Repair it or replace it — and the age is the wrong place to start

This is a repair at any age

The part that failed is an ordinary consumable and the cost of replacing it is nowhere near the cost of a system. Age does not change that — a capacitor on a twenty-year-old condenser is still a capacitor.

• Ask what the repair costs before agreeing to anything, and ask for it separately from any replacement quote.
• Ask why it failed. A part that failed because of a restriction, a bad connection or a charge problem will do it again.
• If you are also being quoted a replacement, that is not automatically wrong — but you are entitled to both numbers and to decide with them in front of you.
• If the system is genuinely near the end, the honest framing is “this repair is sensible and here is what to expect next”, not “it is not worth repairing”.

A major failure this early should not be yours to pay for

A compressor or sealed-system failure under about eight years is unusual, and on most equipment the part is still covered. Nobody should be quoting you a replacement system before the warranty position is established.

• Find the model and serial numbers and the installation date. Registration within the manufacturer’s window frequently extends the term.
• Parts and labour are usually separate. The part may be free and the labour not, which is a real cost but a very different one.
• Ask why it failed this early. A compressor that died at six years usually had help — low charge running for a long time, a restriction, an electrical fault, or a system that was never commissioned.
• If it is not covered, then this becomes the eight-to-fifteen arithmetic, and you should see both numbers.

This is genuinely arithmetic, not judgement

A real repair on equipment in the ambiguous band. Neither answer is obviously right, and anybody telling you it is obvious has not done the sum in front of you.

• The repair cost, written down, including parts and labour.
• The replacement cost, written down, for equipment sized from a calculation rather than matched to the old plate.
• The age from the serial number, not an estimate.
• What else is likely next. A contractor who has just had the panels off can tell you the condition of everything they saw, and that is the piece of information that actually decides it.
• What the ductwork can carry. If a new system needs more air than the ducts can deliver, the replacement quote is incomplete and you will be disappointed.

We will give you both figures and a recommendation, and we will tell you when the repair is the better bet even though it is the smaller invoice.

But it should still be shown, not asserted

A major sealed-system failure on equipment over fifteen years is the case where replacement usually does win the arithmetic — particularly on R-22, where the refrigerant cost alone can be a substantial part of the repair.

• Ask for the repair figure anyway. Not to argue, but because a recommendation you can check is worth more than one you cannot.
• Ask what the diagnosis was based on — readings, not impressions.
• Insist the replacement is sized from a heat loss and heat gain calculation. Matching the old plate repeats whatever mistake was made the first time, and equipment fitted before about 2000 was routinely far too big.
• Have the ductwork measured in the same visit. It is the most common reason a new system disappoints, and the cheapest moment to find out.
• Get the commissioning figures afterwards — airflow balanced and recorded, charge verified. Without them a new system is an unknown quantity from day one.

This one is not a money decision

A cracked heat exchanger is a safety finding. The appliance is shut off and tagged and it should not be run while anybody decides what to do next, whatever the weather is doing.

• If a carbon monoxide alarm has sounded, or anybody feels unwell, leave the building and call 911 from outside, then the gas utility. That comes before every other line on this page.
• Ask to be shown the finding, and ask for it in writing. A condemned appliance is a serious statement and a reasonable contractor will document it without being asked.
• A second opinion is entirely reasonable on a condemnation, and no competent contractor will be offended. What is not reasonable is running the appliance while you get one.
• Check the warranty on the part. Exchangers often carry a long or lifetime parts warranty; the labour usually is not covered, and on an older furnace that labour frequently approaches the cost of a new appliance.
• Ask about temporary heat if this is January. That is a real problem and it deserves a real answer rather than pressure to sign something today.

Nothing has failed, so replacing is a gamble

Replacing working equipment to cut a running cost is the one version of this decision that regularly disappoints, because four of the five things that make a system expensive to run are still true the day after a new one is installed.

• Duct leakage, tested rather than inspected. It is a number, and in a house with ducts in an attic or crawlspace it is usually the largest single figure.
• Static pressure and register airflow. High static pressure means the system is fighting the ductwork, and better equipment fights it harder.
• The condenser coil and the charge. A blocked coil or a system running short costs you continuously and neither is visible on a bill.
• Sizing. An oversized system short-cycles, never dries the air, and costs more than a right-sized one.
• Auxiliary heat on a heat pump — invisible, expensive, and a whole season goes by before anybody looks.

If those all come back clean, then a replacement on efficiency grounds is a reasonable conversation — and it will be a much better one, because you will know what the new system is being asked to work with.