About hvaccalc.dev

hvaccalc.dev provides free, instant HVAC calculators for homeowners and professionals. No signup required. No data collected.

Our Mission

We believe everyone deserves access to accurate HVAC sizing and cost information. Whether you're a homeowner planning a new system, a contractor double-checking calculations, or an HVAC student learning the trade, our tools are here to help.

How It Works

All calculations run directly in your browser. We don't send your data to any server, and we don't store any information. Enter your values, get instant results, and print them to take to your contractor.

Important Disclaimer

Our calculators provide estimates based on industry standards and general guidelines. They are not a substitute for a professional Manual J load calculation or on-site assessment. Always consult a licensed HVAC professional before purchasing or installing equipment.

Our Calculators

• BTU Calculator — Size heating and cooling for any room
• AC Unit Size Calculator — Find the right AC tonnage
• Heating Load Calculator — Size your furnace or heat pump
• Duct Size Calculator — Size ductwork correctly
• Air Filter Size Finder — Find the right filter
• Energy Cost Calculator — Calculate running costs
• Refrigerant Charge Calculator — Estimate refrigerant needs
• Heat Pump vs Furnace — Compare heating systems
• Ventilation CFM Calculator — Calculate airflow needs
• HVAC Cost Estimator — Estimate installation costs

Have suggestions? We're always looking to improve. Check out our HVAC Glossary to learn common terms.