Google Nest Thermostat Installation in London

• Learning Thermostat (3rd gen): the Heat Link is wired near the boiler or at the junction box, in place of your programmer, on a 230 V supply that Google's UK diagrams show through a 3 A fuse
• Its relays: terminals 1 to 3 switch the heating and 4 to 6 the hot water, while OT1 and OT2 take an OpenTherm boiler's two wires; the display takes 12 V DC from T1 and T2 over your old thermostat cable, or sits on a stand
• Thermostat E: the Heat Link E goes on the wall where your old room thermostat was, on just the common and normally-open wires or the two OpenTherm wires, and runs on two Energizer L91 lithium AA cells
• Its display talks to the Heat Link E over Thread only and stands on a shelf, on its plug-in adapter

• The swap: your programmer, timer or old receiver comes off and the 3rd gen Heat Link goes on the same cables, or at a wiring centre outside the boiler
• Cylinder systems: on a vented S-plan or Y-plan system the wiring centre is rewired so the Heat Link drives the zone valves; a new valve body means draining down, so it is booked as plumbing
• Power: a fused spur can be added to an existing circuit outside the bathroom; a new circuit is for a registered electrician
• OpenTherm: if an OpenTherm cable already works at the boiler end, only the wall device changes; connecting OpenTherm at the boiler, or switching between OpenTherm and relay control, goes to a Gas Safe engineer
• Boiler terminals: live and neutral taken from inside the boiler, or a first connection on a combi with no external controls, goes to a Gas Safe engineer too, and unvented cylinder controls to a G3-qualified installer
• No room thermostat to replace, or a boiler with a built-in receiver: Google's UK terms then put the Heat Link E next to the boiler, which JACK sends to a Gas Safe engineer unless a wiring centre outside the boiler can take it

• That the heating works now: Google's UK guide says the system must work and meet building and safety rules before a Nest goes in
• The load: Google lists switched-live and volt-free systems up to 3 A as compatible and rules out high-current heating such as electric radiators or electric underfloor; wet underfloor is on its UK list for the 3rd gen
• Space and range: 30 cm clear either side of the Heat Link and no more than 30 m to the thermostat
• Where the display will read the room: 1.2–1.5 m up on an inside wall away from draughts and heat, or on a stand

• It has left the Nest and Google Home apps, gets no updates, and has lost remote control and Home/Away Assist
• Its own schedule keeps running and it can still be set on the device, though Google warns performance may decline; Nest Protects no longer link to it, so Emergency Shut-off stops
• A pro can replace it at the wall with a supported smart thermostat on the same wiring

• On 1 November 2026 Google's UK store showed the Nest Thermostat E with an Add to basket button and the 3rd gen Learning Thermostat as out of stock
• Google said in April 2025 that it will no longer launch new Nest thermostats in Europe
• The Nest Learning Thermostat (4th gen) and the Nest Thermostat (2020) are US and Canada models, and Google says those will not work on European systems

A vetted pro prices your Nest job from the model and your photos, and the JACK app shows that fixed price before you book.

On heating, where the Heat Link goes moves the price most: a 3rd gen Heat Link in place of a programmer on the same wiring is the plainest job, while hot water on a cylinder, an S-plan or Y-plan wiring centre or an old wired thermostat to take out of the circuit adds to it. Anything that must be wired at the boiler itself is left out of the price and handed to a Gas Safe registered engineer.

On doorbells and cameras, power comes first: a battery doorbell or Nest Cam with a good 2.4 GHz signal is the lightest job, a weak bell transformer is swapped on its existing supply, and the Nest Cam with floodlight is priced as electrical work on your outside-light circuit. For a camera high on a gable, your pro can ask another pro on JACK to help through the Pro2Pro feature.

JACK does not sell devices, so the Nest kit is yours to buy. Accessories the job needs, such as a bell transformer, a fused spur or an outdoor junction box, are agreed and added at cost before you book, and so is parking where it has to be paid for. Several devices go on one booking for one fixed price. Prefer to pay for time? As a guide, hourly hire is typically £45–£95 per hour for smart home work and £55–£110 per hour for electrical work, and a full-day handyman booking is a flat £350–£400 for up to 8 hours on site.