New kitchen - extractor or recirculation fan?

heavysnow

Hi - I am getting a new kitchen installed in a couple of weeks time but I'm unsure what to do about the cooker hood fan.

We have been advised to go for a recirculation fan but there is an option to go for the extractor fan option. The only problem is that there will be a fairly large amount of ducting required. To get to the outside, the ducting will have an initial 90 degree bend and then a straight run of 3.8m through our attached garage. I have done a bit of googling and it would seem that 5m would be the advised maximum length of ducting and a 90 degree bend counts as 1m, so we are just on the limit of effectiveness. The guy arranging the kitchen installation said that the unheated garage through which the ducting would pass may cause some condensation issues within the ducting.

Personally, I would rather have an extractor fan as it is more efficient, removes moisture far more effectively, and doesn't require the maintenance costs of carbon filters. I also think that an extractor fan would reduce any risk of Carbon Monoxide gas escaping into the kitchen.

However, is the 4.8m effective length of ducting too long? Would condensation in the ducting be an issue?

Any advice greatly appreciated!

Mankysteve

If your going for a long run, one option would be to have a fan at the far end of the piping run. I don't know how the wiring would work but I'm sure a decent electrician could sort something out.

phill99

Extraction is always best, without a doubt.

Condensation will be an issue but can be overcome quite simply by basic insulation on the ducting in the garage. Consider a more powerful extractor so that it can push more than 5 metres.

ryder72

3.8m ducting run is not a problem at all as long as you follow some guidelines.

Keep the ducting run as straight as possible
Get rigid ducting, not a flexible one
If condensation is a possibility put in a slight gradient away from the hood and lag the ducting.
Get the highest capacity extractor you can afford with atleast 20-30% more capacity than required by your room. This will allow you to run it at lower speeds creating less noise.

heavysnow

Great advice - thanks everyone for your help

sooz

Move the planned hob position.

And always extract if you can.