Great ways to cut your electricity bill

My summer energy saving tips are designed to help you cut your electricity bill.

If you use air conditioning, you probably pay a lot for electricity in hot weather. If your climate is hot year round, the costs really add up.

I’ll be honest up front: you may have to sacrifice a little comfort if you’re serious about saving.

In our household in Toronto, where summers are hot and muggy, we have learned to survive without any air conditioning, thanks to some home energy upgrades and some daily rituals around getting heat out of the house at night, and keeping it out during the day. So to start with, I have a tip on how we stay comfortable and cool, without spending a cent on air conditioning.

After that, I’ll share my philosophy for staying cool cheaply:

If you get rid of indoor heat sources, such as incandescent lights and electric appliances, you’ll stay cooler and have less need to run your air conditioner. If you keep the outside heat outside by using outdoor shade, window coverings, and better insulation and sealing, the heat won’t sneak in and overwhelm you or your air conditioner. I’ll also tell you how to keep your roof and attic from heating your house from above.

Energy used outside the house in the summer is also worth discussing, since it is part of your energy bill.

Finally, I give some tips for reducing your dependence on air conditioning, and using the system you have more efficiently.

Toronto summers without air conditioning

Toronto summers are hot, hazy and humid. That’s why many families escape to cottages further north for much of July and August. And it’s why most of my neighbors run their central air conditioners for two months straight.

We have an old, inefficient central air conditioner, but we never used it much, and haven’t at all in the past two summers. Here are my tips on staying cool without air conditioning.


Get the hot air out at night: Every evening we open the downstairs windows, and use powerful window fans in upstairs windows to suck large volumes of hot air out of the top floor of the house. On really hot evenings, we also run bathroom and kitchen exhaust fans for an hour. The window fans run all night long. By 1:00 a.m. the house is usually a comfortable 23C or 73F.

Seal the cool overnight air in: Every morning we stop the window fans and close the windows to seal the cool night air inside during the day.

Keep the hot air out during the day: This is one of my best summer energy saving tips. By keeping all windows and doors shut, we keep hot, humid outdoor air from entering the house. Curtains and blinds are drawn to keep sunlight from turning into heat inside. And because we have extensively insulated and air-sealed our home in order to keep our house warm in winter, our house stays cool longer in the summer. See my Energy saving window coverings page for lots of tips on saving energy with blinds, shades, curtains and awnings.

Don’t make heat indoors: We do everything possible to avoid producing heat inside the house. Cooking is kept to a minimum. We eat lots of salads and cold fruit. We never use the oven in the summer. We try not to turn on lights, andwe’ve switched most of our lights from heat-producing incandescent or halogen to energy saving CFLs. We avoid opening the refrigerator wherever possible, since this produces heat inside your house.

It’s surprising how much our house feels like an air-conditioned house, even though it isn’t. One visitor even complained that we kept the house too cold and asked us to turn off the air conditioning!

Our summer electricity bill is tiny, about $35 per month. Because fans use so little energy, and we don’t need as much lighting during long summer days, our summer electricity use is no higher than during the rest of the year.

Get rid of indoor heat sources

Here’s a summer energy tip for anyone who likes to leave the lights on, run computer downloads all day, or bake cookies: Any energy you use indoors produces heat, so the less you use, the less your house heats up, and the less energy you’ll use cooling it.

Some common sources of indoor heat:

  • Incandescent and halogen lightbulbs
  • Cooking, baking, making coffee
  • Dehumidifiers (although removing humidity can make it feel cooler)
  • Dishwashers
  • Washers and dryers
  • Water heaters
  • AC to DC power converters, computers and electronics
  • Refrigerators and freezers

Let’s provide summer energy saving tips on each of these heat sources:

Replace incandescent and halogen light bulbs with CFLs or LEDs. Not only will you save on lighting costs, but incandescent and halogen bulbs convert most of their energy to heat, so they make your air conditioner work even harder.

Avoid cooking, baking, making coffee on hot days. The more energy you use to cook indoors, the hotter your house gets and the more work your AC has to do to cool the indoor air.

Avoid using your oven. Use a microwave, convection microwave, or outdoor barbecue instead. (But if you live in a smog zone, remember that barbecuing contributes to smog, so don’t barbecue on smog days.)

