Carbon filters vs cigarette smoke & sewer smells

[Mike]

A question for the non-smokers.

 

My upcoming MVHR install, in an apartment, has only two possible places where the outside air intake can go:

1. Within 1m of an external landing, where people sometimes smoke - and the smoke will sometimes get draw into the inlet. This option would have a short intake pipe, but a significantly longer exhaust (x 4).
2. Within 1.5m of the top of a neighbouring SVP - and the smell from that will also sometimes be drawn into the inlet (not so often, but for longer). This would reverse the pipes - a short intake and a much longer exhaust.

 

Due to space restrictions, the exhaust can only go in the other location to the intake, so I have to decide between a choice of smell-source vs exhaust pipe length. The pipes will be well insulated, but can only run through the ceiling space.

 

In theory either smell should be eliminated by the carbon filter that I'll be installing, and if so I have a preference. But has anyone got experience of how well either smell gets filtered in practice?

[Russdl]

We live in the country, not too far from a large pig farm. On occasions with the wind in the wrong direction it can absolutely wreak outside. The smell has never made it indoors via the MVHR and we have no carbon filters. I’ve no idea why. Someone scientific may be able to explain?

 

Also when it gets chilly out the wood fires start from the houses all around and that is also very obvious when outside but again the smell has never got indoors through the MVHR.
 

It may not be the problem that you think it will be. 

[SteamyTea]

8 hours ago, Mike said:

Within 1m of an external landing, where people sometimes smoke

I am happy, for £200/day + expenses, to come around and do some smoke tests.

Edited October 7, 2023 by SteamyTea

[ProDave]

Our neighbour discharges a septic tank into the burn just the other side of our fence, and the MVHR inlet is on the wall facing that, but at least 10 metres away.

 

On a completely still morning in summer it can get a bit pongy there and the smell can get drawn in.  If I notice it, I turn off the mvhr until a bit of wind builds to clear the air.

 

The only filters I have are the built in filters either side of the heat exchange core.

[Iceverge]

@Mike

 

Can you run an intake pipe up the external wall to above the level of the offending smells? 

[Mike]

6 hours ago, Iceverge said:

Can you run an intake pipe up the external wall to above the level of the offending smells?

No, it's a historic building so there's no possibility of adding external pipes, unfortunately. I'm stuck with what I've got!

 

 

[Iceverge]

1 hour ago, Mike said:

No, it's a historic building so there's no possibility of adding external pipes, unfortunately. I'm stuck with what I've got!

 

 

 

In lieu of a rant about UK housing policy I'll try to stay on topic. 

 

Have you committed to MVHR? A demand controlled extraction ventilation with humidity controlled through wall vents may be a second best option. 

You could use an ESHP like 

@Thedreamer

[Mike]

1 hour ago, Iceverge said:

Have you committed to MVHR?

Yes, I have - it's the only solution that will filter out the urban pollution on the supply air too, as well as pushing the EPC rating up from D to mid-way up the C band (in France, so UK housing policy is off the hook this time), which is much more important over here than it is currently in the UK.

 

The only outstanding decision is which way round to put the terminals.

[Iceverge]

I stand corrected. 

 

My vote is for the smokers over the sewer pipes in that case and some proper carbon filters. 

[Mike]

Thanks for your comments and suggestions!

 

I've gone with the smokers, and have found enough space to squeeze in a Zehnder filterbox that can take a carbon filter in addition to a regular pre-filter, if needed.