Boiler and radiator repair in Ottawa: fix the old boiler or replace it

Hot water heat in Ottawa houses

Statistics Canada found about 9% of households in the Ontario part of Ottawa-Gatineau heating mainly with a boiler and radiators in 2021, about six in ten of them on natural gas. Name the boiler plainly in your request, with its fuel, so the company knows it is hydronic heat before it calls. Under Ontario’s certificate rules, a G.2 gas technician may service gas or propane appliances up to 400,000 Btuh.

What to report when it acts up

HomeStars lists the usual signs: no heat or hot water, odd noises, leaks and pressure trouble. Note which rooms are cold, whether a whole radiator stays cold or only its top, what the gauge reads, any code on the display, and where water appears. HomeStars notes that the boiler model, when the problem started and any leaks or noises help local pros give an accurate quote.

Smell gas: Enbridge says leave at once and call 1-866-763-5427 or 911 from a safe distance. A sounding CO alarm means everyone out and 9-1-1 from outside; see the carbon monoxide page.

What a repair costs

On HomeStars’ Canada-wide page, a diagnostic visit runs $100–$200 and a thermostat or control panel $150–$400. The Ottawa page names what raises a bill: an older boiler, a high-efficiency or combi unit, pressure and circulation faults, and after-hours work. Ask which part failed, and get parts and labour as separate lines.

The rule behind every replacement

Under the federal Energy Efficiency Regulations, household gas boilers for hot water systems made since 1 July 2023 need an AFUE of at least 90% and no constantly burning pilot. NRCan calls that level condensing, so a replacement gas boiler is a condensing one. NRCan’s retrofit guide lists what that changes:

• Venting. A new exhaust pipe, usually with an air intake, often through a side wall. The exhaust condenses into a corrosive liquid, and PVC is allowed only where flue gas stays at or below 65°C.
• Condensate. It must be neutralized and drained; far from a drain, a pump is added.
• Sizing. After new windows or insulation, or where the old boiler was oversized, the new one may be smaller and cheaper to run.

Old radiators, new boiler

A condensing boiler condenses only when the water returning to it is cool, typically under 130°F. That depends on radiator surface. A system built around an old boiler may run too hot for part or all of the season. NRCan’s remedies: outdoor reset, which lowers the water temperature on milder days, and extra radiators where a room falls short. Ask how your radiators fit.

Replacement prices and paperwork

Published Ottawa replacement prices are scarce. Next to the standard condensing price above, the same Toronto-area 2026 list gives $6,500–$11,000 for a high-efficiency model, $4,500–$9,000 for a combi that also heats tap water and $3,000–$6,500 for an electric boiler, plus $300–$1,200 for a venting change.

In Ontario, home repair work over $50 needs a written agreement, an estimate in it can rise 10% at most without your signed change, and a contract signed at home has a 10-day cooling-off period. Rental plans exist too; renting or buying weighs them.

Pipe wrap, heritage streets and heat pumps

Health Canada lists insulation around hot water pipes and tanks among pre-1990 uses of asbestos and advises a professional test before work disturbs it. Mention any old wrapping.

The City exempts heat pump installs from a building permit, except on designated heritage buildings and in Heritage District Overlays. A radiator house may have no ducts; ductless mini-splits cover that case.

Who handles your request

Ottawa Heating Desk passes your boiler request to one independent local heating company. That company calls you back, looks at the boiler and radiators, prices the repair or replacement and does the work.