Homeowner tool · rebuilt from my original proof of concept
What size AC does your home need, and what will it cost to own?
Answer in simple ranges, no tape measure needed. You'll get a size estimate and good, better and best options compared by what each costs to own over the years.
About your home
Ranges are enough. Each answer adds or removes points that adjust the size.
What's driving your size
Your options
Cumulative cost to own
A dealer confirms the size on site with a full load calculation (Manual J).
- Sizing: a points model. Home size sets the base load, and each answer adds or removes points, the same way my original version weighted factors learned from real housing data with known system sizes. This rebuild uses published rules of thumb, not that data.
- Climate: your ZIP sets a climate band (hot, mixed or cold) that adjusts the size and the hours your AC runs each year.
- Prices: installed costs are mid-range 2026 estimates for a 3-ton system, scaled by size. Outdoor unit only is estimated at 70% of a full system. Maintenance is $150 a year for a new unit. An older unit's efficiency drops about 1.5% a year while its maintenance and repair costs climb.
- This is an estimate for planning, not a quote. It's a personal project and isn't affiliated with or endorsed by any manufacturer.