HOW TO CHOOSE AN ENERGY EFFICIENT WINDOW
The Lingo of Energy Efficiency
When replacing an existing window with a new one, a question that you should ask yourself is this – Is this new window going to be energy efficient? If you are reading this and live in Texas, you understand that the summers can get warm and the winters cold. Aside from energy savings from opting for green replacement windows, you save money and improve the overall comfort of your home. Energy efficient window may cost a little more upfront, but they will more than compensate for the initial financial costs overtime. There are many state and federal incentives available for both residential and commercial property owners. To explore State incentives visit http://www.seco.cpa.state.tx.us/consumers/incentives/
So, how do you find out if a window is energy efficient? Thanks to Energy Star, the process of choosing energy efficient windows is made easy.
A window should have both of these labels – a blue and yellow Energy Star label, and a white NFRC (National Fenestration Rating Council) label.
Energy Star is a joint initiative by the U.S EPA (Environmental Protection Act) and the U.S Department of Energy. The idea is that any Energy Star backed product (windows, in this case) should help the consumer save money and should be environment friendly as well.
The NFRC is an independent, non-profit agency that tests and certifies windows based on 5 parameters.
Any window with the Energy Star label will be energy efficient. Further, you can see and compare between different energy efficient windows on the basis of the NFRC ratings.
Take note, however, that of the 5 NFRC criteria, the Energy Star considers only the first two parameters (U-factor and SHGC) for qualifying windows as energy efficient; and usually, those are the most important ones.
The 5 parameters for NFRC ratings are –
The U-factor is used to measure the rate of heat transfer through the window – which means that it measures the insulating capabilities of the window unit. U-factor values usually are in the range of 0.25-1.25. – The lower the U-factor value, the better is the insulating property of the window.
Rule of thumb – Windows with lower values are better. Because in warm weather, they protect you against the heat from outside, and in cold weather, they prevent the heat in the room from moving out. This translates into lower cooling and heating costs.
2. Solar Heat Gain Coefficient
This measures the fraction of solar heat transmitted through the window. Values can range from 0-1. If the SHGC value is low, less solar heat is transmitted through the window, meaning it blocks out heat caused by sunlight.
Rule of thumb – In cooler climates, this rating should be higher. For warmer climates, this value should be low.
3. Visible Transmittance
It refers to the amount of light that can pass through the window. The values can be measured on a scale of 0-1. A higher VT allows more passage of light through it.
Rule of thumb – If you want your room to be brighter, which is usually the case, go for the window with a higher VT value.
4. Air Leakage
Air leakage measures the rate at which air passes through the window. This is measured by the amount of cubic feet of air passing through one square foot of window area per minute. The lower the air leakage value, the lesser is the passage of air through the window, i.e. lesser air leakage. Most industry standards require a maximum AL of 0.3.
Rule of thumb – Air leakage should be as low as possible, so a lower value is what you want.
5. Condensation Resistance
This is a measure of how much moisture/water build up the window allows on its surface. The higher this rating is, the more resistant the window unit is to moisture building up. It ranges from 0-100.
Rule of thumb – A higher value is better. Moisture accumulation can cause damage.
A very important factor when choosing the energy efficient windows that you will replace or newly install, is the installation itself. Poor installation can result in energy loss. It is important that the window installers are experienced and use best practices for maximum energy and cost saving results.
Metroplex Windows & Glass has been providing energy efficient window replacements and quality installations services in Dallas and throughout the Metroplex for nearly 20 years. We are committed to quality service, from pricing to installation. We will help you to decide what the best options are for you and your home.
Call Metroplex Windows & Glass Today.