Extractor Fan Replacement - 100mm to 150mm

[Polskasweetie]

Hello all, and i do apologise in advance if this has been asked before, but have no reliable people to turn to here for this.

Currently have an Airflow Loovent Eco 100mm extractor fan in the kitchen, that stopped working a few days ago. Looking around, and in consideration of the square hole the existing fan will leave when replaced, I am thinking of replacing it with the Airflow QuietAir QT150B.

1) is it safe / ok to replace with a bigger fan, or do i have to stick with a 100mm fan as a replacement?

2) Read in the forums about centrifugal etc. I know the Loovent is centrifugal, but the QuietAir is "axial high efficiency impeller" (from the description). Do i stick with another cntrifugal model, or can i switch to this axial one?

It is a residential kitchen measuring 3m x 2.2m x 2.2m. Also, considering the fan models mentioned above, if you have suggestions and why I'm more than happy to hear them.

Thanks!

[The Natural Philosopher]

I'd go for whatever fits the vent hole. In fact you may simply have lost a starter cap.

some axial fans are quite noisy. check noise levels

[Polskasweetie]

Sorry, forgot to mention it is for a 2nd floor (of a 3 floor) flat so unsure how long or short the ducting is, or where it actually goes out to.

[Theo]

There isn't a square hole - there's a 100mm circular hole. The unit is screwed to the wall/ceiling outside of that area - that may leave a square-ish part where the paint finish differs if the area has been painted since the unit was fitted.

A 150mm unit will need a 150mm hole. Whether you can cut that depends on what the hole is in. Don't forget there may be a duct behind it, so it's not just cutting the ceiling but you'd also need to upgrade the duct and exhaust vent as well. Unless there's a good reason to get a bigger fan (airflow, noise?) it wouldn't be worthwhile, IMHO.

Centifugal means the air comes into the unit from the sides, axial means it comes in from below (assuming the unit is ceiling mounted). Axial means you can see into the fan from below, not for centrifugal. Which is best depends where the vapour you're trying to extract is coming from.

Theo

[Polskasweetie]

Thanks very much for all of your input, it’s very helpful indeed. I’ve decided to play it safe, replace like for like, so now looking around for boxy 100mm centrifugal fans that are hopefully not too expensive, around the 100-200 quid mark. Thanks again!

[Owain Lastname]

Axial is okay for through the wall or with short lengths of duct.

For longer lengths of duct you really need centrifugal to overcome the duct resistance to airflow.

Owain

[Brian Gaff (Sofa]

Well leave home owners club and use a proper news client as it will make life far less stressful in the long run. Anyway, apart from noise or voltage differences a larger fan should simply move more air, so as long as you can get it in in a tidy way, I'd say go for it, you might also have a look and see why the old one actually failed. it might be just seized up after all. Brian

[Roger Hayter]

It is probably best to assume a moderate length of duct then, because you need a fan suitable for a duct as the common, cheaper ones will not work very well at all with any significant length of duct (more than 400mm or so). The exact length of duct will affect efficiency but if you don't know the length then it it is reasonable to get one designed for ducted use so it will work even if you don't know exactly how well.

[Owain Lastname]

In that case get a centrifugal fan.

Owain