Hot Tub in Winter: Keep Running or Winterize? Costs and Risks Compared

Winter is the toughest time of year for a hot tub. The water inside holds at 37°C while outside it can drop to −15°C — and that temperature gap is what determines how much your hot tub consumes in winter, and whether it survives the frost undamaged. You essentially have two paths: let the hot tub run all year round, or drain and winterize it completely. The wrong choice can mean either needlessly high electricity bills or, in the worse case, a burst pipe costing tens of thousands of crowns to fix.

In this article you’ll find a concrete comparison of energy use between a well- and a poorly insulated hot tub, clear rules for both strategies, and the exact winterizing procedure step by step.

How much a hot tub actually uses in winter

The main cost driver of winter operation is maintaining the water temperature. The better insulated the hot tub — full-foam shell insulation, a quality thermal cover, an insulated base — the less heat escapes and the less the heater has to work to compensate. The gap between a well- and a poorly insulated tub is dramatic in winter — easily double the consumption.

The table below compares approximate consumption and costs at outdoor temperatures around freezing, with electricity priced at roughly 6–7 Kč/kWh (approx. €0.24–0.28/kWh) — Czech market pricing, used here for reference, with the table calculated at a mid-point of 6.5 Kč/kWh (approx. €0.26/kWh):

Parameter	Well-insulated hot tub	Poorly insulated hot tub
Winter consumption (kWh/day)	4–6 kWh	8–12 kWh
Monthly consumption (kWh)	approx. 120–180 kWh	approx. 240–360 kWh
Monthly cost (at 6.5 Kč/kWh)	approx. 800–1,200 Kč (approx. €32–48)	approx. 1,550–2,350 Kč (approx. €62–94)
Cost per winter season (5 months)	approx. 4,000–6,000 Kč (approx. €160–240)	approx. 7,800–11,700 Kč (approx. €312–468)

The difference over a single winter can easily exceed 5,000 Kč (approx. €200) — purely down to insulation. If you have an older tub with a thin cover that’s also become waterlogged, expect figures toward the upper end. For a more detailed cost breakdown covering heating, filtration, and chemicals, see how much a hot tub costs to run per month.

What affects consumption the most

• Cover quality — a waterlogged or cracked cover is the biggest heat thief of all. Replacing it typically pays for itself within one or two winter seasons.
• Set temperature — every extra degree means greater heat loss. Between 37 and 40°C, the difference is noticeable in winter.
• Heater type — a hot tub with a heat pump heats more cheaply than one with a standard electric heating element, though heat pump efficiency drops in severe frost.
• Shell and base insulation — full-foam insulation retains heat far better than the reflective foil used in cheaper models.

Strategy A: Year-round operation

Keeping a hot tub running through winter makes sense if you genuinely plan to use it — a hot tub steaming away in the snow is an experience many people buy one for in the first place. But running it requires discipline, because any lapse in care is punished harshly in freezing conditions.

When year-round operation pays off

• You use the hot tub at least once a week, even in winter.
• You have a modern, well-insulated tub with a quality thermal cover.
• The property is permanently occupied and you have a reliable power supply (low risk of a long outage).
• Your hot tub has a freeze-protection mode (a “smart winter mode”).

How to run a hot tub safely through winter

1. Maintain a steady temperature of 37–38°C. Don’t lower the temperature “to save money” between uses — reheating water that’s cooled down uses more energy than you’d save, and increases the risk of freezing in cold weather.
2. Ensure continuous circulation. Set the filtration cycles so the pump runs regularly throughout the day and night. Moving water doesn’t freeze — standing water in the pipes does.
3. Invest in a quality insulating thermal cover and add a floating thermal blanket on the water surface. Always fasten the cover down securely so heat doesn’t escape, even in wind.
4. Watch the water level and chemistry. A low water level can expose the jets and heater. Maintain pH at 7.0–7.4 and the recommended disinfectant level even in winter — cold water changes chemical demand more slowly, but don’t skip the checks.
5. Verify the freeze-protection function. Check whether your hot tub can automatically start circulation or heating when the water temperature approaches a risky threshold. If not, an uninterrupted power supply becomes all the more important.
6. Clear snow off the cover. A heavy layer of wet snow will dent the cover, damage its insulation, and speed up waterlogging.

Strategy B: Full winterizing with draining

The second option is to shut the hot tub down completely for winter. That means draining all the water — not just from the tub itself, but critically from the pipework, jets, pump, and heater. It’s the residual water left in the plumbing that cracks things once it freezes.

