Underfloor heating mainly groundfloor with one room basement - one manifold works?

[Tony C]

I have a 2-bedroom detached house with a ground floor and a one-room basement. Additionally, there is a detached one-room annex, making the total volume around 150m³, including the detached studio. I plan to install an LG Therma V 7kW ASHP with a 250L V-Cyl Pre-Plumbed HP and a 50L Buffer.

Two underfloor heating companies (Wunda and Underfloor Heating Direct) have recommended that I need separate manifolds for each area, resulting in a total of three manifolds:

1. One for the main ground floor (110m2)
2. One for the one-room basement (20m2)
3. One for the detached one-room annex (20m2 served via insulated pipe underground)

However, I've read in various posts that installing a manifold on the upper floor and using it to serve the room below can work well. This approach suggests that I could potentially serve the one-room basement from the ground floor manifold, simplifying the installation.

Has anyone tried a similar setup successfully? Any advice or insights would be greatly appreciated!

[JohnMo]

If you have the same (or similar) design temperature - or just about, you could do it all with no mixers or pumps and no buffer, drive it all as a single zone? This takes a little getting your head around.

 

I do our main house UFH and a  garden room with fan coil as a single zone. I have two thermostats either can call for heat, but both have to be off to stop heat. Basically the house acts as a buffer for the summer house. Took a little fine tuning, but it works.

 

Trouble with mixers is they always mix, so if you want to flow 30 degs, you may need to flow 35 to 40 from heat pump, you also have mixing in the buffer, so you easily be flowing 42 to get 30 into the floor. Giving rubbish running efficiency and high running costs. Keep it as simple as possible.