HVAC Calculators
A budget and size envelope—not a load calculation.
Replacing a furnace, air conditioner, or heat pump is a five-figure decision in many US markets. This calculator offers two honest things: a rough tonnage band from square footage and climate, and an installed-cost range from editable unit prices. It is not Manual J, Manual S, or Manual D. Oversizing and undersizing both waste money and comfort. Use the output to talk to licensed contractors, not to order a unit online and hope the ducts match.
Calculators
How to measure
Use conditioned floor area, not garage or unfinished basement unless those spaces are heated and cooled. Note existing system type, fuel, and whether ducts will be reused. Climate zone here is a coarse mild / mixed / hot-or-cold selector, not an ASHRAE bin analysis.
Related categories
FAQ
- Why isn’t this a Manual J calculation?
- Manual J needs insulation, windows, orientation, infiltration, and design temperatures. A website that asks only for square footage and then names a exact tonnage would be pretending. We show a range and tell you to hire a load calc.
- What does one ton of cooling mean?
- One ton is 12,000 BTU per hour of cooling capacity. Rules of thumb like “one ton per 400–600 square feet” are starting points only. A tight, shady house and a leaky west-facing ranch are not the same load.