Hot Tub Winter Care: Keeping Your Spa Running in Colorado's Cold

Colorado gives hot tub owners some of the best soaking weather in the country — crisp 30-degree evenings, steam rising off 102-degree water, snow falling around you. It also gives your spa the toughest conditions it will ever face.

Freeze-thaw cycles, heavy snow loads, and long stretches of sub-zero nights are routine along the Front Range. A spa that's cared for properly sails through all of it. A spa that's neglected can suffer cracked plumbing, damaged pumps, and repairs that cost far more than a season of maintenance.

After 50 years of selling and servicing hot tubs across the Denver metro, we've seen every kind of winter mistake. Here's the playbook we give our own customers in Littleton, Highlands Ranch, Parker, and Castle Rock.

Decision One: Keep It Running or Winterize It

Most Colorado owners keep their spa running all winter — and honestly, that's the easiest path. A running spa maintains its own temperature, circulates water constantly, and is far less likely to freeze. Winter soaking is also the whole point for most families: there's nothing like a 102-degree soak while snow falls around you.

Winterizing is the right call only if you'll be away for months, the spa is at an unoccupied property, or you've decided not to use it until spring. Done correctly, winterization means draining every line, blowing out plumbing with compressed air, and adding antifreeze to residual low points. Done halfway, it's the #1 cause of springtime freeze damage we see in our repair shop.

If you're not comfortable winterizing yourself, our service team handles it — and un-winters the spa correctly in spring so you start the season with balanced water and clean filters.

The Freeze-Thaw Cycle Is Your Spa's Worst Enemy

Front Range winters swing wildly — a 60-degree Tuesday can be followed by a minus-5 Thursday. That swing is what kills equipment. Water expands roughly 9% when it freezes, and even a few ounces trapped in a pump wet-end, a filter housing, or a low loop of plumbing can split fittings or crack a manifold overnight.

A running spa is protected by circulation and heat. If you lose power during a cold snap, don't panic — a full, covered spa holds heat for days — but do check on it. If the spa must sit powered-off in deep cold, keep the cover locked and call a service tech before restarting. Never pour hot water into a frozen spa; thaw it slowly and let a professional inspect for damage first.

Your Winter Running Checklist

Keep the water level at its normal operating height. Low water exposes heater elements and skimmer intakes — the fastest route to equipment damage. Top off with a garden hose on warmer afternoons; Colorado's dry air and low humidity evaporate water faster than most owners expect, even in January.

Test and balance weekly. Cold water reads differently than warm, and our region's hard water pushes calcium hardness up quickly. Keep sanitizer, pH, alkalinity, and calcium in range so you're not fighting a green or cloudy spa when you want to soak. Rinse filters every few weeks and swap in a clean set monthly — a clogged filter in winter strangles flow right when circulation matters most.

Leave the breaker on. It's tempting to save a few dollars by powering down between soaks, but a spa designed for cold climates — like every Aspen Spa we sell, with full-foam insulation — costs less to keep warm than to reheat from a cold start. Let the thermostat and circulation cycles do their job.

Snow Load and Cover Care

A heavy, wet spring snow can weigh hundreds of pounds. Brush snow off your cover after every storm instead of letting it melt and refreeze into an ice shell. A saturated, waterlogged foam cover loses insulating value, sags in the middle, and can tear at the seams — and lifting a 150-pound frozen cover is a back injury waiting to happen.

This is exactly why we carry the THRML AIRCAP 1™ foam-free cover. Because its air-core insulation can't absorb water, it weighs the same in April as it did in November — no waterlogging, no ice shell, no R-value loss. If your current cover is more than a few years old, winter is when it fails. You can see the full comparison on our AIRCAP page.