Better yet, stick to salads and foods that don’t take much heat to prepare.

Don’t peek into the oven if you do cook with it; a lot of heat escapes with each peek.

If you use a bread maker, plug it in outside in a protected area (like a veranda or porch for example) so you can bake bread without baking your house.

Always cook liquids with a lid, to reduce home heat and humidity.

Don’t leave the coffee maker on for hours. Buy a coffee maker that comes with a thermos, or pour the coffee into a thermos once it’s brewed. It will stay warm without warming the house up.

Here’s a solar powered summer energy saving tip! If you’re a tea drinker, make sun tea by placing water and some tea bags (black tea or herbal) into a glass jar. Place the sealed jar in the sun. In a few hours you’ll have a lovely tea. Remove the tea bags, cool overnight outdoors (so you don’t bring that heat inside!), then refrigerate in the morning.

If you live in an area with year-round hot weather, consider installing a “summer kitchen”, an area outside with a stove where your cooking won’t heat the inside air. Outdoor kitchens have been around for centuries. A summer energy saving tip from the 1800’s!

Minimize your dehumidifier use. Dehumidifiers can use a surprising amount of electricity, and they produce heat. Dehumidifiers use a cooling compressor to extract heat from cooling coils. The cold coils in turn cause water to condense out of the humid air. The flip side of this is that the extracted heat has to go somewhere. And guess what? It is blown into the ambient air. So cutting your dehumidifier use not only saves the electricity used to run the dehumidifier, it reduces the amount of heat produced inside your home.

Follow my Energy efficient dehumidifiers tips to reduce home humidity levels, and to choose the right dehumidifier.

Dishwashers use hot water, and most energy efficient models heat the water hotter before washing. So make sure you only run full loads, and don’t use the sanitizer or sterilizer setting. Avoid the heated dry option. When the final rinse cycle is done, open the dishwasher and let the dishes air dry. It’s awfully wasteful to run a heating element to dry your dishes, at the same time that you’re running an AC unit to cool your home.

If you don’t mind the odd drop of water in an overturned coffee cup, run your dishwasher at night, starting it when you go to bed, or using its delayed start feature. The dishwasher will release its heat during the night when your windows are open and hot air can escape, and you’ll be using off-peak electricity. This will save you money if you are billed on a time-of-use plan, and it may reduce the amount of CO2 emissions you are responsible for, as off-peak electricity in many regions tends to have a lower proportion of coal generation than peak electricity.

Do laundry the old fashion way. Wash in cold water, and hang the clothes out to dry. If you don’t like the rough feeling of air-dried towels, you can always partially dry them on a clothesline, then finish them off in the electric or gas dryer. See my pages on Energy saving washers and Energy efficient dryers for more energy saving laundry tips.

Turn down your water heater. If you haven’t already done so, turn your hot water heater down from its factory setting. The default setting is usually 60C or 140F, but 49C or 120F is both safer and more efficient. This not only saves hot water energy but cuts the heat escaping from your water tank. Better yet, install a tankless water heater (also called a forever water heater), which uses less energy and releases less heat into your home.

Unplug those black bricks and other phantom loads. Every house seems to have a half dozen AC to DC power converters plugged in all the time, even when the device they’re meant to power isn’t being used, or isn’t attached to the converter. Unplug these converters when they’re not needed. Some of them use electricity even when nothing’s attached to them, and they produce heat when the consume power. Feel each plugged-in power converter. If it’s cold, it is not using much electricity and isn’t warming your house. If it’s hot, unplug it if possible.

Other phantom loads that both consume electricity and warm your home include stereos, electronic equipment, computers and peripherals, and even your thermostat (if you aren’t using central air). See my page on How to save electricity for more information about phantom loads.

Don’t gape at your open fridge or freezer. Don’t stand in front of the fridge looking for snack inspiration. It might make you feel cooler, but the refrigerator has to work harder to expel all the heat that creeps in. And that extra work means more heat in your house.

The same applies to freezers – open them as little as possible. The more cold you let out, the more the freezer will heat up the surrounding air. See my Energy efficient freezers page for tips on cutting your freezer energy use.

If you have an old beer fridge or other old second refrigerator, unplug it, at least for the summer. Old fridges can use up to three times more electricity than the newest models, and heat the house that much more.

