Direct air vent

[Blackmyre]

I'm planning to have a 5kW wood burning stove installed. The regulations here in the UK don't require any air venting provision for older houses like mine because they're considered leaky enough to cope with stoves up to this size. Some stoves can be fitted with direct air vent kits to feed air directly from the outside but most suppliers/installers I've spoken to have little experience or interest in them because they're considered an unnecessary cost.

The way I see it, a stove that's vented from inside the house would be sucking air into the room. Ultimately that means sucking cold air into the house from outside. I guess it also means that noise from outside has a route into the room, as it does with an open chimney (UK regulations require that the vent can't be completely closed). I figure a direct air vent could prevent draughts and noise, while guaranteeing the best possible air supply at all times. Apart from the relatively small additional costs I don't see a downside but, as the attitude of the suppliers/installers is just "No, you don't need one", I've not really been able to have an intelligent discussion with anyone about it.

Are there any downsides to having a direct air vent for a wood burning stove?

 

[snaple4]

I am a fan of using outside air for combustion. I’m work in the HVAC business and reducing drafts and carbon monoxide risk is part of it.

Pros:
Reduces drafts.
Better air quality (pulling less dry unfiltered air into house).
Reduces carbon monoxide risk during downdraft event.
Can reduce overdraft issues.
If you have an air gate then you can use it as a safety shutoff for the stove.

Cons:
Extra Cost.
Chance the size is to small and it starves the stove.
Improper material could cause a fire hazard during downdraft event.
If not insulated it could cause condensation and mold/rot in building.
Could be visually unappealing.

 

[Blackmyre]

Thanks for the reply (and apologes for my delay in responding). The kind of stove I'm looking at has a manufacturer-supplied direct air kit option so there should be no worries about it being undersized, nor about aesthetics as it should be barely visible (vented either through the wall directly behind the stove, or into the underfloor space directly below it).

My main interest is preventing draughts, and my main concern is the possibility of extra noise from an additional hole. In your experience, do external air supplies result in more noise?

 

[Ludlow]

The reason most suppliers/installers dont like them when they arent required is that it is labor intensive and they lose money on it. There are no downsides once installed correctly. You could always add one later DIY if the shop wont grant your request. I dont blame the installers really. Its like an upgrade they just dont wish to deal with. If code requires it, they will acquiesce to make the sale. Just business.