Single zone acoss house?

[hfj]

Hello. First post here, so be gentle with me

I am renovating my house, and am looking to replace my 45 year old boiler with something a bit more up-to-date.

As I'm moving internal walls around as well as adding in some wet underfloor heating in a new extension, and moving the kitchen location, I thought I would move the location of the boiler as well to somewhere more appropriate. I am therefore thinking of replacing the whole central heating.

The house has a wide footprint, with the new kitchen on one end alongside the new location for the bolier/cylinder. The 2 bathrooms are in the middle upstairs (one an en-suite), with a new mini bathroom at the far end of the house.

I've had a couple of plumbers come to have a look. One said he wouldn't touch plastic. The other said he only did plastic. One wanted to put in lots of zones across the house. The other wanted to put in a single loop connecting everything up and using Honeywell Evohome to digitally create zones as needed. The new underfloor heating would go on a seperate loop. Another plumber I got to have a look hadn't heard of the system.

I like the idea of the flexibility of a single loop & Honeywell evohome control, but wanted to check the idea with people who know more than me.

Is this single loop&Honeywell Evohome idea a sensible, viable option? Any cons with it?

Thanks in advance for any comments.

 

[Worcester]

It all depends uon the total size of the house wether you it would be best with one, two or more 'zones'.

The Honeywell evo system is excellent, 90% of our installs have it, however if you use the evohome trv's (which are excellent) you can only have one zone valve unless you install two separate evohome controllers...

The evohome system will pay for itself in therms of energy efficiency within only a few years (3-4 from experience)

Ignore plumber 3, on the basis he is behind the curve on energy efficiency.

Given the chance on a whole house retorfit, I'd go underfloor heating downstairs with room by room control and radiators with evohome trv's upstairs.

If you're ripping everything up downstairs, then underfloor heating can work out less than radiators.

Honeywell evohome will give you up to 12 zones plus DHW on a single controller and more control than multiple zones.

Pipe sizing will be critical, done properly plastic can be OK, we use it on heatpump systems, copper on biomass. when we use plastic, we use a crimp fitting not a push fitting for peace of mind.

A 28mm plastic is equivalent to a 22mm copper pipe..

A good heating guy will do room by room heat loss calculations to size all your radiators / underfloor heating.

Depending upon the total number of rads (we have 21 in our property) well designed I'd go for evohome because of the level of control available. (Get the wifi version it'll link direct to the net)