How to Save on Home Air Conditioning & Energy Costs in the Summer
Summertime has a lot going for it: pool parties, backyard cookouts, baseball games. The only thing that’s not so great about summer is the heat. On a blazing July day with the temperature in the 90s (and on the East Coast, soaking humidity on top of that), it can be tempting to stay indoors all day with the air conditioner cranked up.
Unfortunately, air-conditioned comfort comes with a high price tag. In 2019, carbon emissions-reducing technology company Sense analyzed household electric bills from across the country to calculate summer cooling costs. It found the average cost ranges from around $25 in Washington state to over $450 in blazing-hot Arizona.
But there are ways to reduce that cost. An energy use chart from Lowe’s says a large central A/C system uses about 3,800 watts, or 3.8 kilowatt-hours for each hour it’s used. By contrast, a small window air conditioner uses 1,200 watts, and a box fan uses only 200. Thus, running your central A/C less can shrink your utility bill — and your carbon footprint as well.
How to Save Money on Summer Home Air Conditioning and Energy
One easy way to cut your A/C use is to keep your home from heating up in the first place. There’s not much you can do about how hot it gets outside, but there are plenty of ways to keep the heat out of your home.
Improving your insulation and sealing leaks helps keep hot air out and cool air in. You can also stop the sun from overheating your home with careful choices about window treatments, roofing, paint, and landscaping.
Use Science to Cool Your Home
It’s basic thermodynamics : When it’s hot in one spot and cool in another, heat naturally moves toward the cooler area. So when the summer sun comes beating down on your home, it eventually makes its way into the interior. This effect is known as “ solar heat gain .” You can prevent solar heat gain throughout the house with a combination of insulation and blocking technologies in addition to avoiding the addition of extra heat.
1. Keep Windows Shut
Keep your windows closed during the day when it’s hotter outside than it is inside. Even if they provide only a little insulation, a little is better than none. In the evening, when it has cooled down outside, open the windows to let in cooler air.
2. Upgrade Your Windows
According to the United States Department of Energy (DOE), your windows account for anywhere from 25% to 30% of the heat your home gains and loses. The older your windows are, the more heat can leak through them. Many old windows have just one pane of glass, and their frames aren’t well insulated.
But newer windows have two or three panes with an insulating layer of gas sandwiched between them. Modern energy-efficient windows also have better-insulated frames, so you lose less heat around the edges of the glass. According to Energy Star , upgrading to Energy Star-rated windows can cut 7% to 24% from your energy bills.
However, replacing windows is a costly job. According to Angi (formerly Angie’s List), a typical cost is $200 to $1,300 per window. If your current windows are reasonably new and in good shape, replacing them probably isn’t worth the cost.
For example, according to Energy Star , the average U.S. homeowner spends about $875 per year on heating and cooling. If that’s the case for you, new windows can only save you $210 per year at most. If you replace 10 windows at $600 each, it will take over 28 years for them to pay for themselves. That could be longer than you expect to own the home.
3. Add Storm Windows
A cheaper way to get the benefits of a multipaned window is to install temporary storm windows. These are rigid panes of glass or plastic you can put either outside or inside your existing windows, trapping a layer of heat-blocking air in between.
The DOE estimates that new storm windows cost between $60 and $200 per window and can save you anywhere from 12% to 33% on your annual heating and cooling bills. Installing them is a simple DIY job that takes 20 to 30 minutes per window.
4. Insulate Your Attic
Many houses in this country, especially older ones, have less insulation than they need. A map on the DOE website shows how much insulation you should have in different parts of your house based on where you live.
Insulation is crucial in your attic, which the blazing summer sun can heat to oven-like temperatures. Adding insulation to the attic keeps all that stored heat from spreading into your living space.
The cost of adding insulation to an attic and the potential savings on your summer cooling bill vary widely. They depend on factors like where you live, the size of your house, and your current insulation level. You can use the Home Energy Saver tool created for the DOE to figure out how much this project could save you.
5. Install a Radiant Barrier
You can insulate your attic still more by adding a radiant barrier — a coating of reflective material across the underside of the roof that blocks radiant heat from the sun. Radiant barriers are usually made from aluminum foil applied to a backing of paper, cardboard, plastic, or wood.
