I've got one of these cheap R290 units in the gym shed, and the wifi app is quite usable for monitoring temperature and adjusting settings remotes. Despite going through Chinese servers (actually central europen data center, but Tuya is the chinese company in control of it) it's far easier to use and more responsive than the Mitsubishi MELcloud app on our A2W hp in the house

https://www.appliancesdirect.co.uk/p/eiq-12wminv/electriq-eiq12wminv-wall-split-air-conditioner

 

Not specifically pushing that model, just saying if fairly entry level units have reasonable app support then I'm sure more luxury brands would (although honestly think their proprietary apps could be worse, given the Mitsu experience). Doing a multisplit unit might complicate built in wifi controls a bit, I don't know

 

As a bonus I linked mine to Home Assistant so have made automations to act as frost protection, auto power off after a period of inactivity in the shed, etc. but it's fine to use without that. (The Tuya Smart Life app has some basic routines support built in, and you can link to Google/alexa routines too if wanted)

 

 

I'm leaning towards a ducted system rather than multi split. Probably without any room-by-room adjustment after the initial installation.

So hopefully control will be pretty simple.

Do you have a handle on your annual space heating and DHW requirement? Given your unique use case I think solar PV heated water might be the best. If you have an idea of consumption you can make an informed decision.

 

Reminds me of the opposite of a story I heard where student accommodation installed solar DHW for buildings that were unoccupied from April to October........

 

For space heating install some pull chord fan heaters. 

 

 

If you mount them on stud walls they'll make such a racket that soon everyone will decide they're warm enough and turn them off again. 

9 minutes ago, Iceverge said:

Do you have a handle on your annual space heating and DHW requirement? Given your unique use case I think solar PV heated water might be the best. If you have an idea of consumption you can make an informed decision.

Unfortunately, not really. I can dig out the meter readings and see what the split is between DHW+heating, and everything else.

20 hours ago, Crofter said:

So if I'm understanding correctly, you set up four different schedule options, and use the app to move from one to the other? And if you're offline, it'll just continue with whatever schedule it's on?

I set on / off schedule for each day using the remote controls. Currently 2 programs in use Monday - Friday to put the heating on early morning and shuts it off before I head to work. This doesn't use the app.

 

If I'm working at home, I just operate with remote control. If I'm in the office, I'll use the app to turn on the heating as I start my commute home as that isn't a fixed time.