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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsShort answer: Google announced on 23 September 2022 that it would replace some faulty Heat Links supplied with third-generation Nest Learning Thermostats in the UK and other European countries at no cost, including affected units outside their warranty period. It was not a blanket replacement programme for every European Nest owner, and the current terms must be confirmed with Google Nest Support before you pay for a part or installer.
What Google announced
The announcement covered some third-generation European Nest Learning Thermostat Heat Links. Google said affected units could be replaced at no cost regardless of whether they were still under warranty. The reported arrangement differed by country:
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- UK: Google worked with BOXT to supply and professionally install a replacement Heat Link.
- Other affected European countries: Customers could select an installer and Google would reimburse the repair cost under the announced process.
The announcement did not describe a statutory product recall, publish a universal list of affected serial numbers, or say that every out-of-warranty Heat Link qualified. The issue was also not explained in detailed technical terms. For that reason, treat the free-replacement news as a historical programme for qualifying devices—not as proof of a universal policy in September 2026. Ask Google Support for the current country-specific position.
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See the original contemporary report at 9to5Google and compare it with Google’s current Heat Link replacement instructions.
#1 Best Overall
- ENERGY STAR certified smart thermostat for home that helps you save energy and stay comfortable.Product note: You can also check your system’s compatibility before purchasing a Nest thermostat with our online Nest Compatibility Checker on the Google Nest support page.Connectivity Protocol : Wi-Fi.Connectivity Protocol : Wi-Fi
- The Nest Thermostat is designed to work without a C wire in most homes, but for some systems, including heating only, cooling only, zone controlled, and heat pump systems, you’ll need a C wire or other compatible power accessory. Lock feature: No
- Nest Thermostat turns itself down when you leave, so you don’t waste energy heating or cooling an empty home; easily program an energy efficient schedule in the Google home app on your Android or iPhone
- Remote control lets family members change the thermostat temperature from anywhere on a phone, laptop, or tablet[1]
- Savings Finder looks for more ways your thermostat can help you save, and suggests tweaks to your schedule in the app; check with your energy provider to learn more about rebates and more ways to save on a Nest thermostat
What the Heat Link does
The Heat Link is a separate relay and control unit used by European Nest systems. It communicates with the Nest thermostat and switches the heating system; depending on the installation, it can also control domestic hot water. It is not the thermostat display, thermostat base or boiler itself.
European Nest installations use this architecture for boiler and other European heating arrangements, including certain compatible heat pumps, hydronic underfloor systems and OpenTherm installations. Compatibility depends on the specific heating system and wiring. Google’s European Heat Link guide explains the distinction between European and North American Nest hardware.
Which devices may be covered?
The 2022 announcement referred to some third-generation Nest Learning Thermostat Heat Links supplied in the UK and other European markets. Do not assume that any of the following automatically qualifies:
- Every European third-generation Heat Link.
- Every out-of-warranty unit.
- Every Nest Thermostat E or Heat Link E.
- A second-hand device inherited with a property.
- A Heat Link with wiring, water or physical damage.
- A unit whose problem is actually the boiler, fuse, power supply, thermostat or wiring.
Nest Thermostat E installations use a Heat Link E, while the third-generation European Learning Thermostat uses its corresponding Heat Link. North American Nest thermostats are built around different wiring and HVAC arrangements and are not direct substitutes.
Rank #2
- ENERGY STAR certified smart thermostat for home that helps you save energy and stay comfortable.Connectivity : Wi-Fi - 802.11b/g/n 2.4 GHz, 802.11a/n 5 GHz Wi-Fi., Wireless interconnect : Bluetooth Low Energy Please refer to the product description section below for all applicable legal disclaimers.Product note: You can also check your system’s compatibility before purchasing a Nest thermostat with our online Nest Compatibility Checker on the Google Nest support page
- The Nest Thermostat is designed to work without a C wire in most homes, but for some systems, including heating only, cooling only, zone controlled, and heat pump systems, you’ll need a C wire or other compatible power accessory
- Nest Thermostat turns itself down when you leave, so you don’t waste energy heating or cooling an empty home. Lock feature: No
- Programmable thermostat that lets you create an energy efficient schedule in the Google Home app on your Android or iPhone
- Remote control lets family members change the thermostat temperature from anywhere on a phone, laptop, or tablet[1]
Signs that the Heat Link may be at fault
Possible warning signs include:
- The Heat Link has no status light despite a confirmed power supply.
- The thermostat cannot communicate with the Heat Link.
- The thermostat reports an H71 or similar connection error.
- The heating does not respond to thermostat commands.
- Hot-water control fails where the Heat Link was configured for it.
These symptoms do not prove that the Heat Link has failed. An H71 error, for example, indicates a communication problem but can have more than one cause. Start with Google’s H71 troubleshooting guidance, and check power, fuses, connections and the heating system without opening mains-voltage equipment.
How to request a replacement
- Identify the equipment. Photograph the Heat Link, model markings and any serial information. Note the country where it was installed and whether it is a third-generation Learning Thermostat or Thermostat E system.
- Record the fault. Write down the thermostat error, the Heat Link light pattern and what happens when you request heating or hot water. Photographs can help support diagnose the case.
- Contact Google before buying hardware. Use the Nest thermostat support hub and ask specifically whether the device qualifies for a current replacement or goodwill arrangement.
- Get the terms confirmed. Ask whether Google will supply the part, arrange installation, reimburse an installer, or offer only paid support. Obtain a case number and, where possible, written confirmation before hiring anyone.
