Evaluating your windows based on how energy efficient they are is imperative if you want to make sure that you would be able to minimize your energy costs as well as make your home better insulated and more comfortable to live throughout the whole year. Here are some things that you do to get the energy efficiency ratings of replacement home windows.

You should first check how much sunlight the windows you are planning to replace are receiving. This would help you in determining how much energy efficient your replacement windows should be.

As you go through your options, check the U-factor rating. The lower this rating is, the better the window is able to retain heat in your home during the colder months and keep heat out during the hotter months. Generally, the recommended U-rating for windows should not be more than .35 but for areas with warmer climates, a U-factor of not more than .60 is recommended.

It is also important to check the solar heat gain coefficient or SHGC of the windows you would be going through. This would measure the amount of solar heat that is transferred from the outside through the window and into the home. A window with a lower SHGC would mean that it allows a lower amount of warming from the sun, making it a good option for homes which are located in areas with warmer climates. If your home is located in an area with a colder climate, however, a window with a higher SHGC rating would be better since it would help you to reduce your heating bills.

Experts also recommend to check the air leakage ratings for replacement windows. The air leakage rating is a measurement of how much air can flow through the window. Energy Star recommends a rating of not more than .30 for all climates.

Another rating that you need to check in the windows would be their visible transmittance rating. This is a measure of how much visible light goes through the window. The higher this rating is, the more visible light is allowed through. The recommended visible transmittance rating for your home would generally depend on the location of the windows you would be replacing.

You should also make sure that you would be choosing windows that come with the Energy Star label, as these would be the windows that have met the minimum Environmental Protection Agency requirements or criteria, which would ensure that you would be able to lower your heating and cooling costs.