Home Systems Calculators
Insulation coverage and cooling capacity for comfortable rooms.
Insulation Calculator
Packages of insulation from area and the coverage on the label.
Air Conditioner BTU Calculator
Cooling capacity for a room by size, sun, kitchen, and people.
Water Heater Size Calculator
Tank size and first-hour rating target by household size.
Furnace BTU Calculator
Heating capacity by home size, climate zone, and insulation.
Dehumidifier Size Calculator
Pint capacity by room size and how damp the space is.
Comfort systems are sized, not guessed. Insulation is bought in packages rated for a specific coverage at a specific R-value, and air conditioners are rated in BTU per hour, where both undersizing and oversizing cost you: an undersized unit runs constantly, and an oversized one short-cycles without pulling humidity out of the air.
These calculators use the standard sizing rules: insulation coverage comes straight from the package label you plan to buy, and cooling capacity starts from the common 20 BTU per square foot baseline with adjustments for sun exposure, kitchens, and occupancy. For whole-house HVAC sizing, a contractor's Manual J load calculation is the real answer; the estimates here are for single rooms and standard situations.