Keep Above
Repair or replace the furnace
A furnace that won't fire — or keeps needing another visit — comes down to the same two-sider as any failing appliance: what a repair would cost against what a replacement would. Each side is counted over its own expected span to a cost per year, the only figure the two share. The years are your estimates, and no winner is declared.
Your estimate, not the page's
Not counted while this is $0
Your estimate, not the page's
Not counted while this is $0
Comes off the replacement
Put in what the fix would cost and what a replacement would cost. Nothing here is read from your budgets, and nothing is saved.
| Repairing | Replacing | |
|---|---|---|
| Up front | — | — |
| Running costs over its life | — | — |
| Total over its life | — | — |
| How long that covers | — | — |
| Cost a year | — | — |
| Cost a month | — | — |
Is replacing a furnace the same thing as swapping the unit?
A furnace is one part of a heating system rather than an appliance standing on its own. It is joined to ductwork, to a flue and to a thermostat, and a replacement has to suit all three — so the figure that belongs in the replacement box is the installed one, which can carry work on the connections around the unit as well as on the unit itself.
It cuts the other way on the repair side. Some faults sit in the unit and some sit outside it, in the ducting, the thermostat or the supply, and a replacement renews only the first kind. Where the fault is outside the box, fitting another furnace would leave it exactly where it was — and that is something neither cost-per-year figure on this page can see, because both of them count the furnace alone.
This is one of the tools built into Keep Above
Keep Above is a budgeting app where you enter your bills and income and it works out the balance you need to keep — so you can see what's safe to spend. No bank connection, no ads on your data.
A replacement arrives as one bill on one day, which is the kind of expense a sinking fund exists for — how budgeting apps handle money set aside for later bills.
About this calculator
What counts as the repair cost for a furnace?
The full quote for this visit — call-out, the ignitor, blower motor, board or exchanger part that failed, and labour. The cost per year divides that whole amount by the extra years you think the fix would buy, so the complete figure is the one that fits the box.
What goes into running costs a year here?
Heating is where running costs can genuinely differ: where the old furnace and a replacement would burn noticeably different amounts of fuel or power across a year, that difference is a real yearly figure for the boxes. Where they'd run much the same, both can stay at $0.
What is the matching time?
The number of years the repair would have to carry the furnace for its cost per year to match the replacement's — a position in the arithmetic, nothing more. Where heating the house with the old furnace already takes more each year than the replacement does all-up, no number of winters would bring the two level, and the line says so rather than printing a figure.
What about selling or scrapping the old one?
Whatever the old furnace would fetch comes off the replacement's cost, which on a unit being taken out of a duct run comes down to scrap value or nothing at all. At $0 the box drops out of the arithmetic and the replacement side reads as its full cost.