Electric vs Water Underfloor Heating: Which is Right for You?
Choosing between electric vs water underfloor heating is one of the first and most important decisions when planning a new heating system. The right option will depend on the size of the project, budget, and the heating source available.
In this guide, we’ll compare electric and wet underfloor heating systems, outlining their key differences, advantages, and considerations to help you make an informed decision.
What is electric underfloor heating?
Electric underfloor heating is exactly as it is described. It is a heating system that uses only electricity to heat a floor, which then radiates into the room it’s installed in, to give a nice, comfortable heated environment.
Types of Electric Underfloor Heating
The heat is transferred to the floor by one of the following system types:
- Mesh underfloor heating mats with heating wires embedded. The mats are manufactured with a variety of cable spacings. The closer the cables are spaced gives higher heating outputs. The further away the spacing is, the lower the heating outputs.
- Foil faced mat with cables embedded. These are typically used in wooden, laminate or vinyl floors.
- Loose cables. Cables supplied in drums are rolled out onto the floor and taped into position. The cable spacing can be varied to provide various heating outputs. This system is particularly useful when installing electric underfloor heating into irregular shaped rooms or installing it around bathroom fixtures for example.
Controls & Thermostats
The heating is normally controlled by a thermostat in combination with a floor probe. This gives the ability to set up the heating to operate by measuring only air temperature, measuring floor temperature or by measuring both. This is useful when you have a floor material that can suffer damage if it is overheated by setting a maximum floor temperature regardless of what the air temperature is.
Systems are compatible with either wireless, Wi-Fi-connected or wired thermostats, giving some flexibility on how you want to control your heating
Installation Considerations
Electric underfloor heating is generally simpler and quicker to install than water-based systems. It doesn’t require a connection to a central heating system, and the low profile of most mats and cables means there’s usually minimal impact on floor height.
However, careful planning is still important. Heating elements should not be placed beneath fixed units or furniture, and extra safety precautions like insulation boards and RCD protection should be included when installing in bathrooms or wet rooms.
For spaces where concrete subfloors are in place, a wet underfloor heating system may be more appropriate.
What is water underfloor heating?
Water underfloor heating is a heating system that works by pumping heated water around pipes installed under the floor.
Any heat source that provides heated water can be used in wet underfloor heating systems. They will work well with high temperature systems such as gas, oil or biomass boilers. This system is particularly well suited to low temperature systems such as air source or ground source heat pumps.
Key Components
The fundamental parts of a wet underfloor heating system are as follows:
Underfloor Heating Manifold
The manifold is situated in a convenient location. The input side of the manifold will be supplied with heated water from the heat source; the output side of the manifold will have a number of ports which the underfloor heating pipes are connected to. We design each loop to have a maximum length of 105m, any longer than that and the heated water will have given up too much of its heat by the time it gets to the end of the loop.
A large room can have more than 1 loop. The manifold can have between 2 and 12 ports, and the number of ports will be determined by the number of heating loops required.
A typical project might look something like:
- Living Room – 2 loops – zone 1
- Dining Room – 1 loop – zone 2
- Kitchen – 1 loop – zone 3
- Hall/ Cloaks – 1 loop – zone 4
- Bedroom 1 – 1 loop – zone 5
- Bedroom 2 – 1 loop – zone 6
- Bedroom 3 – 1 loop – zone 7
So, in this example there would be 8 loops covering 7 heating zones. This would require an 8-port manifold.
There are occasional single room projects where only 1 zone is required and would only need a single zone.
Manifold Control Pack – also known as Manifold Pump Unit
On some systems where the manifold is fitted directly to a heat pump the manifold control pack is not required (depending on the heat pump and the complexity of the system a manifold pump maybe required. VPS supply a pump system, without a blending valve, designed for this purpose.
On most water underfloor heating installations, the manifold control pack is the heart of the system. Whenever heating is required, the pump will switch on and will pump heated water from the heat source around the heating zones requiring heat. The heated water supplied by most high temperature heating systems is too high for underfloor heating. The manifold control pack has a blending valve (also known as a mixing valve) fitted. This blending valve mixes the heated water coming from the heat source together with the cool water on the return side of the manifold. The blending valve can be adjusted to set the desired temperature that the underfloor heating system needs to heat the heating zones properly without being so high that it becomes uncomfortable or damages the floor finishes.