Make sure the outside heat stays outside

As much as possible, shut your house off from the hot outside weather. There are several summer energy saving tips you can use to accomplish this:

  • Use natural shade
  • Create indoor shade
  • Insulate and weatherize
  • Move outdoor heat sources away from the house

Take advantage of natural shade by planting deciduous trees on sun-facing areas of your yard. The leaves shade your house in hot weather, and when the leaves drop in the fall, you get sunlight to help heat your home. Well treed neighborhoods are typically up to 3C (6F) cooler than treeless neighborhoods in the summer.


Create indoor shade. Make use of curtains, shutters, blinds, and awnings to keep sunlight from turning into indoor heat. Look for energy efficient window coverings that have bright surfaces so that they reflect more light outside – but choose ones that block the light out too. If you use curtains, use a light fabric but have a dark liner.

If you’re at all handy with a sewing machine you can make them for just the price of the fabric and thread, and a little hardware available from most building centers.

Terrell Sundermann teaches you exactly how to create “window hangings”, her combination of a wall hanging and a roman shade. This book gets great reviews from customers and is written in clear prose with excellent illustrations.

You can also install energy saving window films or coatings directly on your windows, or buy windows with low-E coatings, to cut down on infrared light, which reduces heat production in your home. These coatings work both ways: they keep heat outside in the summer, and keep heat inside in the winter.

Insulate and weatherize. I can’t stress enough how important it is to have a well-insulated, well-sealed house if you want to survive a hot summer without blowing your energy budget. The better insulated and weatherized your house is, the easier it is to keep the house cool with free, passive techniques like the summer energy saving tips I suggest, and the less you’ll spend on electricity if you do use air conditioning. There’s no point in air conditioning the out of doors!

Keep your roof and attic cool

Most house roofs are giant heat absorbers that soak up sunlight all day and convert it into attic heat. Most attics in turn are giant heat sinks that release that heat day and night, outside if you’re lucky, down into your house if you’re not.

Here are some ways to cut the heat from your roof in summer:

  • Ventilate your roof
  • Choose lighter shingles
  • Install a rooftop garden or green roof
  • Insulate your attic
  • Use reflective insulation on roof rafters.

Ventilate your roof. Heat build-up in your attic can reach 150F or 66C in the summer. By installing attic vents near the bottom and top of your roof, you allow natural convection to draw hot air out the top vents, which draws cooler air in the bottom vents.

You can also add ventilating baffles from your soffits, up through your rafters, to the attic space above the level of any insulation. (Soffits are the downward facing overhang between your house wall and the extension of your roof.)

You can supplement natural ventilation with a switch- or thermostat-controlled exhaust fan mounted to an outside wall in your attic. Fans use very little electricity, and by drawing the hot air out quickly, they reduce the amount of heat your attic contributes to indoor temperatures.

Choose lighter shingles so they absorb less heat. If you need to reroof your house, choose the lightest shade of shingle available. The darker the shingles, the more sunlight gets converted into heat, which travels through the roof into your attic.

If your shingles are in good shape, you can lighten them up by using a reflective shingle paint, which will not only reflect all that light away from your roof and keep you cooler, but will make your shingles last longer.

Install a rooftop garden or green roof. Rooftop gardens or green roofs provide a lot of insulation in both winter and summer, up to an insulation factor of R-60. (Few attics are insulated beyond about R-36.) These gardens keep your house cool even when the sun is blazing. A watering system keeps the soil moist, and the evaporation from the soil helps cool the roof.

Your rooftop garden should be designed and installed by a professional green roof installer to avoid causing structural damage to your house or injury to residents or neighbors.

Insulate your attic. If you have blown-in insulation, climb into the attic every couple of years and rake it level to increase its insulating effect. You should have at least a foot of blown-in insulation. If your attic has bat insulation between the joists, the bats should be at least R-36; higher than that is even better. Don’t walk on the bats or blown-in insulation; compressing it reduces its R value, and you might fall through the ceiling. Make sure the door to the attic is also insulated and well sealed. For lots more on this topic, see my full article on attic ceiling insulation.

