Homeowners Professionals

Can you have underfloor heating with a combi boiler?

Underfloor heating (UFH) is generally considered a luxury extra and something that lots of people wish they had. If you’ve ever experienced walking onto cold tiles in the morning in winter, then we’re sure it’s something you’ve considered before, too. But how does UFH work and can you have it installed with a combi boiler?

How does underfloor heating work?

There are two main types of UFH that you could have installed: wet and dry.

In a wet UFH system, the pipes carry hot water that has been heated by the boiler. This system works in a similar way to radiators, only the pipes are installed over a much larger surface area and much closer together.

When the hot water has flowed around the pipes in the floor, it will return to a temperature sensor. This sensor determines the temperature of the water, as it may have cooled down on its journey around the pipes. If the water is still hot enough, it will be resent around the system by the boiler. If it isn’t hot enough, the boiler will reheat it. This process allows the floor to stay at a more regular temperature while the radiators run separately.

In a dry UFH system, a series of electrical wires are installed underneath your flooring. These systems can vary in wattage and this will depend on the size of the room and how well insulated the property is. First, a layer of insulation is laid down and then the electric cables are placed on top. The insulation prevents the heat from travelling down into the ground instead of up into your home. The wires are then connected to the mains by an electrician.

According to Which?, the majority of people (65 per cent) with UFH have a dry system and 66 per cent of homes have it installed in just one room, such as a bathroom or a kitchen. A dry UFH system is more popular because it doesn’t interfere with your central heating system and is usually easier to install.


What are the benefits of an underfloor heating system?

Firstly, although many people assume that it can only be installed with tiles, UFH can in fact be installed with a variety of flooring types, including stone, ceramic, lino, vinyl, laminate, wood and even carpet. It can also cost less than you might have assumed.

Secondly, you won’t find cold spots like you do with radiators. With a boiler system, you may find that the radiators heat the edges of the room but leave the centre feeling colder. Underfloor heating covers the entire floor, so these cold spots will be banished. And there’s the added bonus of putting your feet onto a warm floor in winter.

Thirdly, rooms such as kitchens may not have the space for a radiator. Though we don’t advise that you get rid of all of your radiators, you may find that you want to forgo one in the kitchen and replace it with underfloor heating. Doing this could free up to 10 per cent of your wallspace and allow you to be more creative if you’re having a brand new kitchen installed.

Can you install underfloor heating if you have a combi boiler?

If you have a  combi boiler  in your home, you can still have underfloor heating installed. However, some adjustments may need to be made. If your radiators run off the same boiler as the underfloor heating, you’ll need to have a suitably qualified heating engineer install a two-port valve. This is a valve that controls the flow of water in a central heating system, particularly the water that goes from the boiler to other parts of the system. If you don’t have one of these installed, your boiler might try to run the underfloor heating and the radiators at the same time, which means it could overheat and go into fault mode. The valve will allow the systems to run separately.  

How to use an underfloor heating thermostat

It’s likely that you already have a thermostat in your home. It could be located on a wall, either as a dial or a digital screen, or it could be plugged into the mains so you can choose a location yourself.

Your underfloor heating will work with a similar thermostat, so it’s up to you which type you choose. You could stick to the traditional dial thermostat, or get a digital one that you can control remotely from your phone or tablet.

As with your standard heating system, you should set a temperature that you’d like the room to be and the boiler will do the rest for you.  

Do you need radiators with underfloor heating?

IOne of the disadvantages of underfloor heating is that it can be expensive to run, particularly if you’re planning to use it throughout your entire home and get rid of the radiators altogether. However, you can keep the cost down by running underfloor heating in some rooms and radiators in others.

If you want to have a wet underfloor heating system installed, you’ll be able to create zones in your home. For example, in some rooms you may just want the underfloor heating on, and in others you may want the radiators. You can make the radiators come on in some parts of the house and not others.

If, like many people in the UK, you want to have UFH installed in just one room, you’ll need radiators to heat the rest of your home.

You don’t necessarily need radiators with underfloor heating, but we advise that you keep them just in case your underfloor heating ever fails.

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