Underfloor Heating Pipe
The underfloor heating pipe is connected to the manifold and then run out to the different zones according to the design layouts.
There are a number of different specifications of pipe. The most common size of pipe fitted is 16mm diameter. Some ultra-low profile systems use 12mm diameter pipe.
Most underfloor heating pipes will have a life expectancy of 50 years or more. In reality, if the system is kept clean the pipe will last a lifetime.
Controls
Thermostats
Wet underfloor heating is very flexible when it comes to controlling it. The entire system could be controlled by a single thermostat, or every zone can be controlled individually. Or a combination of both, where thermostats control more than 1 zone.
Most end users decide on multi zone controls as this is the most fuel-efficient way of running a heating system. For example, there is no point in heating a dining room all day if it’s only used for a couple of hours in the evening.
There is a wide choice of thermostats in terms of manufacturers, functionality, and ease of fitting.
Probably the most important choices to make are:
Hard Wired or Wireless
Undoubtedly the best choice for installing thermostats is for them to be hard wired. Once they are fitted there are no issues with changing batteries or in some stats they can be recharged via USB cable. There are also no issues with signals not being received via the wireless connection.
The main advantage with wireless thermostats is that they are very easy to fit. No need to cut channels in walls to run cables. Sometimes it can be impossible to find cable routes from the thermostats back to the wiring centre at the manifold.
Signal loss is much less of a problem than it used to be, with newer technology having much better connectivity. There are also various ways of boosting the signal which are very effective.
Wi-fi Controls or not
Many users love being able to set up their heating systems on their mobile phones, tablets or PCs. It gives lots of convenience such controlling the various heating zones remotely and turning heating on or off if the end users schedule varies from normal.
Other users do not want the additional complications of this new technology and prefer something simpler that costs a little less money.
Actuators
In order for the thermostats to control individual zones actuators must be fitted to the underfloor heating manifold. Each time a thermostat calls for heat the actuator(s) on the zone calling for heat will let the heated water pass through the pipe in the loops. When the heating interval is finished or the desired temperature has been achieved the actuators will cut off the supply of hot water to the loops.
The only time when actuators are not required is when the heating system is being operated as a single zone.
Differences between electric and water underfloor heating:
Whilst both electric and water underfloor heating produce the same comfortable heat that underfloor heating is renowned for, the fundamental differences in the technology make a considerable difference to the installation costs and the running costs.
Installation costs
In general terms water underfloor heating systems will be more expensive to install than electric systems.
Electric systems have fairly simple materials. Either a mat with cable incorporated into it or a long reel of cable. The labour costs are normally much lower as well and a single room can be ready for final floor finishes in as little as an hour.
The wet systems have more complex components and can be much more complex to install. Costs can vary quite a bit depending on whether the installation is in a new build property or a renovation of an existing property, The labour costs are generally higher also.
Electric vs Water UFH Running costs
The average cost per kWh for electricity in the UK in 2025 is 24p, for gas it is 6.5p.
The running cost information in the following table has been gleaned from these sources: Energy Saving Trust / National Grid / Octopus / EDF / British Gas
| Heating Type | Annual Cost | Monthly Average |
| Gas Boiler | ~ £780 | ~ £65 |
| Electricity | ~ £2,880 | ~ £240 |
| Air Source Heat Pump | ~ £960 | ~ £80 |
In any larger project the only time electricity will have comparable running costs is where the only option is using electricity as a direct heating source. In this case the additional investment in water underfloor heating is not worth it.
It should always be borne in mind that the efficiency savings that can be made are over the long term and the initial cost will be recovered over time.
Project Suitability
When deciding on whether water or electric underfloor heating is the better choice some thought should be given on what is the more suitable option, or indeed if underfloor heating is suitable at all.
Key things to consider are:
New build Property: Almost always better with a water-based system as the system can be designed into the house plans from the start. The only time that an electric system would be preferred is if the only source of heating is from electricity and there are reasons why a heat pump cannot be installed.
Retrofit in existing property: Consideration needs to be given to
- How easy will it be to fit? Things like suitable pipe routes, type of floor to be fitted on, insulation levels, Some systems will need heightened floor levels, which will mean significant work raising skirtings, shortening doors, etc.
