A properly installed, ENERGY STAR certified sliding glass door can reduce heating and cooling costs by an average of up to 13% compared to non-certified products. Coastal Windows & Exteriors is a woman-owned exterior remodeling company installing ENERGY STAR-certified sliding glass doors that seal tightly and help cut heating and cooling costs, with 7,000+ installations completed since 2011 across 730+ towns in Massachusetts, New Hampshire and Maine.
What Homeowners Need to Know
- ENERGY STAR certification is the benchmark: Installing ENERGY STAR certified windows, doors, and skylights can reduce heating and cooling costs by an average of up to 13% nationwide. For a household paying roughly $600 per month in utility costs, that adds up fast.
- Air sealing is as important as the door itself: Even an energy efficient door loses its advantage if the frame isn’t properly sealed. Air leakage in homes can be reduced by an average of 25–30% by sealing gaps in the building envelope — proper installation matters as much as the product rating.
- Thermal performance is a top industry priority: Thermal performance (U-factor/R-value) is a priority for 87% of windows and doors professionals. A lower U-factor means better insulation — confirm the rating before purchase.
- Energy costs are real: With households averaging roughly $600 per month on energy bills, any reduction in air infiltration has an outsized impact on annual costs. Energy efficient doors are one of the most practical upgrades available.
- The investment pays back: The ROI of a steel entry door is 216% in 2026 according to national cost-vs-value data. Replacing exterior doors with energy-efficient units adds measurable resale value alongside the monthly savings.
- Most U.S. homes are under-insulated: 89% of U.S. homes are under-insulated, meaning many homeowners are losing conditioned air through gaps they may not realize exist. A properly installed, sealed sliding glass door addresses one of the most common leakage points in a home.
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Last Updated: August 2026
Sources:
- Installing ENERGY STAR certified windows, doors, and skylights can shrink energy bills by an average of up to 13% on heating and cooling costs nationwide, compared to non-certified products. ENERGY STAR – Residential Windows, Doors & Skylights ENERGY STAR’s official resource on certified products and estimated energy savings. (No date – Accessed August 2026)
- Massachusetts households spend roughly $600 per month on energy bills. Boston.com – Massachusetts Utilities Report Boston.com reporting on average monthly utility costs for Massachusetts homeowners. (2024)
- The ROI of steel entry doors is 216%. JLC Online – Cost vs. Value 2025 JLC Online’s national cost-vs-value report for exterior door replacement ROI data. (2026)
- 89% of homes in the U.S. are under-insulated. Insulation Institute Press Release ICF report cited by the Insulation Institute revealing the prevalence of under-insulation in U.S. homes. (2024)
