Dear All

First of all : Sorry for the long post, and thank you for those that have the patience to read it.

I'm renovating my house and I am very interested in Evohome . But not sure about a few things

My house is like this:

- Three levels
- Remeha Calenta Gas boiler, and a separate cylinder for hot water (plus considering a hybrid heatpump assisting the boiler)
- about 16 radiators in total (I'm considering Jaga Strada low temp radiators)
- Wet Floor heating in kitchen

My builder suggested this setup:
- One Honeywell zone valve on each floor (so 3 zonevalves, 3 thermostat - heating control for each floor as a whole)
- Another Honeywell zone valve for floor heating (wife wants this to work even when normal radiators don't demand any heat)

This at first made sense to me, control of each floor separately seemed good enough, but then I realized that in this setup it will not use OpenTherm (modulating the boiler) and the 4 zonevalves BDR91 would send simple on/off commands to the brand new Gas boiler, which I read was not efficient, causes wear on the boiler, which is capable of OpenTherm. OpenTherm just sounds better on paper.

So now I am leaning towards no zone valves at all and HR92 on 12 of the radiators plus HCE80 for floor heating. I think this setup will use Opentherm then as there are no BDR91.

Now to the questions:

1. With the HR92 setup (and HRA80 at the boiler instead of BDR91) , will it in fact use openTherm instead of on/off? So my Boiler can gradually change its heat output and deliver only the heat that is needed by the room with the highest demand?

2. Then which of the 2 setups makes more sense to you guys: Zone valves using ON/OFF or HR92 opentherm?

3. A question about Evohome logic: Since I have more than 12 radiators , I will have some radiators (and convectors) without any HR92. So what happens to these? My thinking was that I can simply add a dedicated thermostat to this "uncontrolled" zone, and have the Evohome system modulate the boiler to satisfy this thermostats demand, so in a way the uncontrolled radiators become their own zone but have no actuator except for the opentherm module (HRA80) at the boiler and the regular TRV's? I was thinking that this should be possible because some people may want to only buy one or two HR92 and the rest of the house's radiators must still be controlled somehow, right?

Any other opinions or suggestions how I can make my new system optimal would be much appreciated.