- If the heat source is electric only and the property is not suitable for installing a heat pump, the simplest way to install underfloor heating would be to install an electric system. There are no efficiency benefits to be gained by installing a wet system in this scenario. There will also be significant cost savings in installing an electric system rather than a wet underfloor heating system.
- Bear in mind that UFH (Underfloor Heating) can increase the value of property between 3-5%. So even if the project is difficult and relatively expensive, it may be worth doing as all of the benefits of underfloor heating would be achieved and the capital costs could be recovered from the increase in house value.
Which UFH System is More Efficient?
Water underfloor heating is normally more efficient than electric UFH. This is especially true of large areas, or entire houses are to be heated. Some of the reasons for this are:
- Wet underfloor heating systems run at low temperatures. Boilers run more efficiently when they are run at lower temperatures.
- This low temperature is ideal when the heat source is an Air Source Heat Pump, and these units allow heating using electricity much more efficiently than using electricity as a direct heating source.
- In small areas such as an en-suite or small bathroom, it can be more efficient to install an electric UFH system due to the much lower installation costs.
Heating Response Time
Electric UFH is more responsive than a wet system. It heats up and cools down quicker. It typically heats up in 15 – 30 minutes depending on the floor. Makes it ideal for on demand use. E.g., heating a bathroom in the morning. Because it cools down much quicker it is less suitable for long term warmth unless the thermostat is programmed to maintain the room temperature.
Water based UFH is slower to respond. This can vary with the type of system installed. A screeded floor can take between 1 and 3 hours to be effective at heating a room. It is better at retaining heat and sensible use of timers and thermostats can create a very comfortable and pleasant environment and does so very efficiently.
Maintenance and longevity
Both Electric and Water underfloor heating systems are fairly low maintenance, particularly electric underfloor heating.
Electric UFH Longevity
Electric underfloor heating is a simple cable system under the floor. There are no moving parts or pipes or fluids. Providing no one sticks a nail or screw through a cable the system is maintenance free.
Most manufacturers provide long warranties, and they can do this with confidence as there is so little to go wrong with the underfloor heating part of the systems. Occasionally the thermostats can fail. These are simple and inexpensive to replace.
Electric UFH systems will last at least 20 years and in most cases much longer.
Water UFH Longevity
When properly installed a wet system is very reliable and low maintenance.
All the key components such as manifolds, pumps, actuators and controls are all accessible for maintenance.
Maintenance is limited to an annual check of the system which would normally be done as part of an annual boiler or heat pump service.
A system flush is recommended every 5 – 7 years, but with proper system chemicals and a system filter, even that can be extended.
All of the parts should last a long time, but there will be the occasional part failure. The parts are readily available at low cost and any heating engineer should be able to replace them easily. The pipework is mostly designed to last a lifetime with most manufacturers saying their pipe will last for 50 years or more.
Electric or water UFH Pros and Cons
| Feature | Electric UFH | Water UFH |
| Upfront Cost | Lower | Higher |
| Running Cost | Higher (electricity) | Lower (with gas/ASHP) |
| Best For | Small areas, retrofits | Whole homes, new builds |
| Installation Complexity | Simple | Complex |
| Maintenance | Very low | Low (annual check) |
| Speed to Heat | Fast | Slower but retains heat |
Pros and Cons of electric UFH
Pros:
- Lower upfront cost
- Simple installation
- Very low maintenance
- Heats quickly (fast response time)
- Ideal for small areas and retrofitting
Cons:
- Higher running costs (uses electricity)
Pros and Cons of water UFH
Pros:
- Lower running costs (particularly with gas/air source heat pumps)
- Ideal for whole homes and new builds
- Retains heat for longer periods after heating stops
- Low maintenance (annual check)
Cons:
- Higher upfront cost
- Complex installation
- Slower to heat up
Get expert advice at VPS Underfloor Heating
Both types of systems are good options.
For smaller installs or installs where the only fuel source available is direct electricity an electric underfloor heating system would be ideal.
In all bigger installs, unless direct electricity is the only fuel, then a water underfloor heating system would be the preferred option.
In all cases it is advised to seek professional advice from a knowledgeable heating engineer, or you can call the technical staff at VPS for friendly professional help.
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