BTUFit › About
About BTUFit
BTUFit answers one question: how big should the equipment be? The answers come from the published rules of thumb the HVAC industry itself uses, applied consistently and labeled honestly.
Methodology
Room cooling starts from the ENERGY STAR room air conditioner sizing table (floor-area brackets, 8 ft ceilings) with its standard adjustments: −10% heavily shaded, +10% very sunny, +600 BTU per occupant beyond two, +4,000 BTU for kitchens. We add +5% per foot of ceiling over 8 ft. Whole-house cooling uses climate-tuned load factors from ~15 BTU/sq ft (cold zones) to ~24 (hot-humid), ±10–15% for envelope condition, rounded to half-ton equipment steps. Heating uses the five-band US climate-zone rule (midpoints 33–55 BTU/sq ft) with ±20% for insulation, converted to furnace input at 96% and 80% AFUE. Garages take the room table times an envelope factor (+20% partly insulated, +45% uninsulated, +10% sun-baked door). Unit recommendations round up to real equipment sizes: mini split heads 6k–36k, window units 5k–24k, central systems 1.5–5 tons.
Every static number on every page is generated from the same code that runs the live calculators, so the tables and the tools can't disagree.
Limitations
These are rules of thumb, good for budgeting, shopping and sanity-checking quotes. They don't know your windows, orientation, air-tightness or ducts. Before buying central equipment or a whole-home heat pump, get a Manual J load calculation (here's when it matters). Electrical work belongs to licensed electricians, refrigerant work to licensed HVAC technicians, and local codes outrank this site everywhere they speak.
How this site makes money
Some pages carry advertising, and some links (marked "sponsored") refer you to equipment retailers or contractor-quote services that may pay us for the referral. That never changes the math; the loads are the loads.
Contact
Via the contact page.