Replacement cooker hood / ducting issue

[DIYnoob32]

Hi everyone

I'm looking to replace my cooker hood (it's a bit warped) - I think it's been there since the apartment was built in 2007. I've attached a couple of photos.

I assume it has 100mm ducting since the square hole in the ceiling through which the hose goes is about 115mm wide. I'm aware most modern cooker hoods have 125-150mm outlets (including the current version of the Luxair LA60-STD, which is the model I have) but I have found one that is compatible with 100mm (the Luxair LA-60-Delta).

Another issue is that when I unscrewed the top of the hood to see what the setup is like, I noticed that the hose has some small tears.

My questions, if anyone is able to advise, are:

(a) Is it likely that the hose can be replaced easily without cutting through the ceiling? I have no idea what happens once it's through the square hole but I did stick my hand in and I can feel some kind of plastic (perhaps the ducting the hose connects to?) If not, could the tears just be taped?

(b) the replacement model mentioned above is pretty basic and I would be willing to pay more, but should I stick to one that the manufacturer states is 100mm compatible, or get a more upmarket model and get a 125mm to 100mm converter thing?

Many thanks

 

[JohnD]

I use a converter because my duct goes through a dense upstairs wall.

it is said that at high speeds the reduced diameter will make airflow noisier due to constriction.

 

[jj4091]

I use a converter because my duct goes through a dense upstairs wall.

it is said that at high speeds the reduced diameter will make airflow noisier due to constriction.

I doubt you will hear any increase in airflow noise with an extractor fan running. Once you have the chimney out you should be able to see if the Flexi is connected to round or flat trunking in the ceiling.

 

[ajohn]

The square part of the hood going up to the ceiling is sometimes an add on. Just a trim. Might pay you to look at that and see how the duct is connected to the main part of the hood. You may need to do that anyway to remove the existing hood. Fixings vary.

You may be able to see what's going on above the ceiling with a mirror and a torch especially if the trim is removable. It is on the few I have come across like that.