Window air conditioners can help save on summertime cooling costs. Central air conditioners and refrigerators are the two largest consumers of energy in the average home. Supplementing or replacing a central air conditioning system with a window unit can dramatically reduce your electricity consumption and overall energy costs. By selecting the proper window unit for your needs, and by setting the unit to operate at peak efficiency and during proper times, you can expect to save big on your summer cooling bills and conserve electricity at the same time. Measure the room that you want to cool using a window unit by multiplying the length of the room by the width of the room. This will give you the room's square footage. Write down the total and bring it with you when shopping for a new window unit. Compare the labels on the side of the window units to find the unit that best matches the square footage of your room. Purchasing a window unit that is designed for larger rooms will consume more electricity than a smaller unit that is designed for a smaller room.

Select the unit that best matches your needs for the most energy-efficient unit. Compare the labels on the window units that best match the size of your room for their seasonal energy efficiency ratio, or SEER rating. The higher the number, the more energy efficient the unit is. If there are multiple options that fit the size of your room, selecting a unit with a higher SEER rating will save you more money on electricity bills over time. Set the unit's programmable timer, if it has one, to 78 degrees. This is a generally comfortable temperature that requires less energy to reach and maintain than cooler temperatures. For every one degree increase in the air conditioner setting, you will use between 1 percent and 3 percent less electricity (See Reference 3). Set the programmable timer to operate only during the hours when you are home. It's a huge waste of electricity and money to cool a room that doesn't have any people in it. Setting the timer to begin when you arrive home from work and to end when you leave for the day will save money and energy.

Set a mechanical timer at the AC outlet where the air conditioner plugs in if the unit does not have a programmable timer. Set the unit to the "On" position and set the mechanical timer to turn on when you arrive home and off when you are away. This is a simple alternative for units that don't come with as many features. : /Getty Images Suggest a CorrectionA through-the-wall air-conditioning unit will cool a single room. In climates with just a few hot, humid nights each summer, it doesn't make sense to use central air conditioning to cool an entire home. For those few nights, many homeowners invest instead in an air conditioner that mounts in a bedroom window or in an opening through an exterior wall. When it comes to the cost of cooling a bedroom this way, doing the math is straightforward. Electricity Costs Check your electric bill to determine your cost per kilowatt-hour (kWh). Depending on where you live, the rate can range widely. The average rate in the San Francisco area, for June 2013, was 22.8 cents per kWh;

the national average was 13.7 cents per kWh. Power Usage An appliance's nameplate displays the amount of power it draws while running, measured in watts. A good estimate for a medium-sized window or wall air-conditioning unit is 900 watts. Power Cost Because you are billed for units of kilowatt-hours, you need to estimate how long the unit will run. For example, a 900-watt air conditioner running for eight hours would consume 7.2 kWh (900 watts * 8 hours, divided by 1000). cost to replace hvac unitIf you pay 22.8 cents per kWh, running such an air conditioner will add about $1.64 per night to your power bill, plus taxes and fees. ac window unit in garageReferences Bureau of Labor Statistics: Average Energy Prices, San Francisco-Oakland-San Jose - June, 2013Seneca Air Conditioning: How Many Watts Does an Air Conditioner Use?does spraying your ac unit with water help

Summer 2016 is off to a sultry start, and that means one thing for millions of people: air conditioning. And while we may take A/C for granted, it's generally an expensive luxury. Americans spend more than $11 billion a year on electricity to cool their homes with air conditioning. That accounts for at least 6% of all energy used in some homes. If you're shopping for a new air conditioner, you'll notice quite a few different sizes and models. Here's a quick primer on staying cool and keeping your wallet from overheating while picking out an A/C unit. Chances are you already know that BTU stands for British Thermal Unit, and the more BTUs an air conditioner cranks out, the stronger its cooling power. (No disrespect to the Brits, but maybe we need an American Thermal Unit, where 1 AMU corresponds to 1 square foot?) Lobbying for the AMU aside, you don't have to guess how much BTU power you'll need to cool your space. Instead, see the chart below, taken from a handy Energy Star document.

It simply correlates the area you want to cool into BTUs per hour. So for example, an air conditioner with a rating of 8,000 BTUs can cool a room that's 300 to 350 sq. ft., or one that measures about 18 ft. x 18 ft. Of course, you still have to measure your room, but we trust you can work a tape measure and apply this formula: area equals length times width. For irregularly sized rooms, you can always estimate by breaking down the room into smaller geometric shapes, and calculating the size of those. It's one thing to run an air conditioner in your room. They generally start at about $40 a piece. The nice thing about a ceiling fan is it can make you feel anywhere from 3 to 8 degrees cooler. Easy, Breezy Buying: Our Comprehensive Guide to Ceiling and Room Fans When you buy any air conditioner these days, it should come with one of those bright yellow Energy Guide stickers on the box that tells you exactly how much the unit will cost to run. Take this into account, as it's part of your total cost for both buying and operating the unit.

Most folks think bigger is always better, but not so. According to the Energy Star folks, "Air conditioners remove both heat and humidity from the air. A properly sized unit will remove humidity effectively as it cools." Damp and clammy isn't much better than sweltering. If your unit is more than 10 years old, seriously consider replacing it. According to U.S. Department of Energy estimates, you'll use about 10% less energy with a new Energy Star appliance than one without that designation. Depending on how long you hold onto that new unit, you could save $60 or more over its lifetime in energy costs alone — a de facto rebate just for upgrading to an Energy Star model. The key number to look for is the Energy Efficiency Rating (or EER): The higher the EER, the more efficient the unit. An energy-efficient unit will cycle the compressor on and off so it doesn't operate continuously. And Energy Star central air units are 14% more efficient on average than standard models.

If you're thinking about upgrading to central air, it's easy to beat yourself up for being an energy hog, or to get intimidated by the sticker price. 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 for a home. Well-designed central systems also win out in terms of being able to filter the air for allergens and pollutants, and for controlling humidity. Again, keep in mind that window units aren't necessarily more energy efficient than central air units. A less efficient system will cost you more to run. It's easy to think that buying a new air conditioner or two will solve all of your summer cooling problems. With central units, for example, a programmable timer or thermostat can save you about $180 every year in energy costs by regulating the temperature when you're out of the house, and by turning on only when you return home. With window units, air filters get dirty, and fast. Regardless of the type or age of the unit, you should change your filters after every 90 days of use.

10 Things You Should Throw Away Right Now What's more, you'll use less energy cooling down a room by keeping direct sunlight out during the day. Sunlight can raise the room temperature by 10 to 20 degrees. The less heat gets into your home, the less you have to pay to remove it. It just so happens that drapes block sunlight and heat better than blinds. DealNews keeps an ever-updated list of air conditioning deals for you to peruse and compare. For instance, BJ's Wholesale Club offers this LG 10,000 BTU Window Air Conditioner ($249.99 with free shipping, a low by $49). Of course, this time of year, A/C sales are as plentiful as backyard barbecues. The worst thing to do is feel a heat wave hit you in the face, rush to the first store you can find, and buy the first unit you see. Do some comparison shopping, checking out multiple units for price, efficiency, reliability, and features. The few minutes you spend comparing notes and using your shopping smarts will do more than show off how cool you are.