HVAC Sizing Calculator for Ontario Homes
Estimate the right furnace, air conditioner, and heat pump size for your home in seconds. Enter your square footage and insulation level to get a realistic starting point for the GTA climate.
Your Home
Insulation and windowsFurnace size
80,000 BTU/hr
Estimated heating load ~80,000 BTU/hr for a typical 2,000 sq ft home.
Central AC size
3.5 ton
About 42,000 BTU/hr of cooling (~3.7 ton raw).
Heat pump size
3.5 ton
A cold-climate heat pump is sized to the cooling load and carries most of the heating season. On the coldest Ontario days a backup furnace or electric coil covers the rest.
This is a quick estimate, not a formal calculation. Correct sizing depends on more than square footage: ceiling height, window count and orientation, air leakage, ductwork, and local design temperatures all matter. Oversizing wastes money and causes short-cycling, undersizing struggles in a cold snap. Before you buy, EcoFrost runs a proper Manual J heat-loss and heat-gain load calculation during your free in-home assessment.
How HVAC Sizing Works in Ontario
Furnaces are rated by heat output in BTU per hour, and air conditioners and heat pumps by tons (one ton equals 12,000 BTU/hr of cooling). Ontario sits in a cold climate zone, so heating sizing runs higher here than in milder provinces. As a rough rule, homes need 30 to 50 BTU per square foot of heating output and 18 to 26 BTU per square foot of cooling, depending on insulation and air-tightness.
| Home size | Furnace (average) | Central AC / heat pump |
|---|---|---|
| 1,000 sq ft | 40,000 BTU | 1.5 - 2 ton |
| 1,500 sq ft | 60,000 BTU | 2 - 2.5 ton |
| 2,000 sq ft | 80,000 BTU | 3 - 3.5 ton |
| 2,500 sq ft | 100,000 BTU | 3.5 - 4 ton |
| 3,000 sq ft | 120,000 BTU | 4 - 5 ton |
These are starting points for a typical GTA home. For firm pricing on the right size, see our HVAC cost guide or compare heat pump vs gas furnace for your home.
HVAC Sizing FAQs
How many BTU do I need to heat my house in Ontario?
In Ontario's cold climate, plan on roughly 30 to 50 BTU per square foot of furnace output. A well-insulated 2,000 sq ft home needs about 60,000 BTU, an average home about 80,000 BTU, and an older drafty home can need 100,000 BTU or more. A Manual J load calculation confirms the exact number.
What size air conditioner do I need for my square footage?
Central AC is sized in tons, where one ton equals 12,000 BTU/hr. In the GTA, a typical home needs about one ton per 500 to 650 square feet. A 2,000 sq ft home usually lands at 3 to 3.5 tons. Oversizing an AC leads to short-cycling and poor humidity control, so bigger is not better.
How do I size a heat pump for a cold climate?
A cold-climate heat pump is sized to the home's cooling load, then paired with a backup heat source (gas furnace or electric coil) for the coldest days. That keeps the heat pump running efficiently most of the year while guaranteeing comfort in a deep freeze. Sizing it purely for peak heating usually oversizes it for cooling.
Why not just get the biggest furnace or AC to be safe?
Oversized equipment short-cycles: it heats or cools in quick bursts, then shuts off, which wears out components, leaves uneven temperatures, and does not remove humidity well in summer. Correctly sized equipment runs longer, quieter cycles and lasts longer. This is why we run a load calculation rather than guessing high.
Is this calculator accurate enough to buy from?
It is a solid starting estimate for planning and budgeting, but not a substitute for a professional load calculation. Ceiling height, window area and orientation, air leakage, and duct design all change the answer. EcoFrost runs a full Manual J assessment at no charge before recommending equipment.