Now your hot tub heats only when electricity is cheapest — automatically

You already know a spa costs a small fortune to run. This new £495 device fixes that — without you using it any less. And over time, it pays for itself.

David Mercer

Hot tub owner since 2017

If you own a hot tub, I don't need to tell you they're expensive to run. You feel it every time the bill lands.

What you might not know is that, until recently, there was nothing you could really do about it. You set the temperature, the spa did the rest, and it quietly cost whatever it cost.

That's the part that's just changed. There is now a small device that heats your spa only when electricity is cheapest — automatically. A few years ago, something like this didn't exist. If it had, it would have cost thousands. Today it's a £495 box you can fit yourself in about half an hour.

Here's what happened when I put one in.

What it actually does — the simple version

It's called SpaPilot. It's a small box that connects to your spa's existing control system — Balboa or Gecko. You don't replace anything.

Once it's in, it does one clever thing: it looks at the day's electricity prices and heats your spa during the cheapest hours — usually overnight — so the water is warm and ready by the time you want to get in. You set your temperature once. It takes care of the rest.

That's it. No timers to fiddle with. No getting up at 3am. And you use the spa exactly as much as you do now.

Why it saves so much, if you're wondering

Here's the part nobody tells you. A normal spa heats whenever the water cools — including during the most expensive hours of the day. On a variable tariff, peak-time electricity can cost several times what it costs overnight, and your spa has no idea. It just pays whatever the going rate is, whenever it happens to need heat.

SpaPilot shifts almost all of that heating to the cheap hours instead. Same hot water. Same spa. Bought at a far better price.

• Heats at the cheapest hours, automatically — without you lifting a finger
• Ready when you want it — set it once and it's warm every time
• Control it from your phone, wherever you are
• See live prices and what you're spending in real time
• No subscription — ever

Fitting it was the part I dreaded — and it was the easy part

I'm not especially handy, so I expected a faff. It connects to the control box with the included connector, and most owners fit it themselves in about half an hour with a screwdriver and the guide in the box. If you'd rather not, any spa engineer can do it in the same time.

The app paired straight away. Within an hour I could see live prices, the spa's temperature, and exactly when it was planning to heat next.

What it did to my bill

We're on a variable tariff, and it showed up on the very next bill.

We use the tub just as often as we always have. Nothing changed about how we enjoy it. The only thing that changed is what we pay.

The part that actually sold me

I'll be straight about the price, because it's the thing that made me pause: £495 is real money. Two things got me over the line.

First, I didn't have to pay it all in one go. I split it into three interest-free payments with Klarna — so it was £165 to start rather than the whole lot landing on the card at once. That on its own made it an easy yes.

Second — and this is the bit that changed how I look at it — the spa now costs me around £29 less every single month. At that rate the £495 works its way back to me in a little over a year; Aquenity put it at around 15 months, and mine's tracking about there.* And after that? Here's the odd part: it doesn't really cost anything to own. It's the opposite. Month after month it just quietly hands money back — for as long as I've got the tub.

So I stopped thinking of it as a £495 gadget. It's a £495 gadget that buys itself back, then keeps paying. Spread over three payments, it barely felt like spending at all.

"I set it up once, told it when I want the spa ready, and I haven't thought about it since. The bill just dropped."

Not sure which system you have?

This was my one worry before buying — would it even fit my tub? Aquenity make that part free: take a photo of your control box, email it to them, and they'll confirm whether it fits — usually within a few hours, at no cost.

Stop heating your spa at the most expensive hours of the day

*Savings and payback depend on your electricity tariff, regional prices, spa insulation, how you use it, and your climate. The figures above reflect one customer's real-world experience and are not a guarantee of results. Klarna: pay in 3 interest-free instalments. 0% interest; 18+, UK residents only, subject to status. T&Cs apply. Aquenity is an independent reseller and is not affiliated with, endorsed by, or sponsored by Balboa Water Group or Gecko Alliance; those names are used only to describe compatibility.