Everyone loves a picture window, but it can greatly affect the efficiency of a house. The bigger the window is, the less efficient it is, and the more windows there are in a house, the more energy will be lost. If you are set on having a window overlooking a scenic vista, you can invest in energy-efficient window models to reduce the negative impact of lost efficiency.

Window placement also affects the amount of heat absorbed. Windows on the western side of a house heat up homes like an oven in summertime, but the same window may make that room warm and comfortable during the winter months.

Crank windows that operate using cranks or levers are the most efficient designs, as they allow the window to seal tightly against the frame. Double-hung windows that slide up and down or sideways are less efficient because they must be loose enough to allow sliding, which also means they are loose enough to let air in and out.

Double-pane windows made using two sheets of glass with an air cavity in between are much more efficient than traditional single-pane windows. In cold climates, when the space between the panes is filled with argon and the glass is covered with a low-emissivity coating, heat reflects back into the living area. In warm climates, windows with a similar coating reflect the heat back outside, preventing it from settling in the house.

One factor to keep in mind is that the chemicals used to make the coating may be harmful to the environment, causing some of the same problems as pesticides. Windows with low-emissivity coatings may be more difficult to recycle because the treated glass does not easily fuse with other glasses.

The standard skylight design has changed as well, making it more energy efficient. Canister or tube models let light in while eliminating the potential for leaks and heat seepage. Regardless of what type of windows you get, they need to be installed properly to ensure a tight seal.

Check doors to make sure they shut snugly. This keeps the temperature even inside the house. Doors should fit properly in the frame and can include magnetic weather stripping to decrease drafts. More important, to reduce the time the compressor or furnace is running, shut the door.