Why Trust FurnaceSizeCalculator.com?

At FurnaceSizeCalculator.com, we’re dedicated to helping you find the perfect furnace for your home with confidence. Our mission is simple: provide accurate, user-friendly tools backed by decades of HVAC expertise. Here’s why thousands trust us to guide their heating decisions.

Our Expert Team

Our team of four seasoned HVAC professionals brings over 50 years of combined experience in heating system design and installation. From residential homes to commercial spaces, we’ve seen it all—and we’ve poured that knowledge into our furnace size calculator. Whether you’re replacing an old unit or building anew, we ensure your results are precise and reliable.

Industry-Leading Calculator

Our calculator is built on ASHRAE standards, the gold standard in HVAC engineering. It accounts for every detail—square footage, climate, windows, insulation, and even occupants—to deliver tailored BTU and heat loss estimates. Unique features like insulation adjustments and PDF result saving set us apart, making your furnace selection process seamless and informed.

Transparency and Trust

We believe in empowering you with clear, actionable insights. That’s why our calculator shows all inputs (like insulation or climate zone) in downloadable PDFs, so you can review or share results with contractors. No guesswork, no hidden steps—just honest, expert-driven guidance.

Ready to find the right furnace? Calculate Your Furnace Size Now