Automating radiator control - Electronic TRVs

[Peter Theobald <pete@xxxxxxxxxxxxxxx>]

Hi everyone,
I'm new to this group but i've been lurking around looking at home automati=
on for a while. I want to build a system to automate the heating control in=
 my flat (uk btw) but I can't find a good solution especially if I want to =
keep the cost down.
Currently I have 4 rooms with 4 water filled radiators connected to a gas b=
oiler. Each one has a normal wax/liquid filled TRV and it works pretty well=
. I want to change this so I can control the state of each TRV remotely, i.=
e. with a computer control so I can heat the bedroom up later on in the eve=
ning and the morning, but have the living room warm only when I get home fr=
om work and then cool down when i'm asleep. Are there any products on the m=
arket that can be retrofitted to my existing radiators? I've seen the z wav=
e products from danfoss which look reasonably priced, but the control units=
 look expensive and i'm not convinced radio comms is going to be reliable. =
Also, has anyone got any experience of doing this to a house?
Regards
Pete