Repair or replace · August 2026 · HVAC Iowa City

Repair or replace: the honest furnace math

Sooner or later every furnace owner in Iowa City faces the same question: fix it again, or replace it? Companies that only sell replacements answer one way, and companies that fear the big conversation answer the other. Here's the actual math we use, the same way we'd use it in our own basements.

Start with age, because age decides most of it. Manufacturers publish a service life of about 15 to 20 years for a gas furnace. And in this town, age is the common case: the median Iowa City home was built in 1984, per Census Bureau housing data, which means most houses here are on their second or third furnace already. Knowing where yours sits on that clock is half the answer. The install date is usually on a sticker on the cabinet, or we can read it from the serial number.

Then weigh the repair against the age. A young furnace with a small repair is an easy yes: fix it. An old furnace with a big repair is the honest no: a new igniter in year eight is money well spent, but a blower motor and a control board in year nineteen is spending real money to buy a short reprieve. The gray zone in between is where you want both numbers, repair and replace, side by side in writing, so you're comparing facts instead of fears.

Our own tiebreaker is the two-winters test. Iowa City winters are long, and a furnace here works hard for five months straight, so the question that matters is simple: does this furnace honestly have two more winters in it after this repair? If yes, we say so and do the small fix. If no, we say that too, even though it's the harder conversation. Some of our favorite calls end with us telling someone not to buy a furnace yet.

A few signals that push toward replace, whatever the age: repairs are stacking up season after season, the heat exchanger is cracked, parts for your model are getting hard to find, or the gas bills keep climbing while the comfort keeps falling. None of these alone is a verdict. Together, they're the furnace telling you where this is headed.

There's also a way to buy yourself better information: maintenance. A fall tune-up on an aging furnace comes with a written condition report, which turns next winter from a guess into a forecast. Plenty of Iowa City homeowners run a furnace confidently into year eighteen because the report says it's healthy, and plenty of others get a season's warning that the end is coming, which is exactly the head start you want on a decision this size.

Whichever way your math points, the process is the same with us: we diagnose it in your Iowa City home, show you the failed part, and put the price in writing before any work, with both paths quoted when age makes it a real question. Repair or replace, the decision stays yours.