# Heat Pump Maintenance: A Seattle Owner's Guide > Heat pump maintenance for Seattle homes: filters, coil care, clearances, condensate drains, coastal corrosion and what affects lifespan. Start with the basics. URL: https://seattleheatpumpco.com/guide/heat-pump-maintenance/ Updated: 2026-10-21 *Most of what keeps a heat pump healthy is simple and up to the owner. Here is what to do, how often, what salt air near Puget Sound changes, and which signs need a technician.* Heat pump maintenance is mostly simple owner work: keep the filter clean, keep the outdoor coil clear and rinsed, leave space around the outdoor unit, and make sure the condensate drain flows. Those few habits protect airflow, which protects efficiency and the compressor. Near Puget Sound, salt air adds regular rinsing of the outdoor coil to the list. [The Seattle Heat Pump Company](https://seattleheatpumpco.com/) plans ducted heat pump installations and replacements across Seattle and King County, carried out by licensed and insured contractors. It does not sell maintenance plans or service visits; this guide is education for owners, whoever installed the system. It covers the routine tasks, what salt air changes, what affects heat pump lifespan, and which symptoms mean it is time to call a qualified service technician. **Key takeaways** - Filters, outdoor coil care, clearances and the condensate drain cover most owner maintenance. - Carrier advises washing coastal outdoor units about every three months; no manufacturer publishes a distance threshold. - Lifespan depends on sizing, airflow, installation quality and care; there is no single reliable figure. - Persistent ice, frequent backup heat and water near the indoor unit are signs to call a technician. ## The filter The filter protects the indoor coil and the blower from dust. A clogged one restricts airflow, and restricted airflow is the root of many heat pump problems: lower efficiency, longer run times, more backup heat in winter, and in cooling mode, an indoor coil that can get cold enough to freeze. Check it monthly during the heating and cooling seasons. Replace a disposable filter, or clean a washable one, when it looks dirty or on the schedule its maker lists. A heat pump runs longer hours than a gas furnace, often most of the day in a Seattle winter, so filters load up faster. Higher-rated filters trap finer particles, which helps during wildfire smoke, but a dense filter in a slot designed for a thin one can choke airflow. If you want a higher-rated filter, ask whether the system's filter rack and blower can handle it, or whether a deeper media cabinet makes sense. That airflow question connects to the ducts themselves; see [heat pumps with existing ductwork](https://seattleheatpumpco.com/heat-pump-existing-ductwork/). ## The outdoor unit ### Clearances The outdoor unit pulls air through its coil and blows it out the top or front. Anything that blocks that path makes it work harder. Keep plants, fences, stored items and debris back from the unit, a couple of feet as a general rule, and follow the manufacturer's stated clearances where they are larger. Leave the top clear. In fall, leaves collect against the coil and in the base pan; clearing them by hand is the easiest maintenance there is. Seattle rarely gets enough snow to bury a unit, but on the few days it does, keep the top and sides clear and the base free to drain. A unit should sit on a pad or bracket high enough for defrost water to drain away. ### The outdoor coil Dust, pollen, cottonwood fluff and grime build up on the coil fins over time. With the power off at the disconnect, rinse the coil gently with a garden hose from the inside out where the cabinet allows, or from the outside in at low pressure. Never use a pressure washer, which flattens the thin fins. Bent fins can be straightened with a fin comb; large areas of damage are a technician's job. ### Defrost and ice In damp weather near freezing, frost builds on the coil and the unit runs regular defrost cycles to clear it, with steam and a pause in the fan. That is normal. A coil that stays solidly iced, or ice that builds up in the base pan and climbs into the coil, is not. It can point to blocked airflow, a defrost control fault, a drainage problem or low refrigerant, and needs a technician to tell which. The [how a heat pump works guide](https://seattleheatpumpco.com/guide/how-a-ducted-heat-pump-works/) explains the defrost cycle. ## Salt air and coastal corrosion Near salt water, airborne salt settles on the outdoor coil and cabinet. Salt holds moisture and accelerates corrosion of the aluminum fins, the joints between fins and tubes, fasteners and the cabinet. Corroded fins lose contact with the tubes and stop transferring heat well, and corrosion at joints can eventually cause refrigerant leaks. Carrier's owner guidance says coastal units need extra maintenance, including periodic washing about every three months. Mitsubishi Electric offers a protective coil coating and a seacoast protection package on some outdoor models. Neither manufacturer publishes a distance from the water at which coastal care begins, so the practical approach is to treat homes with clear exposure to Puget Sound winds, such as shoreline areas of [West Seattle](https://seattleheatpumpco.com/service-areas/west-seattle/), [Magnolia](https://seattleheatpumpco.com/service-areas/magnolia-queen-anne/) and [Burien](https://seattleheatpumpco.com/service-areas/burien/), as