Savings Experiment: Cooling Your Home for Less




When summers get as hot as this one, it’s difficult to imagine what people did before air conditioning existed. Swimming holes, hand-held fans and ice cubes down your back will only go so far when sooner or later, you have to return to the confines of some stifling domicile that badly needs frosty air.

And while we may take air conditioning for granted, it wasn’t that long ago — 1881, to be precise — when a team of naval engineers built a cooling contraption to comfort a dying President James Garfield. While the device — which blew hot air upwards and employed rags soaked in freezing water — could lower room temperatures by 20 degrees, it also ate up a quarter-million pounds of ice a month. (Think of all the Pina Coladas they could’ve made instead.)

Modern air conditioners wouldn’t become commonplace until the 1920s, yet one enigma remains: figuring out how to most efficiently cool a room or a home. Window units or central air? Do ceiling fans really help? Are there other novel ways to make sure my living space stays cool, so I can use air conditioners less? One thing’s for sure: Savings are always chill, so let’s crank up some righteous coolness with this latest installment of the Savings Experiment.

If you’ve gotten sticker shock from your latest electric bill, you may already suspect that Americans spend billions of dollars a year on electricity to cool their homes with air conditioning — which accounts for at least 15% of all energy used in some homes, and in warmer climates can represent up to 70% of your summer electric bill.

Here’s another way of looking at it: While a floor fan uses only 100 watts on the highest speed, and ceiling fans use only 15 to 95 watts depending on speed and size, a window unit AC uses 500 to 1440 watts — and a 2.5-ton central system uses about 3500 watts. That’s a massive amount of energy and suggests that if you’re using air conditioners alone to cool your home, you’re not thinking in economic or environmental terms.

Let’s get this straight: We’re not asking you to give up your beloved air conditioner if it keeps you cool and dry during an insufferably hot, humid heat wave. But with just a little bit of planning you could start to bring those power bills back down to size. Just because the thermometer is soaring doesn’t mean your debt has to follow suit.

Costing less than a penny an hour to run, ceiling fans will have an immediate impact on your domestic comfort once you buy and install them. They start at about $40 a piece and you can find them at just about any hardware store. Home Depot stocks more than a dozen models of Hunter fans (some with lighting fixtures) below $100.

The nice trick to ceiling fans is that they don’t need to run while you’re out of the room. The fan cools you by triggering evaporation from your skin. Since the fans force hot air down and away from you, using a ceiling fan will make you feel anywhere from 3 to 8 degrees cooler. Be sure to factor in the cost of installing the fans, if you’ll need help from an electrician, and shop around for bargains, as sales on fans are plentiful this time of year.

Speaking of fans, bedtime is a big time for cooling down. Ironically, most people prefer to sleep with covers, even though that traps the heat your body creates. So you can run an expensive AC to cool the whole house just so you can be comfortable under the covers … or simply use a bed fan. It’s a small, gentle fan that operates right under the covers. You can order one for $99.95 at

Read on, and you’ll see that some of these strategies won’t cost you a cent — though they can save you quite a bit of money, as well as wear and tear on your air conditioning units.

Make sure your doors and windows are well sealed
You’ll pay a lot more to cool your home when the cold air escapes easily. Do-it-yourself weather stripping for doors and caulk for windows is easy to install, and cheap. Also make sure to caulk around the holes where pipes go into the wall under sinks.

Keep direct sunlight out
Direct sunlight can raise room temperature by 10-20 degrees. The less heat gets into your home, the less you have to pay to remove it. Drapes block sunlight and heat better than blinds.

Use solar screening
Solar screening is a special mesh that reflects much more sunlight than regular screening. It’s available at home improvement stores, and can block 60%-70% of heat from sunlight. Get screens that don’t block too much light, because if your building gets too dark and you wind up using more lighting inside as a result (which generates heat), you’ve defeated the purpose of the screens.

Use reflecting film on your windows
About a third of a structure’s cooling requirements are due to solar energy entering through glass. Reflective film bounces the sun’s heat from your windows, and can block 40-60% of heat and modern films reflect heat away without blocking the light, so you can still have nice, bright rooms. Film costs about $3-$7.50 per square foot installed, or do-it-your-selfers can get the material from a home improvement store for about $1-$2 a square foot. The payback period is 3 to 5 years (or less, if the cost of electricity continues to rise). It’s critical to use film that blocks very little light, otherwise you’ll run more lighting inside.

