Nest Thermostats and Underfloor Heating: Latest Info Guide

Underfloor heating provides soft, gentle heating from underfoot throughout the day, giving a nice, natural feel to a house’s heating provision. This is especially compared to an occasional blast of warm air (or heat from a wall-mounted radiator) that many houses provide.

So I wanted to explore how well the Nest Learning Thermostat range and the Nest Thermostat E does with supporting underfloor heating. Whilst the answer is that it varies depending on your system and thermostat, the gist is:

The Nest Thermostat range does support hydronic (water based) underfloor heating, whereas support for electric UFH is more limited. Plus Nest Thermostats can only control a single heating source, not multiple.

What is the Nest Thermostat range?

Two Google Nest thermostats in store, the Learning Thermostat 3rd Gen and Thermostat E.
Two Google Nest thermostats (the Learning Thermostat 3rd Gen and Thermostat E)

The Nest Thermostat range includes a few hard wireable Nest Learning Thermostat models, and also a free standing Nest Thermostat E. These all fall into the category of ‘smart thermostats’ and they basically replace your existing home’s thermostat.

They then starting learning all about how your house uses the heating system – including the times of day that people are likely to be in the house, the temperatues that people like the house, and more.

Nest’s smart thermostat will then start adjusting your heating schedule so that it matches what people in the house like (and expect), whilst also hopefully saving you money on your fuel bills. Nest have previously calculated an expected saving of $131-$145 each year on the heating aspects of your bills.

You can also turn your heating on or off (and up and down) using a smartphone app or your voice (via a smart speaker such as Google Home) which is also useful.

Finally. Nest is compatible with a wide range of heating and cooling systems. However read on for more information about their support of underfloor heating systems.

Hydronic (water) vs electric underfloor heating

As I mentioned in my introduction, underfloor heating is quite a nice form of heating since it’s warm underfoot (as you’d expect from a bunch of heating pipes/wires an inch or two below the floor!), but it also naturally heats the room bit by bit so the heat never feels overpowering or false (like with some electric body heaters which can feel like ‘fake heat’).

There’s two main types of underfloor heating: electric and water (hydronic) based. Hydronic based underfloor heating systems can work by running pipework off your central heating system, and under the floor:

Diagram of water based underfloor heating, showing the heating manifold and the pipework going through the floor, and spread out underfloor.
Hydronic underfloor heating, with pipes going under the floor.

Each pipe is fairly small and is often laid into an insulation grid with pre-cut holes for the pipes (this isn’t shown above). This allows the heat to remain for as long as possible, whilst also providing stability to the floor.

Secondly, you have electric-based underfloor heating systems which are essentially like electric blankets that you can get for your bed. It comes in a big roll of mesh matting which has heatable cables stuck onto it, and it’s then wired into your house’s electrics:

A Klima underfloor heating mat with various heating coils, and a bundle of cable on the side to wire up.
A Klima underfloor heating mat with various heating coils/wires.

So how well does Nest Thermostat support each of these? Let’s take a look!

How Nest Thermostats work with hydronic (water) underfloor heating

In general, hydronic underfloor heating sytems are hooked into your hot water based central heating systems in the usual way, meaning that it’s just one part of your wider heating system.

As a result, Nest thermostats have no issue with controlling hydronic underfloor heating systems. Indeed, such systems are specifically listed on the Nest Thermostat compatibility page in the UK and there’s nothing in the American version to suggest otherwise either.

If you aren’t too sure however, just check out the online Nest compatibility tool which runs you through your current system, and then tells you if it’s compatible. If there’s any issues, you can speak to someone on the phone or online chat.

One final note is that Nest’s thermostats work with a single zone. If your underfloor heating is part of a multi-zone setup, you will need a separate Nest thermostat for this. However to be honest, this will actually work out better because you may want to run your underfloor heating at a different temperature to the rest of your heating system.

A potential problem: some Nest Thermostats only works with 1 heat source

It’s worth noting that Nest Thermostats in some parts of the world only work with a single heat source, such as in the UK.

In this case, if your underfloor heating (be it hydronic or electric) is configured such that it’s a separate heat source, you would need to purchase a separate Nest Thermostat to handle this.

This differs from the North American model of the Nest Thermostat which supports dual (or multi) heat sources and thus it could work fine in this case.

Can Nest Thermostats work with electric underfloor heating?

Nest products in store, including the Learning Thermostats and smart security cameras.
Two Nest Thermostats (and some Nest cameras) in a UK store.

Nest’s thermostats – including the cut-down ‘E’ model – all work with electric underfloor heating too. Indeed, their compatibility pages make clear that it supports electric heating:

Google Nest thermostats are designed to work with most 24V systems, even older systems. They work with all common fuel types including natural gas, oil, and electricity.

Google Nest support pages, discussing their compatibility.

Having said that, how you actually install this will vary depending on where you live in the world.

For example, in Europe your Nest Thermostat comes with a Nest Heat Link, a device which is wired into your heating control unit or system and then communicates with the Nest Thermostat.

This means that the Heat Link can be wired into the electric underfloor heating system as required. However this doesn’t come by default with America due to the different wiring requirements, and such a device probably isn’t required in America.

However there are a few things that you need to be careful of before buying the Nest thermostat:

  • Firstly, even though it should work fine with your electric underfloor heating, just double check Nest’s compatibility page to make sure.
  • As mentioned earlier, if you have a multi-zone or dual-fuel heating system, you’ll probably need multiple Nest thermostats.
  • The Nest Thermostat requires 20-30V, so if your electric heating system is high voltage (such as 110V or above), it either won’t be compatible or you’ll need a step down transformer fitted.

Does Nest’s True Radiant feature help with underfloor heating?

Nest’s thermostats support a neat feature called True Radiant which is specifically designed for in-floor heating systems that rely on slow, radiant heat to warm a space.

The way this works is you can specify that the Nest Thermostat turns on your heating earlier than it usually would (with a quicker-fire heating system, that is), with the aim that everything will be nice and warm when you need it. Equally, the system will turn off earlier than it otherwise would, to stop a space heating up too much.

This is really useful because underfloor heating relies on slow-and-steady heating to heat a room, introducing heat from below that brings the temperature up more gradually than with forced air and other heating systems.

Without true radiant, your thermostat would learn that you get home at 6pm, but if it only turned your underfloor heating on at 5:45pm, your home would still be cold at 6pm! So instead your Nest thermostat will learn that there’s actually a 1.5 hour ‘warm up time’ with your underfloor heating, turning the heating on at 4:30pm instead (for example), so that your house is sufficiently warmed by 6pm.

You can disable this option if you’d like, or change the time for when your thermostat will turn things on. This is useful if you find that it actually takes 2 hours to heat everything up properly.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.