Based on data from CostHelper , a radiant barrier costs between $150 and $375 for a 1,500-square-foot attic. Hiring someone else to install it adds another $300 to $500. The DOE reports that in a warm, sunny climate, adding a radiant barrier to your attic can reduce your overall cooling costs by 5% to 10%.
6. Seal Doors and Windows
Even the best-insulated walls can’t keep your house cool if big gaps around your doors and windows allow cool air to escape. Fortunately, it’s easy to seal these air leaks with caulk or weather-stripping.
The DOE says caulking is an easy DIY job that takes just a couple of hours, costs less than $30, and can cut your energy use by 10% to 20%. Weather-stripping around windows is even cheaper and easier, requiring just one hour and $5 to $10.
7. Absorb Less Heat With Light-Colored Paint
Dark surfaces heat up a lot more in the sun than light ones. In a 2018 experiment by CNET , a brown stucco wall got 25 degrees F warmer on a sunny day than the same wall painted white. So painting your house a lighter color can help reduce the amount of heat it absorbs from the sun, reducing your air-conditioning costs.
The downside is that a lighter-colored house also absorbs less warming sunlight in the wintertime. Thus, this trick will only save you money if your summer cooling costs are higher than your winter heating costs. The Home Energy Saver tool can tell you if that applies to you.
Having your house professionally repainted costs between $1,7750 and $4,211, according to Home Advisor . However, you can do it yourself with $700 to $1,300 worth of paint and supplies.
8. Install a Cool Roof
The next time you need to replace your roof, consider a “cool roof” — one made with special reflective materials or coatings to block out the sun’s rays. According to the DOE , cool roofs could stay over 50 degrees F cooler in the summer sun than standard dark-colored roofs, and they cost about the same.
However, cool roofs also absorb less heat in the wintertime. Thus, like light-colored paint, they’re most useful in warm climates where people spend more on summer cooling than they do on winter heating.
9. Plant Shade Trees and Shrubs
Trees cool the area around them in two ways. They provide shade, and they move and release water vapor through their leaves. According to the DOE , the air temperature directly under a tree can be as much as 25 degrees cooler than the air directly above a nearby road.
Deciduous trees — the kind that lose their leaves in the fall — can provide summer shade while still letting the sun shine through their bare branches in wintertime. Tall trees on the south side of your home offer the best shade for the roof, while trees with limbs closer to the ground are helpful on the west side for blocking out the lower afternoon sun.
The DOE says a 6- to 8-foot-tall deciduous tree can provide shade for your windows as soon as you plant it. Within five to 10 years, it can begin shading the roof.
According to Angi , a 6-foot tree from a nursery typically costs between $50 and $200 if you plant it yourself. However, hiring a professional landscaper to deliver and plant it adds between $100 and $500 to the cost.
You can also strategically place smaller plants, such as shrubs and vines, to shade specific parts of your home and yard. For example, you can plant a hedge to shade your sidewalk or build a trellis for climbing vines to shade a patio. Vines can also help shade your home’s exterior walls, and you can place large potted plants like bamboo in front of sunny windows.
This Old House explains how to build a shade arbor for your patio with $800 to $2,000 worth of materials. There are many types of climbing plants you can grow to cover it from a $2 packet of seeds.
10. Put Up a Shade Cloth
If you have an outdoor living area, such as a deck, patio, or playground, you can keep it cool by adding a canopy of shade cloth. Floriculturists use this loosely woven synthetic material in greenhouses to shield plants from direct sunlight, but it can do just as good a job of providing shade in your yard.
Rolls of shade cloth cost around $0.30 per square foot at Home Depot . You can attach the material to an existing pergola or any other sort of wood or metal frame.
11. Shade Your Windows
According to the DOE , about 76% of the sunlight that falls on a double-pane window in the summer months transfers its heat to the house.
Any type of window treatment can reduce this solar heat gain. Simply close the curtains, blinds, or shutters on windows facing the sun. If you’re home during the day, cover east-facing windows in the morning, uncovering them in the afternoon in favor of covering west-facing windows. If you’re away all day, darken the house entirely until you come home.
