Democratizing professional-grade HVAC sizing for homeowners and DIYers.
At HVACCalc, we believe that comfort shouldn't be a guessing game. For decades, the HVAC industry has relied on outdated "rules of thumb" that leave homeowners with oversized, inefficient, and expensive systems.
With the 2026 DOE regulatory changes introducing stricter SEER2 standards and A2L refrigerant limits, accuracy is more important than ever. Our mission is to provide a compliant, physics-based Manual J load calculator that anyone can use in under 2 minutes.
An oversized air conditioner is not an upgrade. It cycles on and off too frequently (short cycling), failing to remove humidity and wearing out parts prematurely. By calculating the exact load based on your insulation, windows, and climate, we help you:
We are a team of software engineers and HVAC building science enthusiasts passionate about energy efficiency. We noticed that professional load calculation software costs hundreds of dollars and requires a steep learning curve. We built HVACCalc to bridge that gap.
Our articles and guides are researched against ACCA Manual J (8th Edition) protocols and ASHRAE fundamentals. While we strive for engineering precision, our content is designed to be accessible to the average homeowner.