have a question, I live in phx az so cooling the is very important to us. It is about a 1600 sq ft home 3 bedrooms the living area of the home stay pretty cool and the master bedroom as well, the problem is the 2 smaller bedrooms facing the north stay really hot. What can we do to keep those rooms cooler?

  4. Andy: I don’t run central A/C except when it’s close to 100 degrees outside but I think it depends on your house and your furnace. My furnace fan uses a fair amount of power and keeping it on all the time makes the compressor run more when it’s very hot (because it circulates the warmer air from the attic into the rest of the house). So, in my house, running the fan all the time uses more power (and furnace filters). The only way I think it could save energy is if you had a very very cold basement (with air returns) that stayed cold on the hottest days and a new, efficient furnace fan. Even then, I’m not sure.

  5. One point about the portable A/C. I have the exact portable A/C unit in the pic, and it does have a high EER rating. I had to buy that because my attic windows were too small for any window unit. Now that my dog can’t go upstairs, I’m downstairs. I bought a small Kenmore window A/C and use that instead of the portable one. Even though it has a lower EER (10.2), it uses much less power to cool the same room. I think this is because: 1-It has a lower BTU and therefore uses less watts and 2-It is more efficient because it does not pull warm air in from other rooms. In the same room, the portable’s compressor would run almost all night and use 7kw/hrs per night while the window unit runs about half the time and uses about 3.5 kw/hrs per night. If you don’t need a portable, a properly sized window unit seems to be more efficient.

  6. I have a question: Is keeping the A/C unit fan on all the time ideal, verses having unit fan on Auto? Will keeping fan on keep my home cooler, thus saving energy or will the constent fan use more energy?

  7. Delighted to see you included shade trees and lawn vegetation in your article. My home was shaded by a large tree on the west until two years ago, when it died; the difference is striking. I have trees growing to replace it; many quality trees like pinoaks grow quite quickly. A friend’s home was shaded by a large sycamore in my childhood and they never had air conditioning and only a few days a year was uncomfortable.
    Trees also provide huge benefit for noise and air pollution and reducing the wind in the winter.

  8. LED lights seldom produce more lumens per watt that compact fluorescent lights. That’s part of the reason ENERGY STAR only certifies a few specialty LEDs so far.

    Disabling the air-dry feature on your dishwasher will typically turn on the heated dry option, which adds even more heat to your home.

  9. Whole house fans are an amazing way to cool down a structure at or after sunset. In humid areas like Florida they are very common. I live in Arizona at a 4,400 ft elevation and an hour or so after sunset the temp drops significantly. The typical differential between day and night in the summer is 25-30 degrees. At higher elevation (think Flagstaff at 7,000 feet) the differential is 40 degrees. The later you operate the fan the cooler the house becomes.

    Kick on the whole house fan with windows cracked and screen doors open and within 10-20 minutes the inside temp is the same as the outside. It is particularly effective for wood frame houses since they do not have masonry or brick walls to absorb the daytime/seasonal heat and will not continue to radiate that heat after the inside air has been exchanged with the cooler outside night air. Masonry houses are a bit more difficult to cool down however will retain the cool longer the next sunny day.

    There are excellent modern whole house fans that are metaefficient. Old units like my friend’s in Sedona are 36 x 36 inches and can suck a letter out of your hand if you stand below it while it’s running. New models have super-efficient fans with high-tech bearings. Less noise and less friction. One unit I resarched was a mere 16 x 16 inches. These newer units also have digital settings (of course) for auto-opening and closing of their louvers and user-set operational times.

  10. If you have forced air HVAC system and a basement with a return in it, and ideally a HVAC system with an efficient fan (e.g. with ECM motor) then consider running the fan to mix air from cooler basement with the rest of the house.

    If you are upgrading HVAC consider a zone controller with SmartVent e.g. RCS ZCV series ( This will automatically draw in cooler air in the evening to cool house down. But you need a duct from the outside of the house to the return of your air system.

    If you are reroofing go to and find out about installing about 4″ of polyisocyanurate on top of the existing deck and then a new deck on top of that. Also consider a white roof, especially for low slop roofs using TPO membrain rather than asphalt based.

    Consider using a small efficient dehumidifier to reduce humidity (and latent heat), this may have more effect than A/C. Ideally position the dehumidifier close to the return of a forced air system to help circulate around the whole house.

  11. I have to take a little issue with the idea of turning the AC off when you leave the house. You will save a little bit of electricity this way, but you would be better served by making sure your house or apartment is well insulated. The energy saved by turning off your AC while you are gone a few hours is only equal to the loss of coolness (gain of heat) created by the difference in temperature gradient between the warmest your house is and the coolest it is. If you have a well insulated home with several occupants it can actually be cheaper to use AC than a fan in each room. Remember too, that if you cool off a room and keep it shaded and don’t leave the door open, etc. it can stay cool quite a while, but once you turn off a fan a fan’s benefits stop.

    What’s worse is, lots of us get home at the same time, so suddenly we all turn on the AC at the same time. All the AC units struggle to get the temperature down, working at maximum power (not it’s most efficient mode and probably shortening the life of the AC) and creating a huge draw on utilities. Since generators take time to power up and power down this peak load means the power companies need to keep more capacity available, which means they generate a lot more power than they otherwise would have to keep that extra capacity online, even when it’s not needed. Power is being sent out over the lines that never gets used. A timer on your AC helps a little, but only until everyone gets one, then you’re right back where you started. NY State (I think it was NYSERDA) actually ran adds asking people to leave the AC on.

    Unless you have plants in the windows the middle of the day might also be a good time to have some of your shades drawn. As to trees for shade, remember if you live somewhere cold you don’t want evergreens. As much as you don’t want the sun in the summer you do in the winter.

    Also, turning the AC up will in fact get it colder faster. (The reverse doesn’t always work for heating units.) Turning up the AC, at least on the model I have, turns the fan up and pumps more air into the apartment. A heating or cooling system that only turns itself on and off to adjust the temperature won’t adjust the temperature faster on a higher setting. A system that actually adjusts the temperature it’s operating at or adjusts the airflow will.

    -I group I used to belong to had a speaker from NYSERDA once. He told an interesting story about a public housing complex. HUD decided it was paying too much in energy bills so they came in and fixed up all the windows, insulated the place, did everything they could to lower the heating bill. The heating bill didn’t come down. Our speaker was called in to figure out what was up. The first thing he noticed was that it was bitterly cold out. The second thing he noticed was that there were a lot of windows wide open. The solution was pretty simple. They lowered the rent, but they individually metered the apartments. Now the tenants payed the heating bill. Those windows closed up.

    I live in an apartment where I pay my own heating bill. The problem I have is the complex won’t make sure the place is well insulated. There is no incentive for them, since they don’t pay the bill. The apartment next to mine is has a long, uninsulated wall that borders on an unheated space. (My apartment would too, except I’m lucky enough to have a laundry room next to me instead.) I imagine if the complex and I had to split the bill we’d probably do pretty well.

  12. Wow! Thanks for that Useful article! I didn’t even imagine how much energy (and money) can be wasted for simply not caring about cooling or heating a home. The thing that happens to me is the case with a fridge.

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