Use energy efficient reflective insulation on roof rafters. You can buy aluminum-coated, insulated materials such as Reflectix to attach to the rafters under your roof. You staple the material between rafters, leaving an opening at the top and bottom to allow good airflow. These materials reflect radiant heat from the sun back out through the roof. They require an air space on either side of them to have any effect. While these materials can reduce your cooling costs, they also cut the amount of heat entering your house in cold weather when you actually want it.

Cut your energy use outside the house

Some outdoor summer energy saving tips from my own experience:

  • Cut your pool costs with a thermal pool blanket and filter timer
  • Minimize outdoor lighting, use solar lights instead
  • Get rid of your gas mower
  • Cool the kids off with the lawn sprinkler
  • Have a backyard tent sleep over

Cut your pool costs. A solar thermal blanket when the pool is not in use can cut your pool heating costs. Sunlight passes through the blanket and is converted to heat, but heat doesn’t escape through the blanket as quickly as through an uncovered pool. The cover also keeps leaf litter and other detritus from falling into your pool, and cuts down on algae growth, so you may be able to run your filter less.

Add a filter timer to your pool filter if you don’t already have one. There’s no need to run the filter all day and night. And keep your drain baskets clean to reduce stress on the pump.

Consider installing a solar heating system for your pool. The payback for solar-heated pools is among the shortest of any home energy upgrade. Your energy savings will pay for the up front investment within just a few years.

Minimize outdoor lighting, use solar lights instead. You might think your home is safer when it’s lit up with security lights at night. But you’ll be creating light pollution (to the horror of amateur astronomers), and there’s evidence that security lights decrease security, by making it easier for thieves to find their way to the easiest entry point.

If you must have outdoor lighting, use lights with motion sensors, or ones with a low light setting. Don’t over-illuminate your yard, porch, or patio. If you need lighting just to find your own way through your yard at night, try solar garden lights, which don’t cost you anything to operate once they’re installed.

Get rid of your gas mower. Gas mowers are a major contributor to local smog. A single gas mower produces more smog than a car idling for the same amount of time. Use a push-mower, or an electric mower for a bigger lawn.

Better yet, get rid of your lawn and plant ground covers, or put in an ornamental or vegetable garden. If you’re worried about kids not having a place to play, put stone paths in your garden and they’ll have as much fun running on the stone paths as they did playing on the lawn.

Not only do gardens mean less mowing (and less energy waste), they keep the ground cooler around your house, so your house stays cooler too.

Cool the kids off with the lawn sprinkler. If the kids complain of being hot, don’t turn on the air conditioner – turn on the sprinkler. You can water your lawn at the same time (if you still have one).

Have a backyard tent sleep over. If you have young kids, there’s nothing they’ll like better on a hot summer evening than sleeping in a tent with friends.

Use air conditioning less (or not at all)

You might think you can’t live without air conditioning, depending on your local climate and your own tolerance for heat. But your body will acclimatize to life without AC if you give it long enough.

My summer energy saving tips for using your air conditioner less, or not at all:

  • Live like our ancestors, without AC
  • Avoid air conditioned areas outside your home
  • Seal off unused rooms
  • Dress lightly indoors
  • Use ceiling and room fans
  • Move your bedroom or home office to the basement
  • Install a whole house attic fan
  • Use cool outdoor air when you can find it

Live like our ancestors, without AC. As radical as it may sound to live without an air conditioner, give it a try. (Don’t just turn off the AC; use the other summer cooling tips in this page to keep your house cool without AC.)

Think about the fact that until sixty years ago, nobody used air conditioning. Entire cities have sprung up in the southern US thanks to the spread of air conditioners; such cities are not livable without it. But in less extreme climates, air conditioning is not essential, at least not all the time.

Avoid air conditioned areas outside your home. The more time you spend in air conditioned buildings or cars outside your home, the more difficult it is for your body to acclimatize to a home where the air conditioning is turned off or down. So don’t hide in air conditioned buildings during hot spells. Don’t drive with the AC on, open the windows and let the hot air blast in your face. Better yet, bike. I work in a very cool office building, and stepping outside after work can be like walking into a furnace. But after my hour-long bike ride home, with the natural air conditioning of a 20-mile-an-hour wind, my naturally cooled house feels perfectly comfortable.


