About FurnaceCalculator.com

FurnaceCalculator.com makes free, plain-English tools that help homeowners understand furnace sizing and replacement costs before they talk to a contractor.

We show our math. Every adjustment is listed on the methodology page with its source — or a clear note when it's our own judgment.

We are not an HVAC contractor, we don't sell equipment, and our estimates don't replace a professional Manual J load calculation or an in-person quote.

Our little flame helps keep things friendly. It doesn't give advice.

Spotted an error or have an idea? Email feedback@reallyusefulpages.com.