What size boiler do I need for my home?

As a rule of thumb in the Lower Mainland, a heating-only boiler needs roughly 30 BTU/hr per square foot for a newer, well-insulated home, 40 BTU/hr for an average home, and up to 50 BTU/hr for an older or draughty home. A 2,000 sq ft average home therefore needs around 80,000 BTU/hr. A combi boiler must also meet peak hot-water demand, so it is sized to the larger of the two loads. A licensed technician confirms the exact size with a CSA F280 heat-loss calculation.

Is a bigger boiler always better?

No. An oversized boiler short-cycles — turning on and off frequently — which wastes gas, increases wear, and reduces comfort. An undersized boiler cannot keep up on the coldest days. Correct sizing, not maximum size, gives the best efficiency and lifespan.

How is combi boiler sizing different?

A combi boiler provides both space heating and on-demand domestic hot water from a single unit. Because it must deliver enough hot water for simultaneous taps and showers, its output is usually driven by peak hot-water demand (the number of bathrooms) rather than by space heating alone.

Boiler Size Calculator

Estimate the right boiler output (BTU/hr) for your Greater Vancouver home in seconds — then get an exact, no-obligation quote from licensed CANRO technicians.

Estimate your boiler size

Heated floor area: 2,000 sq ft

5006,000 sq ft

Home age & insulation

System type

Recommended output

75,000–90,000

BTU/hr

Space heating80,000 BTU/hr

Get an exact quote: 604-359-1081 Request a free sizing assessment

This is a planning estimate only. Before installation, our licensed technicians perform a full CSA F280 heat-loss calculation to size your boiler precisely.

How boiler sizing works

Sizing a boiler means matching its heat output to how much heat your home loses on a cold day. Get it right and the boiler runs efficiently for 15–20 years. Get it wrong and you pay for it in gas bills, comfort, and premature wear. Three factors drive the estimate above:

Floor area

The heated square footage is the starting point — more space to heat means more output required.

Insulation & age

A draughty 1960s home loses far more heat than a modern, well-sealed build — so it needs a higher BTU-per-square-foot factor.

Hot-water demand

A combi boiler also makes your hot water, so peak demand (bathrooms running at once) often sets the required output.

Why a professional heat-loss calculation matters

Accounts for window area, orientation and ceiling height
Uses the correct Lower Mainland design temperature
Factors in zoning, radiators and in-floor loops
Prevents oversizing that causes short-cycling
Required for rebates and code-compliant permits
Protects your manufacturer warranty

Our calculator gives you a solid planning range. For an exact specification, our licensed, Red Seal–certified technicians complete a full CSA F280 heat-loss calculation as part of every free installation quote. Read the full boiler sizing guide.

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GasBoilers.ca is the dedicated gas-boiler division of CANRO Boilers Heating & Air Conditioning Ltd. (CanroHeat.ca), a licensed Greater Vancouver heating company operating since 1999. Every job is backed by the same Burnaby head office, the same Red Seal–certified, TSBC-licensed technicians, and the same 25+ years of field experience — now focused entirely on gas boilers.

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Plan your boiler project

Boiler Sizing GuideThe full guide to BTU & heat loss Efficiency GuideAFUE ratings & energy savings Boiler InstallationProfessional install, permit & commissioning Combi BoilersHeat + hot water in one unit Installation CostWhat a new boiler costs in BC Rebates & IncentivesBC energy efficiency programs

Know your size? Get an exact quote

Our licensed technicians confirm the right boiler with a full heat-loss calculation — free, with no obligation.

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