The DOE says window treatments can make a big difference in your home’s temperature. For instance, a medium-colored curtain with a white plastic lining can reduce heat gain by 33%. To get the most benefit from curtains, hang them close to the windows and let them fall all the way to the windowsill to block the light fully.
Other ways to block solar heat gain from windows include:
Exterior Shutters. Shutters on the outside of the windows can block sunlight before it even hits the glass. But it only works with real shutters that open and close, not the fixed decorative kind.
Exterior Shades. If your house doesn’t have shutters, you can hang roll-up shades made of bamboo or vinyl strips outside your home’s sunniest windows. These typically cost $25 to $120 each and roll up and down with a pull cord. Close them in the morning to block out sunlight, and open them in the evening to let in cool breezes.
Awnings. The DOE says awnings can cut solar heat gain by up to 65% on south-facing windows and 77% on west-facing ones. It recommends awnings made of a light-colored, opaque, tightly woven synthetic fabric that’s water-repellent and mildew-resistant. These cost around $200 to over $1,000 each. You can remove or retract them in the winter to let sunlight in.
Solar Screens. Solar screening is a dense mesh that can replace a standard window screen. It’s particularly effective on east-facing and west-facing windows, which get direct sunlight in the morning and evening. Solar screens can fit outside or inside your windows. They cost about $45 per window, according to Efficient Window Coverings .
Window Film. There are several types of translucent films that adhere to your windows, blocking up to 60% of the sun’s heat without blocking the view. They’re best for warm climates since they also block out desirable solar heat in the wintertime. According to Efficient Window Coverings , films can cost between $10 and $125 per window.
12. Create Less Heat
Blocking the heat doesn’t do much good if you create more heat indoors. Sources of indoor heat include:
Cooking. Running the stove or oven puts a lot of heat into your kitchen, which eventually spreads to the rest of the house. You can cut down on cooking heat by cooking your meals in a microwave or slow cooker or outdoors on a grill . If you have to use the stove, run a ventilation fan to blow out the hot air.
Appliances. Run your dishwasher and clothes dryer at night, when the air is cooler, to reduce the burden on your air conditioner. You can also reduce the heat these appliances put out by using the air-dry setting. And if it’s sunny out, you can skip the clothes dryer completely and use a clothesline to dry your laundry .
Showers. Even in the summertime, some people prefer to start the day with a hot shower. If you’re one of them, turn on the bathroom fan to vent all that steamy air instead of letting the heat and humidity build up in your home.
Electronics. Your computer, stereo, and TV all generate heat that bumps up the indoor temperature. Even when they’re not on, these gadgets continue to draw a trickle of heat-producing current. To keep your room as cool as possible, unplug these devices when you’re not using them or plug them into a power strip you can shut off.
Lighting. If you still have any old-fashioned incandescent lightbulbs, swap them for cooler LED bulbs. During the daytime, you can also use daylight without adding too much heat by opening the blinds on windows that aren’t in direct sun.
Aside from reducing your cooling needs, most of these heat-reducing steps also save energy directly, reducing your electric bill still more. And as a bonus, they’re good for the environment as well.
Cool Yourself Without Air Conditioning
Many online articles and videos claim you can make your own air conditioner with less than $30 worth of parts. A typical setup involves boring some holes in a bucket or ice chest, filling it with ice, pointing a desk fan into the bucket, and directing the airflow through pieces of PVC pipe.
There are two problems with this idea. First, it’s not really an air conditioner. It’s more similar to a swamp cooler, which means it’s useless in humid climates.
And second, these DIY swamp coolers don’t actually work very well. In a test conducted by Consumer Reports , an ice-chest “air conditioner” was only able to cool a room by 2 to 3 degrees F — and only for about 30 minutes. A bucket-based design tested by the Philadelphia Inquirer reduced the temperature by no more than 1.5 degrees F.
The bottom line is that these homemade air conditioners do little if anything to cool a room. In most cases, you’ll get better results using the desk fan in the traditional way and saving the ice for a cold drink.
But that doesn’t mean turning on the air conditioner is your only alternative to sweltering. There are many legitimate ways to stay cool that use a lot less energy and money.
13. Use Fans
A fan doesn’t cool your room. Instead, it cools you directly by blowing away the cushion of warm air that accumulates around your body.