Seal off unused rooms. If you run central or room air conditioning and there’s a room you don’t use much, keep the door closed. If you have central forced air, seal off the register. It’s a terrible waste to keep a room cool when no one is benefiting from the cooling.

You can also purchase an energy saving programmable register such as the one pictured at right, also available in other heating register sizes. These vents are battery powered and have a 7-day 24 hour program; you set them to open or shut the vent at specific times. Using such a vent you could, for example, ensure cool air to a bedroom at night when the occupant is sleeping, but turn the AC to the room off during the day.

Dress lightly indoors. Dress as lightly as you can, so you don’t overheat and require a lower indoor temperature. Remember that sweat is the body’s way of cooling itself. There’s nothing wrong with sweat in itself, just make sure you stay hydrated, and shower before that date or job interview!

On hot nights I spray myself with a plant mister filled with clean water. It cools me down, especially when the ceiling fan is blowing down on me, and evaporating the water.

Remember, there’s no law against sleeping naked, or scantily clothed – and it will help you stay cooler.


Use ceiling and room fans. Ceiling and room fans are great for keeping you cool both in bedrooms as you sleep, and in living areas as you move about. They keep air circulating, which helps the sweat on your body evaporate and cools you down. The white noise of a fan can also make it easier to sleep at night, even when it’s uncomfortably hot.

Here’s a summer energy saving tip many people could use: Don’t leave fans running in a room that’s empty! I don’t know how many times I’ve seen people leave fans on when they leave. Fans are not like air conditioners. They don’t actually cool the air, they just move it around, making it feel cooler. Fans blowing air around in an empty room are just wasting energy.

Move your bedroom or home office to the basement. If you have only a month or two of hot weather, move your bedroom or home office to the cool basement. You’ll be more comfortable and spend less on cooling. We have our home office, home entertainment center, and a spare bed in our basement; we sleep there on the two or three horribly hot Toronto nights each summer.

Install a whole house fan in your attic. Whole house attic fans draw large volumes of air up out of your house and into the attic space. You run a whole house fan at night, usually just for a half hour or so.

A whole house fan draws hot air out of your home and draws cool air in through the windows. Although the hot air it draws out goes into your attic, that air is still cooler than what’s in the attic in the first place. Since attic heat build-up is a major source of heat entering upstairs rooms, you’ll keep those rooms cooler.

A whole house fan can save up to 5% on your summer electricity bill, weather you use air conditioning or not.

Use cool outdoor air when you can find it. Turn of the air conditioner and open your windows, whenever it’s cooler outside than inside.

It’s more efficient to draw cool air into your home using natural circulation or window fans, than to use an air conditioner to suck the heat out of your house into the cool night air. Plus your air will be fresher.

Use air conditioning more efficiently

I have a whole page on energy saving air conditioners. For these summer energy saving tips, let’s focus on some easy things you can do to get better mileage out of your air conditioner. My tips for air conditioners are:

  • Set your air conditioner to a higher temperature
  • Turn off your AC when you go on vacation
  • Don’t turn the temperature way down to cool the house faster
  • Keep your air conditioner serviced
  • Keep your central air outdoor unit shaded but with good airflow
  • Get a PeakSaver or equivalent device from your local utility
  • Don’t buy the cheapest window AC you can find
  • Don’t air condition the out of doors
  • Don’t air condition the attic
  • Seal your ductwork.

Let’s look at each more closely:

Set your air conditioner to a higher temperature. If living without air conditioning isn’t possible for you (or isn’t a luxury you’re willing to give up), at least raise the temperature setting. Push up the temperature one degree a day until it gets uncomfortable. Your body will adjust!

For every degree Fahrenheit you raise your thermostat, you save 6% in air conditioning costs. For every degree Celsius, you save nearly 11%.


Install a programmable thermostat on your central air, and set the temperature higher at times when you’re regularly away, such as on weekdays or weekday working hours. Set it higher at night as well, when you’re asleep; your body can tolerates higher temperatures when you’re sleeping. If you have to sleep with more than a sheet on top of you, and the air conditioner is running, you should be able to raise the temperature and toss off the covers.

Turn off your AC when you go on vacation. If you leave your house for more than 24 hours, there is no point in keeping the house cool while you’re gone. It will only take an hour or two to get down to a comfortable temperature, especially since, while you were gone, little heat was produced from cooking and other activities inside the house. You can waste a lot of money cooling the house for nobody.

