Windows account for up to 30% of residential energy use (heating and cooling). Therefore, energy-efficient windows are an essential consideration for your home. What’s more, taking steps to reduce energy loss through your existing windows makes your home comfortable. It will also save you money on energy bills.
If you wish to improve the level of comfort in your home, especially in cold winter months, you can replace your existing windows to improve efficiency.
So what are the best energy-efficient windows in the Twin Cities?
How to Determine Window Energy Efficiency
Fortunately, you have everything you need to figure out a window’s energy efficiency on its National Fenestration Rating Council (NFRC) rating. The NFRC operates a voluntary national program to test, certify, and label windows, skylights, and doors based on energy performance ratings. Thus, the NFRC rating is a reliable way to determine a window’s energy properties and compare products.
You can find the NFRC rating on all ENERGY STAR® qualified products (windows, skylights, and doors). When shopping online, compare different window products using NFRC’s online Certified Products Directory or ask for Energy Star when ordering. However, ENERGY STAR only uses solar heat gain coefficient and U-factor ratings as the basis of its qualification.
Features of Energy-Efficient Windows
Energy-efficient windows rely on several features, which affect:
The right window will:
- Give you the aesthetic look you want
- Offer energy efficiency
- Provide weatherproofing and long-lasting qualities
Certifications are one consideration when you are looking for energy-efficient windows. Look for NFRC or ENERGY STAR® certifications. They show which zones a given window is rated for and if it’s efficient for your area’s climate.
Window glass (glazing) also affects a window’s energy efficiency. Single-pane glass allows easy transfer of heat and is rarely energy efficient. Double- and triple-pane glass windows offer better insulation.
Low-E coating and argon gas filler between panes also boost the energy efficiency, keeping your utility bills low.
What Your Windows Need to be Energy Efficient
Windows gain and lose heat through:
- Air leakage through them
- Direct conduction through the glass, frame, or glazing
- Heat radiation through your home (typically from the sun) from room-temperature objects (furniture and interior walls)and people
To balance performance and cost, select an NFRC-rated, low-E, double-glazed, and argon-filled window meeting the 2010 ENERGY STAR guidelines. Energy-efficient products should have the following properties:
- A whole window U-value of 0.32 or less
- Visible light transmittance of 0.5 or more
- Solar heat gain coefficient between 0.30 and 0.60
- Air leakage of 0.3 or less
The following energy performance characteristics form the basis of the above window properties and ratings:
- U-factor rating: The rate at which windows conduct non-solar heat flow. It primarily refers to a window’s glass only.
- NFRC U-factor rating: This represents the whole window performance. A low U-factor rating means the window is highly energy-efficient.
- Solar heat gain coefficient (SHGC): This refers to the fraction of solar radiation a window admits into the home. It’s either transmitted directly or absorbed and released inside the house. A high SHGC rating means the window collects solar heat in winter effectively, while a low rating means it’s effective at reducing cooling loads during summer (blocks heat gain from the sun).
- Air leakage: The rate of air movement around windows due to a specific pressure difference across them. A low air leakage product rating means it’s tighter.
What are the Best Energy-Efficient Windows?
When you select high-performance, ENERGY STAR-rated windows, you:
- Reduce your heating and cooling energy costs
- Improve your home comfort
- Reduce fading of interior furnishings and finishes
- Reduce window condensation under moist conditions
Window frames are another essential feature to consider because they influence efficiency, style, and the ability to withstand harsh weather. Frames constitute 15 to 20 percent of a window’s surface area and are made of either fiberglass, wood, aluminum, or vinyl. Wood offers relatively good insulation properties over the rest but does not last as long as aluminum or vinyl. Furthermore, consider these window features.
- Type of seal
- Type of glass (double- or triple-pane)
- Low-E coating
- Argon gas filler between panes
Windows also come in various styles, including casements, bay windows, sliders, single-, or double-hung.
How Window Installation Affects Energy Efficiency
No matter the quality of the windows you choose, you need experts to ensure proper installation. Improper installation could lead to energy inefficiency through air leakage, costing you more in the short-run (high cost of quality energy-efficient windows) and the long run (heat loss in winter). Midwest Roofing Siding & Windows offers functional, energy-efficient replacement windows suitable to your specific needs in Twin Cities, MN. We provide quality double-hung, single-hung, sliding, casement, bay, bow, and awning windows from top-rate industry manufacturers and suppliers. In addition, we emphasize the essence of proper installation on all our expert technicians to ensure the energy efficiency of your replacement windows. Contact us today.