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Radiators or Underfloor Heating?

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Choose between these heat emitters with our guide to the systems’ main pros and cons
Schluter underfloor heating cross-section

Whether you’re self-building, renovating or extending, selecting the right heating system is a major decision. From design considerations through to energy efficiency, running costs and other practical concerns, there’s a lot to wade through when choosing between underfloor heating (UFH) and radiators. Here’s what you need to know. 

What are the design options?

Whatever the style of your home, you’ll easily find an underfloor heating system or radiator arrangement to suit your tastes and requirements. One of the most popular reasons to choose UFH is because, as the name suggests, it is hidden beneath your floor covering. This allows for clean lines and an open flow throughout your home that isn’t interrupted by radiators. It also frees up wall space so will give you the feeling of extra room, too.

There are hundreds of design options when it comes to radiators, so don’t fall into the trap of thinking that you can’t get something to suit your interior scheme. Vertical radiators are growing in popularity, as their configuration means they don’t have as much of an impact on furniture placement. In terms of material, aluminum is a strong choice for achieving unusual shapes and finishes, plus it heats up quickly. For period charm, consider column radiators in cast iron. You could even try coating this in a bespoke colour for a modern feel – try Bisque for ideas.

Can I retrofit underfloor heating and radiators?

There are two types UFH to choose from – wet and dry. The former connects to your central heating system (powered by a boiler or renewable alternative) and warm water streams through piping laid beneath the floor, often set in screed. Dry UFH runs off of domestic electricity, with electric coils placed under the surface. The advantage of this is that the wiring is quite thin and simple to fit – so there’s relatively little disruption involved during fitting.

Key considerations for heating systems

  • Heat pumps can offer an efficient route to powering wet underfloor heating. “Both technologies work at a lower temperature level than boilers and radiators, which can help to increase the efficiency of both of these options and also reduces overall running costs,” says Martyn Bridges at Worcester, Bosch Group.
  • Radiators have a quick response time, so they can react faster to external temperatures than the gentle, trickle-down heat from UFH.
  • Interestingly, unlike traditional radiators, no dust or carbon particles are passed around the room with UFH as it doesn’t rely on convection. This will reduce house dust mites, which is a major benefit to asthma sufferers.
  • With wet UFH systems, make sure you dedicate space for a cupboard to house the control manifold. Each room or zone will run from here off its own valve, giving you excellent flexibility in terms of climate in each area.

Installing wet UFH can be a more complex process, as it requires more space for pipework. Plumbing connections and tests will need to be carried out and the floor must be properly prepared and insulated in order to ensure the system works efficiently. There needs to be enough room to accommodate this and the piping, so you might have to elevate the floor level, especially if it’s being retrofitted into an existing space. Because of this, it’s easier to install wet underfloor heating in a new build as these adjustments can be planned from the start.

However, there are now a lot of low-profile systems available to enable easier installation of wet UFH. Using thin pipework, special screeds or thin overlay boards, these reduce floor height build-up and won’t disturb other fittings as much. Check out Nu-Heat’s LoPro 10 or Polypipe’s Overlay system, which measures just 18mm in depth.

If you’re renovating an old property and updating the radiators, it might be necessary to plan for a new boiler and possibly upgrade the pipework. You’ll need a qualified heating professional (such as a Gas Safe registered engineer if you are on gas, or OFTEC approved for oil) to do the installation for you. This will involve working with them to choose a suitable boiler, and maybe cold water tank, radiators and suitable controls for the system.

Where do these heat emitters work best?

Underfloor heating is great for use in large rooms – so it’s ideal for open-plan spaces. The gentle warmth of underfloor heating also makes it a good choice for bathroom spaces.

One potential downside is that UFH takes a long time to get up to temperature, so it needs to be on fairly constantly during the heating season (albeit at a low temperature, which leads to good efficiency and cost-savings in use).

When fitting radiators, you ideally need to have one installed every 4m in a room, so they aren’t ideal for large open-plan kitchen extensions, for example. But they work well in bedrooms, which tend to be smaller in size.

