people standing on retrofit underfloor heating

The Ultimate Underfloor Heating Guide

What Is Underfloor Heating?

Underfloor heating is a way to gently and effectively heat your home without the use of radiator or electric heaters. By placing electric coils or pads, or warm water filled pipes beneath your flooring, you can heat a room from the bottom up. This has long been a popular home heating method in Scandinavia, and results in a warm and comfortable space.

In addition to heating your home effectively, wet underfloor heating systems are one of the energy efficient options on the market. This is increasingly important to people concerned about their environmental impact, and for those who want to save money on their bills.

How Does Wet Underfloor Heating Work?

Wet underfloor heating uses lengths of pipes that have been plumbed into your boiler, either by a professional plumber or as a DIY project. The thermostat is wired into your mains, allowing for easy control. While wet underfloor heating is often best used with stone or tile flooring, it can also be laid underneath carpeting with a tog of less than 1.5.

Why Are More and More People Buying Underfloor Heating?

Underfloor heating is more popular than ever before for just a few of the following reasons:

  • Easy, low cost maintenance
    One of the most commonly cited reasons hat people choose underfloor heating systems is that it is virtually maintenance free. Both electric and hot water underfloor heating systems usually come with 25 year warranties.
  • Energy efficiency
    Heating your home with underfloor heating is far more energy efficient than traditional radiator heat, and is therefore results in lower utility bills. As your floor is heated, it holds onto heat for far longer than radiators do (which usually cool down quickly, cooling the room quickly as well). Wet underfloor heating using gas as fuel, and they tend to be a lot more efficient than electric systems.
  • A comfortable home

A cold, clammy home simply does not feel comfortable or relaxing. Underfloor heating keeps your home at a consistent, pleasant temperature and eliminates hot and cold spots.

  • It is more hygienic than traditional heating

Radiators and convection heating systems allow for cold and damp to remain at ground level. The result? Dust mites breed, triggering allergies and asthma in your family members. Some studies have even shown that underfloor heating can reduce the number of dust mites in your home by up to 80%.

How To Use Wet Underfloor Heating Most Efficiently

The following tips will help you to maximise the efficiency of your underfloor heating system.

  • Increase the dial by small amounts
    When you get home and the house is cold, your natural instinct might be to crank the dial. Resist the urge, as turning the thermostat up all the way does not increase the speed at which the room will get warm.
  • Use a programmable thermostat
    If you want to avoid the problem of arriving home to a cold house completely, you can choose a programmable thermostat. You can set them to default settings for different times a day, and have your floors start warming up for you an hour before you arrive home. Some systems even have app compatibility, allowing you to alter the temperatures from afar.
  • Have your underfloor heating system serviced once a year
    As with any household appliance or system, preventing an issue is always better than fixing one after it manifests. Having a professional assess your underfloor heating system once a year.

With What Types Of Flooring Can You Use Wet Underfloor Heating?

Many people make the mistake of thinking that underfloor heating systems can only be installed under stone, ceramic or terracotta tile floors, but this is not the case. You can also find models and systems that will work well with wood, linoleum or carpet.

The following types of flooring are compatible with wet underfloor heating:

  • Carpet (1.5 – 2.5 tog or lower)
  • Stone
  • Ceramic
  • Slate
  • Terracotta
  • Vinyl and laminate
  • Wood Floors

If you are planning to place wet underfloor heating below a wood floor, you need to remember that the wood will naturally expand and contract with different temperatures and moisture levels. This happens with wood more than with stone or tiles. You can address this issue by using a layer of polythene foam between the heating system and floating wooden boards.

How To Install Wet Underfloor Heating

While most people choose to have a professional install their wet underfloor heating system, this can really add to the cost. If you consider yourself handy and you have the time and patience to do the job yourself, you can follow these steps.

Step 1 – Prepare your installation

Preparation is everything. Make sure you have the instruction manuals and CAD drawings on hand, and go over them to get an idea of the process. Start by identifying where the system manifold will be housed – will it be in the same room, or elsewhere in the house? If it will be in another room, drill the holes now (one hole for in, one hole for out on the loop).

Sweep the space thoroughly, and sand away any sharp edges. Run a hoover over the whole room on the highest setting.

Step 2 – Lay down the installation

This is one of the most time consuming parts of the process, and deserves its own guide. Check out this link for a step by step guide.

Step 3 – Installing the manifold

Start by affixing the manifold in place on a wall, following the recommended positioning on the CAD drawings. For future ease of servicing, make sure there is adequate space around the unit. Next, connect the manifold’s pump and mixing valve to your water supply. Planning to also run radiators? You will need to attach a zone valve so that you can control these methods separately.

Step 4 – Lay out the grip rails

You need to ensure that your pipes are secure before the screeding process, and so don’t overlook this important step. Lay out your grip rails (don’t remove the paper backing yet) 90° from where you actually intend to lay them down. Get your pipe staples handy.

Step 5 – Lay out the pipework

Place your pipes at approximately 200mm intervals (or according to your custom plans) in a snaking pattern back and forth, making sure to leave enough space for the pipe to loop back around to the wall along the doorway. Leave enough pipe to reach the manifold.

Staple your pipes in place where they bend in order to add extra security. They will hold down the pipes without getting in the way of the screed. You can even add staples to the straight lengths of pipe if you think they need extra bolstering.

Step 6 – Connect the pipes to the manifold

As you work, always ensure that each pipe end is cut cleanly with a pipe cutter (saws leave jagged surfaces that prevent a good seal). Cut all of your pipes to their desired lengths, and then slide the nut and compression ring over the top of each. Hold each pipe firmly and fit it snugly with the hose pillar, and then into the valve in the manifold. Tighten the nut by hand, and then finish with a spanner (but do not over-tighten).

