Repair or replace
Age × repair cost
over $5,000 → replace
Take the age of the unit in years. Multiply it by what the repair costs. If the answer is over five thousand, replacing is the better spend. That is the rule this shop uses, it is on the website so you can run it before we arrive, and if our recommendation disagrees with it we owe you a reason.
Six worked examples
| The situation | Age | Repair | Product | The rule says |
|---|---|---|---|---|
| Eight-year-old furnace, capacitor | 8 | $185 | $1,480 | Repair |
| Twelve-year-old furnace, blower motor | 12 | $640 | $7,680 | Replace |
| Fourteen-year-old furnace, ignitor and a flame sensor | 14 | $420 | $5,880 | Replace |
| Sixteen-year-old furnace, control board | 16 | $620 | $9,920 | Replace |
| Eighteen-year-old air conditioner, compressor | 18 | $1,900 | $34,200 | Replace |
| Twenty-two-year-old furnace, heat exchanger | 22 | $1,800 | $39,600 | Replace |
Three times the sum is wrong
A rule with no stated exceptions is a rule somebody gets held to on the day it does not fit. These are ours, printed next to it rather than mentioned afterwards.
A cracked heat exchanger, at any age
Replace, and we will not repair it. That is the one place where we will not take the money, and it is the only carbon monoxide sentence on this website.
You are selling the house within two years
Repair, usually, even when the sum says replace. A new furnace does not come back in the sale price and the next owner gets a system they did not choose.
The system is R-22 and needs refrigerant
Replace. Not because the equipment is bad, but because R-22 has not been made since 2020 and the reclaimed stock is now the most expensive part of the repair.
What the rule cannot know
Whether the ductwork is any good. Whether the furnace was oversized when it went in — about a third of what we see here is, and an oversized unit short-cycles and dies early whatever the arithmetic said. Whether there is a second failure a fortnight behind the first one. A technician can see all three and a formula cannot, which is what the $135 is actually buying.