HVAC Calculators

Estimate central air conditioner tonnage and furnace BTU output/input from your square footage, climate zone, insulation, ceiling height, sun exposure, and occupancy

Estimate heat pump tonnage, balance point, and backup/auxiliary heat needed from your square footage, climate zone, insulation, and heat pump type (Standard or Cold-Climate)

Estimate ductless mini-split indoor head sizing per room and the total connected indoor capacity, for a single-zone or multi-zone system, from square footage, climate zone, insulation, ceiling height, sun exposure, and occupancy

Size a window, wall, or portable air conditioner per Energy Star's official sizing chart, including the real SACC rating a portable unit needs versus its marketed ASHRAE BTU number

Calculate design airflow from sensible load, estimate equipment CFM from tonnage, or allocate known cooling and heating airflow room by room from design loads

Estimate round supply/return trunk and branch duct diameters from your CFM, sized to ACCA Manual D's recommended velocity for each duct category

Measure and classify Total External Static Pressure (TESP) from manometer readings against your equipment's rated capacity, or compute Available Static Pressure and friction rate for designing new ductwork

Estimate bathroom exhaust fan CFM from square footage and fixtures, or kitchen range hood CFM from cooktop width, mount type, and fuel type, including the 400 CFM makeup air threshold

Estimate whole-house fan CFM, required attic exhaust vent NFA, and required window opening area, per HVI/DOE sizing guidance

Size soffit intake and ridge or gable exhaust vents for your attic from its floor area, per IRC R806.2's Net Free Area (NFA) requirement

Estimate whole-house humidifier capacity (gal/day) per ARI Standard 630-74, or portable dehumidifier capacity (pints/day) per an AHAM-based sizing chart, from your space's area, height, and conditions

Estimate required CFM airflow and cooling pad area from cross-sourced residential sizing rules, plus a preliminary suitability screening based on your climate's humidity level

Estimate required Net I=B=R boiler output per the I=B=R Testing and Rating Code, or hydronic baseboard length per manufacturer BTU/ft ratings, from your home or room's area, climate zone, and insulation

Estimate required PEX tubing length and loop count from a manufacturer's spacing table and RPA loop-length guidance, plus a preliminary screening of whether your floor covering can deliver enough output for your room's heat loss

Estimate total equivalent length, capacity impact, and additional R-410A refrigerant charge for a line set, using Goodman/Amana's own published long-line application guideline

Size an HVAC condensate drain line's minimum pipe diameter per IMC Table 307.2.2, plus estimated condensate flow, trap depth, and slope drop from your system's tonnage

Find a cast-iron radiator's EDR (Equivalent Direct Radiation) and BTU/hr output, or the sections needed for a target heat output, for steam or hot-water systems

Compare your current AC or heat pump's annual energy cost against a new, more efficient unit — normalizing SEER and SEER2 ratings to the same basis, with a simple payback period

Size a supply register's or return grille's required free area and gross face area from CFM, velocity target, and core type, including ACCA's filter vs. non-filter grille distinction

Check whether a gas appliance space is confined under IFGC/NFPA 54, and size the combustion/makeup air openings or mechanical supply it needs, with all four sizing methods compared side by side