Heating Blog | Thermosphere

What is the best thermostat to use for underfloor heating?

Written by Chris Hedges | Jan 18, 2022

What is the best thermostat to use for underfloor heating? When it comes to the best thermostat to use for underfloor heating, there are so many to choose from and it really boils down to what type suits your lifestyle more than others. From a manual thermostat where you simply turn a dial to adjust the temperature to changing the temperature using your voice with a smart thermostat. There’s a wide range of options from a lot of brands to choose from.

So, to answer the question; ‘what is the best thermostat to use for underfloor heating?’ we’ll walk you through everything you need to know before deciding what is best for you.

Quite simply, there is no right or wrong answer, just some key points you need to be aware of.

Ready? OK. Let’s begin…

Not all thermostats work with underfloor heating

When trawling through the internet you’ll probably find mixed opinion on what type of thermostats work with underfloor heating systems. Some thermostats are simply for a traditional central heating system, some can do both (with help of clever wiring from an electrician) and others only control underfloor heating.

A very common question we get asked is ‘Can Nest or Hive thermostats control electric underfloor heating?’.

The short answer is no. But here’s why.

Thermostats like Nest are designed to switch low electrical current systems of up to 3A. Electric underfloor heating systems are high current systems and can be up to 16A and therefore you will need additional wiring and relays to use a thermostat such as Nest. However, the Nest Thermostat has no problem in controlling wet underfloor heating systems.

There is also another key reason. With an electric underfloor heating system, the recommended maximum temperature to run it is 270C. This is particularly important for wood or carpeted floors because any higher could result in damage to the floor finish. Typically Nest and Hive thermostats measure temperature of the air and not the temperature of the floor so you are unable to effectively set a safe temperature for the floor (i.e. 270C) and therefore incur a greater risk of unwanted damage which will cost you both time and money to fix.

What range of underfloor heating thermostats are available?

When choosing a thermostat to control your underfloor heating, there is such a wide range of functionality, design, size and even colour to choose from. As mentioned previously, it really boils down to what type of thermostat is best suited to your lifestyle. More about that later.

Manual thermostats

These types of thermostat are entry level. You can adjust the temperature, turn your underfloor heating system on/off and include ambient (air) and floor sensor functionality. Manual thermostats are not LOT 20 compliant because they don’t include energy saving features which means installing one will have minimal impact on reducing your energy bills.

Due to the limited function of a manual thermostat, you’ll find these are the cheapest option to control your underfloor heating system but not the most efficient.

Programmable thermostats

The most common type of underfloor heating thermostats. Quite simply the bread and butter of underfloor heating control. Programmable thermostats automatically adjust the temperature of the room to your ideal comfort level, when you want it to. You can create a heating schedule to fit your lifestyle. Do you want warm floors at 6pm when you arrive home? No problem.

Other features of programmable thermostats include functionality such as sensing when a window or door is open. The programmable thermostat will automatically switch your underfloor heating system off which ensures you reduce heat loss and aren’t paying money for heat that’s literally flying out of the window.

Another cool feature of programmable thermostats is a smart adaptive start-up function. What’s this? Well, many programmable thermostats learn how long it takes your floor to heat up as it varies depending on the build-up, floor finish etc. However, by learning how long it takes your floor to heat up, the programmable thermostat makes sure your room is at the right temperature at exactly the time you want it to be. Clever isn’t it?

What about connectivity?

There are lots of different types of programmable thermostats out there. Some connect directly to your WiFi, some connect to your internet via a hub and others use Bluetooth connectivity such as the BT21. When considering Bluetooth connectivity is important to note that you have to be in range of the Bluetooth signal to control your heating via the app. If controlling your underfloor heating on your phone is a ‘must have’ it’s worth asking your retailer for a demonstration of the app before parting with the pennies as some apps are much more intuitive than others. YouTube is a great resource for checking out demos, reviews by installers and feedback by homeowners.