When winterizing is the better choice

• You won’t be using the hot tub over winter.
• It’s at a cottage or holiday property without regular supervision.
• Extended power outages are a risk, or you’re closing up the property for winter entirely.
• You have an older, poorly insulated tub where winter running costs are disproportionately high.

Winterizing procedure, step by step

1. Disconnect the power. Switch off the hot tub and the circuit breaker — neither the pump nor the heater should ever run dry.
2. Drain the tub. Open the drain valve and route the water away from the tub so it doesn’t freeze at the base of the structure.
3. Blow out the pipework and jets. Using a wet/dry vacuum on blow mode, or a compressor, push air through every jet until no more water comes out. This is the single most important step in the entire process.
4. Drain the pump and filter. Loosen the pump fittings and let any residual water run out. Remove the filter cartridge, rinse it, and store it somewhere dry.
5. Remove residual water from low points. Use a sponge or vacuum to soak up water from the floor, seats, and any recesses where it could pool and freeze.
6. Dry and dehumidify. Let the tub and the equipment bay dry out thoroughly. For enclosed or indoor hot tubs, a dehumidifier helps prevent mold from forming.
7. Cover the hot tub. Fit the thermal cover and, ideally, add a winter tarp against snow and debris. Secure the cover against wind.

If you’re not confident about the winterizing process — especially blowing out the plumbing — have a service company handle the first winterizing and watch how it’s done. For an overview of what to book with a professional, see end-of-season pool service: what to book.

Risk of freezing: the most expensive damage a hot tub can suffer

Whichever strategy you choose, the biggest threat remains water freezing inside the system. As water turns to ice it expands, and it will literally tear apart whatever contains it — plastic pipework, jet fittings, the pump body, and the heater. It only takes a few hours of hard frost on a hot tub that’s stopped circulating (say, due to a power outage or a pump fault).

The consequences tend to be unpleasant and expensive:

• Burst pipes and fittings are often hidden inside the shell — repairing them means taking the tub apart, and can cost anywhere from a few hundred to several thousand euros.
• A damaged pump or heating element has to be replaced.
• Water from a burst system can undermine the surrounding structure.
• Insurance often won’t cover frost damage caused by neglected maintenance.

So the simple rule stands: either keep the hot tub warm and circulating (Strategy A), or get every last drop of water out of it (Strategy B). The worst state is the one in between — a powered-off hot tub with water forgotten in the pipes. That’s exactly the setup most likely to crack at the first hard frost.

Which strategy should you choose

Simplify the decision with a few questions: Will I actually use the hot tub in winter? Is it well insulated? Do I have a reliable power supply and someone to keep an eye on it? If you answer yes to most of these, year-round operation makes sense. If the answers lean toward no — especially for holiday properties and older tubs — go with full winterizing. Either way, checking the condition of the tub, cover, and plumbing before winter always pays off.

Frequently asked questions

Is it worth running a hot tub in winter at all?

Yes, if you actually use it and it’s well insulated. Winter operation of a well-insulated hot tub costs roughly 800–1,200 Kč (approx. €32–48) a month. For a poorly insulated tub that isn’t used regularly, full winterizing is more economical.

What’s the ideal hot tub temperature in winter?

For comfortable, safe use, maintain 37–38°C. Don’t lower the temperature between uses “to save money” — reheating water that’s cooled down uses more energy, and raises the risk of freezing in cold weather.

What happens if a hot tub freezes in winter?

Frozen water expands and can split open the pipework, jets, pump, and heater. Repairing plumbing hidden inside the shell can cost anywhere from a few hundred to several thousand euros, and insurance often won’t cover damage caused by neglect.

Do I have to drain a hot tub completely when winterizing it?

Yes. Draining just the tub isn’t enough — the critical part is the residual water in the pipework, jets, pump, and heater. These need to be blown out with a compressor or a wet/dry vacuum, since that’s exactly where water cracks things when it freezes.

How long does winterizing a hot tub take?

If you know the procedure, plan on 1–3 hours depending on the tub’s size and how thoroughly you blow out the plumbing. It’s worth doing your first winterizing alongside a professional so you know what to watch for.

How much can I save with better insulation?

A well-insulated hot tub uses roughly half as much energy in winter as a poorly insulated one — typically a difference of 700–1,000 Kč (approx. €28–40) a month, or well over 5,000 Kč (approx. €200) across a winter season. Replacing a waterlogged thermal cover therefore pays for itself very quickly.

Get help with winterizing

Not confident about blowing out the plumbing, or would rather not risk a burst pipe? Hire a service company to winterize it for you — submit a request and compare quotes from vetted companies in your area.