A Guide to Energy Efficient Windows & Doors in Northern Virginia

Your windows and doors have more of an impact on your home’s energy efficiency performance than you might think. The type of light they let in, the fit, the material, and how they’re constructed can be the difference between an energy efficient home and one that causes higher utility bills, poor temperature control, and even unhealthy indoor air.

Replacing or upgrading your doors and windows, combined with proper installation, can go a long way in making your home in Northern Virginia or the D.C. metro area more energy efficient and increasing its value. 

What Type of Windows are the Most Energy Efficient?

Windows are considered energy efficient when they reduce or eliminate the amount of heat transfer. This allows your family to run your HVAC system considerably less often, cutting down on how much energy you consume. 

The best energy-efficient windows will have two or three panes, have a Low E coating on the panes, a gas fill between the layers, and ideal framing materials.

The most energy-efficient windows on the market are those that have been rated by ENERGY STAR. The ENERGY STAR ratings for windows will always be displayed on a label on each product. What the rating measures can tell you more about what makes it energy efficient. To get the full benefit of energy-efficient windows, look for the following qualities and note their scores. 

1. U-Factor

The U-factor is related to insulation, or the rate of heat loss from a building. According to the EPA, the lower the U-factor, or U-value, the better a window insulates your home in Northern Virginia. Most products fall between the 0.25 and 1.25 range. The best energy-efficient windows will fall below 0.3. 

2. Solar Heat Gain Coefficient

The Solar Heat Gain Coefficient (SHGC) measures how much solar heat passes through the glass or vinyl into your home and is expressed on a scale from 0 to 1. High SHGC windows indicate that the glass is permitting a significant amount of heat into your house, which could mean having to run your air conditioning system more often. Low SHGC numbers indicate the glass is preventing a large amount of solar heat from entering your home's interior.

A good SHGC score depends on your region. In the Southern regions, a lower score is ideal, while in the colder, Northern regions, a high score allows more heat gain during the cold months, which can be beneficial in reducing the amount of heat your HVAC needs to produce. This is why the SHGC and the U-Factor scores are usually taken in relation to each other when the window is given a rating. 

3. Visible Transmittance

Visible transmittance (VT) is expressed as a number between 0 and 1 and measures how much visible light can pass through the glazing material on your windows. You want a high VT to maximize sunlight and be able to use artificial light less frequently, reducing the amount of energy your home consumes. Double- and triple-pane windows usually have a VT value between 0.3 and 0.7. 

4. Low-Emissivity 

Low-E glass windows are designed to maximize the light coming into your home while minimizing UV rays and infrared rays that can damage interior materials. The Low E coating on a window is a microscopically thin layer of metallic oxide that is added to the glass surface to reduce the amount of heat that is emitted through a window. The coating reduces the amount of energy your HVAC system uses to keep your house cool or warm, compared to windows without this coating. 

5. Air Leakage

The Air Leakage (AL) score measures the rate of air that is allowed to leak through the window. An acceptable score is equal to or less than 0.3. The lower the score, the less your HVAC system will have to work to keep your home comfortable. 

6. Condensation Resistance

Condensation Resistance isn’t required for window makers to consider, but the NFRC includes it in their testing when possible. It measures how well a window resists the build-up of condensation and reports the score on a scale from 1-100, with a high score being the goal. 

How to Choose the Right Windows and Doors for Your Home

For its ENERGY STAR program, the Environmental Protection Agency (EPA) has created a map that breaks the United States into four separate regions, or climate zones. The right windows, doors, and skylights for your residential property can vary, based on your region. For example, Northern Virginia and Washington D.C. are in the North-Central Zone. The EPA’s suggested ratings for this zone are:

• Skylights: U-factor at or below 0.53 and SHGC at or below 0.35
• Windows: U-Factor at or below 0.3 and SHGC at or below 0.4

You can evaluate the U-factor, SHGC numbers, and other characteristics when looking for vinyl and glass windows from a variety of manufacturers. For example, both ProVia and Marvin Windows offer several product lines that balance quality and comfort with energy efficiency. 

These manufacturers have various styles, shapes, framing materials, glazing and weather-stripping options, spacers, and fillers to help you find high-performance windows that will enhance the energy efficiency of your home and look great. 

Do Energy-Efficient Windows Increase Home Value?

Replacement windows and installation in the Northern Virginia and Washington, D.C., area can cost around $25K per ten windows, according to the Cost vs Value Report. The return on investment is between 64% and 66%, depending on the material you choose. The cost of energy-efficient windows is made up over time by reducing your energy bills, keeping your interiors in great condition, and improving your indoor air by keeping mold and mildew at bay. 

Installing Energy Efficient Doors & Windows in Northern Virginia

The windows and doors you select for your home renovation must also be properly installed to maximize the advantages. Our team at Window and Door Showplace have built a reputation over the decades for excellent and efficient installation. Not only do we have access to some of the best product lines, but we also have the right tools and techniques to install them properly, helping you maximize the return on your investment and obtain the long-lasting benefits of energy efficiency. Contact our team at Window and Door Showplace today to schedule an in-home assessment and consultation.