Best/most economical temperature sensors and radiator actuators

I am considering automating my home heating system using OpenHAB. I need quite a few temperature sensors, and quite a few radiator valve actuators. I may also need room occupancy sensors (PIRs) and other things. What are the cheapest/best devices to use for this that can easily be interfaced into OpenHAB?
Often these things seem to cost £50 or more - this will make the whole project unaffordable to me. I need something much cheaper than this.

Thanks - Rowan

There a lots of solutions depending on how much DIY you want. Combining a temperature sensor like the DHT 11 or its variants with an ESP8266 would be very inexpensive.

Do you have motorized valves already?

I don’t mind quite a bit of DIY.

So far I have 4 motorised valves of 3 different types. The rest are all wax-stat type TRVs, so what I would like to do is remove the wax-stats and fit actuators to the existing valves. The three types I have bought so far (Comet Blue, Equiva EQ3, and Xavax) all have bluetooth, but they have lots of functions that I don’t need (local control buttons, display, temperature sensor, local facility for programming time periods with different temperatures etc.) so are presumably a lot more expensive than they need to be for just remote control of the valve (and monitoring of the battery voltage). Does anyone know of anything like this?

Thanks - Rowan

I have several motorized valves I have gotten from aliexpress. 1" are about $35.

MySensors is also really good, fun and robust.

Cheapest ?


Best ?

So your have thermostatic radiator valves already?

Cheapest or best ?

Well, of course, it’s a balance between the two.

So you have thermostatic radiator valves already?

Yes, I have the valves, what I need is the actuators (the thing that presses the little metal pin in to close the valve, and releases the pin to open it, when it receives a wireless signal from OpenHAB). Since I can buy an equiva EQ3 for less than £20, with all sorts of features that I don’t need (a user interface, and temperature sensor etc.) uit seems to me that I ought to be able to buy a Bluetooth actuator for less than this.

Thanks - Rowan