Use less light
Lights create a lot of heat, which your AC system has to remove. Replace your lights with compact fluorescent (CFL) bulbs, which use 75% less energy and create 70%-90% less heat at the same time. Regular lights give off 10% light and 90% heat, while CFLs give off 90% light and 10% heat. Whatever kind of lighting you have, turn it off when you’re not using it. It’s not just using electricity, it’s also adding heat. (That said: Don’t try to heat your home with lights in the winter; lighting is an inefficient way to generate heat.)

Delay your chores
Any heat generated in your home has to be removed by your cooling system, so avoid generating heat inside your home whenever possible. Your dishwasher, washer, and dryer give off heat when they’re in use, so run them in the early morning or late evening. Your air conditioner won’t have to work as hard to offset the heat produced by the appliances. What’s more, running those appliances during off-peak hours reduces the stress on the power grid, helping to prevent brownouts. You might also pay less for the electricity if your utility charges less per kilowatt-hour during non-peak hours.

Shower more
Yes, it’s true: Cool showers can help keep you comfortable for quite some time afterward. Right before bedtime is an especially opportune time to jump in, as it sets the stage for a restful night’s sleep.

It’s true that central units will use a lot more power than, say, a single window unit on each floor of a two-story dwelling. But if you have more than two rooms to cool, then your best bet is to go with a central unit, which also provides long term resale value and humidity control. “Well-designed central systems win out in terms of being able to filter the air for allergens and pollutants, and for controlling humidity,” says Mike Rogers, a senior vice president with Green Homes America, a company that provides residential home performance contracting solutions.

If humidity isn’t your problem but you’d just like to cool your home, you could get away with one window unit on each floor, if your home is well insulated. (Check out this Energy Star document to figure out the right-sized air conditioner based on a room’s size.)

Keep in mind that window units aren’t necessarily more energy efficient than central air units. A window unit that is too small to cool a room may run continuously, wasting energy. Central air units cool multiple rooms more quickly and filter out airborne particles — but they also use more power than window units. When you’re shopping for a central air conditioning system, make sure the SEER number (seasonal energy efficiency ratio) is 13 or better (14 in warmer climates). A less efficient system will cost you more to run.

If you’d rather go with window units, then consider these factors:

  • Look for an EER (energy efficiency ratio) of 11 or higher for room air conditioners. Today’s ACs use 30%-50% less electricity than 10-year-old models. If you replace an old EER 5 unit with a new EER 10 unit, you’ll cut your cooling costs in half. You should also look for the “EnergyStar*” and “EnergyGuide” labels when purchasing a window unit. The higher the energy efficiency rating (EER) the more efficient the unit will be. An energy efficient unit will cycle the compressor on and off so that it doesn’t operate continuously. (U.S. homeowners can get a 30% tax credit for installing an EnergyStar-rated AC.)
  • Make sure your AC is sized properly. It is important to use the right size AC, and replacing your old AC with one of the same size is often a mistake. Air conditioners are rated according to the amount of heat (measured in British thermal units, or BTUs) they remove from the air per hour. Select a unit that removes an average of 20 BTUs per square foot of living space or higher, depending on how much sunlight the space receives, how many large appliances are located within it, and how many people occupy it. An AC that’s too small (or too big) will waste energy.
  • Clean your AC filter every month. A dirty filter makes your AC work harder, which uses more electricity. Regardless of the type or age of the unit, be sure to change filters after every 90 days of use.


  • A programmable thermostat is ideal for people away from home during set periods of time throughout the week. Through proper use of pre-programmed settings, a programmable thermostat can save you about $180 every year in energy costs.
  • Run your air conditioner(s) less frequently. You can reduce your annual energy bills by about 10% by turning up your programmable thermostat 10º to 15º F when you’re out of the house.
  • Energy Star-qualified models use about 25% less power than ones made before late 2000.
  • Don’t lower the air conditioner’s temperature when you turn it on. It won’t cool the room any faster, but it will use more energy. On humid days, set the fan speed on low to remove more moisture from the air.

When it comes to keeping your space cool for the least amount of money, it pays to apply the same sort of consciousness you would use when taking care of you car. Just as you would always be on the lookout for how much gas you have in the tank or air in the tires, cooling your home is much more than a “set it, forget it” proposition.

Take a look at those electric bills to see if you’re spending more than you like. Read over these tips and see if applying a few, or more, could make a big difference. Not only will your wallet thank you, but you can still get through the season in relative comfort.

Which, if you ask us, beats hauling out thousands of rags and a quarter million pounds of ice.

More from the Savings Experiment:
How to Save on a Mattress
How to Nail a Manicure Deal
Get Your Grill On and Save


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