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#1 in Best Smart Thermostats in the UK for 2026
Best overallWATTB91/100

tado° Smart Thermostat X (Wireless Starter Kit with Hot Water Control)

Our verdict · The most future-proof, upgradeable all-rounder — as long as you accept its best features sit behind an optional £3.99/mo plan.

Buy it if

You want one thermostat that covers most boilers today and can grow into full room-by-room zoning on a modern platform tomorrow.

Skip it if

You refuse any subscription — its geofencing and insights sit behind AI Assist, so Wiser or Honeywell give more for free.

Where to get it

tado° Smart Thermostat X (Wireless Starter Kit with Hot Water Control)

WATTB Score

91/ 100

Our research-based editorial assessment.

How we score →

From ~£129.99 (indicative; RRP £159.99)

Indicative price at the time of review.

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Opens a live price comparison and retailer search for current prices and availability.

tado°'s Smart Thermostat X leads our ranking because it does more things well than anything below it. This wireless starter kit pairs a Wireless Temperature Sensor X with a Programmer X — which handles OpenTherm boiler/hot-water control and doubles as the Thread border router — so it controls a hot-water cylinder and suits system and heat-only boilers, not just combis. It is priced at an indicative £129.99 on sale (RRP £159.99) at tado°'s own shop — cheaper up front than Drayton Wiser's Kit 1. (tado° also sells a cheaper Wired Starter Kit for combi/heating-only homes without a cylinder.) What sets it above the field is future-proofing and expandability: it's built on Thread/Matter rather than the older Zigbee stack rivals use, and you can add Smart Radiator Thermostat X units (indicatively ~£79.99 each) for true room-by-room control later. Core heating control and the app are free, but the headline geofencing, Open Window Detection and Energy IQ insights are bundled into the optional AI Assist subscription at an indicative £3.99/month — the main reason a subscription-averse buyer might prefer Wiser. TechRadar's 2026 UK round-up names it best overall.

The good & the bad

Pros

  • Works with combi and system boilers, with hot-water control in the starter kit
  • Modern Thread/Matter platform plus a cheap, native path to room-by-room zoning
  • Strong geofencing and Open Window Detection, the features most tied to real savings

Cons

  • Geofencing and energy insights need the optional ~£3.99/mo AI Assist plan
  • No native Apple HomeKit support

How it compares

PickWATTB ScorePriceBest for
1.tado° Smart Thermostat X (Wireless Starter Kit with Hot Water Control)This pick91/100From ~£129.99 (indicative; RRP £159.99)overall
2.Drayton Wiser Smart Thermostat Kit 190/100From ~£141 (indicative street; RRP £195)no-subscription value
3.Hive Thermostat (with Hive Hub)84/100From ~£119 (indicative; includes Hive Hub)simplicity and pro-install
4.Honeywell Home T6R Wireless Smart Thermostat82/100~£160-200 (indicative street price)Apple Home and system boilers
5.Google Nest Learning Thermostat (3rd gen)79/100From ~£219 (indicative; £199 for Thermostat E)hands-off auto-learning design
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Key facts

Best for
overall
Typical cost
From ~£129.99 (indicative; RRP £159.99)
Boiler compatibility
Combi & system/heat-only (OpenTherm/relay)
Hot water control
Yes (starter kit includes programmer)
Platform
Thread/Matter (Programmer X is the border router)
Zoning path
Add Smart Radiator Thermostat X (~£79.99 each)
Subscription
Core free; AI Assist optional ~£3.99/mo

Insider tip · System/heat-only homes with a hot-water cylinder should confirm the starter kit's programmer/HW channel matches their setup before buying — it's what makes this more than a combi-only device.

Researched by WATTB

Published
19 September 2026
Updated
19 September 2026
Last verified
19 September 2026
Sources
13 sources

We research and rank options from public data, official information and published reviews. How we research →

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