The home maintenance checklist nobody hands you with the keys

A heat pump heats and cools, so it runs through most of the year instead of one season. A yearly check covers refrigerant, coils, the defrost cycle and the electrical parts.

Your AC pulls water out of the air and drains it through a small pipe. Algae slowly clogs that pipe. When it backs up, it overflows into the ceiling or basement, or trips a float switch that shuts the AC off on a hot day.

A yearly service checks combustion, the venting and the pressure-relief valve. A poorly burning boiler wastes fuel and can produce carbon monoxide.

Air gets trapped at the top of a radiator. The top stays cold while the bottom is warm, you hear gurgling, and the boiler works harder to heat the room.

The mesh filters behind the front panel clog quickly. A clogged one cuts airflow and gives you that musty smell when the unit starts up.

A dusty filter makes the unit work harder and blow warmer air. It also lets dust coat the coil, which is much harder to clean.

Minerals from the water harden the pad until it stops absorbing water, and a crusty, damp pad grows mold that gets into the ducts.

Burning wood leaves creosote in the flue. It builds up and it is flammable, and it is what starts chimney fires. The fire safety standards (NFPA 211) call for a yearly inspection.

The anode rod corrodes on purpose, so the tank doesn’t. Once the rod has worn through, the tank starts to rust from the inside, and that is how most tanks end up leaking.

Scale coats the heat exchanger, so the water comes out lukewarm, the heater throws error codes, and the exchanger wears out early. With hard water, descale more often.

A sump pump can sit idle for months and then has to work during the worst storm of the year. A stuck float or a dead motor means a flooded basement.

Once the salt runs out, the softener can’t recharge and hard water comes back. It scales the faucets, the shower glass and the water heater.

A full cartridge drops your water pressure and stops filtering, and old sediment can grow bacteria.

The pre-filters protect the membrane. Once they’re spent, the membrane fouls and the water starts tasting off. Pre-filters usually last 6 to 12 months and the membrane 2 to 3 years.

Solids build up in the tank. If it isn’t pumped, they flow out into the drain field and clog it. A failed drain field is one of the most expensive repairs a house can need. The EPA suggests an inspection about every three years.

No one tests a private well for you. The EPA suggests testing every year for bacteria, nitrates, pH and dissolved solids.

Filters stop working once they’re full, and a slow ice maker or dispenser is often just a spent filter. Most makers say every six months.

Baked-on spills smoke and smell every time you preheat, and a thick layer can flare up.

Food and grease clog the little ports and the igniter, so a burner clicks without lighting or burns with a lazy yellow flame. A clean burner burns blue.

A seal that doesn’t close all the way lets cold air out, so the fridge runs longer to make up for it.

The metal filter under an over-the-stove microwave catches grease from every pan below it. Once it’s coated, smoke and grease get right past it.

If your microwave blows air back into the kitchen instead of outside, a charcoal filter soaks up the smells. It can’t be washed, and once it’s full it stops working. If yours vents outside, you don’t have one, so untick this.

Food film builds up under the splash guard and on the grinding chamber, and that is where the smell comes from.

Soap residue and moisture grow mildew, especially in front loaders. That is where the sour smell in clean towels comes from.

The auto-reverse is what stops a closing door from crushing a child, a pet or a car. Sensors get knocked out of line. Door makers and the CPSC say to test it monthly, so that’s the default. You can stretch it from the task if you need to.

Water left in the lines freezes, expands and splits pipes and valves, and you find the damage at spring startup.

Winter cracks heads and loosens fittings. A broken head or a leaking joint wastes water every time the system runs, and it’s easiest to catch while you watch it come back on.

The backflow preventer keeps sprinkler water, fertilizer and all, from being pulled back into your drinking water. Many water companies require a test every year by a certified tester.

Sealcoat keeps sun and water from breaking the asphalt down, and that’s what turns small cracks into potholes. Pick an asphalt-based sealer, not coal tar. Coal tar is full of chemicals linked to cancer, and several states have banned it.

Once the sealer wears off, the wood soaks up water, then it greys, cracks and splinters. If water soaks in instead of beading up, it’s time.

A dull blade tears the grass instead of cutting it, and old oil and stale gas are why a mower won’t start in spring.

Vacuuming doesn’t reach the grit that sinks to the bottom, and that grit wears the fibers down. Carpet warranties often require a professional cleaning about every year and a half, with a receipt to prove it.