What are the most energy-efficient windows/doors?

The most energy-efficient windows and doors are those that have been certified by the National Fenestration Rating Council (NFRC). The NFRC is a non-profit organization that rates the energy performance of windows, doors, and skylights based on several factors, including U-factor, solar heat gain coefficient (SHGC), visible transmittance (VT), and air leakage. Here are some of the most energy-efficient types of windows and doors:

1. Double- or triple-pane windows: These windows have two or three panes of glass with an insulating layer of air or gas between them. They can significantly reduce heat loss and save on energy bills.
2. Low-E (low-emissivity) windows: These windows have a special coating on the glass that reflects heat back into the room in winter and blocks heat from entering in summer, making them ideal for climates with extreme temperatures.
3. Fiberglass windows and doors: Fiberglass is a durable, low-maintenance material that provides excellent insulation and resists expansion and contraction due to temperature changes.
4. Vinyl windows and doors: Vinyl is another low-maintenance material that provides good insulation and is available in a variety of styles and colors.
5. Wood windows and doors with low-E glass: Wood is a natural insulator that can provide good energy efficiency when paired with low-E glass.

When selecting windows and doors, look for the NFRC label and choose products with a low U-factor and SHGC, and high VT. This will ensure that you are getting the most energy-efficient products for your home. Additionally, make sure to have your windows and doors professionally installed to ensure they are properly sealed and insulated.