That doesn’t help much in extreme heat (over 95 degrees F) because there’s no cooler air to replace it. But at lower indoor temperatures, a fan can make you feel several degrees cooler. According to the DOE, running a ceiling fan allows you to feel equally comfortable with the thermostat 4 degrees F higher.
You can buy a basic desk fan for as little as $15 and a more powerful tower fan for around $60. Even on its highest setting, a tower fan uses less than 100 watts of energy — far fewer than the 1,200 watts a typical one-room air conditioner uses.
To get the most benefit from your fans, dress lightly. If you’re sitting around in jeans and a sweatshirt, those heavier clothes are trapping hot air next to your body. Switching to lighter clothes, such as shorts and tank tops, makes it easier for your sweat to evaporate and keep you cool.
14. Apply Some Cold
If a cooling breeze isn’t enough to keep you comfortable, you can cool yourself directly with cold water or ice. Taking a cold shower reduces your temperature immediately. You can also soak a cloth in cold water and drape it around your neck. Because this is a pulse point, a spot where the blood vessels are close to the surface, applying cold to this area makes you feel cooler .
If that’s not cold enough, try an ice bag or commercial cold pack you chill in the fridge or freezer. You can buy cold packs at drugstores for $5 to $10. For between $50 and $200, you can get a cooling vest with pockets for multiple cold packs. That keeps them close to your body while you carry out other activities.
15. Bring Cooler Air In
At night, when the air is cooler, it makes sense to bring as much of that cool air as possible into your home. You can open the windows, but a window fan , which costs less than $100, can pull in cold air much faster. A typical window fan uses no more than 100 watts of electricity.
If you want even more airflow, you can install a whole-house fan. It mounts in your ceiling and pulls in air through the open windows. According to Family Handyman , the fans can lower your home’s temperature by 5 degrees F or more in minutes using one-tenth the energy of an air conditioner. Expect to spend a few hundred dollars on the fan and another few hundred to have it installed.
16. Use a Swamp Cooler
A swamp cooler, also called an evaporative cooler, blows warm air over water-soaked pads. As the water evaporates, it cools the air by as much as 40 degrees F. According to the DOE , swamp coolers cost about half as much to install as an A/C unit and use only 25% as much energy.
Free-standing swamp coolers start at around $130. You can have a whole-house evaporative cooling system installed for about $2,500, according to HomeAdvisor .
The primary drawback of this type of cooling system is that it only works in dry climates. This map from the appliance company Sylvane shows which parts of the country are best suited for evaporative coolers.
Run Your Air Conditioner Efficiently as Needed
In some parts of the country, a good fan and a couple of ice packs are all you need to survive the summer heat. But in really hot, humid areas, there’s no way to make it through a whole summer without switching on the A/C. On those days when air conditioning is a must, the best way to save energy and money is to keep your A/C system running as efficiently as possible.
Air conditioners are based on the physical principle that when a liquid gets converted to a gas, it absorbs heat. They work by circulating a fluid through a series of coils, evaporating and condensing repeatedly. As the fluid evaporates, it absorbs heat, removing it from the air inside. When it condenses, it loses heat, which it releases into the air outside.
An air conditioner has three primary components:
Evaporator. The evaporator is the part of the air conditioner that sits inside the house. The evaporator sucks warm air from the room through a filter and passes it over a series of coils filled with liquid refrigerant. As the air cools, a fan blows it away from the evaporator and circulates it through the house.
Compressor. As the liquid in the evaporator takes in heat from the indoor air, it turns to gas. This gas flows into the compressor, which sits outside the house. The compressor squeezes the gas, increasing its pressure to aid its transfer back into a liquid.
Condenser. The compressor pumps the hot, compressed gas into the condenser, where its heat gets transferred through a series of fins like those in a car radiator. A second fan blows across these heated fins to disperse the heat into the outdoor air. As the gas cools, it turns back into a liquid and flows back to the evaporator to start the process again.
There are several tasks you should do regularly to maintain your unit in addition to strategies to reduce the burden on your unit (and your budget).
