How to winterize a hot tub comes down to one choice first: keep it full, hot and covered all winter, or shut it down completely. If you use the tub and your power is reliable, running it is usually simpler. If it will sit unused through freezing weather, drain it, get the water out of the pipes and pumps, protect the cover, and restart in spring. Your owner’s manual has the final word on your model.
Keep it running or shut it down?
The Caldera Spas Paradise Series owner’s manual says its spas are designed for year round use in any climate, and that you should drain and winterize only if the spa will sit unused for a long period in severely cold weather, because a power or equipment failure could let it freeze.
| Your situation | Better choice | Why |
|---|---|---|
| You soak through winter | Keep it running | Moving, heated water is the best freeze protection |
| Vacation home or long trips away | Shut it down | A power outage with no one home can freeze the plumbing |
| Frequent winter power outages | Shut it down, or have a backup plan | A cold tub with full lines is the main risk |
| Mild winters with rare frost | Keep it running | Draining and refilling adds work and chemicals |
Hot tub freeze protection while it runs
Keep the cover locked when the tub is not in use. The Caldera manual notes that extremely cold temperatures (below 10°F) combined with strong wind may partially freeze the jet pump even while the water in the spa stays at temperature. It suggests an insulating kit for the equipment compartment from your dealer, and says to remove it when weather warms to about 60°F to 70°F so the pump does not overheat. Many control systems have their own freeze routine; check your manual to see whether yours does and what it covers, rather than assuming.
How to winterize a hot tub: closing a hot tub step by step
Basic draining and safe power disconnection are covered in step 1 and step 2 of how to move a hot tub. Winterizing goes further, because a drained tub still holds water in its pumps, heater and lines. The Caldera manual warns that mistakes can cause freeze damage not covered by warranty and recommends having a dealer do it. The sequence:
- Turn off power at the breaker or disconnect. For a hardwired 240V tub, a licensed electrician should handle the disconnect if you are unsure.
- Drain the tub through the drain valve per your manual. Caldera’s manual says to open the waterfall valve and set the diverter to the middle position.
- Remove the filters, clean them, and store them somewhere dry indoors.
- Blow out lines with a wet/dry vac. In climates below 32°F, Caldera says a five gallon combination vacuum and blower shop vac must be used. Vacuum the jets from the top down, the filter suction fittings and filter area, and the main drain.
- Open the equipment bay. Remove the pump drain plugs and loosen the pump unions so trapped water drains out. Bag the plugs and leave them by the pump.
- Dry the shell with a clean towel.
- Close the cover, lock the straps, and protect it from snow (see below).
Hot tub antifreeze: only if your manual says so
Some manuals include antifreeze as a final step. Caldera’s says to use only propylene glycol, which is non toxic, poured into the standpipes, filter suction fittings and jets. It warns never to use automotive antifreeze (ethylene glycol), which is toxic. Leslie’s winterizing checklist also adds hot tub antifreeze to the pumps and filter cavity. Other manufacturers handle this differently, so follow your own manual. If it does not mention antifreeze, ask the manufacturer before adding any.
What freezes first
The weak points are where water sits in small spaces after a drain:
- The jet pump and circulation pump housings
- The heater housing and nearby plumbing
- Low spots in the jet lines and the main drain line
- Unions and fittings in the equipment bay
Leslie’s notes that water left in the plumbing lines can freeze and cause serious damage. That is why the vacuum and union steps matter most.
Cover care and snow load in winter
The Caldera manual says to lay two pieces of plywood over the closed cover to spread the weight of snow and ice, then secure a plastic sheet or tarp over the top. If your cover is waterlogged or no longer seals, replace it before the snow. For how covers fit into heat loss and climate choices, read hot tub insulation explained.
| Product | What it does | Listed details | Price |
|---|---|---|---|
| 7 ft Hot Tub Cover Weather Guard | Shields your existing cover from ice, snow, sap, rain and UV | Up to 7 ft spas, 12 in elastic skirt, woven polyethylene, 90 day warranty | $99.99 |
| 8 ft Hot Tub Cover Weather Guard | Same cover cap for larger tubs | Up to 8 ft spas, 12 in skirt, 90 day warranty | $120 |
| OEM Spa Cover, Richmond, Black | Replacement hard cover for the Richmond | Not listed | $949.99 |
| OEM Spa Cover, Cambridge, Black | Replacement hard cover for the Cambridge | Not listed | $949.99 |
| Top Mount Cover Lifter | Lifts the cover off with less strain on hinges and vinyl | Fits spas up to 96 in, needs 10 in clearance behind the spa | $299.99 |
| Bottom Mount Cover Lifter | Lifter with no large mounting plates on the cover | Black anodized aluminum, moderate clearance | $349.99 |
The Weather Guard listing says it is not a safety cover or an insulating cover, and that it should be removed before you open or close the hard cover.
Tubs built for cold climates
Shopping for a tub to run all winter? Look at insulation and heater size. Two Canadian Spa Company models show the tradeoff:
- Canadian Spa Cambridge ($7,999.99): 6 person, 34 jets, 240V 50A, 5.5 kW Balboa heater, closed cell foam with a heat retention blanket, and a 5 in/3 in hardtop cover. The manufacturer says it is built for harsh cold climates. It needs a hardwired circuit.
- Canadian Spa Richmond ($10,249): 6 person, 27 jets, 120V 15A plug and play, 1.5 kW heater, 900 L capacity, 79 x 79 x 32 in. The listing says it stays heated in winter, but its 1.5 kW heater is far smaller than the Cambridge’s, so the cover matters even more.
Prices come from our listings and can change. Planning a cold plunge too? See cold plunge outdoors in winter. More care guides are on our hot tub maintenance page.
Restarting in spring
Remove the plywood and tarp, then reinstall the pump drain plugs and tighten the unions before you add water. If you used antifreeze, Caldera’s manual says to fill without the filters, superchlorinate to break down the antifreeze (a defoamer may help), drain again, then reinstall the filters and do a normal fill. If the heater will not come up to temperature, work through our heater troubleshooting guide.
Frequently asked questions
Is it better to keep a hot tub running in winter?
Usually yes, if you use it and your power is dependable. Shut it down if it will sit unattended through freezing weather.
What is the most important step in closing a hot tub?
Getting water out of the pumps, heater and lines. Draining alone leaves water behind, so blow out lines with a wet/dry vac and open the pump drain plugs and unions.
Can I use RV antifreeze in my hot tub?
Caldera’s manual calls for non toxic propylene glycol and warns against automotive ethylene glycol. Follow your own manual, and skip antifreeze if it does not call for it.
Does a cover cap help with hot tub freeze protection?
Not directly. The Weather Guard is not insulating; it protects your hard cover from ice, snow and UV so the cover keeps sealing well.
Need help getting ready for winter?
Call us at 866-777-2590, Monday to Friday, 9AM to 6PM PST, for help matching a cover, cover cap or lifter to your tub. Orders of $999 or more ship free by freight; below that, shipping is a $200 flat rate. See our return and refund policy before you buy.