Smart thermostats

If you are looking for an underfloor heating thermostat with all the bells and whistles, then check out some of the smart thermostats available for underfloor heating. Yes, smart thermostats are a type of programmable thermostat but they are jam-packed full of energy saving features which makes it easier to control your heating in a simple and more efficient way.

No matter where you are in the world, smart thermostats let you control your underfloor heating whenever you are connected to the internet. With rise of the ‘connected home’ or the internet of things (IoT, a network of interconnected devices in the home that speak to each other and can be controlled remotely) the popularity of smart thermostats continues to grow. By embracing interconnectivity of a smart thermostat, you can control underfloor heating via the app and/or control it with your voice using smart speakers such as the Amazon Echo.

Will smart thermostats save you money?

Yes! They will save you money through better efficiency over a period of time but don’t expect and instant change to your bill that you would get from changing energy suppliers.

Dual control thermostats

If you are wanting the convenience of controlling a heated floor and another heating appliance like an electric towel bar with one thermostat, then a dual control thermostat is just what you need. A dual control thermostat gives you the ability to set a heating schedule for your floor and for the towel bar (or mirror demister). This is all thanks to independently switched dual relays inside the thermostat.

I hear a lot about Lot 20 compliance, but what does it mean?

Way back in January 2018 LOT 20 was introduced. It is a piece of legislation which comes from the European Ecodesign Directive (2009/125/EC) and was a significant change within the electric heating industry. The purpose of the directive was to provide a framework for all energy-using products to adhere to which would help drive a reduction in wasted energy and meet carbon reduction targets.

Under LOT 20 all electric heating systems sold in the EU need a minimum efficiency rating. This is rated by how many energy saving features are built-in to the heating product. A great example is the Dual Control thermostat which includes features such as automatic open window sensor and energy saving adaptive start.

Hang on. Does LOT 20 still apply since we left the EU?

In the House of Lords document ‘Brexit: environment and climate change’ it stated: ‘Around half of the UK’s overall trade (import and export) is with the European Union, though this figure is higher in some sectors. For those engaged in trade, therefore, continuing co-operation on environmental standards is likely to be a key priority.’ So, LOT 20 and the principles of it aren’t going away any time soon.

What’s the best temperature to set my underfloor heating to?

When it comes to floor temperature we always recommend a maximum floor temperature of 270C. For ambient temperatures, 180C-200C for bedrooms and 210C-230C for living areas are most common.

In the average UK home, if you reduced the room temperatures by just 10C you’ll help reduce CO2 emissions but as much as 300kg and your heating bill by £65 – £75 each year. Check out the Energy Saving Trust website for the latest facts and figures.

So, which is the best underfloor heating thermostat for you?

As mentioned right at the beginning of this article, it’s all about lifestyle. No matter your lifestyle, there’s an underfloor heating thermostat for you.

The Technophobe

If technology isn’t your thing and you only want to control the heating in a room that isn’t used frequently, then a manual thermostat will suit you well.

The Environmentalist

If you are eager to reduce your energy consumption, and make a positive dent to your heating bills, then a programmable thermostat is probably more your thing. With lots of energy saving features it will help you heat your living space in an environmentally sympathetic way.

The Tech Enthusiast

Are you already embracing smart home technology in your home? Love gadgets and the latest tech? If so, smart thermostats are a great choice. Monitor your energy consumption and control your heating with the an app and even your voice.

The Spa Goer

Looking for that 5-star luxury feel? Combine the control of your heated floor with an electric towel bar, ladder rail or mirror demister by installing a Dual Control thermostat. Total control made easy.

A final top tip before you buy!

Before fully committing to your thermostat purchase, why not check out the reviews from Trustpilot because it will give you a good flavour of what thermostats homeowners and installers like, dislike and why.

Here is a list of Trustpilot sites for some common underfloor heating brands:

Warm Up

Heatmiser

Heat Mat

Prowarm

ThermoSphere

As always, if you have any questions about underfloor heating thermostats, contact one of the team. Just head on over to the contact us page to start the conversation.