17. Maintain Your Air Conditioner
Routine maintenance can make a world of difference when it comes to your air conditioner running efficiently — and efficiency saves you money on your cooling bill each month. Easy tasks you can do yourself include:
Clean or Replace the Filter. Over time, particles clog the filter (which keeps the evaporator clean), making it harder for air to pass through and forcing the evaporator to work harder, which makes your energy bills go up. The DOE notes a dirty filter can lower your system’s efficiency by 5% to 15%. Inspect the filter monthly and clean or replace dirty ones according to the manual. Most disposable air filters cost less than $30, while reusable ones cost between $30 and $200. To clean a reusable filter, vacuum it to remove debris; wash it in warm, soapy water; and let it air-dry before replacing it.
Clean the Coils and Fins. While you’ve got the filter out, check the evaporator coils for dust or debris. Remove particles gently with the upholstery attachment on your vacuum cleaner. Also rinse the coils and fins with a hose before each summer. Shut off the power to a central A/C unit at the appliance shutoff box or circuit breaker first. Unplug and remove a window air conditioner. Check to see if any fins are bent, and straighten them with a fin comb , which you can purchase from a home center for about $15.
Clear Away Debris. If you have a central A/C system, you need to keep the condenser unit clear of debris, such as tall grass or dead leaves. This kind of clutter restricts airflow around the condenser so it can’t disperse heat as effectively. Remove weeds and other debris when you clean the condenser at the start of each season.
Clear Clogs. Your air conditioner’s evaporator doesn’t just remove heat from the air — it also removes moisture. This excess water drains outside through a pipe called the drain line or condensate line. Over time, this pipe can get clogged with dirt and debris. To prevent that, run a stiff wire through the drain lines from time to time to remove any blockages.
Check Seals. A window air conditioner has a seal around the edges where it fits into the window frame. Moisture can gradually damage this seal, allowing cool air to escape. Inspect A/C seals each summer to ensure they’re making contact with the unit all the way around, and replace them if they’re damaged. A new foam seal costs just a few dollars.
Cover It Up. When cold weather comes, cover the outdoor parts of your central air conditioner to protect it from debris and harsh winter weather. If you have a window air conditioner, either cover it or put it in storage for the winter.
18. Reduce A/C Energy Use
Aside from regular maintenance, you can take several other steps to reduce your air conditioner’s energy consumption. For example:
Adjust the Thermostat. There’s no need to keep the indoor temperature so hot you’re stifling, but don’t just assume that you need to keep it at 70 degrees F year-round. Instead, experiment. Wear lighter clothing, use an ice pack, or turn on a desk fan, and you can stay comfortable with the thermostat set at 80 degrees F or even higher.
Seal Your Ducts. If your home has forced-air heating, you could be losing as much as 30% of your cooled air to leaky air ducts. You can hire a contractor to find and repair holes and leaks in your ductwork or do it yourself with mastic sealant or metal tape (but not duct tape, which despite its name, does a poor job of sealing ducts). In some areas, the local utility company will test your home’s ductwork for leaks for little or no cost.
Set a Timer. Many central and window A/C units have built-in timers, so you can set them to switch off automatically when you leave for the day and turn back on half an hour before you arrive home. That’s enough time to get the house cool and comfortable by the time you get home, and it uses much less energy than letting it run all day.
Use a Programmable Thermostat. If your air conditioner doesn’t have a timer, you can set it to shut off in your absence with a programmable thermostat. The DOE says using a programmable thermostat can save you up to 10% on your year-round heating and cooling costs.
Try a Smart Thermostat. Alternatively, install a smart thermostat, such as the Nest . These gadgets can do everything a programmable thermostat does and then some. For instance, you can control them remotely from your phone, allowing you to turn the temperature up or down when you’re on your way home from work or a vacation. They can even learn your family’s habits and adjust the temperature automatically based on when you’re usually home.
Use the Energy-Saver Button. On most window air conditioners, the compressor shuts off when the room reaches the desired temperature — but the fan continues to run, wasting energy. But many units have an energy-saver button that turns off the fan when the compressor shuts off.
One energy-saving tip you should ignore is closing the registers in rooms you don’t use, such as a spare bedroom or formal dining room. A 2003 study at the Lawrence Berkeley National Laboratory found that in a typical house, doing so actually increases the air conditioner’s energy use because it leads to more leakage in the duct system.
