An AC unit is designed to cool your home once your home has already started to heat up. Moreover, if your home is heating up faster than your AC unit can cool it back down, your home will heat up despite the fact that your AC unit is constantly running. As a homeowner, the fact that the money you spend on operating your AC doesn't seem to go toward keeping your home cool can be immensely frustrating. To give your air conditioning unit a fighting chance, you need to take steps to reduce heat gain in the first place. 

How Does Your Home Heat up?

There are both internal and external sources of heat gain. For example, every electrical appliance in your home will release some heat into the surrounding air. You can reduce some heat gain by limiting how much you use these appliances, especially your oven. On the other hand, your biggest concern should be the heat leaking in from the outside. Your roof and windows are the two biggest sources of external heat gain. 

Energy-Efficient Roofing

To choose a roofing material that will help to keep your home cool, you have to pay attention to both color and material. Dark-colored roofing will absorb more of the sun's energy than light-colored roofing. It may seem like a small thing, but white roofing can reduce your cooling costs by as much as 20%. Some roofing materials natural reflect the sun's energy. For example, metal roofing is naturally reflective and when treated with an emissive coating, a metal roof can reduce your cooling costs by up to 40%. If you are building a new home or replacing the roof on an older home, make sure you consider cooling costs be when choosing your roofing material. 

Windows that Filter out UV Rays

Replacing your roofing comes with quite a cost, so you should not feel like you have to replace your roof just to keep your cooling costs down. Instead, you should start with the second source of heat gain—your windows. The key here is to choose material that will filter out the sun's UV rays which would otherwise stream through your windows and heat up you home. Low-e window film, for example, will filter out up to 99.9% of the sun's UV rays, reduce heat gain, and thus decrease cooling costs by up to 23%. 

The above examples should be enough to illustrate what really drives cooling costs. Heat gain can leak into your home in a number of ways, and every step you take to reduce heat gain will help to reduce cooling costs by keeping your home cooler. Especially if it seems like your AC unit is not keeping up with heat gain, you should take steps to reduce heat gain.