The HVAC Maintenance Checklist

HVAC maintenance splits into two layers: the monthly DIY layer, which is mostly filters and keeping equipment clear, and the annual professional layer, which covers combustion, refrigerant, safety controls and measurements you cannot take yourself. This checklist covers both layers for furnaces, heat pumps and AC systems in Puget Sound homes, including the checks specific to our wet, mild climate.

What filter schedule should you actually follow?

The filter is the single most important item on this list, and the schedule depends on the filter you run.

• Basic 1-inch filters (MERV 6 to 8): replace every 1 to 2 months during heating season. They are cheap and they load fast.
• Better 1-inch filters (MERV 11 to 13): replace every 2 to 3 months. Higher MERV catches finer particles, including wildfire smoke, which matters more here every summer.
• Media filters (4 to 5 inch): replace every 6 to 12 months. If your system has a media cabinet, this is the best filtration-per-hassle deal in the house.

Two cautions. First, higher MERV is not automatically better: a dense filter on a system with weak airflow makes the airflow worse. If you want MERV 13, confirm your blower and ducts can support it. Our explainer on what MERV ratings mean covers how to choose. Second, a heat pump runs year round, so it eats filters year round. Do not stop checking in June.

What do coils and the condensate system need?

Heat moves through coils, and dirty coils move less of it. The outdoor coil sits in Northwest weather collecting fir needles, cottonwood fluff and moss shade debris. Twice a year, cut power at the disconnect, rinse the outdoor coil gently with a hose, and keep two feet of clearance on all sides. Do not use a pressure washer, which folds the fins. The indoor coil is a professional job: it lives inside the air handler and cleaning it wrong causes damage.

The condensate system is the quiet failure point. Cooling and high-efficiency heating both produce water that leaves through a small drain line, and that line grows algae until it clogs. A clogged drain shuts the system down on the hottest week or leaks water into the furnace cabinet and the floor below. Check that the drain drips during operation, and have the line flushed at the annual service. If your system has a condensate safety switch, test it. If it does not, ask for one.

What should heat pump owners check in winter?

Puget Sound winters are heat pump weather: cold enough that the outdoor coil frosts, wet enough that it frosts often. A healthy heat pump runs a defrost cycle, and knowing what normal looks like is the check. Normal is a brief pause, a whoosh as the system reverses, steam rising off the outdoor unit for a few minutes, then back to heating. Worth a service call: ice that builds into a solid block and never clears, defrost cycles running back to back, or the unit sitting encased in ice after a freezing rain. Also keep the base of the unit clear so defrost meltwater can drain instead of refreezing underneath, and never chip ice off the coil. Defrost also makes noises that alarm first-time heat pump owners: a swoosh, a brief gurgle, sometimes a soft thud as the reversing valve shifts. Those are normal. Grinding, screeching or a compressor that hums without starting are not, and they justify a service call the same week.

Why do ducts and static pressure belong on the checklist?

Your equipment is only half the system. The ducts are the other half, and in local homes they often run through crawlspaces where connections loosen and rodents test the insulation. Once a year, look at the visible duct runs: disconnected joints, crushed flex duct and dirt streaks at seams, which mark air leaks.

The number behind duct health is static pressure, the resistance your blower pushes against. High static pressure makes systems loud, weakens airflow to far rooms and shortens blower life, and it is the hidden reason many correctly sized systems underperform. Read what static pressure is to understand the measurement, and ask for it at your tune-up. If rooms will not heat or cool evenly, or your ducts are older than the house's second owner, run the numbers with our duct replacement calculator before assuming the equipment is the problem.

What does a professional tune-up actually include?

A real tune-up is measurement, not a filter change and a glance. On the heating side: combustion analysis, heat exchanger inspection, gas pressure, safety control verification and a carbon monoxide check. On the cooling and heat pump side: refrigerant charge verification, capacitor and contactor checks, coil condition, defrost operation and amp draws against nameplate. On both: static pressure, temperature rise or split, condensate service and a written report of what was measured. That report is also your warranty documentation, since most manufacturers require proof of annual professional service. See what our seasonal tune-up covers, and book heating service in early fall before the first cold snap fills every schedule in the region.

How does this fit your yearly routine?

Simple cadence: filters monthly, outdoor unit and condensate checks in spring and fall, duct walk-through once a year, professional heating service in fall, cooling or heat pump service in spring. This checklist is the deep single-trade layer of a larger system: our annual home maintenance checklist covers every system in the house, and home maintenance by season arranges it all on a Puget Sound calendar.

Common questions

Can I skip professional service if I change filters religiously?

Filters protect airflow, and nothing else. Refrigerant charge, combustion safety, electrical wear and static pressure all drift without any symptom a homeowner can see, and they are where the efficiency and safety problems live. Filters are necessary, not sufficient.

How often does a heat pump need professional service?

Twice a year, because it is both your heating and your cooling system and it runs in both seasons. A furnace plus AC setup can also justify two visits: heating in fall, cooling in spring.

Is duct cleaning part of maintenance?

Not routine maintenance. Duct cleaning has real but narrow use cases, like post-construction dust or verified contamination. Duct sealing and static pressure correction fix more comfort problems than cleaning does. Be suspicious of anyone selling it annually.

What to do next

Check your filter today, put the schedule that matches your filter type on your calendar, and book the professional visit for whichever season is next. Eco services furnaces, heat pumps and AC across the Puget Sound. Start with our heating services or book online, or call (206) 970-1031, 6 AM to 6 PM every day.