Drayton Wiser efficiency.

[RichD1]

Have been thinking about smart control for a couple of years now but with 16 radiators the cost is fairly considerable. One question I have about the system is; if just one of the TRV's is calling for heat is this going to be very inefficient, especially if the boiler is cold.

 

[harrythefurrysquid]

It does probably help to combine TRVs from adjacent rooms to make bigger zones. I have all my downstairs TRVs linked together since I leave all the doors open. This means you've got more radiator surface area to effect heat changes more quickly, which should mean the boiler generally doesn't fire for so long as if you had a single rad bleeding heat into adjacent colder areas.

Wiser will also run the boiler in such a way that it's not constantly cycling on and off, and if you have Opentherm support it will throttle it down according to demand.

Having said that, you can absolutely end up in a situation where you want a single room warmer than elsewhere (I do this) and the boiler is firing just for the benefit of that one rad. Wiser can take care of stuff like predicting when the heat needs to come on, but you do need to think a bit about how much you want to allow rooms to cool down, and how well isolated your zones/rooms are from each other.

TL;DR: Bigger zones as needed

 

[Mister Banks]

Have been thinking about smart control for a couple of years now but with 16 radiators the cost is fairly considerable. One question I have about the system is; if just one of the TRV's is calling for heat is this going to be very inefficient, especially if the boiler is cold.

I'm just starting with my Wiser heating system so I am still thinking of the best way to zone my house. Initially I was planning on one room per zone but now I am wondering if having just 2 zones (downstairs and upstairs) might be more efficient. I have 13 radiators (7 downstairs, 6 upstairs with a smart room thermostat controlling each zone) but only 9 radiators will have smart TRV's on them. These rooms are 3 bathrooms and a utility room which means they will all heat when either zone calls for heat. So in total there will be 5 smart TRV's downstairs, 4 smart TRV's upstairs. I have no idea which setup will be best from a comfort/efficiency viewpoint but the Wiser system means I can experiment with both setups.