MVHR for single room studio

[Andrew]

We have a large detached double garage planned as part of our build with a 42m2 studio space in the roof above. This is mostly an open room but there's a small toilet and shower room in there too. I work from home two or three days a week and the idea is this will be my office so will be used quite frequently - it can also double up as extra guest accommodation if needed (sofa bed). Due to the frequent use the plan is to insulate it and make it as airtight as the main house. It's only approx 3-4m from the plant room in the main house at its closest point (as shown on the plan, obviously longer to run the pipes underground and up into the studio) so the plan is to bring the services from the house in terms of UFH and DHW. However I don't think it's practical to run MVHR ducting underground to service the room above the garage?

 

So, is there a small MVHR unit that would be suitable for the studio space or perhaps some other solution? Or perhaps there's no point with such a small space and I should have trickle vents? 

 

I've attached a site plan for context. 

[Jeremy Harris]

There are several single room MVHR units available that might be worth considering, but care is needed to ensure that building regs can be complied with, especially with regard to the ventilation rate for the WC and shower room.  The inability to comply with building regs was the thing that stopped me from exploring the use of a very neat wall-mounted MVHR solution.  It may have been OK in other countries but couldn't be made to comply here.

 

However, it should be fairly simple to install a small MVHR with extracts from the shower and WC and fresh air feeds into the working area without too much trouble.  If you're going to be using this area for long periods every day then it makes sense to try and make the environment in there as pleasant as possible, plus there should be a useful saving in heating cost.

[Nick1c]

Viking house were pushing a system called FreshR, making all sorts of claims about its efficiency, a while ago. Not heard much about it recently though. 

[Jeremy Harris]

46 minutes ago, Nick1c said:

Viking house were pushing a system called FreshR, making all sorts of claims about its efficiency, a while ago. Not heard much about it recently though. 

 

That was the system I looked at very closely, to the extent of going to see a unit and examining how it worked.  The show stopper was it not being able to meet building regs, as the design was intended to use diffusion from one room to another to avoid the need for a unit in every room (when I looked at them they were the best part of £2k each).  Building regs don't allow for diffusion ventilation from kitchens, bathrooms or WCs, so the advice from the Dutch manufacturer of the Fresh R unit was to install extractor fans in those rooms.  For us that would have meant fitting 5 extractor fans, on top of 2 Fresh R units, and the impact on overall thermal efficiency (not to mention our budget) was way too high.

[Nick1c]

IIRC there was a kit which allowed extract and supply to be in adjacent rooms. Maybe no good for most houses, but it might work in this situation. 

[Andrew]

Thanks both, I'll take a look at the Fresh R. 

 

As @JSHarris says there are several single room units and actually they are quite good value - e.g. https://www.blauberg.co.uk/en/blauberg-komfort-ultra-d105-a-single-room-heat-recovery-unit. If an extract in the bathroom and a supply in the main office is able to meet building regs then this would be quite a neat solution. The ceilings are vaulted but there will be some storage in the eaves which I'm sure could accommodate a single room unit and ducting. 

 

[Crofter]

I've just installed a Kair single room MVHR for my bathroom. It seems to work fairly well- the incoming air is definitely warmer than ambient outside temperature- but it's pretty noisy, essentially the same as a normal bathroom extractor fan. Uses 8w, but I don't know how much air it shifts off hand.

[jfb]

15 hours ago, Crofter said:

Kair single room MVHR

 

I'm in the market for something similar and am worried about noise levels - Crofter are you using it in continuous trickle mode or full blast? Looking at the spec it suggest a noise level of 21db on trickle mode and 45 db on boost. Is it only when it goes into boost that you hear it?

 

Edited January 30, 2019 by jfb

[Crofter]

8 hours ago, jfb said:

 

I'm in the market for something similar and am worried about noise levels - Crofter are you using it in continuous trickle mode or full blast? Looking at the spec it suggest a noise level of 21db on trickle mode and 45 db on boost. Is it only when it goes into boost that you hear it?

 

 

I guess I am hearing the full 45dB. I bought is quite cheap as an incomplete unit on eBay- no controller. It's simply powered off the bathroom light via a 12v transformer driving the two fans inside (they are just computer PSU fans, 4w each).