System Sizing

Before it can price anything, the estimator works out what size system the home needs, then uses your prices at that size. You don't set the size — but the Sizing basis switch in Company Settings → Price Book changes how it's chosen, and the sizes you've priced decide whether the homeowner gets prices at all.

How a size is picked

• From the home's square footage and age. Older homes need more capacity per square foot. A homeowner who answers Not Sure to "When was your home built?" is treated as having an older home, which can mean a bigger system.
• From both heating and cooling needs. The estimator works out both, and your Sizing basis decides which one sets the size.
• Rounded to the nearest size you can price: 1.5, 2, 2.5, 3, 3.5, 4 or 5 tons. There's no 4.5 — a home that falls between 4 and 5 tons gets whichever is closer.

Climate, ZIP code, number of stories and insulation aren't asked about for each home — your account's sizing assumptions are set for your region instead. If sizes consistently look too big or too small for your market, see Prices Look Too High or Too Low.

What homeowners see

Above your options, a line such as "Based on your 2,000 sq ft home, we typically recommend a 2.5 Ton system", then your prices at that size.

• Single-room mini-splits are sized from the room instead: "Based on your ~300 sq ft room, we typically recommend a 9,000 BTU ductless system". See Mini-Splits.
• Hydronic heating isn't sized, so there's no line — every homeowner sees the same starting prices. See Hydronic Heating.

Homes outside 1.5–5 tons

A home that works out below 1.5 tons or above 5 tons is offered a home visit instead of prices. That's usually a very large home — around 4,000 sq ft or more — or a very small one, around 1,000 to 1,200 sq ft or less depending on its age. So is a homeowner who answers "I don't know my square footage". See Online Estimate Home Visits.

Sizing basis: heating or cooling

Each system's page has a Sizing basis switch — Heating or Cooling — that decides which need sets the size. It's set per family, so a family's 80% and 95+% systems share it. It isn't offered for AC Only, Multi-Zone Mini Split or hydronic heating.

• Until you pick one, the size comes from the cooling need — even for furnace-only systems — and neither button looks selected.
• Once you've picked, you can switch between Heating and Cooling, but you can't go back to having neither selected.
• It rarely changes the result. With the standard sizing assumptions, heating and cooling almost always land on the same size, so most contractors never need to touch it.

It saves the moment you click, and applies in both pricing modes.

Price every size you sell

A homeowner whose home lands on a size you haven't priced is offered a home visit, even if every other size is priced. If you do sell a size, give it a price for every option — see Equipment, Tiers & Prices.