According to ENERGY STAR, an energy-efficient glazed door system must have multiple panes, improved core materials, and advanced weather stripping. The problem, however, is that it can be hard to objectively separate energy-efficient units from low-performance ones with these components alone. Looking for a product with the ENERGY STAR logo helps, but it’s imperative to read the NFRC (National Fenestration Rating Council) seal too.
The NFRC label is a small sticker with a big message. It can help you choose the apt sliding glass doors in Salt Lake City, Detroit, Albany, or whatever American city you live in. If you’re familiar with your climate zone’s energy efficiency requirements, the NFRC seal contains all the information you need to make an informed decision.
Here are the energy performance ratings you can find it:
U-Factor
This metric refers to the ability of the unit to keep the heat in. Expressed between 0.20 and 1.20, the lower the number means the better the door is at preventing your conditioned air from escaping your indoor space.
Solar Heat Gain Coefficient
SHGC for short, this rating measures how well the product can reflect the sun’s infrared light, and minimize heat gain. Ranging from 0 to 1, the lower the SHGC, the better.
Visible Transmittance
This one expresses how efficient the unit is in terms of allowing daylighting. From 0 to 1, the higher the VT means, the better it is at admitting sunlight.
Catching as much natural light as possible helps lower your energy costs. The more you can illuminate your interior with the sun, the less you depend on artificial lighting. Since 90% of the power traditional bulbs use turns into heat, keeping them off help slow down your electric meter, and keep your rooms cool.
Air Leakage
This rating pertains to the ability of the door to keep air infiltration to a minimum. Ranging from 0.1 to 0.3, units with low numbers are the best at denying unwanted drafts.
Find out the ideal combination of energy performance ratings for glazed doors in your area, and read what your prospective product’s NFRC seal says. If you exercise due diligence, you can choose the right door system to elevate your home’s energy efficiency.
