Evohome - U.K. Install

Hi All,

So, I’ve decided to swap out my nest thermostat with a Honeywell evohome so I can create zones.

I have a basic question …

Can the wall panel be powered by existing wiring that powers the nest ? The controller looks like an easy swap out and I’ve found a guide that maps the nest wiring to the evohome controller. But I’m not sure about powering the control panel itself?

My nest was a straight swap out for my dumb thermostat



you can create zones with nest manager.

The Evohome wall plate needs a constant mains feed so it is likely it would need some rewiring at the control end as most thermostats are switched feeds rather than constant. (I’m not an expert but this was my finding)

I fitted an Evohome to my house and was able to use the existing thermostat wires to pass mains to the thermostat but it will vary house to house I suspect. For me this wasn’t too hard because I had to rewire the switching units to the boiler valve and hot water valve anyway and changed the wires at the boiler end.

I think Nest has a battery to deal with the times it isn’t powered which is also the case for Evohome but my experience is it needs a permanent feed the batteries aren’t great.

Hope that helps.

I would say the guys at https://theevohomeshop.co.uk/en/ are very helpful and seem to answer questions before a purchase. The prices from that site are pretty good as well, that is where mine came from.

It is a great system once you have it all setup to your needs, just wish it wasn’t so expensive.

Thanks for the reply. Appreciated

Actually, that’s not strictly true. The wall plate comes with a separate transformer, and that can be located remotely. So in my case I have the transformer in my airing cupboard, and the old thermostat wiring now delivers the low voltage to the Evohome controller.

Thanks all for the replies.

Is anyone familiar with the nest who has also installed the evo home ?

Does the nest thernostst have the same power requirements i.e. If I have a nest installed (which I do), would this be a simple swap out ?


The Nest is 12 volt and the Evohome is 5 volt but there’s no reason why you can’t use the existing Nest wiring between the receiver and the stat to power the Evohome. You’ll just need to use the PSU that comes with the evohome.

Depending on what boiler you have, and the way the Nest receiver has been wired, you may have to get a gas safe registered engineer to install the evohome. If you need to open up the boiler to access the wiring, you are not allowed to do this yourself.