Here s another great tip from BobVila.com. Get a jump on the hot weather by making sure your room air conditioner s up to the challenge. Before you pull it out of storage, consider the age of your air conditioner. Efficiencies have improved so much that replacing an old clunker from the 70s with a new 10-seer unit could cut your cooling costs in half. Regardless of age, all units need maintenance every season and about once a month during the season. First, unplug the unit and see your manual for instructions on discharging the capacitors to avoid a shock. Dirt is your air conditioner s worst enemy. Clean out the drain ports with a length of wire. Vacuum the evaporator and condenser coils and gently straighten any bent fins with a fin comb, which you can get at most hardware or plumbing supply stores. Remove the filter and wash and dry it thoroughly or replace it with a new one if it s the disposable kind. Run the unit for a few minutes to see how it performs. If the fan s making noise, try tightening the blade s set screw as well as the bolts that hold the fan unit to its housing. If the power cord, switch or thermostat is worn or faulty, you can replace it without having to buy a new unit. The coils, compressor and motor are all sealed and should be repaired by a professional. On the bright side, if you do this check early, you won t be put on someone s waiting list in 90-degree heat! Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com

Here s another great tip from BobVila.com. Choosing a room or unit air conditioner wisely and installing it correctly can keep you from getting hot under the collar this summer. Room air conditioners are rated by the number of BTUs, or British thermal units, of heat that they can remove per hour. Contrary to what you might think, it doesn t make sense to run out and buy the most powerful unit you can find. You could wind up spending much more than you need to. Upgrading to the highest efficiency you can afford, however, is a good investment. In very hot climates you need an efficiency rating of 10, but 9 will do in milder climates. To calculate the number of BTUs you need, measure the room you re cooling and multiply by 35. A room that s 12 x12 or 144 square feet, for instance, needs a unit with a capacity of around 5,000 BTUs to keep it cool. If you ve got a shady window to install the unit, you can lower that number by 10 percent. For a sunny window, add 10 percent. If it s in the kitchen, add 4,000 BTUs. And if it s a room used by more than two people during cooling hours, add 600 BTUs per person. Most room air conditioners can be plugged into a standard 110V 15- or 20-amp circuit as long as it s not shared with any other major appliance. Larger 7.5-amp units need their own dedicated circuit. Make sure to measure the window you re installing in before you buy. While it should come with expandable filler panels, you ll need weatherstripping and tape to seal the unit to the window and keep heat from leaking in. Have some spare lumber and screws handy in case you need to build up the window frame or sill to accommodate the unit. Most importantly, have a friend help you. Even small air conditioners are heavier than they look and you don t want to drop the unit out the window. Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com

Here s another great tip from BobVila.com. Before you crank up the A/C this summer to keep cool, try a little old-fashioned ventilation first. Just keeping air moving can make your home feel much cooler. But it goes beyond opening a window. There s a little science to it. If you live where the nights are cool, keep your house sealed during the heat of the day. If it s well-insulated, it should only heat up about a degree an hour. Open windows and circulate cool air in the evening and early morning. Get some cross-ventilation going by opening windows on opposite sides of the house. Homes designed with cupolas, clerestory windows, vented skylights or even attic vents have the ability to create what s called a thermosiphon. Hot air escaping from the top of the house pulls warm air with it from the rest of the house and cooler air through lower windows, creating a constant cooling flow. Take advantage of those features or install an attic fan to create the same effect. It helps to minimize the heat you generate inside the house by using the oven, dishwasher and dryer in the evening or early morning hours. Even light bulbs can heat things up, so making the most of the daylight is both cheaper and cooler. If you still can t get the air moving, there s always the underappreciated window fan. For much less than it costs to run your air conditioner, a fan can give you the summer breeze you re looking for. Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com

Electrician Harry Cunningham and Kim Hansen of Square D / Schneider Electric join Bob to explain the electrical box that supports the household power and backup generator. Two power sources feed into the service box -- the utility and the generator. There is a safety check in place to prevent the generator from automatically taking over the power load or feeding out into the street to power the neighborhood. The switch in the box must be flipped to protect power from surging through the outlets when work is being performed or the environment is unsafe. The generator allows for flexible power and the opportunity to switch between circuits. The homeowners can decide to power up an air conditioner during a storm, switch circuits to do laundry, or power up the TV and family computer. In an emergency, the system allows homeowners to tailor their energy use to suit the needs of their home and family.

