How Long Do Inflatable Spas Take to Heat Up?

You’ve finally got your inflatable spa set up in the garden. Excited, you fill it with water, turn on the heater… and then wonder, “How long before I can actually get in?”

The short answer: most inflatable spas take 12 to 24 hours to heat from cold tap water to a toasty 104°F (40°C). But that’s only the average. The real time depends on things like the starting water temperature, the weather, and how well your spa keeps heat in.

Let’s break it down so you know exactly what to expect—and how to speed things up.

Factors That Influence Heating Time

Inflatable spas usually heat at 1–2°F (1–1.5°C) per hour. That means patience is part of the deal, but a few key factors can make a big difference.

Initial Water Temperature 🌡️

If you start with icy cold hose water, be prepared to wait. It’s like boiling a kettle that’s just been filled from the fridge—it’s always going to take longer.

Some spa owners get clever and use warm tap water to get a head start. That can shave hours off heating time. Just don’t go overboard—scalding hot water can damage the liner and even void your warranty.

Ambient Air Temperature ☁️

The outside temperature is the single biggest factor. Heating your spa on a warm summer’s day is far quicker than trying to do the same on a frosty evening in January.

Wind doesn’t help either. A chilly breeze strips heat away surprisingly quickly. If possible, place your spa in a sheltered spot—near a fence, wall, or even under a gazebo.

Spa Size and Water Volume 💧

Bigger isn’t always better when it comes to heating time. A 6-person spa with hundreds of extra litres will naturally take longer to warm than a compact 2-person tub.

If you’re planning regular quick soaks, keep spa size in mind before you buy.

Insulation and Cover Quality 🛡️

A good insulated cover is your spa’s best friend. Most heat escapes straight up through the water’s surface, so keeping the lid on while heating makes a massive difference.

Want to go one step further? Pop a foam mat or thermal blanket under the spa. That little extra barrier stops the cold ground from sucking away your hard-earned warmth.

How to Speed Up the Heating Process

You can’t make your spa heat in minutes, but you can make it more efficient. A few simple tricks will save both time and energy.

Use the Spa Cover

Always, always keep the cover on while heating. Think of it like putting a lid on a pot of boiling water—it traps the warmth and halves the energy wasted.

Fill with Warm Water

If your tap allows, start with lukewarm water. It’s a safe shortcut that can knock several hours off. Just be cautious—anything too hot could damage the spa before you’ve even had your first soak.

Turn Off the Jets

Those lovely bubbles might feel great once you’re in, but while heating, they’re your enemy. Jets pull in cold air from outside, cooling the water. Keep them off until you’re ready to climb in.

Keep the Heater On

If you’re using your spa often, don’t let the water drop stone cold between dips. It’s usually cheaper and faster to maintain a steady lower heat than to keep reheating from scratch.

Wrapping Up

So, how long does it take? On average, 12 to 24 hours from cold to hot, depending on your setup. But with a warm starting fill, a sheltered spot, and a quality cover, you can cut that wait down considerably.

A little planning goes a long way. Want a Saturday evening soak? Switch the heater on Friday morning, keep the cover tight, and by the time the sun sets, you’ll be slipping into steaming bubbles.

Key Takeaways

• Most inflatable spas heat at 1–2°F (1–1.5°C) per hour.

• Expect 12–24 hours for a full heat-up from cold hose water.

• Warm starting water, sheltered placement, and a good cover = faster heating.

• Larger spas take longer due to more water volume.

• For regular use, maintaining heat is often more efficient than reheating from cold.