Guide · buying
Worth fixing, or not: the arithmetic on a Thermador built-in
The 50% rule applied honestly to a fitted appliance: repair bands on one side, replacement cost on the other, and the cabinet opening in between.
Published Sep 23, 2026 · Updated Sep 23, 2026
The rule people quote
50%
What decides it
2 tables
The rule people quote is 50%: replace the appliance once the repair costs more than half of replacing it. On a Thermador built-in that line falls a long way out, and the two tables further down this page are why — run the rule against the replacement figure for a fitted appliance rather than a showroom price and most of what we are called to sits comfortably under it.
The rule itself is sound. It is the second number that goes wrong, almost every time, because people compare a built-in against the price of a freestanding machine they saw on a shop floor.
The two numbers, and why one of them is bigger than people expect
The tables further down this page are both real and both ours. One is what the repairs we actually carry out come to here, parts and labor together. The other is what a comparable built-in costs as an appliance, before anyone has delivered it, fitted it, or touched the cabinetry.
That second number is the one that moves the decision. A freestanding refrigerator is replaced by wheeling one out and another in. A column, a wall oven or a rangetop is fitted into an opening that was cut for it, on a circuit that was run for it, behind trim that was made for it. Replace it and you are buying the appliance and, frequently, the joinery that makes the new one fit.
Run the fifty-percent rule against that second number rather than a showroom price and the line lands much further out than most people assume. Most of what we are called to sits well under it.
Where the judgement actually gets difficult
Three situations turn a clear answer into a close one, and none of them is about the size of the quote.
A second fault of the same age is already visible. One failed component on an appliance where nothing else has been touched is a repair. The same component on an appliance whose door has started to drop and whose panel has gone intermittent is a package reaching the end of a wear class together, and the honest answer changes.
The part is superseded or scarce. A current stock part is a repair with a known end. A part that has been superseded twice, or that is not sold to independent trade at all, is a repair whose outcome nobody can promise, and we would rather say so before the diagnostic fee than after it.
The opening no longer suits anything current. Cutout dimensions move. If the appliance in the wall cannot be matched by a unit on sale now, replacing it is not an appliance purchase — it is a cabinetry project, and it belongs in the comparison at its real size.
What to measure before you decide
If you are weighing this up before calling anyone, three measurements and one look are worth more than any amount of reading:
- The height, width and depth of the opening, taken at the opening rather than off the appliance.
- Whether the appliance is panelled into the run or trimmed against it.
- The rating plate, which is usually behind the door or on the side of the cabinet opening — it decides which parts exist for your unit.
- Whether anything else in the same kitchen has started misbehaving.
What we do with it
The diagnostic proves which part has failed, which puts you on a single row of the repair table rather than somewhere in the whole book. Against that, the appliance-only replacement figure. Both are written down, the comparison is made in front of you, and if the answer is replace, that is what the estimate says.
We do not sell appliances. That is precisely what makes the recommendation worth reading.