Home Automation - Controlling Radiators

I’m trying to find a way to control the flow of hot water to individual radiators around my house. I thought it would be simple to replace the existing TRV heads with motorised units linked to house wifi and send commands from my software. There are quite a few devices on the market but all seem to be tied to a propitiatory system and lack a published API.

Has anyone come across motorised wifi enabled trv heads with published API. Alternatives to Wifi would be considered e.g. Bluetooth, radio etc. Has anyone built a DIY version?

just a thought - have you checked McMaster-Carr for motor-actuated ball valves? If the logic is done by a controller - then it is not “TRV”. I don’t know a lot about these systems. Do you need a TRV unit for the purpose of safety? Or is the only consideration turning on and off for heating?


Probably the best bet would be to get some 434/868MHz ones and reverse-engineer the protocol as these are usually simple OOK…

@mjkuwp94 TRVs are common in the UK (“central heating” involves a hot water loop and radiators; there is often no central thermostat, just a timer, and individual rooms use TRVs on the radiators themselves to adjust the heat)

I use these thermostats:

They can be controlled over 868Mhz or via the cube that can be bought to it. As of now I only use the standard software. There are some projects that can be found on the web.

I’ve been monitoring this project

Thanks all for replies.

Mikuwp94 my aim is to control flow of heated water through individual radiators. Certainly stop/start. I would also like the option to slow down flow to enable finer control.

Currently all radiators have manual TRV. I would like to remove the existing heads and replace with electronic TRV’s which are capable of connection to my bespoke system enabling two way communication for control and data collection. Current plan is to have a number of Imps distributed round house to monitor room sensors and control connected devices. A central computer (currently Raspberry Pi) will coordinate, monitor and plan the system.

Hugo’s description of UK central heating system is an accurate description of existing system.

I’ve searched the web and cannot find a TRV with published API, aimed at the hobbyist. This surprises me given the amount of interest there is in home automation. CloudControl, as far as I understand it, http://www.earth.org.uk/open-source-programmable-thermostatic-radiator-valve.html has not yet produced a product, still in the design stages.

Hugo, reverse engineering, if simple, is probably best way forward. I understand I require sniffer software and it captures the conversation. Anyone have experience of this?

Also having a look at the Mac! product hacks Hannez82. Interesting!

I’ve considered doing this as the article outlines. http://www.mike-stirling.com/2012/10/hacking-wireless-radiator-valves-with-gnuradio/

I’ve also built a relay imp that I used to control a thermoelectric valve these are used on both Rads and the manifold of wet under floor heating. THEBEN-Actuator-ALPHA4-24V

Also for the Raspberry PI I would recommend http://nodered.org/ I’m using it in conjection with the imp.

This website may delight you ?


Thermoelectric Actuators are available from Danfoss, are available Normally Open or Normally Closed, 24V AC/DC or 240V and consume a couple of Watts.

I know its been a while since this post was placed, but in response, it might be worth looking into Magnum Energy’s product “The Perfect Pair”.


It is an Enocean based product that is solar powered. I believe it is an interesting starting point to either try using directly, or to adapt it to use the electric imp as the base platform. Additionally, we are in the final phase of development prior to release of a similar control valve for steam with one difference…we modulate Btu output in addition to turning a radiator on or off. Unfortunately, our hydronic version will not be released for another 12-18 months.