There's something special about walking across a warm floor in the middle of winter, knowing your next door neighbour is freezing their toes off trying to hop to the bathroom. No icy shock first thing in the morning, just even, radiant heat wrapped around you like a hug.
Now, I'm not going to pretend that underfloor heating will suddenly make you leap out of bed at 6 am with a smile on your face. Let’s be honest, nothing beats staying wrapped up under the duvet. But when you do have to face the day, having a floor that greets your feet with gentle warmth instead of an arctic blast definitely makes it easier.
And if you’re reading this, you’re probably already convinced that underfloor heating is the way forward, but now you’ve got a decision to make.
Do you go wet?
Do you go electric?
Both will keep your toes toasty. Both will make the whole room feel perfectly warm without the clunky radiators. But they work in very different ways and depending on your project, one will be a better fit than the other. So, let’s walk through how each works, where they shine, what they cost to install and run, and which one is going to make you happiest in the long run.
Think of underfloor heating as a way to turn your room into a giant invisible radiator. Instead of hot air blasting from a specific point out into the ceiling of your room (convection heat), you've got heat gently radiating up (hence radiant heat) filling the space evenly.
Also known as water or hydronic, wet underfloor heating (WUFH) is a series of pipes installed under the floor finish. Warm water is pumped through them from a boiler or a heat pump with a manifold keeping the water at the right temperature and flow rate. There are a couple of different ways you can set up a WUFH system. Screeded floors are common in new builds and renovations, while suspended systems are available if you have joisted floors. If you already have a heat pump or boiler (or you're planning to install one) it would be a good idea to double check that it is compatible before you commit.
Electric underfloor heating
Electric systems on the other hand are perfect for retro fits and smaller rooms. They have little impact on floor height, are quick and easy to install and can warm up in as little as 15-20 minutes. This is why you will often see them in kitchens, bathrooms and conservatories. But they’re not just for renovations anymore. In recent years, they’ve been popping up in more and more new builds, thanks to some pretty appealing advantages:
Electric underfloor heating can come in a range of power outputs, from as low as 57W/m² all the way up to 200W/m². The higher the wattage, the faster the heat-up time. For a bathroom, 150W/m² is usually the sweet spot, while high heat loss spaces like conservatories benefit from the full 200W/m². But, they can draw a fair bit of electrical load, which sometimes makes wiring a challenge and they’ll cost more to run over large areas if they’re on for hours at a time. You’ll also get the best efficiency if you program them to come on only when you actually need them, so they’re perfect for quick, targeted bursts of comfort rather than all-day heating for huge spaces. For those of you installing a ThermoSphere EUFH system, check out our installation guide for some tips and tricks to make your life easier.
⛏️💷 EUFH INSTALLATION GUIDE 💷⛏️
Material costs tell a similar story. You can pick up a water underfloor heating kit for a 12m² area for just under £700, thermostat included. A 12 m² ThermoSphere Mesh 150W/m² electric system (with thermostat) comes in under £600. But remember, water systems will also need manifolds, plumbing work and possibly boiler upgrades, so the total price tag tends to climb faster.
| Room / Floor Space | Typical Use | Wet UFH (Installation / Running Cost) | Electric UFH (Installation / Running Cost) | Why It Works |
|---|---|---|---|---|
| Bathroom / 3–6 m² | Small bathroom or en-suite | £400–£700 / £0.50–£1.00 per hour | £250–£500 / £0.20–£0.50 per hour | Electric heats quickly, low installation impact, perfect for short-use spaces |
| Kitchen / 6–12 m² | Medium-sized kitchen | £800–£1,200 / £0.50–£1.00 per hour | £500–£900 / £0.30–£0.70 per hour | Electric still economical for moderate areas; wet UFH starts to become efficient for longer heating periods |
| Living Room / 15–20 m² | Large open-plan living area | £1,200–£2,000 / £0.60–£1.20 per hour | £900–£1,500 / £0.80–£1.50 per hour | Wet UFH retains heat longer and is cheaper for large, continuously-heated spaces |
| Conservatory / 10–15 m² | High-heat-loss area | £900–£1,500 / £0.60–£1.20 per hour | £700–£1,200 / £0.50–£1.00 per hour | Electric with higher wattage works well for quick heat-ups and intermittent use |
| Whole Floor / 25 m²+ | Multiple rooms or open-plan | £2,000+ / £0.60–£1.50 per hour | £1,500+ / £1.50–£3.00 per hour | Wet UFH is most efficient for heating large areas over long periods; electric less economical for full-floor use |
Electricity costs more per unit than gas, roughly 25.7p/kWh compared to about 6.3p/kWh for gas so on paper, water systems are cheaper to run when paired with a gas boiler, especially in larger spaces*. That’s why wet underfloor heating is popular in big, open areas that are heated for long stretches. Lower the flow temperature and you can save even more.
Electric underfloor heating, is 100% efficient at the point of use. There’s no energy lost along the way, every penny you spend turns into heat right where you need it. So, in smaller spaces or rooms that only need heat for a couple of hours a day, electric can still be very cost-effective.
For example, if you’ve got a 3 m² electric underfloor running for four hours a day, you might be paying somewhere between 70p and £1 a day. That’s spa-level comfort for less than your morning coffee.
*accurate at the time of writing
📊➕ RUNNING COST CALCULATOR ➕📊
Water systems don’t require constant tinkering, but there are a few things to keep in mind. If you’re using a gas boiler or a heat pump to supply the hot water, it’s important to have it serviced annually, this keeps your system running efficiently and prevents any nasty surprises. If the boiler or heat pump goes down, your lovely warm floor goes with it, so regular check-ups are worth it. Heat pumps are very efficient, but their running costs depend on your electricity tariff and the system’s coefficient of performance (COP), which basically measures how much heat you get out for each unit of electricity you put in.
It’s also smart to check the manifold now and then for leaks. The washers and valves inside can wear over time and catching any small issues early can save a lot of hassle. On the very rare occasion that a pipe bursts, most modern systems allow for localized repairs but it can be disruptive, you may need to lift a section of floor to access the affected pipe. The good news is that properly installed systems with good-quality materials make this extremely unlikely, so it’s more of a “just in case” point than something you’ll need to worry about every day.
Electric systems are a lot more hands-off. No moving parts mean there’s nothing to service. The main thing is to make sure the system is tested at three key stages during installation: before, during and after. That way you can keep your lifetime warranty intact and have peace of mind that it hasn’t been damaged along the way.
🔧⛑️ REPAIRING EUFH ⛑️🔧 ✔️💭 THINGS TO CHECK 💭✔️
Electric systems don’t have the heat-loss problem that wet UFH has. Every joule of energy is converted to heat right under your floor, making them 100% efficient at the point of use. To put that in perspective, traditional central heating systems lose around 25–30% of their energy through pipework and radiators before the heat even reaches the room, while water underfloor heating typically loses 20–40% of energy as it travels through pipes. In addition to this, a gas boiler is only ~85% efficient so you lose you on efficiency here too. That means electric UFH can actually be more efficient than a wet system or radiators for small rooms or spaces that only need heat for a short time.
This is why electric systems are often the go-to for precision heating in smaller rooms, whereas wet UFH still makes sense for whole-house systems, where the lower running cost of gas or heat-pump water can outweigh the slight inefficiency in transit. If you’re interested in saving even more energy, check out our blog on how to increase the efficiency of your underfloor heating, we know how to save you a penny or two, and as luck would have it, we’re feeling generous!😉
🌲⚡ ENERGY EFFICIENCY TIPS AND TRICKS ⚡🌲
There’s no single “right” answer, it all comes down to your project. If you’re working on a new build and heating a large area, water underfloor heating could be the smarter choice. But if you’re upgrading a bathroom, adding comfort to a kitchen or retrofitting a single space, electric is hard to beat.
Think about your budget, your floor build-up, your running costs and how quickly you want the space to heat up. The right system is the one that fits your life and whichever you choose, you’ll never miss those cold floors again.
If you’d like to dig deeper into electric underfloor heating, from running costs to installation tips, check out the other articles on our heating blog. If you’ve got specific questions, our team at ThermoSphere is always happy to help. Warm floors are just a conversation away.
Electric heating made easy
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