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Boilers with underfloor heating

There are more choices than ever when it comes to heating, but most homes still use gas, oil or LPG. One way to enable a modern condensing boiler to operate more efficiently is to link it to a warm water underfloor heating system.

But what is the best boiler for underfloor heating, and what temperature should you set it to?

Underfloor heating boiler requirements

UFH will work effectively and efficiently with combi, system, conventional gas, oil, LPG and condensing boilers.

According to the Energy Saving Trust, boilers account for around 60% of annual energy bills. By replacing an old gas boiler with an A-rated high-efficiency condensing boiler and improving heating controls, homeowners could save as much as £300 per year. Using the best boiler for underfloor heating can also significantly cut carbon dioxide emissions.

The quality of the system design is key to good performance when integrating underfloor heating with a boiler. Nu-Heat always take elements such as existing insulation and heat loss parameters into account. This ensures that not only the desired amount of heat is provided, but that the system is also economical and efficient.

What is the best boiler for underfloor heating?

There’s no best boiler for underfloor heating because UFH works well with all modern condensing boilers.

If you’re looking to really maximise efficiency through the low flow temperatures of underfloor heating, take a look at air source heat pumps. Heat pumps are a low-carbon heat source that are incredibly efficient when producing low flow temperatures. This is why they work so well with warm water underfloor heating.

Using condensing boilers with underfloor heating

Underfloor heating can help to make the most of the efficiency aspect of condensing boilers.

Here’s why a condensing boiler works well with underfloor heating:

  • Condensing boilers recover as much as possible of waste heat, which is normally ejected into the atmosphere from the flue of a conventional boiler. The combustion process in the boiler combines fuel with oxygen from the air, but as well as releasing heat there are by-products of carbon dioxide and water.
  • The water is in the form of vapour; the steam that can be seen emitting from many older boiler flues. The critical temperature is called the ‘dew point’; this is when the vapour will condense into liquid. Condensation releases a significant amount of latent heat energy from the vapour, leading to the efficiency gain.

In order for a boiler to operate in condensing mode, the return temperature of the heating system must be lower than the dew point (53°C). Radiators sized traditionally to a design flow temperature of around 70°C, with a return temperature of 60°C, are outside of a condensing boiler’s range, so cannot make the most of its capabilities.

Underfloor heating requires a flow temperature of 50°C flow and 40°C return, so using UFH with a condensing boiler is ideal for taking advantage of this.

LoProMax laying pipe

How do I choose the right boiler size for my underfloor heating?

Your boiler size will depend on how well the property is insulated and the heat output required from the underfloor heating.

If you’re unsure what boiler size is best for underfloor heating project, please contact our customer service team.

Should I use a boiler with underfloor heating or radiators?

Connecting underfloor heating to a boiler can offer better energy efficiency than a radiator system. It also frees up wall space and provides a more comfortable, even heat.

Underfloor heating is efficient because the entire surface area of the floor is far greater than that of a radiator, allowing the flow temperature to be lower to achieve the same room temperature.

Where a radiator may be heated to between 60˚C and 75˚C, underfloor heating can often achieve the same performance running at just 50˚C, which allows the boiler to operate in condensing mode. This also means less wear and tear on the boiler.

UFH produces a radiant heat rather than the convective heat associated with radiators, so it gives a very different temperature profile. Heat rises from the floor, heating from the ground up, rather than being carried by convection currents and heating the room from the top down. This means that UFH offers the ideal comfort profile of warm feet and a cool head.

Find out more about underfloor heating and radiators in our dedicated blog post.

Is underfloor heating right for me?

Underfloor heating is simple to install in a wide range of scenarios, whether you’re building your own home or embarking on a renovation project.

The Ultimate Underfloor Heating Buyer’s Guide

Find out how to choose the right underfloor heating for your home.

Download free guide

The Ultimate Underfloor Heating Buyer’s Guide

More about Jo Snell

As the Self Build Manager here at Nu-Heat, I am focused on making sure our customers get accurate and honest advice on the best heating solutions for their homes.

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