coastal. For an owner, coastal care means a gentle freshwater rinse of the outdoor coil and cabinet on a regular schedule, more often after windy winter storms. For a new installation or replacement, it means asking whether the model offers a coated coil or coastal package and where the unit can sit with the house sheltering it from the prevailing wind. The [heat pump replacement](https://seattleheatpumpco.com/heat-pump-replacement/) page covers what a replacement involves. ## The condensate drain In cooling mode, the indoor coil pulls water out of the air and drains it through a condensate line. Algae and debris can clog that line over time, and a clogged line backs up into the pan and overflows. Many installations include an overflow switch that shuts the system off when the pan fills, which protects the house but leaves you without cooling until the drain is cleared. At the start of each cooling season, check that water flows from the drain's end point when the system runs. Some drains have an access cap where a cup of water or a mild vinegar solution can be poured in to keep the line clear; follow the equipment maker's guidance. Water on the floor near the indoor unit, or a system that shuts off on a hot day, often points to the drain. ## Thermostat settings A thermostat set up for a furnace can make a heat pump lean on expensive backup heat. Avoid deep nighttime setbacks, check that emergency heat isn't left on, and confirm that the backup heat lockouts haven't been reset to defaults after a thermostat change. The [backup heat settings guide](https://seattleheatpumpco.com/guide/heat-pump-backup-heat-settings/) explains each setting. ## What a professional checkup covers Some tasks need a qualified HVAC service technician: cleaning the indoor coil, checking electrical connections and capacitors, measuring airflow and static pressure, checking refrigerant pressures if performance has dropped, testing the defrost controls and the backup heat. A refrigerant charge should not need topping up; a system that is low has a leak, and adding refrigerant without finding the leak only postpones the problem. Manufacturer warranty terms vary, and some list maintenance or registration conditions, so it is worth reading yours. The commissioning records from installation are valuable here. They give a technician a baseline of airflow, pressures and temperatures to compare against. The [installation process guide](https://seattleheatpumpco.com/guide/heat-pump-installation-process/) describes what those records contain. ## What affects heat pump lifespan There is no single reliable heat pump lifespan figure, and any number quoted without context is a guess. What can be said is which factors shorten or lengthen service life: - **Sizing.** An oversized system short-cycles, and frequent starts wear the compressor. The [sizing guide](https://seattleheatpumpco.com/guide/heat-pump-sizing-manual-j/) explains why. - **Airflow.** Restrictive ducts and dirty filters make every component work harder. - **Installation quality.** Clean brazing with nitrogen, a proper pressure test and a deep vacuum keep moisture and debris out of the refrigerant circuit. - **Correct charge.** Too much or too little refrigerant stresses the compressor. - **Care.** Clean coils and filters, clear drains and clearances. - **Exposure.** Salt air near the water, without regular rinsing or coatings. ## Signs to call a technician Some symptoms have several possible causes, so they need diagnosis rather than a guess: persistent ice on the outdoor coil, backup heat running often above freezing, short cycling, rooms that no longer warm up, water near the indoor unit, a sudden rise in electricity use, or new rattles, grinding or buzzing. When a repair is large and the system is old, the decision between repair and replacement deserves its own look; the [refrigerant guide](https://seattleheatpumpco.com/guide/heat-pump-refrigerant-change/) covers how Washington's refrigerant rule affects it, and the [replacement cost guide](https://seattleheatpumpco.com/guide/heat-pump-replacement-cost-seattle/) covers the budget. ## Questions ### How often should I change my heat pump filter? Check it monthly during the heating and cooling seasons and replace or clean it when it looks dirty, or on the schedule the filter maker lists. A heat pump runs long hours and needs more airflow than a furnace, so a clogged filter costs more efficiency than it would on a gas system. Houses with pets, dust or wildfire smoke need more frequent changes. ### Does salt air damage heat pumps near Puget Sound? Salt carried in the air can corrode outdoor coils and cabinets near salt water. Carrier advises extra maintenance for coastal units, including washing about every three months, and Mitsubishi Electric offers coil coatings and a seacoast protection package on some outdoor models. Manufacturers don't publish a distance threshold, so shoreline homes should plan for regular rinsing. ### What shortens a heat pump's service life? Mostly conditions that make the compressor and fans work harder than designed. An oversized system that starts and stops constantly, ducts or filters that starve it of air, moisture or debris left in the refrigerant circuit at installation, a wrong charge, and salt corrosion on an unrinsed outdoor coil all take a toll. No reliable single lifespan figure exists, so care and installation quality matter more than a number.