Size an air conditioner, heat pump, furnace or mini split for your home and climate, and see what it will cost to install and run. Free, no sign-up, and every calculator shows how it gets its answer.
Find the equipment size your home needs before you ask for quotes.
Size the equipment that keeps hot water and power running.
Budget a replacement and compare running costs with prices adjusted for your state.
Each calculator starts from your home's size and climate zone, using the International Energy Conservation Code (IECC) map that divides the U.S. into zones from hot (1) to very cold (7). From there it applies published engineering methods: heat loss and gain per square foot, design temperatures that are exceeded only 1% of the year, equipment output at those temperatures, and the sizing limits in ACCA Manual S.
Cost estimates come from national installed-price ranges adjusted by a labor index for each state. Every result page lists its assumptions, and the methodology page explains the formulas and sources in full.
The results are planning estimates. They help you understand what size and price to expect, check a contractor's proposal and ask better questions. They do not replace an on-site load calculation by a licensed HVAC professional.