How to Stay Cool while Saving Energy

This guide by RMI provides strategies for maintaining cool indoor temperatures while reducing energy consumption and carbon emissions, particularly during heat waves. It outlines passive cooling methods, natural ventilation techniques, and efficient cooling technologies, supported by two case studies of net-zero and super-insulated homes in Colorado.

• To prevent heat gain, the guide recommends shading western and southern sides of houses with plants and trees, using light-colored materials on building facades to reflect radiation, and installing Energy Star rated windows with overhangs or light-colored interior shades.
• Natural ventilation, specifically a "night flush" where windows are opened at night and closed in the morning, is an effective cooling strategy in areas with large diurnal temperature swings, though it is not recommended in heavily polluted cities or areas affected by forest fires.
• For active cooling, the guide suggests using evaporative cooling (swamp coolers) in dry climates and ductless heat pump systems in all climates due to their low electricity requirements. Additionally, heat recovery ventilators (HRVs) can be used to precool and dehumidify incoming fresh air using the energy from outgoing cool air.
• Case studies in Colorado demonstrate the efficacy of passive strategies: one home in Boulder used a 10 kW solar PV system, high-performance windows, and HRVs to maintain an indoor temperature of 80°F when it was 103°F outside without air conditioning. Another home in western Colorado utilized straw bale construction (R-30 to R-45), adobe floors, and a solar oven to stay cool in mid-90s temperatures without air conditioning.

APA

RMI (2020). How to Stay Cool while Saving Energy. https://rmi.org/resources/how-to-stay-cool-while-saving-energy/

Chicago

RMI. How to Stay Cool while Saving Energy. 2020. https://rmi.org/resources/how-to-stay-cool-while-saving-energy/.

Wikipedia

{{cite report |author=RMI |title=How to Stay Cool while Saving Energy |date=19 August 2020 |url=https://rmi.org/resources/how-to-stay-cool-while-saving-energy/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2020how, author = {{RMI}}, title = {{How to Stay Cool while Saving Energy}}, institution = {RMI}, year = {2020}, month = aug, url = {https://rmi.org/resources/how-to-stay-cool-while-saving-energy/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }