Imagine coming home, kicking off your shoes, and not bracing for that shock of a freezing cold floor. That quiet comfort is what draws a lot of people to underfloor heating. It feels like a bit of luxury, even if the rest of the house is chaos.
Now, if your place wasn’t built with it, adding it later might sound like a nightmare. You might be wondering if it’s even possible without tearing everything up. Or if it’s going to drain your budget. Maybe you’ve heard it’s efficient, but don’t quite know how it stacks up to radiators.
What Is Retrofitting Underfloor Heating?
It simply means installing underfloor heating in a house that wasn’t originally built with it. So, you’re not starting from scratch. You’re working with what’s already there, like existing floors and structures.
There are two types of underfloor heating systems: electric (dry) and water-based (wet). Each comes with its own pros, cons, and installation process.
Electric systems use wires or mats that generate heat when electricity passes through them. These are usually thinner and easier to fit in homes without having to rip everything up. Water-based systems involve pipes under the floor, warmed by a boiler or heat pump. They’re trickier to install but often cheaper to run in the long term.
Why Consider Retrofitting Underfloor Heating?
Honestly, who doesn’t like warm floors in the winter? But it’s not just about comfort.
1. Energy Efficiency
Radiators blast out heat in one part of the room. Underfloor heating spreads it evenly. That means you can often keep the thermostat lower and still feel warm. For water-based systems especially, if they’re hooked up to a modern boiler or a heat pump, the system can run more efficiently.
2. Space-Saving
No bulky radiators sticking out of the wall. It frees up space, especially in smaller rooms like bathrooms or kitchens. You can push furniture right up against the wall without worrying about blocking the heat source.
3. Comfort
There’s something lovely about the feel of a warm floor under your feet. It’s a kind of luxury that sneaks up on you. Once you’ve had it, going back is tough.
Sounds Great. But What’s the Catch?
Retrofitting isn’t always straightforward, and it does come with a few hiccups.
1. Installation Disruption
Let’s not sugarcoat it. There’s mess. Depending on your flooring, the installer might have to lift everything up, lay insulation, install the heating system, and then put it all back together. It’s easier if you’re already planning a renovation, like a new kitchen or bathroom. Otherwise, you’re looking at some serious upheaval.
2. Floor Height
Most underfloor heating systems add height to your floor. That might sound minor, but it can affect doors, skirting boards, and even the feel of the room. Electric systems are thinner, often only a few millimetres, but water-based ones can require much more build-up, up to 20–50mm with insulation.
3. Cost
Yep, it’s not cheap. We’ll get into the details in a bit, but between materials and labour, you’ll need to budget carefully.
Electric vs Water-Based: Which Should You Choose?
Here’s where things get a bit more personal, depending on your home and how you use it.
Electric Systems
Pros:
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Easier and quicker to install
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Lower upfront cost
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Great for small spaces or single rooms
Cons:
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More expensive to run (uses electricity directly)
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Less suited to whole-house heating
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May not be as energy-efficient over time
Electric systems work well in places where you’re not heating all day. Think en-suite bathrooms, cloakrooms, or kitchens. You flick them on when you need them, and off when you don’t.
Water-Based Systems
Pros:
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Cheaper to run long-term
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Ideal for larger areas or whole-house heating
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Works well with low-carbon systems like heat pumps
Cons:
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Much more complex installation
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Higher upfront costs
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Not always practical in upstairs rooms
If you’re doing a major refurb or building an extension, water-based is usually the better bet. Just know you’re in for more work up front.
Retrofitting Costs: What Are You Looking At Approximately?
Let’s get to the bit everyone wants to know, how much?
Electric Systems:
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Materials: Around £30–£50 per square metre
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Installation: Around £200–£400 per room depending on size and complexity
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Running costs: Varies, but expect it to be higher than gas-based heating. Some homeowners see around 3–4p per hour per square metre.
Water-Based Systems:
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Materials: Around £40–£100 per square metre
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Installation: Can range from £2,000 to £6,000+ depending on the space and the work involved
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Running costs: Generally lower, especially with a modern boiler or renewable system
Just remember, every house is different. If your floor structure needs reinforcing, or you’ve got an odd layout, that might push costs up. The same goes if your boiler needs replacing or you want to pair the system with solar panels or a heat pump.
Can You Retrofit in Every Room?
Short answer: almost. Bathrooms and kitchens are the most popular, mostly because they’re already being redone or the flooring is tile (which holds heat well). Living rooms and open-plan areas work too, especially if you’re replacing carpets with wood or laminate.
Upstairs bedrooms? A bit trickier. The joists and flooring might need adjusting, and the effort might outweigh the benefit unless you’re doing a full refurb.
Tips for a Smooth Retrofit
If you’re seriously considering this, a bit of planning goes a long way. Here are a few things I’ve seen help:
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Time it with other renovations. Pulling up flooring for no reason feels like a waste. Do it when you’re already making changes.
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Insulation matters. Don’t skimp. Proper insulation beneath the system helps stop heat escaping downward.
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Use a reputable installer. I know, it sounds obvious. But someone who knows what they’re doing will save you money and stress.
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Check floor coverings. Not every type of flooring works well. Tile and stone are excellent. Vinyl and carpet need a bit more thought.