Repair or replace? A homeowner's guide to roofs and furnaces

Age on its own is not a reason to replace something that works. It is a reason to stop paying to fix it. Use this as a planning table, and note where the number is published by a government source and where it is trade consensus.

The rule most HVAC people will quote you is the age-times-repair-cost test. Multiply the equipment's age in years by the estimated repair cost. Over about $5,000, lean toward replacing. Under, lean toward repairing.

Be clear about what this is. It is industry folklore with no traceable institutional origin, and some in the trade argue it is dated because it does not account for refrigerant transitions or how much modern equipment costs. It is still a genuinely useful thirty-second sanity check, and it beats deciding on how you feel about the number.

This is where the numbers are strongest, because Natural Resources Canada publishes them.

NRCan's own figure: replacing a 20-year-old furnace at 78 percent AFUE with one at 95 percent reduces annual energy costs by about 18 percent. Their worked example goes further. Move from 60 percent to 96 percent on an $800 annual heating bill and the saving is roughly $300 a year, about 37 percent.

There is also a rule that quietly settles part of the argument for you. Since 3 July 2019, federal regulations have required residential gas furnaces manufactured for Canada to be at least 95 percent AFUE. British Columbia moved earlier, to 92 percent, on 1 June 2015. So when you replace, you are getting a condensing furnace whether you planned to or not, and the old mid-efficiency versus high-efficiency conversation is over.

If a technician finds a crack in the heat exchanger, the conversation about cost is over. A cracked heat exchanger can allow combustion gases, including carbon monoxide, into the air you breathe. Replace the unit.

The same applies if a technician red-tags and shuts down the appliance. That is not an upsell tactic, it is a licensed person accepting liability for a decision. If you genuinely doubt it, get a second opinion from an independent company that is not selling you the replacement. Do not run it in the meantime.

And whatever you decide: working carbon monoxide alarms on every level of the house, tested, with batteries that are not from a previous decade.

A roof is more forgiving than a furnace, because roof failure is usually local. One failed flashing detail, a cracked rubber boot around a plumbing stack, a handful of tabs lifted in a windstorm. Fix those, and get on with your life.

Patching stops making sense when the shingle field itself has failed rather than a detail on it. At that point every repair is buying you months on a system that is finished, and you are paying a mobilisation charge each time to do it.

The economic version of the question is simple: how many years does this repair buy, and what does the replacement cost per year of service? A $1,500 patch on a roof that needs replacing in three years is fine. The same patch on a roof that needs replacing next spring is $1,500 you will never see again.

Roof age affects home insurance in Canada more than most homeowners realise. Insurers ask for it at application, and coverage on an older roof can be limited. Around the twenty-year mark it can become difficult to place at all.

Broadly, sudden and accidental damage is covered: storm, wind, hail. Wear and tear, deferred maintenance, rodent damage and collapse under snow and ice buildup are generally excluded. There is no single Canadian industry rule here and treatment varies meaningfully between insurers and policies, so read your own wording rather than assuming.

It is worth a call to your broker before you decide, because a surprising number of repair-or-replace decisions quietly rest on the assumption that the insurer will cover the next one.

On heating equipment the rebate money can exceed the gap between repairing and replacing, which is exactly why it belongs inside the decision rather than after it.

Federally, the picture has narrowed. The Canada Greener Homes Grant closed to new applicants in February 2024, and the Canada Greener Homes Loan is now fully committed, with new loan applications no longer being approved. Do not build a plan around either one.

Provincially, there is still real money, particularly in Ontario and Quebec.

Get the repair quoted in writing, and ask the contractor to state how many years it should buy you. Multiply the equipment's age by that repair cost. Check which rebates you would qualify for and whether they require pre-approval. Then ask one question: across the next five years, which path costs less in total, running cost included.

If the two paths land close together, replace. The replacement also buys you something the arithmetic does not price, which is not having the thing fail in February.