Winterizing is standard advice for pools. It gets repeated for hot tubs, and for most BC owners it is exactly the wrong move.
The short version: leave it running. Winter is when a hot tub is worth owning, and a running spa is a safer spa.
Why Running It Is Safer Than Shutting It Down
People assume a drained tub cannot freeze. In practice a drained spa is more vulnerable than a running one, because draining never gets all the water out. Residual water sits in low points of the plumbing, in the pump housing, in the heater, in jet bodies. That is precisely the water that freezes, expands and cracks things, and you will not find out until spring.
A running tub, by contrast, is circulating warm water through every line continuously and has freeze protection in the control system. The pipework never gets near freezing.
The Real Winter Cost
Running costs do rise in winter because the heater works against a bigger temperature gap. On a well-insulated tub in BC the swing is modest. Across the year the range is roughly $10 to $40 per month at BC Hydro's Step 1 and Step 2 rates of 10.97 and 14.08 cents per kilowatt hour, with winter at the upper end. A tub with a waterlogged foam cover sits in a different range entirely, closer to $25 to $75, and winter is when that gap is widest, because most heat loss goes out through the top.
Winter Routine
- Keep the cover sealed. The single biggest lever. Check the seal after wind, and do not leave a corner flipped back.
- Clear snow, do not let it accumulate. A rigid cover rated for 350 pounds handles a snow load, but a saturated foam cover can sag and eventually collapse under one.
- Keep the water level up. Low water can let the pump lose prime, and a pump that cannot circulate is how freeze damage starts.
- Check the filter more often. Cold water is denser and flow drops. A loaded filter matters more in January.
- Do not drop the temperature to save money. Reheating from low costs more than holding, and a lower set point reduces your freeze margin.
- Keep the path clear. The reason people stop using a hot tub in winter is almost always the walk, not the water.
Power Outages, Which Is the Actual Risk
Coastal BC gets winter storms and winter storms take out power. A short outage is nothing: a well-insulated tub with a rigid cover holds usable temperature for a long stretch, and the thermal mass of several hundred litres of hot water works in your favour.
The scenario worth planning for is a multi-day outage during a hard freeze. If that happens:
- Leave the cover shut and do not open it to check. Every look costs heat.
- If power is coming back within a day or so in normal BC winter temperatures, do nothing.
- If it is a genuine deep freeze and the outage is open-ended, either get generator power to the circulation pump or drain the system completely, including the pump and heater. Half measures are worse than either option.
When Shutting Down Does Make Sense
There are real cases: a property empty for months with nobody to check it, a move, or a renovation. If you are shutting down, do it properly. Drain fully, blow the lines out, remove drain plugs from the pump and heater, leave the equipment bay open to air, and cover the tub. Do not leave water sitting anywhere in the system.
Otherwise, run it. February at 39 degrees Celsius with rain coming down is the entire reason to own one. If you are unsure about your specific setup, ask us.
The Mistakes That Actually Cause Damage
Freeze damage in BC is rarely caused by cold alone. It is nearly always caused by a decision. The recurring ones:
- Turning the tub off to save money over a holiday. A powered-down tub full of water in a cold snap is the single most expensive thing on this list.
- A partial drain. Half empty is the worst state a spa can be in. Either full and running, or completely drained and blown out.
- Ignoring a low water level. If the pump loses prime it stops circulating, and freeze protection cannot protect water that is not moving.
- Leaving the cover unlatched. A wind event flips it, the tub sheds heat all night, and you find out in the morning.
- Letting the filter clog in December. Restricted flow reduces heat transfer and can trip the heater on a high limit exactly when you need it.
- Assuming coastal means mild. The Island and the Fraser Valley both get hard freezes, and they usually arrive with the storms that take the power out.
The through line is that a hot tub protects itself as long as it has power, water and flow. Nearly every winter horror story starts with one of those three being removed on purpose.
Frequently Asked Questions
Should I leave my hot tub on all winter in BC?
In almost every case, yes. A hot tub is cheapest and safest to run continuously through winter, and it is the season most owners actually want it. Draining a spa for winter creates freeze risk in whatever water stays trapped in the plumbing, which is the opposite of what people expect.
What happens to a hot tub in a power outage?
A well-insulated tub with a good cover holds usable temperature for a long time, and a short outage is a non event. Extended outages in sub-zero weather are the risk. If you lose power for more than a day in a hard freeze, either arrange generator power or drain the system fully rather than leaving it part full.
Is it more expensive to run a hot tub in winter?
Somewhat, since the temperature difference the heater works against is larger. In BC the seasonal swing on a well-insulated tub is modest, which is why the running range is quoted as $10 to $40 per month across the year rather than a single figure.