How to install electric or water based in floor heating: A step by step guide

In the past, home heating was done mainly by using fireplaces, furnaces, and space heaters. But in recent years, floor heating has become a popular alternative to other methods. In this article, we’re going to explore just how this type of heating works.


In-floor heating is installed below the floorboards or directly into the subfloor and then covered with a thick pad of insulation. The system consists of pipes that carry hot water in the floor. This means that there are no radiators or vents to install or maintain because all of the energy is embedded inside the floors themselves.

To learn more about how installing in-floor heating may work for you and your home, read on!

The Benefits of Floor Heating

There are many benefits to in-floor heating. For one, floor heating is surprisingly more energy efficient than other types of heating. This is because it heats the entire room, not just certain parts of the room. Another thing that sets floor heating apart from others is how fast it warms up a room. In some cases, the heat could be felt within 15 minutes or less!

There are also several ways to control your in-floor heating system. You can set your thermostat so that your system only turns on when you want it to and for as long as you need it to. And if you have an app for your smartphone, you can even control it from there!

Finally, in-floor heating is durable and easy to maintain. Because all of the pipes are below the floors themselves, they’re protected from any moisture or water damage that may occur over time. It’s also easier to clean since there are no vents or radiators that can get dirty with use and build-up of dust and dirt. 

Floor heating can also be very comfortable, especially if you walk around in socks or barefoot. It can give a cosy feeling. 

To learn more about how installing in-floor heating may work for you and your home, read on!

How Do You Install It?

There are 2 types of systems: electrical systems and water-based systems. Let’s discuss each of these.

Water-based systems

Installing in floor heating is a fairly simple process but needs some preparation. 

 If you install it upstairs, you have to make sure that the upper floor can handle the weight. In some instances, you will not be able to install floor heating as your house is not designed to handle this load. Reinforcing it can cost a lot of money and require a lot of studies.

You also have to take the height into account. Floor heating comes on top of your current floors. This can lead to uncomfortable situations, such as height differences between rooms. To avoid this, you can use a machine to create grooves into the floor. This puts the pipes inside the floor instead of on top of it. This is a lot of work and can create dust. These pipes can therefore be embedded in concrete slabs or laid on top of them.

First, you prepare the floor by cleaning it. This is done with a brush to remove all the dirt and dust. 

The outline of the installation is often drawn on the floor using chalk. Then the PEX pipes are rolled out. These pipes are durable and strong and often used for plumbing. Make sure that you fasten them well so that they don’t move around when you pour the concrete.

 There are 3 main patterns that can be followed: counterflow, serpentine, and modulated spiral. The modulated spiral is often the most efficient as it spreads out heat the best.  Once this is done, it is time to install a pad of insulation.

How long to pressure test underfloor heating?

Once the system is installed, it is time to test it. This is done by adding water in it. We then see if the pressure will drop or not. Plumbers perform a quick test to see if there are initial leaks. They have special equipment for this (as discussed in the video below).

If this is not the case, a more extensive test is started. Generally, this will last 7 days but it depends on the system that is being installed and your local code. It is often done by professionals as special equipment is needed.

Once the system has been installed, it is tested. This is done by adding water to it and using a pump to add pressure. This makes sure that the system doesn’t leak. At that point it is still quite easy to fix leaks as the floor hasn’t been installed yet. It is important that you don’t stand on the pipes as they can break under pressure. Once the test has been done, it is possible that an inspector checks it as well. The pipes can then be added to the manifold. After this, isolation is added and the floor is poured. Once this is done, tile can be added to finish the installation. The plumber has to add the heating systems to finish things up. A thermostat can be added as well at this point. 

Floor heating is often used in combination with heat pumps. Heat pumps can use heat from the ground (geothermal) or air. These systems are still quite new but they are getting cheaper and replacing water heaters that use natural gas. Heat pumps are more environmentally friendly so might become more popular in the coming decades. At the moment a lot of people still use a gas heater to warm up their floor heating system.

Electrical systems: can you wire underfloor heating to a plug or do you need a new circuit?  

More recently electric mats have made it easier to install floor heating. You don’t have to roll out the individual pipes but can just open up the mat and connect it to electricity. This shortens the installation time. There is a limit to how much space can be heated with these mats so they certainly have limitations. They also cost more to operate. Things to take into consideration when installing this:

-Do not install it under fixtures

-Install it at least 4 inches away from walls

-Install it at least 6 inches away from toilets

-Install it at least 8 inches away from HVAC equipment

-Perform all the tests outlined in the manual. Some systems have an alarm that warns you that the cables are damaged.

-Do not turn on the system until it is installed in the mortar.

As you can see, this can require quite some planning. You can often cut the mats but knowing where it should lay can take some work as you have to know how far that you can go. Batteries and solar panels will make it cheaper to install this so this system could become more popular in the coming years. 

You shouldn’t install it on a plug as this is not up to code in most places. Often you will require a separate circuit for this. It makes it easier to troubleshoot problems. Foor heating requires quite a lot of electricity and a separate electrical circuit makes sure that the system isn’t underpowered.

It should be possible to install this system yourself. Just make sure that you test it before adding the floor.  

Can you join 2 underfloor heating mats together?

This depends on the system that you get. In most instances, it should be possible if the overlap is not too big. You should check the manual of your system or reach out to the manufacturer of your system.

It is also important to check your local code to see if they have specific requirements. It is important that an electrician signs off on your installation. It is very hard to change things once you start pouring the floor over the heating mats.

When in doubt, you can always send a picture to the manufacturer to get further input.

What Are the Drawbacks of in-floor heating?

Installation is a major factor in the cost of in-floor heating. If you hire a professional to install your system, it will take them at least one day, and it could take up to two days. The heating system also needs to be assessed for its lifespan. In general, the more times the pipes are heated and cooled, the less effective they will become.

Old houses may not be able to handle this type of installation because of their age and size. For example, installing heating pipes below the floorboards or subfloor won’t work if there are already pipes in place; it’s just too difficult to work around them.

 Leaks can be quite hard to fix. It might be needed to open up the floor to find the exact location. This can lead to a lot of damage and costs. For this reason, it is essential that the system is tested before the floor is installed. 

Electrical systems might be less durable but this depends on a lot of factors. These systems have improved a lot during the past few years.

How much does it cost to install floor heating?

Installing in-floor heating is a cost-effective option for homeowners. The cost of installing the system varies depending on a variety of factors, including the size of your home and the type of flooring you have. To estimate how much it would cost to install in-floor heating, use this formula:

Below are some examples. Keep in mind that every system is unique so there are a lot of things that can fluctuate. Electric systems are cheaper to install but cost more to run. The following is for a water-based system. You still have to get a heat pump so the final costs might be higher.

– A 350 square foot house with standard density will cost $1,950 to install heated floors.

– A 350 square foot house with high density will cost $2,450 to install heated floors.

– A 500 square foot house with standard density will cost $3,500 to install heated floors.

– A 500 square foot house with high density will cost $4,750 to install heated floors.

To conclude, we can state that floor heating is becoming more popular. It is quite easy to install. Just make sure that you plan everything in advance to avoid leaks or problems. 

Can you put a bath mat on a heated floor?

We all love the soft feeling of a bath mat after we have taken a shower. It also absorbs some moisture. You might hav installed heated flooring and wonder if you can use a bath mat.

This is generally not a problem. Make sure to read the instructions on the bath mat though. Some have rubber in them. This material can melt and create a mess. For this reason, you should only get high-quality rugs.

Check the temperature of your heated floor. If it goes above a certain temperature, your bath maths might start to break down.

Permanent mats that cover the whole floor can cause problems though so you have to be careful with this.