If you’re terrified of arriving home to a hot house, reprogram the programmable thermostat for your central air conditioner, so that it has a high temperature setting until two hours before you’re due to arrive home. The air conditioner will hardly run while you’re away, and you’ll still be comfortable on your return. Just remember to reprogram it again when you get back, or you’ll heat up 7 days later!

For window or other room air conditioners, you can put them on a 24-hour timer so that they shut off at times when you tend to be away, such as work hours. (Some room air conditioners come with a built-in timer.) Most electronic timers have an override that lets you turn the attached device on even during an off period, so you will never have to live without cooling when you need it. Just make sure the timer can handle the amperage of your room air conditioner.

Don’t turn the temperature way down to cool the house faster. If you come home and find the house too hot, don’t try to cool the house faster by setting the thermostat really low. The house will still cool at the same rate, but you’ll forget what you did, and wake up freezing a few hours later. Even worse, if you leave the house and forget you’ve set it really low, you could be running the AC continuously for hours or days.

Keep your air conditioner serviced. If you have central air, have your unit serviced at the start of each cooling season, or perhaps even twice a year if you live in a hot climate where air conditioning is run year round. You should also change the air filter on a forced air unit whenever required – typically once a month for the cheap square filters, once or twice a year for high-end filters like the Aprilaire filter we use. A clogged filter reduces AC efficiency and puts added strain on the fan motor.

Keep your central air outdoor unit shaded but with good airflow. If your condenser unit is exposed to sunlight, plant shrubs around it, but keep enough free space around it to maintain good air circulation.

A condenser unit kept in shade is more efficient than one in the hot sunlight. If your unit is located in an enclosed or partially enclosed space (for example under a porch), you’ll save a lot on air conditioning costs if you hire an HVAC company to move it to a more energy efficient location. And don’t operate it in an enclosed space without opening the space up at least partially – you could damage the condenser motor.

Get a PeakSaver. If you have central air, you may be eligible for a token subsidy from your local utility – usually between $15 and $60 where it’s offered – if you’re willing to let the utility add a controller to your unit that will reduce its power consumption during peak electrical loads. This doesn’t make much of a dent in your pocket book – the subsidy is usually a one-time payment – but it helps your utility reduce its peak load, which in the long run saves everyone money (since peak load determines the total generating capacity needed for the grid) and means cleaner air and lower CO2 emissions (since the usual source of additional peak-load energy is coal or natural gas).

I had one of these installed on my Toronto AC unit (which I don’t actually use anymore – it’s so inefficient!). It probably didn’t save my local utility much – but it netted me a $25 cheque!

Don’t buy the cheapest window AC you can find. It’s tempting on the first hot day of summer to run off to the building center and buy that $200 window AC unit. But you’ll pay a heavy price in the long term if you buy an inefficient model. Buy only ENERGY STAR qualified air conditioners. That $200 bargain could cost you an extra $100 a year in electricity costs if it’s at the bottom of the mandated efficiency range, instead of at the ENERGY STAR range (although, to be honest, the ENERGY STAR requirements aren’t that much higher than the minimum allowed efficiency, so go for the highest efficiency ENERGY STAR model you can find).

Don’t air condition the out of doors. You really don’t make the neighborhood any cooler when you let cold air escape from your house. In fact, in the long run you make it hotter. So when a neighbor knocks on your door to chat, don’t stand in the doorway, step outside or invite them in. And never leave windows open when the AC is running.

Don’t air condition your attic. If you have ductwork running through your attic for your air conditioning, hot attic air will push heat into the ductwork, which won’t do much to cool your upstairs. This summer energy saving tip can make a huge difference to your air conditioning bill. Make sure your attic ductwork is properly sealed and very well insulated.

Seal your ductwork. Leaking central air ducts can increase central air energy consumption by up to 30%. Wherever you can access your ducts, check them for leakage while the unit is running. Seal leaks with duct tape. If the exposed ductwork shows signs of major deterioration, don’t just tape it together. Have an HVAC or sheet metal specialist install new ducts.

If the exposed ductwork is damaged, there’s a good chance that the ductwork inside walls and floors is damaged too. Depending on how bad the damage is, you may need to have it all repaired.

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