Honeywell evohome ATP921R3100 review
Honeywell Home evohome Wi-Fi Connected Thermostat Pack (ATP921R3100)
By Tom Calder
The most capable system here — Resideo quotes up to 12 individually time- and temperature-controlled heating zones plus a separate domestic hot water zone, and the broadest system support of anything on this page, covering most boiler types, heat pumps, district heating, pellet burners and S-plan or Y-plan zone-valve setups. But the pack as sold is a controller, a table stand, a power lead and one wireless relay box: no radiator controllers, no OpenTherm and no hot water control. Judge it as the first component of a professionally installed whole-house system, not as a standalone thermostat.
- Best for
- A large or awkward home being zoned properly by a heating engineer.
- Skip it if
- You want room-by-room control without an engineer-installed system
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.We earn a commission if you buy through the retailer links on this page. It doesn't change our verdict. How we make money →
Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Up to 12 heating zones plus a separate hot water zone, on Resideo's own figures
- Broadest system support here — most boiler types, heat pumps, district heating, S-plan and Y-plan
- The only product on this page designed from the outset to grow to whole-house zoning
Worth knowing
- The pack includes no radiator controllers at all, so it does not deliver multi-zone heating as sold
- OpenTherm needs the separate R8810A1018 bridge, and hot water needs the ATF500DHW kit or a CS92A cylinder thermostat
- Realistically a qualified engineer's job — UK quotes for whole-system fitting run roughly £600 to £900 and up
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Our review
Resideo's evohome is a zoning platform rather than a thermostat, and this pack is its starting point: the colour touchscreen controller on a charging stand plus one BDR91 relay to switch the boiler. The number to hold onto is twelve, the heating zones it can run once radiator controllers are added. It suits a large or awkward house where a heating engineer is designing the zones.
What is in the box, and what is not
You get the ATC928 controller, a table stand with its power lead, and a BDR91 wireless relay box. The controller runs on rechargeable AA NiMH cells that top up whenever it sits on the stand, so it can be carried round the house to programme and beeps after half an hour to be put back. The stand's supply takes 100 to 240V mains; the optional wall bracket runs from a wired 230V supply. Everything else is extra: HR92 radiator controllers for each zone, the ATF500DHW hot water kit with a CS92 cylinder sensor, and the R8810 bridge if you want OpenTherm modulation instead of relay switching. As sold it is a single-zone on/off thermostat with a very good screen.
How a system is built
Resideo's guide puts the limit at 12 heating zones plus one stored hot water zone, all on an 868MHz radio with a quoted 30m range inside a house, separate from Wi-Fi. A zone can be one radiator or several grouped together, and each HR92 reports back, adjusts locally and closes on an open window. The relay box switches 230V at up to 5A and must sit at least 30cm from the boiler casing and other metal. Resideo lists on/off and OpenTherm boilers, district heating, heat pumps through the BDR91T, wood and pellet boilers, manifold underfloor heating with its own controller, and zone valve systems, with the BDR91 standing in for an S-plan or Y-plan valve. Its own wording is that connection and commissioning should only be done by a technically competent person.
Day to day
Schedules run on a 7-day or 5/2 pattern with up to six periods a day per zone. Optimisation learns how early to start each zone, and the Smart Weather settings can switch the boiler off on mild days or compensate for draughty rooms in a cold spell. Quick actions cover Eco or Boost of up to 3°C for one to 24 hours, Away, which drops every zone to 15°C for up to 99 days, Heating Off with frost protection, and a custom mode. The Total Connect Comfort app works with Alexa, Google Assistant and IFTTT, and the controller only joins 2.4GHz Wi-Fi; without broadband you keep control at the screen but lose the app.
How it compares
The Worcester Bosch EasyControl set puts three valves in the box and scales to 20 zones, but only natively on Worcester boilers. Drayton's Wiser Multi-Zone Kit 1 (2nd gen) includes two radiator thermostats, reaches 16 rooms over OpenTherm or relay on a combi, and its radiator heads are a DIY fit. If you have a cylinder and no appetite for zoning, the Honeywell T6R-HW runs heating and hot water from one unit. See our comparison and smart radiator valves.
Warranty and support
The controller is 136 by 93 by 20mm, IP30, and rated for 0 to 40°C. ATP921R3100, the HR92, the BDR91 and the hot water kit all appear on Resideo's five-year warranty list, but read the policy: it is written for Resideo's trade customer, runs 60 months from the date code, and Resideo expects the installer or merchant to pass equivalent cover to you. Get that in writing with the quote. Batteries are excluded as consumables.
Our verdict
Choose evohome if you have a big or awkward house, a cylinder, and an engineer who will design the zones, because nothing else here grows as far or fits as many system types. Do not buy this pack expecting room control out of the box; it is the foundation, and the radiator controllers are where the real money goes. For a combi flat or a three-bed semi, a Wiser kit does most of it for less. If an old boiler is the real problem, start with repair or replace.
A researched review, built from the maker's specs, manual and UK listings; facts checked 21 Oct 2026. Sources: Resideo UK: ATP921R3100 evohome Wi-Fi connected thermostat pack; evohome installation guide (32303494-001 C, EN); evohome user guide (EN, 2024); evohome system builder (zones, heat sources, components); Resideo 5 year warranty policy and eligible product list (September 2024).
Who shouldn't buy this
Don't buy it if you want room-by-room control without an engineer-installed system — Drayton's Wiser Multi-Zone kits include two radiator thermostats in the box, and this pack includes none.
Key specs
| Works with | Most boilers, heat pumps, district heating; S-plan and Y-plan |
| Control | Relay as sold; OpenTherm and hot water need extra hardware |
| Zoning | Up to 12 heating zones + 1 hot water; controllers extra |
| Fitting | Engineer's job; whole-system fitting quoted c.£600–£900+ |
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for Most UK homes — including heat pumps and cylinder systems — that want hot water control without buying a hub.
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Best for An S-plan or Y-plan home with a hot water cylinder that needs one thermostat to run both.
Read the review →
Best for Room-by-room control on a combi boiler without paying whole-house-system money.
as of 4 Nov 2026, 19:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.Questions
Does the evohome pack include radiator controllers?
No. The ATP921R3100 pack is the controller, table stand, power lead and one BDR91 relay. HR92 radiator controllers, the hot water kit and the OpenTherm bridge are all bought separately.
Can evohome control a hot water cylinder?
Yes, as a separate zone, but it needs the ATF500DHW kit: a CS92 wireless cylinder thermostat with a strap-on or insertion sensor plus a relay for the zone valve. Resideo's guide adds it through the stored hot water option in the installer menu.
Does evohome work with OpenTherm boilers?
Only with the R8810 wireless OpenTherm bridge, which is not in this pack. Without it the BDR91 relay switches the boiler on and off.
How many zones can evohome run?
Resideo's figure is 12 heating zones and one hot water zone from a single controller, each zone holding one or more radiators, underfloor circuits or zone valves.
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