Can You Have Underfloor Heating With A Combi Boiler?


Underfloor heating (UFH) is a great way to keep your home warm, cosy and inviting. It's not just for winter either! You can have underfloor heating systems installed in any season so that you never again have cold tiles, especially on chilly mornings.

The best part about this energy-saving system is that the cost is usually pretty affordable.

If you're looking to do some DIY renovation in your home and want to add underfloor heating, you may be wondering if it's possible to do so with a combi boiler. In this blog post, we'll explore the possibility of using a combi boiler with underfloor heating and provide some tips on how to make it work!

How to Use Underfloor Heating with a Combi Boiler

Combi boilers have two heat exchangers: one is for domestic use for heating water, and the other heat exchanger is for underfloor heating (space heating) for residential use.

If you have a combi boiler and want to install underfloor heating, your boiler will need a few adjustments to run your radiators and the UFH efficiently.

There are two types of underfloor heating systems to keep your home warm in the winter: wet, which requires heated water through a boiler and dry, which uses electrical wires installed beneath the floors.

Dry underfloor heating system

The dry system is an electric underfloor heating system that is connected to the mains. The amount of power to the electrical wires will largely depend on the size of the room. The electrical cables are installed and distributed above a layer of insulation under the floor to prevent the heat from going down.

Wet underfloor heating system

Wet underfloor heating

The wet system works similar to radiators where a central heating system heats water in pipes connected to the rods - and with the underfloor heating, the pipes are spread over a large area, closer together to warm them. This requires more space to install the pipes beneath the floor.

To distribute the heat in the underfloor pipes evenly, the hot water passes through a temperature sensor on the boiler to determine if the water is hot enough.

Notably, you can visit how to install wet underfloor heating, which includes everything you need to know about installation.

Install a two-port valve

The two-port valve controls the flow of water in your central heating system. The valve allows both the radiators and the underfloor heating to run separately at different temperatures to operate individually without affecting each other.

If you don't have a two-port valve installed, both systems will try to run simultaneously, leading to an overheated boiler, and it will go into fault mode.

You can find more information on both within our complete guides, such as what a combi boiler is. We compare both electrical and wet heating systems.

Also, the types of boilers are explained and the most common problems with boilers.

What Is the Best Combi Boiler to Use for Underfloor Heating?

Most combi boilers have sufficient power to run underfloor heating systems, as long as a two-port valve is installed to separate the flow between the radiators and the underfloor heating.

The underfloor heating boiler requirements revolve around how many rooms in the house you intend to have the underfloor heating installed in. The more rooms you want it in, the higher the power your boiler will need to produce.

Luckily, the temperature required to heat underfloor heating is less than what is necessary for radiators.

As a rough guide, a 24kw boiler is sufficient for one room installation, a 30kw boiler for two rooms, and a 35 - 40kw boiler for underfloor heating installation in many spaces. The best combi boilers models used for underfloor heating are Ideal, Worcester, and Valliant.

The right combination boiler will also depend on the number of radiators, so it's best to talk to a qualified plumber for advice.

Which Underfloor Heating System Works Best with a Combi Boiler?


If you want underfloor heating installed in your home with a combi boiler, you will need the wet system. The damp system works with combi and condensing boilers by regulating the hot water passing through the pipes under the floor.

Is Underfloor Heating from a Combi Boiler Worth It?

Having UFH installed has many benefits, from keeping you warm to lowering your energy bill and increasing property value.

Warmth: The main reason is the warmth flowing from beneath the floorboards that give a room an ambient temperature and feels fantastic on your feet compared to radiators.

Efficiency: Since underfloor heating works with lower temperatures, it is more energy-efficient than other heating sources and covers larger areas. The temperature can be controlled by an underfloor heating thermostat, helping to save money on your energy bill.

Sell-on-value: If you want to increase your home value, installing underfloor heating is a worthy investment that attracts buyers. All homes have radiators in the UK, but not all homes have underfloor heating - and that is a plus for home buyers.

Safety: It's good for your health due to the gentle heat and removes the need for a carpet, which collects dust, dirt, and bacteria. Underfloor heating also eliminates the need for radiators in the room, which block areas and are hazardous for babies who may touch them when hot.

You can also learn how to retrofit underfloor heating and visit our electric boilers and electric flow boiler range.


How much does an underfloor heating system cost?


The price will depend on the size of the room you want it installed in and the area you live in. On average, a 100m² home will cost around £1000.

How long does it take to install underfloor heating?

For a 100m² floor, it will take around a day or two, depending on how many installers are there to do the underfloor heating work.

Are there any risks with using underfloor heating with a combi boiler?

No, there aren't any risks involved. It is easier to install underfloor heating with a condensing boiler than a combi if you also have radiators running from the combination boiler. Still, a qualified heating engineer will fit a two-port valve for solving the issue.

Can I install underfloor heating myself?

Yes, you can install electric underfloor heating in a small room if you like doing DIY. Still, for larger spaces, it is better to hire a professional - and for connecting it to your boiler for wet systems, a gas-safe heating engineer is required by law for installing underfloor heating systems.

Final Thoughts

If you're considering adding underfloor heating to your home, the good news is that it can be installed with any boiler. Whether you have a combi boiler or a traditional system, we can work with you to design and install an underfloor heating system that meets your needs.

Underfloor heating is one of the most efficient and cost-effective ways to heat your home.