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Energy Efficient Windows Save You Money


Save Money Heating and Cooling Your New Home In Texas

It’s a story I've heard time and time again. Someone figures out they can save a little money during a new home build by using cheaper windows. Everything is great until the first hot summer or cold winter that comes around, and the homeowner notices how uncomfortable it is to sit anywhere near the windows. They immediately notice the discomfort, and it’s not long before they notice the utility bills that make them equally uncomfortable. Energy efficient windows can make your home more comfortable year round and will often pay for themselves in only a few years. Riverside Homebuilders are committed to saving you a small fortune on your utility bills. Here’s a quick explanation of how windows play their part.

Windows don’t just allow you to take in the beautiful view. They let in heat and cold, and they also let these elements out. A typical home can lose 30% of its heat through the windows, or in the case of a hot summer, require the AC to work 30% harder to maintain the same comfortable temperature. Energy efficient windows help insulate your home 24/7, all year long. That adds up fast. The savings will pay for the windows in a few years, but they can be realized immediately when constructing a new home, as often the builder can save money by using a smaller heating/cooling system. And don’t forget about the lower replacement/maintenance costs that come from using more durable windows…

Keeping Comfortable:

There are four ways that windows let energy move through them. Conduction, convection, radiation, and air leakage.

Conduction is the movement of heat between things that are touching each other. Think of grabbing a hot car steering wheel. In that moment, your pain is caused by conduction. Conduction isn't just limited to solid objects. Liquids and gases conduct heat too, and that’s where multi-glazed windows with low conductance gas between the panes come in. They literally work the same way an oven mitt does.

Convection is the movement of fluids caused by the temperature affecting the density of the fluid. It’s the “hot air rises” principal. On a cold day, the air in your home rubs against the windows, cools off and becomes more dense. This causes it to drop to the floor and new, warm air to take its place. This cycle continues and causes the cold draft near the window and makes you run to go turn up the heat. Reducing this effect will make your home more comfortable and not require you to turn the heat up as high.

Radiation has the connotation of nuclear fallout, but it’s actually something you deal with every single day. When you feel the sun heating your skin, you are feeling radiation. The dew that can form on your car at night is caused by your car actually radiating heat back into space which makes it colder than the air, and water condenses on it. Low-E coatings on windows work by reflecting certain wavelengths of light, keeping radiant heat transfer to a minimum.

Air leakage is responsible for a huge portion of a home’s energy losses. Air leakage through windows is a major factor here. Choose well designed windows with high quality weather stripping and good clamping mechanisms to keep air from escaping. Windows come with ratings for air leakage, usually expressed in terms of cubic feet per minute per square foot of window space. Choose windows with ratings of .30 cfm/ft^2 or less to minimize your air leakage. The lower the rating, the better.

The sun gives off a lot of energy, and only a small portion of it is in the form of visible light. When you look out of a window, you want the visible light to come through clearly, but you don’t want the rest of the sun’s energy coming through, at least in warm climates like we have here in Texas. Low-E glass coatings are designed to allow the visible light through but reflect the infrared and UV components. They can also serve to trap heat inside a home in colder climates, you just change which part of the window is coated. Think of it like a one way mirror. If you coat the outside, it reflects heat back out. If you coat the inside, it reflects the heat back in.

The coatings improve the insulating performance of a window about as much as adding a pane of glass. Low E coatings combined with low-conductance glass fillings boost energy efficiency by nearly 100%. When you consider the cost to add these features is only about 5% of the total window cost, the choice is clear.

There are other factors to consider when shopping for energy efficient windows, but these will definitely get you started. For a very in-depth look at them, check out this amazing article at http://www.finehomebuilding.com/how-to/articles/understanding-energy-efficient-windows.aspx.

And, take a look at some of the other features we use in our homes to make your home more energy efficient and save you money: