MVHR Intake

[Onoff]

Ref MVHR intakes.....what happens if:

 

The fresh air intake is downwind of say muck spreading, a neighbour (or you) emptying their cess pool or a bonfire / adjacent house fire Presumably things get very stinky/smokey pretty quickly. During the day I guess you shut the system down. I appreciate there are filters but down to what level? But at night? Could it get to the point that smokes in the house would go off?

 

 

[PeterW]

fairly unlikely unless there is a significant and dense smoke as filters are pretty good at taking particles out

[Jeremy Harris]

Yes, the smell of a neighbours bonfire can get pulled in, but there's no visible smoke, just the smell.  It's happened once, and by pure chance the Parish Council asked people to stop having bonfires a week or two later, because there had been a significant problem with smoke building up in the valley and causing a nuisance (I wish the Parish Council where our old house is were so pro-active..........).  The result is that I've not had any experience of smoke coming in since then.  I can say that the MVHR does clear any smell of smoke pretty quickly, though.

 

I think the best strategy would be to turn off the MVHR if there was a particularly smelly outside event, a bit like you might shut windows and doors ordinarily.  When the pong has gone, turn the MVHR on again.  Having no ventilation for a few hours isn't going to cause a significant problem.

[Onoff]

Playing Devil's advocate.....is the filter material flammable? Thinking fire embers blown in. Or is there a (metal) gauze to get through first?

[Jeremy Harris]

Ours has a metal grill on the outside, and the filter itself is made of some form of fibre that has an embedded fine wire mesh in it.  I'm not sure what the fibre is, but it may well be some sort of treated paper.  It has to be treated to deal with the humidity changes.  Some MVHR units use treated paper for the heat exchanger plates, I believe.

[DH202020]

9 hours ago, JSHarris said:

Yes, the smell of a neighbours bonfire can get pulled in, but there's no visible smoke, just the smell. 

 

 Happened to me the other night...forgot to switch off unit...smell of smoke everywhere...even the next day...checked the incoming filter chocked with grime and stunk severely...gave it a good wash...good as gold!

P.s we have even smelt neighbours BBQ...you will have to be vigilant when wind is blowing in wrong direction!