Manufacturers’ service intervals are written for a continent. They do not know that your condenser sits four hundred metres from the Salish Sea, or that your crawlspace does not properly dry out between October and April.
The South Coast is an unusually gentle climate to live in and a fairly hard one on mechanical equipment. Here is what that means specifically.
Salt air and outdoor coils
If you are in White Rock, Crescent Beach, Boundary Bay or anywhere with genuine sea exposure, the aluminium fins and copper tubing on your outdoor condenser are under continuous chloride attack.
What it looks like: white powdery corrosion on the fins, pitting, and eventually fins that crumble when brushed. What it costs you is heat transfer — a corroded coil rejects heat poorly, so the system works harder for the same cooling, and the compressor pays for it.
What actually helps:
- Rinse the coil with fresh water two or three times a year. Power off, gentle flow, from the inside out where you can reach. This is genuinely effective and costs nothing.
- Specify coated coils on new equipment near the water. Manufacturers offer factory-applied coil coatings for coastal installation. It is a modest premium at purchase and it materially extends life.
- Do not enclose it. People build decorative screens around condensers to hide them, which traps salt-laden air and blocks the airflow the unit needs.
Humidity and the condensate side
We run high relative humidity for a large part of the year. That means more condensate than a dry climate produces, and condensate lines that stay wet longer.
Wet lines grow biofilm. Biofilm blocks the trap. A blocked trap trips the float switch and shuts the equipment down — on a furnace that presents as no heat, which is why it appears on the furnace troubleshooting checklist.
It also means standing water where you do not want it. We have pulled apart plenty of high-efficiency furnaces where a season of untreated condensate did more damage than a decade of running.
Clearing and treating the condensate path is a routine maintenance item and it is one of the higher-value ones here specifically.
Crawlspaces, and the ductwork in them
A great deal of Lower Mainland housing stock sits over a crawlspace, and a great many of those crawlspaces are damper than their owners believe.
Ductwork running through damp, unconditioned space does two things. It loses efficiency, because you are heating a crawlspace. And it collects moisture on the outside of cold ducts in summer, which over years rots insulation and, in the worst cases, the joists nearby.
Worth checking, if you have a crawlspace and have not looked in a while:
- Is the vapour barrier intact and covering the ground?
- Is duct insulation dry, or does it feel heavy and cold?
- Any visible mould on joists near ductwork?
- Any standing water at all?
This is not glamorous and it is not something anyone sells aggressively, but on older Surrey and Delta houses it is frequently where the real efficiency loss lives.
Mild winters, longer running hours
Counter-intuitive one: a mild wet winter can be harder on equipment than a cold dry one, because the system runs more hours at partial load rather than fewer hours at full output.
More running hours means more filter loading, more blower wear, and more cycles on igniters and controls. Equipment here often accumulates more operating hours than the same unit would in a colder, drier climate that runs it flat out for a shorter season.
Practically, that means filter changes matter more here than the packaging suggests. Quarterly rather than twice a year is realistic in most houses, and more if there are pets.
Heat pump defrost
If you have a heat pump, coastal damp affects it in one more way: frost formation. Humid air at near-freezing temperatures frosts an outdoor coil faster than dry air at the same temperature.
That means more defrost cycles than the same unit would run in Kamloops. It is normal — the unit reversing and steaming for a few minutes is it working correctly, not failing. But it does mean the defrost controls and the sensor get more use, and they are worth checking on service.
What we actually do about it
The routine that suits this climate is not the routine printed in the manual:
- Filters quarterly, not annually
- Condensate path cleared and treated at every service, not just when it blocks
- Outdoor coil rinsed more often than the manual says, especially near the water
- Crawlspace looked at at least once, properly, if nobody has
That is roughly what our maintenance plans are built around, and the scheduled reminders exist because none of the above is memorable. Four filters a year comes with the plan for the same reason.
None of this is exotic. It is just that generic advice written for a continental climate misses the two things — salt and damp — that shorten equipment life here. If you want the full HVAC picture for a coastal house, that is the lens we look through.