Kevin Callahan from Sears joins Bob to talk about the new Kenmore air conditioning condensers that will be installed. The condensers are Energy Star rated and have a life expectancy of over 15 years. Callahan explains the unit's internal components, starting with the copper coils that contain the unit's refrigerant. Heat is transferred out through the fins around the inside edge. These condensers are 3 1/2 ton units (one ton = 12,000 BTU's). Callahan also talks about the SEER rating, the Seasonal Energy Efficient Ratio, which is the measurement of the product's energy efficiency and helps determine its Energy Star rating.

House eleven of the Elmwood project. The air conditioning system for the third floor exercise area is installed.

Bob catches up with Mike Donaghey from American Standard behind the barn to learn more about the compressors. The units are part of the barn's air-conditioning system. They dissipate the heat from inside. The units have a powder paint finish and ceramic-coated screws to prevent rusting for safety as well as aesthetic reasons. Inside the lid is a little motor and a fan and on the interior walls is spined fin - a patented heat transfer agent that's essentially the copper pipe through which the refrigerant flows. Mike takes the sound jacket off to show Bob the scroll compressor which is nestled deep inside the unit. Scroll compressors have now replaced reciprocating compressors because they are more efficient. This a a 12-SEER unit (SEER in an acronym for Seasonal Energy Efficient Rating). The government has mandated that in five years this will be the minimum rating allowed. The compressor and coil both have 10-year warranties but can last much longer depending on the part of country. Rusting out of the casing -- especially with exposure to salt air -- is one big issue with life expectancy but aluminum to aluminum helps as does the powder coating.

A well-maintained air conditioner will run more efficiently, saving you money on utility bills.

Ron Ford from Kohler shows Bob the 12 killiwatt backup generator that has been installed at the Punta Gorda, Florida, home. Backup power is essential in a hurricane to prevent moisture buildup and damaging mold growth. Advances in design mean that home generators now come in smaller, quieter packages. With record destruction from recent hurricanes, Ford says that generator sales have increased 600 percent in Florida alone. The Kohler generator is powered by a reciprocating gas engine that can be powered by natural or LP gas. Ford explains how the design has been enhanced to provide clean power that is suited to advanced electronics like plasma televisions and computers. The generator costs about $7,500 installed.

Here s another great tip from BobVila.com. What you grow in your yard can actually keep your air conditioning costs from growing out of control this summer. Most people know that planting a tree to shade your house is a great way to keep it cool. But contrary to what you d assume, the south-facing fa ade is not the best place for a tree. In winter, the south fa ade is the one that gathers the most heat, but that s not true in the summer. To prevent the most summer heat gain, plant trees to the east or west of the house to block low early and late-day sun. Deciduous trees work best in colder climates since they obligingly lose their leaves at the start of the heating season. Be sure not to plant trees where their roots could damage septic systems, water lines or your foundation. Plants have a kind of built-in air conditioning system called evapo-transpiration. Foundation and yard plantings can really lower your home s temperature if you keep shrubs a few feet away to allow air to circulate. And don t plant a row of them where they block the flow of air from cooler areas like valleys, ponds or woods. Vines on a trellis set a few feet from the house or on a pergola over the patio will also create shade and cool the air naturally. Vines grow faster than trees and are great for color and privacy as well. Replacing paved or bare areas in your yard with low ground covers can turn down the heat by 10 degrees. But before you plant groundcovers, shrubs or trees, find out which ones do best in your area. Hardy natives are more likely to thrive with less water and fertilizer. Work with nature rather than against it and stay cooler this summer! Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com