Upgrade Your Air-Conditioning System
According to the DOE , today’s more efficient central A/C systems use 30% to 50% less energy than those built in the mid-1970s. Even compared to a 10-year-old unit, a new air conditioner can cut cooling costs by 20% to 40%. So if you currently spend $133 per year on summer cooling like the average American household (per Sense ), upgrading your system could save you up to $53 per year.
But if your central A/C system still works, you probably won’t save any money by replacing it. According to HomeAdvisor , buying and installing a new central air-conditioning system costs around $3,800 to $7,500 on average. That means your new system will take over 70 years to pay for itself.
Another question to consider before replacing your central air conditioner is whether to switch to a different type of system that uses less energy. Whether you choose to replace your old A/C with a new central air system or one of the alternatives depends on your heating and cooling needs and how much you stand to save with each system.
19. Increase Efficiency With a New Central Air-Conditioning System
If you have existing ductwork and your old A/C system needs replacing, it’s worth choosing an energy-efficient one. The efficiency rating of a central air conditioner is called its “ seasonal energy efficiency ratio ,” or SEER. It’s a measure of how much energy it uses to produce a specific cooling output. Old air-conditioning systems often have a SEER of 6 or less, while modern ones can reach 20 or more.
The size of your system is also important. If your central A/C system is too small for your house, it can’t cool the entire space on the hottest days.
On the other hand, a system that’s too large for the house costs more and is less efficient. That happens because it only needs to run for a few minutes at a time to bring the temperature down near the thermostat — but that isn’t long enough to remove humidity. An oversized system can also leave some areas too warm because it doesn’t run long enough.
20. Opt for Window Units
There’s no point in cooling a whole house if you’re using only a few rooms. If you tend to spend most of your day in a single room, such as your home office, perhaps you can skip the central air conditioning and just use a window air conditioner in that one room. A new window air conditioner typically costs between $110 and $400 and uses around 1,200 watts to run.
Even if you have to install window units in several rooms, it’s cheaper to cool one room at a time than an entire house at once, and there’s no energy lost to leakage through the duct system. But if you need to cool multiple rooms simultaneously, a central A/C system is more efficient.
21. Put in a Mini Split System
Instead of using a single evaporator and a fan to cool the whole house, these systems have several indoor air-handling units hooked to a single condenser and compressor. This setup allows you to cool specific rooms instead of cooling the whole house. It also eliminates the need for ductwork, so there’s no air leakage.
Mini split systems are easier to install than central A/C systems, especially in houses that don’t already have forced-air heating. Their primary drawback is that they’re usually more expensive. According to HomeAdvisor , a ductless system costs about 30% more to install than a new ducted system.
But that applies only to homes that already have ductwork from an existing heating or A/C system. In a house with no ductwork, a new split system costs up to 50% less than a new central air-conditioning system.
22. Invest in a Geothermal System
A standard air conditioner transfers heat from your house to the air outside, which is already pretty hot in the summer. By contrast, geothermal systems transfer indoor heat to the ground about 10 feet below the surface, which stays at around 54 degrees F all year long.
According to the DOE , a geothermal system uses 30% to 60% less energy than a traditional air-source system. Also, you can use it for heating your home in the winter as well as for cooling it in the summer.
Geothermal systems are expensive — between $10,000 and $30,000, according to Family Handyman . That’s a lot more than a conventional HVAC system. But you may qualify for an Energy Star tax credit to cover part of the cost, and it can save you between 20% and 60% on home heating and cooling bills.
One thing you shouldn’t do to save on your summer cooling costs is let the temperature in your house climb to dangerous levels. When the temperature is above 90 degrees F and the humidity is also high, your body can no longer cool itself by sweating, putting you at risk for heat-related illnesses, such as heat exhaustion or heat stroke.
Symptoms of heat illness include extreme thirst, muscle cramps, fatigue, headache, dizziness, and nausea. If you start to have any of these symptoms on a hot day, forget about your electric bill and cool yourself as quickly as possible, or you may end up in the emergency room .
Fortunately, there’s no need to put yourself in danger — or even discomfort — just to save money. By combining the tips listed here, you can take a big bite out of your summer electric bill without having to swelter in an overheated house.