Nest Learning Thermostat Review: The UK Gets the 3rd Gen, Not the 4th

If you came here for the new 4th-generation Nest, it is not sold in the UK and Google says it will not be. What UK shops still sell is the 3rd generation, launched in 2015, at £219 from Google while stocks last. It is still a good thermostat. It learns, it controls a hot-water cylinder, and it speaks OpenTherm. But it needs a professional fit, Google is not making a successor for Europe, and the energy savings are smaller than the marketing suggests.

Published 8 October 2026 · Reviews last checked 8 October 2026 · Shopbam summarises other people’s testing; we did not fit or live with this thermostat ourselves.

The three reviews this summary is built from

• Trusted ReviewsEditorial test of the UK 3rd gen at £219. The page shows no reviewer name, date or score.
• Urban PlumbersA Nest Pro installer’s Y-plan wiring guide. Posted 2019, modified 19 September 2025.
• DIYnot ForumsAn owner’s Heat Link thread on a Vaillant combi. 6 replies, September 2019.

Specification at a glance

Trusted Reviews

Editorial test UK 3rd-gen review at £219, with no reviewer, date or score shown on the page · trustedreviews.com · the hands-on view of the learning

Who they are: Trusted Reviews is a UK tech and home review site whose editors use each product and pair that with industry-standard tests in equipped facilities; it says manufacturers don’t vet its reviews and it never takes money to test, so it is a strong hands-on source.

Trusted Reviews tested the UK version with its Heat Link. Its pros are short: it “looks fantastic”, it “learns how you use it”, and it has a “sharp and clear display”. The useful detail is how the learning works. You can let the thermostat build a schedule from your manual changes, or set one yourself and let it adjust that. The reviewer preferred the second option and found the result accurate after a few weeks of tweaks. That is longer than Google’s line, “Just use it for a week and it programs itself.”

It explains True Radiant, a setting in the app. Nest learns how long your home takes to warm up, so it starts the heating early and stops before the room overshoots. Savings are described only loosely: the thermostat “can even help you save money”, mainly through Eco mode when nobody is home. The one real complaint is that you cannot add room-by-room radiator control. Expert Reviews, in its 2020 test, made the same point. It also said some of the learned schedules were odd, and you can turn learning off. Trusted Reviews says professional fitting cost £80 more than the unit, and the desk stand £30.

🎬 Watch: Review: Nest Learning Thermostat 3rd gen

Urban Plumbers

Installer “How to install Nest thermostat on a Y plan heating system (UK)”, Urban Plumbers Ltd, posted 4 September 2019, modified 19 September 2025 · urbanplumbers.co.uk · what the fit actually involves

Who they are: Urban Plumbers is a plumbing and heating firm that installs Nest thermostats and publishes step-by-step fitting guides; it gives a working installer’s view of the job, though as a firm that sells installations it is not neutral.

This guide comes from a Surrey firm that offers Nest Pro installation, so it is selling the job it describes. It is also the clearest explanation we found of why most people should not fit this themselves. On a Y-plan system (a hot-water cylinder with a three-port valve), you remove the old programmer and wire the Heat Link in its place. Live and neutral go to L and N. Hot water off and on go to terminals 4 and 6, and heating on goes to terminal 3. Terminals 2 and 5 take a permanent 230 V live. You then move the call-for-heat wire in the wiring centre to the zone valve.

The warnings matter more than the steps. The wiring centre is at 230 V AC. If you put that voltage on the thermostat’s 12 V base by mistake, the guide estimates about £200 of damage. It tells you to photograph the old wiring, check any reused cable with a multimeter, and isolate the supply at the spur. It also explains two things that can look like faults after fitting: Nest’s anti-bacteria cycle can heat the cylinder even when hot water is set to off, and some boilers wait a few minutes before they fire. The guide does not cover combi boilers.

🎬 Watch: How to install Nest thermostat (UK) on a Y plan - system with hot water cylinder & 3 port valve

DIYnot Forums

Community “Sorry it’s another nest heatlink problem”, Plumbing and Central Heating board, 6–10 September 2019, opening post plus 6 replies · diynot.com · what goes wrong on a DIY fit

Who they are: DIYnot Forums is a UK home-improvement discussion board where DIYers and tradespeople answer questions on electrics, plumbing and building; posts are unverified personal experience, so the value lies in consistent advice across many replies rather than any one.

This is one owner’s thread, and it is from 2019, so it is an example, not a survey. It is still worth reading. The owner fitted a 3rd gen with its Heat Link to a Vaillant ecoTEC Pro 28 combi. The house had been converted from a gravity system, and the old programmer and room thermostat were still wired in. The result was hot water but no heating, a boiler fault code, and a blown 3 A fuse after one wiring attempt. The thread ends with no fix: the owner planned to get an electrician to fit a junction box and rewire.

The replies give useful advice. On a combi with no cylinder, one member said, take out the old timeswitch and thermostat and wire the Heat Link straight to the boiler, as you would on a new install. Some boilers need a Gas Safe engineer to open a sealed compartment. Another member pointed out that the Heat Link terminals take one wire each, so you may need a wiring centre. He summed it up: “Nest can be configured to work with nearly any boiler, but you have to sit there and plan it out first.”

🎬 Watch: Nest Learning Thermostat 3rd Generation Installation UK

Strengths and weak points

The savings claim, checked

Google’s UK store says the thermostat “controls 60% of your energy bill”. It also says that since 2011 Google estimates Nest “saved over 39 billion kWh of energy in millions of homes worldwide”. Neither claim names a study. Smart Home Assistant says Google claims 10–12% off heating bills, based on Nest-commissioned research. We did not find that figure on Google’s own pages.

The independent figure is lower. The Behavioural Insights Team reviewed four studies of the Nest Learning Thermostat, including a randomised controlled trial. It found savings of about 6–7% of heating gas, or 4.5–5% of a home’s total gas use. Smart Home Assistant assumes 12,000 kWh of gas a year at about 6.99p/kWh. On those figures, 4.5–5% comes to roughly £38–£42 a year. That is our sum, and we have not checked their gas price. At £219 plus fitting, the thermostat would take years to pay for itself on savings alone. Buy it for control and comfort, not as an investment.

Who it actually suits

Buy it if you have a hot-water cylinder or an OpenTherm boiler, you want a thermostat that builds its own schedule, and you are happy to pay a Nest Pro to fit the Heat Link. If you already use Google Home, it fits in easily. Expert Reviews lists Alexa support as well as Google Home, so voice control from an Echo Dot Max is an option.

Look elsewhere if you want radiator-by-radiator control, a product with a future, or the lowest price. The Hive Thermostat Mini costs about £79 and can add radiator valves through a hub. Tado is the other obvious rival, but we have not reviewed it. If you only want to warm one cold room, a Dreo Atom 316 fan heater on a Tapo P110 smart plug costs much less than heating the whole house. A Philips Hue starter kit is the easier first smart-home buy if you rent.

Sources last checked 8 October 2026. Run-out stock moves fast, so check the price, the part number and whether a Heat Link is included before you order.