Weighing up cooker ventilation options

[dnb]

My (new build) plans currently have the cooker hood extracting to the outside world. I'm begining to think this isn't the best plan for various reasons discussed in other threads (extract volume is large compared to MVHR supply etc... Not really a lot of need to go into all of that again).  If I decide against having this simple extract scheme, is it acceptable for building control to use a set of filters in the cooker hood to recirculate the air, and then have the MVHR to extract from the kitchen at the correct rate, but a decent distance from the hob? And will the scheme keep the majority of cooking contaminants out of the MVHR? We do a lot of cooking so need a robust solution.

[ragg987]

Yes and yes, though I don't think BC are concerned about extract for cooking. Also be aware that charcoal filters are about removing grease and not so good for cooking smells.

[Jeremy Harris]

8 hours ago, ragg987 said:

Also be aware that charcoal filters are about removing grease and not so good for cooking smells.

 

 

Usually the other way around.  Grease filters are usually the washable mesh ones, the charcoal ones are downstream of that to adsorb odours.

 

The grease filters can sometimes just be washed in hot water, or put in the dishwasher, to clean them.  Charcoal filters have to either be replaced or can sometimes be re-activated by subjecting them to dry heat (which drives out the stuff they've adsorbed, so needs to be done outside).  Washing a charcoal filter in very hot water might partially reactivated it, but they really need dry baking at quite a high temperature in order to open up all the pores in the charcoal and drive out everything they have trapped.

 

At our old house, I adapted the charcoal filter in the hood so that I could just refill it with activated charcoal granules.  These can be purchased relatively cheaply for use in pond filters, and it wasn't hard to adapt our filter so that a layer of these could be spread on to the mesh and sandwiched in place with the outer mesh.  As far as I could tell this modified filter worked at least as well as the original one, and cost a fraction of the price to replace/refill.  I didn't bother trying to re-activate the charcoal, as the stuff was so cheap it wasn't really worth the bother.  If anyone wants some I still have a few sealed bags of it here, left over.  We don't have an extractor in the new house (doesn't seem to be a need for one) so I'm never likely to use the charcoal granules for anything.

[joe90]

8 hours ago, dnb said:

My (new build) plans currently have the cooker hood extracting to the outside world. I'm begining to think this isn't the best plan for various reasons discussed in other threads (extract volume is large compared to MVHR supply etc... Not really a lot of need to go into all of that again).  If I decide against having this simple extract scheme, is it acceptable for building control to use a set of filters in the cooker hood to recirculate the air, and then have the MVHR to extract from the kitchen at the correct rate, but a decent distance from the hob? And will the scheme keep the majority of cooking contaminants out of the MVHR? We do a lot of cooking so need a robust solution.

 

This is exactly what we did and it works great. We do find the kitchen/diner gets a bit hot with lots of cooking but with doors open it soon gets around the house (and the MVHR helps).