BTU Calculator
Calculate the BTUs needed to heat or cool any room. Accounts for room size, ceilings, windows, climate zone, and occupants.
↳ 250 sq ft · hot climate → ~9,000 BTU
HVAC Load Calculator
Whole-home simplified Manual J estimate. Enter square footage, insulation, climate zone, and window ratio to get cooling and heating loads.
↳ 2,000 sq ft · moderate → 3–3.5 tons
AC Size Calculator
Quick square footage to AC size lookup. Enter your floor area and climate, get a BTU and tonnage recommendation with a reference table.
↳ 1,200 sq ft · moderate → ~2 ton unit
Furnace Size Calculator
Find the right furnace BTU output for your home. Includes climate zone, insulation quality, and efficiency (80% vs. 96% AFUE) recommendations.
↳ 1,800 sq ft · cold zone → ~80,000 BTU
SEER Savings Calculator
Estimate annual energy savings when upgrading to a higher SEER system. See payback period and lifetime CO₂ reduction.
↳ SEER 10 → 18 · 3 tons · warm → ~$410/yr saved
HVAC Running Cost Calculator
Find out what your AC costs to run per hour, month, and cooling season. Enter system size, SEER rating, runtime, and your electricity rate.
↳ 3 ton · SEER 16 · 8 hrs/day → ~$90/mo
CFM / Airflow Calculator
Determine the airflow in cubic feet per minute required for a space. Set your room dimensions and air changes per hour target.
↳ 400 cu ft · 6 ACH → 40 CFM needed
Duct Size Calculator
Convert CFM into round or rectangular duct dimensions at your target air velocity, with friction loss and a velocity check.
↳ 400 CFM @ 800 fpm → 10" round
Heat Pump vs. Furnace Calculator
Compare annual heating costs for a heat pump and a gas furnace using your home size, climate, and local fuel prices.
↳ 2,000 sq ft · moderate → furnace by ~$170/yr
ACH Calculator
Compute air changes per hour from a fan's CFM and your room size, and check it against the target for the room type.
↳ 80 CFM · 12×10 room → 5 ACH
R-Value Calculator
Get the total R-value of your insulation from material and thickness, compared against the recommendation for your climate zone.
↳ 6" fiberglass · zone 4 attic → R-19.2 of R-60