HomeBTU builds free calculators that help homeowners size and budget heating and cooling equipment before they talk to a contractor.
Hi, I'm Sergio. I started HomeBTU because replacing an air conditioner, furnace or heat pump is one of the largest repair bills most homeowners face, and the decision usually has to be made in a hurry. Quotes for the same house can differ by a ton of capacity and thousands of dollars, and it is hard to tell which one is right.
Most calculators I found online either used a single rule of thumb or belonged to a manufacturer or retailer selling the equipment. I wanted tools that show their working: which climate zone they assume, which design temperature, how much margin, and where each cost line comes from. Every result page on this site lists its assumptions, and the methodology page documents the formulas.
I am not an HVAC contractor, manufacturer or retailer, and HomeBTU does not sell equipment or installation services. That independence is the point: the calculators have no product to push.
The calculators are built from published methods, including ACCA Manual J and Manual S, the IECC climate zone map, ENERGY STAR sizing guidance and U.S. Energy Information Administration price data. When I update a formula or a price range, the date on the page changes.
The site is free to use and is supported by display advertising served by Google AdSense. Advertisers have no influence over calculator results or content, and I do not accept payment for recommending any brand, product or contractor. See the privacy policy for how advertising cookies work.
If a result looks wrong for your home, or you are an HVAC professional with better data for a region, I would like to hear from you. Write to contact@homebtu.com or use the contact page. I read every message and update the calculators when the evidence supports a change.
Results are estimates for planning and education. They do not replace an on-site assessment or a full load calculation by a licensed HVAC professional. Read the terms of use for details.