A room thermostat is chosen according to the language your boiler speaks: on/off, OpenTherm (modulating) or, for Nefit and Bosch, the EMS bus. Below you can see which thermostats fit each situation, with current prices. We stock Honeywell Home, Remeha and Bosch.
Which room thermostat fits your boiler?
Short answer: almost every room thermostat is 2-wire, but over those two wires the boiler speaks either only on/off, óf OpenTherm (modulating), or for Nefit/Bosch EMS bus. Choose the thermostat that speaks the same language as your boiler. Which one that is can be found in the boiler's installation manual or on the terminal block (for example "OT").
Your boiler only switches on/off
Older boilers, or your current thermostat has no OpenTherm logo. Any on/off thermostat works; on most OpenTherm boilers too, but then without modulation.
- Honeywell DT4 wired room thermostat white € 76.32 In stock wired
- Honeywell DT4 room thermostat wired black € 76.32 In stock wired
- Honeywell DTS4R wireless thermostat white € 89.21 In stock wireless
Your boiler has OpenTherm
Intergas, Remeha, ATAG, AWB and most boilers less than 15 years old. A modulating thermostat lets the boiler keep burning at lower output: calmer and slightly more economical.
- Honeywell Round modulating room thermostat € 73.34 In stock modulating, simple
- Remeha qSense Modulating Room Thermostat € 86.23 In stock modulating, simple
- Remeha iSense modulating programmable thermostat, wired € 118.80 In stock modulating with time programme
- Honeywell Chronotherm Touch programmable thermostat € 189.37 In stock programmable thermostat with touchscreen
- Honeywell T6 WiFi wired white € 201.28 In stock smart, with app
- Remeha eTwist – Smart Thermostat € 173.56 In stock smart, with app
You have a Nefit or Bosch boiler (EMS bus)
TrendLine, ProLine, TopLine, BaseLine, 9000i and other modern Nefit/Bosch boilers. You connect the Bosch EasyControl directly to it.
- Bosch EasyControl Smart Thermostat Single Black € 252.89 In stock smart, with app
- Bosch EasyControl Smart Thermostat White + 2 Smart Radiator Thermostats (Set) € 395.70 In stock with 2 radiator thermostats
You want to per room control
Smart radiator thermostats or a zone system: rooms you do not use stay cooler.
- Honeywell evohome 6-zone radiator starter pack € 633.67 In stock zone system
- Bosch EasyControl CT200 white (with 3 thermostatic radiator valves) € 357.02 In stock EasyControl with 3 radiator thermostats
- Honeywell HR93 radiator controller € 86.23 In stock separate radiator controller
Prices incl. VAT and stock are live. If you use a Bosch EasyControl on another brand of boiler, you need the EasyControl Adapter: see does EasyControl fit my boiler?. Instalpunt does not check whether a thermostat fits your specific boiler.
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On/off, OpenTherm or smart: the difference
All three usually use two wires to the boiler. The difference lies in what travels over those wires.
| Type | What it does | Works with | Examples we stock |
|---|---|---|---|
| On/off | Switches the boiler on until the room is warm, then off | Virtually all boilers, including older ones | Honeywell DT4, DTS4R (wireless) |
| Modulating (OpenTherm) | Lets the boiler keep burning at lower output: more even and slightly more economical | Boilers with OpenTherm (Intergas, Remeha, ATAG, AWB and others) | Honeywell Round, Remeha qSense, iSense |
| Smart (app) | Remote control, schedules, presence detection | Depending on the model: OpenTherm, on/off or EMS | Remeha eTwist, Honeywell T6, Bosch EasyControl |
Thermostat brands at Instalpunt
Original thermostats from three manufacturers.
Frequently asked questions
What is a 2-wire room thermostat?
Almost every room thermostat is connected to the boiler with two wires. That does not say how they communicate: over those two wires runs either a simple on/off signal, or OpenTherm, or, for Nefit/Bosch, the EMS bus. So choose a thermostat that uses the same protocol as your boiler.
What is OpenTherm and do I need it?
OpenTherm is a protocol with which the thermostat tells the boiler how much heat is needed, so the boiler can keep burning at lower output (modulate). This gives a more even temperature and a small saving; Milieu Centraal calculates with approx. 3 %. You only need it if your boiler supports OpenTherm; this is stated in the installation manual.
How do I know whether my boiler has on/off, OpenTherm or EMS?
Check the boiler's installation manual under "thermostat connection", or the terminal block (for example "OT" for OpenTherm). Modern Nefit and Bosch boilers use the EMS bus; Intergas, Remeha and ATAG use OpenTherm. If in doubt, check with the manufacturer or your installer. Instalpunt does not check whether a thermostat fits your specific boiler.
Does an on/off thermostat work on an OpenTherm boiler?
On most OpenTherm boilers it does, but the boiler then only switches on and off and does not modulate. You miss the benefit of OpenTherm, but the heating works normally.
Which thermostat fits a Nefit or Bosch boiler?
Modern Nefit and Bosch boilers (TrendLine, ProLine, TopLine, BaseLine, 9000i) use the EMS bus. You connect the Bosch EasyControl directly to it. Worked out per Nefit series: EasyControl on a Nefit or Bosch boiler.
Does a smart thermostat work with a (hybrid) heat pump?
That depends on the heat pump. With many hybrid heat pumps the thermostat stays connected to the boiler or to the heat pump's controller, and that controller determines which thermostats work. Check your heat pump manual for the supported thermostats.
Can I replace a room thermostat myself?
Often yes: disconnect the boiler from the power, unscrew the old thermostat, transfer the two wires and switch on the new thermostat. Take a photo of the wiring first. A wireless thermostat or a zone system adds a receiver at the boiler; if in doubt, have an installer do that.
Choosing a room thermostat
The most important choice is not the brand but the protocol. On an on/off boiler any on/off thermostat works, such as the Honeywell DT4. If your boiler has OpenTherm, a modulating thermostat such as the Honeywell Round of de Remeha qSense gets more out of the boiler. If you want control via an app, choose a smart thermostat that suits your boiler: the Remeha eTwist and Honeywell T6 for OpenTherm, the Bosch EasyControl for Nefit and Bosch.
Room-by-room control is possible with smart radiator thermostats or a zone system such as Honeywell evohome. This saves most if you do not use rooms during the day or at night.
Own stock: ordered before 14:00, dispatched the same working day. Shipping to EU countries from €14.95, 3–5 working days, 14-day right of return.