Better windows are great for the climate and for your comfort

The guide outlines how window upgrades—including multi-pane glass, low-emissivity coatings, and air sealing—reduce heat loss in winter and heat gain in summer, thereby lowering energy bills and carbon footprints. It also highlights non-replacement budget strategies like heat-shrink films and strategic shading to improve energy efficiency.

• High-performance windows reduce heat loss in winter through the use of two, three, or four glass panes separated by inert gas, as well as insulated spacers and frames. The effectiveness of this heat resistance is measured by the U-value, where a lower value indicates a better ability to resist heat flow.
• To prevent homes from overheating in summer, low-emissivity (low-E) coatings are used to reflect solar heat back outside. This performance is measured by the Solar Heat Gain Coefficient (SHGC), with lower values generally being more effective.
• Air leaks and drafts can be mitigated using caulking around interior trim, spray foam in gaps, and weatherstripping around movable windows, which reduces the cost of heating and cooling.
• Budget-friendly alternatives to full window replacement include the use of heat-shrink films, insulated blinds, light-colored curtains in summer, DIY air sealing, and the strategic placement of awnings, shrubs, or trees for shade.
• Project Drawdown classifies the improvement of windows and glass as a highly recommended climate solution because it reduces greenhouse gas emissions associated with powering air conditioners and heaters.

APA

McDiarmid, H., & Igugu, H. (2026). Better windows are great for the climate and for your comfort. Project Drawdown. https://drawdown.org/insights/better-windows-are-great-for-the-climate-and-for-your-comfort

Chicago

McDiarmid, Heather, and Henry Igugu. Better windows are great for the climate and for your comfort. Project Drawdown, 2026. https://drawdown.org/insights/better-windows-are-great-for-the-climate-and-for-your-comfort.

Wikipedia

{{cite report |last1=McDiarmid |first1=Heather |last2=Igugu |first2=Henry |title=Better windows are great for the climate and for your comfort |publisher=Project Drawdown |date=25 February 2026 |url=https://drawdown.org/insights/better-windows-are-great-for-the-climate-and-for-your-comfort |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{mcdiarmid2026better, author = {McDiarmid, Heather and Igugu, Henry}, title = {{Better windows are great for the climate and for your comfort}}, institution = {Project Drawdown}, year = {2026}, month = feb, url = {https://drawdown.org/insights/better-windows-are-great-for-the-climate-and-for-your-comfort}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }