SPACE HEATING

This 2004 RMI guide outlines strategies for reducing home heating costs, emphasizing that a well-insulated building shell is the primary investment. It compares the efficiency (AFUE), installation costs, and operational expenses of furnaces, boilers, in-space heaters, air-source and geothermal heat pumps, and active solar systems, while providing guidelines for system sizing and replacement timing.

• Space heating and cooling represent 45 percent of total home energy use, with space heating alone costing the average homeowner $480 per year, or approximately 32 percent of the total energy bill. In the Northeast, these bills can exceed $800.
• A home's shell—including walls, windows, doors, foundation, roof, and attic—determines the rate of heat loss, and leaky shells can account for 25–40 percent of the heating system's load.
• Natural gas is identified as the most economical fuel choice for boilers, furnaces, and in-space heaters. In California, a small gas furnace costs $16–40 per month to operate, compared to $110 per month for an electric furnace.
• The efficiency of heating systems is measured by Annual Fuel Utilization Efficiency (AFUE). Federal minimum standards from 1992 require new furnaces to have an AFUE of 78 percent and new boilers 80 percent, while Energy Star-rated models can reach 90 percent or higher for furnaces and 85 percent or higher for boilers.
• Geothermal heat pumps can reduce heating costs by 30–70 percent and cooling costs by 20–50 percent, potentially saving homeowners $400 or more annually. However, they are typically twice as expensive to install as other central heating options, costing between $7,500 and $15,000.
• Active solar heating systems, which use electrical equipment like pumps or fans to move heat, cost between $5,000 and $18,000 to install. They are most effective in climates with long heating seasons, high proportions of sunny days, and above-average fuel prices.
• Proper system sizing is critical to avoid damage and inefficiency; oversized systems cause excessive on/off cycles and moisture accumulation in the heat exchanger, while undersized systems fail to heat the home adequately.
• Replacing a heating system is recommended if a furnace is older than 10–15 years or a boiler is older than 20 years, as new systems are at least 30 percent more efficient and typically pay for themselves within 5–10 years.

APA

Yardi, R., Smith, A., & Wang, K. (2004). SPACE HEATING. RMI. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_HEB4SpaceHeat.pdf

Chicago

Yardi, Ramola, Andy Smith, and Katherine Wang. SPACE HEATING. RMI, 2004. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_HEB4SpaceHeat.pdf.

Wikipedia

{{cite report |last1=Yardi |first1=Ramola |last2=Smith |first2=Andy |last3=Wang |first3=Katherine |title=SPACE HEATING |publisher=RMI |date=2004 |url=https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_HEB4SpaceHeat.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{yardi2004space, author = {Yardi, Ramola and Smith, Andy and Wang, Katherine}, title = {{SPACE HEATING}}, institution = {RMI}, year = {2004}, url = {https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_HEB4SpaceHeat.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }