Repair or Replace? The 50% Rule Every Homeowner Should Know

A technician is standing in your kitchen and the dishwasher needs a $380 control board. A new comparable machine is $650. What do you do? This decision gets made badly all the time, usually because it is made under pressure with a technician waiting. It comes down to one piece of arithmetic you can do in your head. ### The rule If the repair costs more than 50% of a comparable new unit, replace it. $380 on a $650 machine is 58%. Replace. The reasoning: you are paying more than half the price of a full working life to buy whatever is left of an old one. On an appliance already near the end of its span, the next failure is usually not far away, and you will have spent the money twice. ### The age adjustment The raw rule ignores age, which matters enormously. Tighten it as the unit gets older: - Under 3 years old: repair almost always, and check the warranty first - 3 to 7 years: apply the 50% rule as written - 7 to 10 years: drop the threshold to about 35% - Over 10 years: repair only cheap, simple failures ### The HVAC version Heating and cooling has its own variant, because the units are expensive and long-lived. Multiply the age in years by the repair cost. Over $5,000 and you should be replacing. A $400 repair on a 10 year old system: 10 × 400 = $4,000. Repair. The same repair on a 15 year old system: 15 × 400 = $6,000. Replace. ### What the rule leaves out Arithmetic is not the whole answer. Adjust for: Efficiency. A 15 year old AC may run at SEER 10 against SEER 16 today. If you are cooling a house through a Florida summer, the running cost difference can be $40 a month, which changes the maths considerably. How long you are staying. Replacing a water heater two months before selling mostly benefits the buyer. A repair may be the rational choice even when the rule says otherwise. Failure pattern. Two repairs in eighteen months is data. The rule looks at one repair in isolation; you should look at the history. Parts availability. On units over about 12 years old, parts get scarce and expensive, and a cheap repair today can become an impossible one next year. ### How to use it on the doorstep Ask the technician two questions: "What is the total for this repair?" and "Realistically, how much life does this unit have left after it?" A straight answer to the second question tells you a great deal about who you are dealing with. A technician who says "honestly, on a unit this age I would put the money toward a replacement" is one worth keeping the number of. ### The decision, in one line Repair cost over half the replacement price, or the unit is past its expected span, means replace. Otherwise repair — and get the total in writing before anyone starts. If you are unsure which side of the line you are on, post the job and our agents will collect both repair and replacement quotes from local technicians so you can see the real numbers side by side.