What's more efficient: underfloor heating or radiators?

UFH can be extremely eco-friendly and affordable to run, as long as it’s installed properly and partnered with the correct flooring material so it can conduct heat. Stone, ceramic, engineered timber or vinyl flooring are best, but always check with your supplier before buying.

Wet UFH can be around 25% more efficient than radiators when paired with a modern condensing boiler; and up to 40% more effective when running from a heat pump. It also tends to work out cheaper to run than electric UFH products, with Nu-Heat suggesting a room size of 10m2 would cost £224 per annum to heat using electric UFH, whereas a wet system would only cost £61 per year.

Closer look: Efficient underfloor heating in a self-build project

James and Corina Barrett were keen to make their modern self-build in South Oxfordshire as energy efficient and low cost to run as possible.

So when considering the best heating setup for their new home, they opted for underfloor heating (UFH) from Nu-Heat with a total of 221.8m2 of high heat-output, pumped liquid screed UFH installed in the house.

Eco house with underfloor heating from Nu-Heat

Nu-Heat was an easy choice for James. As owner of property development and house building company Ashbrook Homes, he has used the brand in other projects: “I have always found the company to be well-priced, prompt and helpful in the design stage,” he says. “Above all, they offer a great product.”

As well as negating the need for radiators, the Nu-Heat UFH system offsets the high heat losses of the mainly glazed new-build, and links up easily with the couple’s home automation system.

liquid screed from Nu-Heat

Photos: Ashbrook Homes

That’s not to say a well-planned radiator setup can’t be efficient, too. However, it’s essential to properly calculate the heat loss of the room (as with UFH) and then find the right sized emitter. The output is measured in BTUs (British Thermal Units) or wattage. There are plenty of online calculators that give a good basic guide to the right output for each room. Factors such as insulation levels, what type of window glazing you have and how your home’s walls are constructed will all impact on the final score, however, so it’s always best to ask your plumber for advice.

The location of a radiator will affect its performance, too. “Wherever you choose to place your emitter, try not to position it behind large items of furniture as doing so will restrict the flow of hot air around the room,” says Nick Baylis, director of Castrads. “Keep the immediate area surrounding the radiator as open as possible to allow the heat to permeate the space efficiently.”

Should I use the same system throughout my house?

If you’re self-building, UFH is simple to fit as it can be installed as the fabric of the house is being constructed. It’s also likely to be the most efficient choice for your primary heating – although don’t rule out radiators completely. A popular solution is to install UFH on the ground floor and radiators upstairs (in bedrooms, for instance). UFH tends to be installed fairly early in the build process as part of the first fix work. With radiators, the infrastructure goes in at this stage but the emitters can’t be fitted until the basic decorating has been completed.

If renovating, the choice between UFH and radiators will depend on the scale of the renovation. If the boiler is being upgraded along with the whole heating network, then it’s worth considering a retrofit UFH system. It’s also possible to create a hybrid setup, with radiators in some areas and UFH in new extensions or main living areas. “This allows the homeowner to enjoy the benefits of underfloor heating in any room they choose without having to change the heating solutions used throughout the remainder of the home,” says Andy Coy, UFH manager at Polypipe.

What are the costs?

The exact price of an underfloor heating system will vary depending on the solution chosen. Nu-Heat suggests that in a typical self-build project, such as a detached 100m2 three-bedroom home, you could expect a bespoke wet UFH system to cost approximately £2,800-£3,000.

The cost of underfloor heating in a renovation is usually higher, because there are more materials needed. In an average Victorian terrace with a downstairs floor area of around 60m2, for instance, a bespoke LoPro10 system from Nu-Heat would come in somewhere in the region of £4,500. You also need to factor in the cost of installation in your heating budget. This amount will vary depending on location, size and type of UFH system being chosen.

Standard double panel radiators start from around £50, whereas designer models can cost anything from £200 upwards. Again, you will need to factor in installation costs. Heating engineers typically charge around £40 per hour.

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