- Use a qualified installer. A Heat Link can switch boiler and hot-water circuits and may involve mains voltage. Google’s replacement guidance recommends professional installation for the European Learning Thermostat.
In the UK, do not assume that booking BOXT independently guarantees free service. The 2022 arrangement used BOXT, but any current booking or authorisation should come through the instructions attached to your Google support case. BOXT’s current site is boxt.co.uk.
Pairing an authorised replacement
Physical installation and electrical connections should be handled by a qualified professional. Once the replacement is installed, the software pairing steps depend on the thermostat.
Third-generation Nest Learning Thermostat
When the H71 replacement option appears, select Replace Heat Link. Wait for the replacement Heat Link’s blue light to blink, then enter the six-character pairing code printed on the bottom of the unit. Follow the remaining on-screen instructions. Google’s full procedure is in its Heat Link replacement guide.
Rank #3
- ENERGY STAR certified smart thermostat for home that helps you save energy and stay comfortable.Control the temperature with your voice using smart home devices that work with Google Assistant or Alexa[3]Nest Renew makes it simple to support clean energy right from home; it works with your Nest Thermostat[5] to help you automatically prioritize your usage[6] to times when energy is cleaner or less expensive.Product note: You can also check your system’s compatibility before purchasing a Nest thermostat with our online Nest Compatibility Checker on the Google Nest support page
- The Nest Thermostat is designed to work without a C wire in most homes, but for some systems, including heating only, cooling only, zone controlled, and heat pump systems, you’ll need a C wire or other compatible power accessory. You can control your Nest Thermostat manually when there's no internet connection.
- Nest Thermostat turns itself down when you leave, so you don’t waste energy heating or cooling an empty home
- Programmable thermostat that lets you create an energy efficient schedule in the Google Home app on your Android or iPhone
- Remote control lets family members change the thermostat temperature from anywhere on a phone, laptop, or tablet[1]. | Control the temperature with your voice using smart home devices that work with Google Assistant or Alexa[3].
Nest Thermostat E
Remove the old Heat Link from the Google Home or Nest setup as directed, then choose Settings → Add product, scan the replacement unit’s QR code and complete setup. App labels can vary by language and app version, so follow the current on-screen flow.
What “at no cost” did—and did not—mean
For qualifying units under the 2022 announcement, “at no cost” was reported as more than a replacement box:
- UK customers were to receive professional supply and installation through BOXT.
- Customers in other affected European countries could choose an installer and seek reimbursement for the repair cost.
That does not establish that the same terms remain available to every customer today. Country, model, fault diagnosis and the status of the original programme may all matter. Do not pay an independent installer on the assumption that Google will reimburse you unless Google has authorised that route and confirmed the amount and evidence required.
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Should you buy a used Heat Link?
A marketplace Heat Link may seem like the quickest solution, but it is a risky substitute for an authorised replacement. Check the exact generation, regional model, thermostat compatibility and condition. A Heat Link bundled with another Nest thermostat generation may not be suitable for your installation, and a visually similar North American component is not an interchangeable European relay.
Rank #4
- The Google Nest Temperature Sensor (2nd gen) makes it easy to manage hot and cold spots throughout your home[1]; put it in any room to get the right temperature, right where you want it
- It’s simple to set up and control in the Google Home or Nest app; just use the app to set the temperature a room should reach at a certain time of day
- The battery lasts up to 3 years, so you can put it on a wall, shelf, or wherever you want[2]
- You can place Nest Temperature Sensors in up to six rooms for maximum comfort; prioritize the temperature of one room, or create an average temperature across them, like bedrooms[1,3]
- The Nest Temperature Sensor (2nd gen) works with the Nest Learning Thermostat (4th gen), Nest Learning Thermostat (3rd gen), and Nest Thermostat E[1,4]
Even a compatible second-hand unit may have no remaining support or warranty. If you do consider one after Google refuses a replacement, have a qualified heating professional confirm compatibility before purchase and installation.
Do not confuse this with Nest end-of-support changes
Google separately announced that first-generation Nest Learning Thermostats, second-generation Nest Learning Thermostats and the second-generation European version would stop receiving software updates and lose app and connected features from 25 October 2025. That change is unrelated to a failed third-generation Heat Link. Google’s announcement is available on the Nest Community blog.
A replacement Heat Link cannot restore connected support to a thermostat whose generation has reached end of support. Conversely, a functioning third-generation Heat Link is not automatically covered simply because older Nest products lost support.
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Use this order of options:
- Ask for an authorised replacement and a clear explanation of the eligibility decision.
- Have the complete installation diagnosed so that a boiler, fuse, wiring or power fault is not mistaken for a Heat Link failure.
- Compare a supported European thermostat system if the Nest hardware is ageing or unsupported. Systems such as tado may be options, but check boiler, relay, OpenTherm, hot-water, zoning, app and installer compatibility first. Google’s 2025 communication reportedly mentioned a 50% tado Smart Thermostat X Starter Kit discount for eligible European users; confirm current eligibility and expiry directly with Google or tado.
- Consider a conventional thermostat or wider heating-system replacement only where the existing boiler and controls make that practical.
A replacement from another ecosystem is not a drop-in Heat Link swap. It may require rewiring, a new receiver and professional commissioning, and it may remove features or integrations you currently use with Google Home.
The Bottom Line
Bottom line: Google did announce free replacement of some third-generation European Nest Learning Thermostat Heat Links in 2022, with installation or reimbursement arrangements that varied by country. In 2026, contact Google Support before spending money: do not assume every Heat Link qualifies, and use a qualified professional for the physical replacement.
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