Step 7 – Check flushing, pressurizing, and filling

Start by double checking that all isolating valves are shut, and then connect all hoses to the manifold’s drain and fill points. The fill point should be connected to the mains tap. You can then open the adjustable balancing and circuit valves on the manifold’s furthest loop, flushing out the system and purging air from the circuits.

Step 8 – Place the screeding over the wet underfloor heating system

Again, screeding is such an important part of the underfloor heating installation process that it needs it own guide. Check it out here for comprehensive, step by step instructions.

Step 9 – Place your flooring

Once your screed has completely dried and cured, you can lay your flooring. The finish line is in sight!

Step 10 – Give your underfloor heating system a try!

Now is the time to take your underfloor heating system out for a spin. Start by

turning it on to around 25° to 30°, and keep at this setting for around 3 days. You can then slowly increase the temperature until it arrives at your desired heat, usually between 40° and 60°.

What Are The Different Types of Underfloor Heating?

The two main kinds of underfloor heating systems are wet (hot water) and dry (electrical). Like a central heating system, wet underfloor heating uses warm water that is pumped through pipes that are underneath your flooring material. These pipes are covered with a screed, a heat conducting material, which retains and radiates the heat throughout the room.

Electric underfloor systems operate similarly, but with a series of electrical wires rather than water pipes. You can also choose heating mats in order to cover larger areas (but electric wires can edge into all nooks and crannies).

What Is Better, Water or Electric Underfloor Heating?

When you are deciding between water and electric underfloor heating, you need to consider your home’s specs. You also need to think about your budget in terms of what you can afford in the short term and the long term.

Fitting and installing wet underfloor heating is indeed more costly that fitting an electric underfloor heating system, but it is more energy efficient. This means that it is less expensive to run, and your heating bills will be lower. This can result in a substantial savings over time.

However, certain homes do not allow for easy installation of wet underfloor heating. They don’t have enough space underneath the flooring for the pipes. In these cases, the floor might need to be raised in order to accommodate the pipes needed for the water. If you are building a new home, you can include this space in your designs. If you want to install underfloor heating in an existing home, an electric wire, electric pad or underfloor heating overlay boards might work best for you.


No matter what kind of underfloor heating system you choose for your home, your living space will be warmer, drier and more comfortable than with radiator heat.

Frequently Asked Questions:

Is underfloor heating expensive to run?

While electric (dry mat) heating can run up your electricity bills, wet    underfloor heating is a much more affordable option.

Can underfloor heating crack tiles?

While it is certainly possible that your underfloor heating can crack tiles, if you install the system correctly it shouldn’t be a problem.

Can underfloor heating replace radiators?

If your home has double glazed windows, your underfloor heating can absolutely replace radiators.

At what temperature does underfloor heating run?

Warm water underfloor systems often generate heat between 40°Cto 65°C. This creates an actual floor temperature of between 23°C and 32°C, and reduces your heating costs over time.

Can underfloor heating go under carpet?

Yes, but you will not feel as much heat radiating from the floor, as the carpet does not conduct heat as well as tile, wood or laminate.

Can underfloor heating go under wooden floors?

Generally, underfloor heating is not compatible with solid wood floors, but more and more manufacturers are creating wooden floor options that are.

Can underfloor heating go on chipboard?

While underfloor heating can be laid on chipboard, different installers will use a buffer material (such a plywood) as an extra layer.

Can underfloor heating go under laminate or vinyl?

Absolutely. The foil mat system is specifically designed for laminate flooring. It is ideal for high-quality vinyl and laminate flooring. Do ensure that the laminate you plan to use is compatible with underfloor heating; some brands have their own partnerships with UFH systems.

Can underfloor heating leak?

In most wet underfloor heating systems, the plastic piping is continuous. This means that there are no joints, and therefore no leaks.

Can underfloor heating be repaired?

Absolutely, but costs will depend on the specific problem.

Can underfloor heating pipes freeze?

No, underfloor heating pipes cannot freeze, as once the system is up and running heat will be consistently maintained in the pipes.

Can underfloor heating be retrofitted?

Yes it can, but you will have to take the specifics of the property into consideration, and costs can vary greatly.

Can underfloor heating be connected to the radiator?

Absolutely – these two systems can work together seamlessly to heat your home affordably and effectively.

Can underfloor heating heat a room?

It certainly can. While you might want to turn on radiator heating in other rooms in cold weather, underfloor heating is enough to heat a room.

Can underfloor heating get air locked?

While this is a rare problem, it can occur. If this happens, consult your underfloor heating professional.

Can underfloor heating mats be cut?

Yes, you can carefully cut the mat and reroute the heating cables.

Can underfloor heating go under kitchen units?

Depending on the weight of the kitchen units, you may or may not be able to install underfloor heating beneath them.

Does underfloor heating smell?

It is always a good idea to use a microbial inhibitor, sanitiser and biocide in your underfloor heating system in order to prevent bacteria growth, corrosion and smells.

Can underfloor heating cause a fire?

While underfloor heating is a very safe technology, in rare instances it can cause overheating and potentially even fire. It is important to follow all recommendations and safety precautions.

Can underfloor heating be used under parquet?

Absolutely. Most underfloor heating systems have been designed specifically to be used under wooden floors and parquet.

Will underfloor heating heat a conservatory?

Many homeowners find that underfloor heating provides more than enough heating for a conservatory, especially if the windows are double glazed.

Do you need a certain type of boiler?

While a condensing boiler is the most efficient for wet underfloor heating, any kind of boiler can be used.

I am an underfloor heating expert and have been writing articles for our blog for over eight years. During this time I have discovered new and inventive ways to introduce underfloor heating to contemporary homes, and I am more than happy to offer advice on saving on energy, maintenance, installation, and much more!

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