Introduction to Hot Tub Heating Using Solar Energy
Solar heating for your hot tub isn’t just a smart move — it’s common sense.
If you’re tired of watching your energy bills shoot up every time you fancy a soak, I can understand completely. We have heard it from a lot of our customers.
Heating a hot tub with electricity can feel like burning money for bubbles.
In my experience, working with families, resorts, and spas across the USA, UK, and Europe — the number one complaint I hear is:
“It costs a fortune just to keep the water warm.”
So, what if I told you there’s a simpler way?
No gas. No huge energy bills. Just clean solar heat.
Let’s talk about how you can heat your hot tub using solar energy — without overcomplicating things.
Why Use Solar Heating for Your Hot Tub?
So this is probably what has happened, and why you have landed on this page.
You bought a hot tub to relax.
Not to stress about monthly running costs.
Solar heating works by using a solar thermal system to warm water. You get heat directly from the sun — not from your mains electricity or gas. That means fewer emissions and lower bills.
What’s better?
On sunny days (which is when you’re most likely to use your hot tub), your system’s pumping out heat for free.
What makes it ideal for hot tubs?
- Most hot tubs don’t need water boiling, just warm and comfortable.
- They typically hold between 200–1,000 litres — perfect size for a domestic solar hot water setup.
- Many are already placed on flat roofs or open patios — ideal locations for hot water solar panels.
The SolarisKit HelioSpa installed in the UK to heat an inflatable type hot tub
What Is a Solar Thermal System?
Let’s break it down simply.
A solar thermal system takes sunlight and turns it into heat using a collector (that’s the bit that looks like a mini sunbed for water).
It works like this:
- Sunlight hits the solar collector – either a flat plate, evacuated tube, or prismatic design solar collector
- The collector warms up water or a heat transfer fluid inside it
- That heat moves through pipes to your hot tub (usually via a solar energy water heater tank or direct pump)
The best bit?
It’s simple, silent, and low-maintenance.
Comparing the different solar heating solutions for hot tub heating
After six years running SolarisKit, we’ve tested all kinds of solar hot water heaters in harsh climates — Rwanda, Kenya, Dubai, even hard water areas in the UK.
Here’s what I’ve seen:
Flat-plate solar panels
- Cheap, simple, but they overheat easily in warmer climates
- Not great for hard water – the minerals cause scaling in copper pipes
- Not modular – hard to move or fix and quite bulky in size. You probably wouldn’t want to install one next to your hot tub.
An example of how a flat plate solar thermal system looks.
Evacuated tube collectors
- Great insulation, but fragile
- Prone to breakages, especially on rooftops
- Often bulky and hard to clean
HelioFlow by SolarisKit (yes, it’s ours – and here’s why I’m backing it)
We designed HelioFlow specifically for:
- Flat roof or ground installations (most hot tubs sit in wide, open spaces)
- Hard water conditions (using a polymer tubing that resists scaling)
- Avoiding overheating – it won’t cook your tub on a hot summer day
It arrives flat-packed, easy to install, and provides a cleaner looking and more modern solution than the usual silver tubes or clunky boxes.
I’ve seen it run efficiently with a 500L hot tub in Dundee Scotland, keeping temps between 37–40°C during sunny periods — with just a small 12VDC circulation pump which consumes less than 15W of electricity.
SolarisKit HelioFlow solar collector is ideal for ground and flat-roof installations because of the prismatic geometry and compact size.
How to Install a Solar Hot Water System for a Hot Tub
You don’t need to rip up your garden or drill into your roof.
Here’s a simple way to set it up:
The Installation Process looks like this:
- Assemble and position the solar collectors. We would recommend having the solar collectors within 10m of the hot tub roughly to minimise heat losses and pumping power.
- Connect the piping between the hot tub and solar collectors. We have a step-by-step video which runs through the whole process to install our HelioSpa solar heating kit.
- Connect the pump and wire to the pump controller. The pump controller automatically controls the entire heating process.
- Install the temperature sensors (normally two) to the controller so it can monitor the temperature of your hot tub and solar collectors.
- Switch on the controller and start harnessing the energy from the sun!
Basic equipment checklist:
- Solar collector (like HelioFlow)
- Pump (DC or AC with controller)
- Piping (insulated for heat loss)
- Pump Temperature controller (to prevent overheating)
SolarisKit HelioSpa installed on the ground with a Jacuzzi hot tub.
Solar Hot Water Cost vs Electric Heating
Let’s talk numbers.
Electric heating for a 300L tub
- Uses about 6kWh per session
- At £0.30/kWh, that’s £1.80 every soak
- Over a month? Easily £50–£80
Solar heating?
- Once installed, it’s basically free to run
- Typical system cost: £900–£1,500
- Pays back in 1–2 years if used weekly
You’re not just saving money. You’re cutting down on carbon.
Heating water is one of the biggest uses of energy in the home. A renewable water heating system helps cut that load.
Maintenance of Solar Hot Water Systems
Here’s the good part — they’re low-maintenance.
With HelioSpa, we’ve designed every part to be easily repairable or replaceable. No hidden screws, no rust-prone parts.
Just check once a year:
- Are pipes insulated?
- Any leaks?
- Is your pump running smoothly?
- Clean the collector glass if dusty
That’s it. Set, soak, forget.
FAQs: Hot Tub Solar Heating
Q1: Can solar hot water heating work in winter?
Yes, though less efficient. Use a backup immersion heater or store solar heat in a tank to top up during colder nights.
Q2: How long does it take to heat a hot tub with solar energy?
Depends on the tub size, sun hours, and system setup. For a 250L tub, expect 3–5 hours of sun to reach 38°C.
Q3: Do I need planning permission to install solar hot water panels?
Usually not, especially for roof-mounted or ground-level setups. But always check local regs if in a listed property or conservation area.
Final Thoughts (And a Friendly Nudge)
Solar heating for your hot tub is a no-brainer if you’re after comfort without cost.
It’s cleaner, cheaper, and easier than most people think.
I’ve worked on systems in hotels, spas, and homes where customers just want one thing:
A reliable soak without the sting of an energy bill.
If you’re considering it — don’t wait.
Contact SolarisKit to learn how a HelioFlow kit could work for your setup.
Better for your wallet. Better for the planet. And still the perfect soak.
Need help heating your hot tub with solar energy?
👉 Get in touch with SolarisKit today
For US enquiries, please contact our distributor Worldwide Solar Solutions.
