So here's my problem. I've had an extension built on the back of the house and the kitchen is now a completely internal room apart from the knock-through into the extension. Where the cooker is, is now a party wall. The current kitchen is the old kitchen that I've repositioned. However it is to remain for a few years while we save for a new kitchen - everything is serviceable, except of course the extractor fan, which doesn't now extract! Now, I have explored several options for ventilation in the kitchen (required for building control). The only accessible external wall in the kitchen is now directly opposite the cooker (see red circle on drawing). I have wired for a wall mounted extractor fan in this position. However, according to the spec, a fan away from the cooker must be capable of 60l/s which as far as I know is a sizeable air movement (and probably noisy for a standard wall fan). There is no way to duct from the cooker position to the outside walls horizontally.
My idea is to use an in line fan in the loft and vent out of the gable end. The house is two storey, but I do have access to the bedroom above and can build box work around the duct. The main issue with this would be the length of the duct. It would be around 3 metres to the loft floor, then another 8-9 metres to the discharge point on the gable wall. I would do it all in rigid duct, would only need 3 x 90 degree bends. My preferred fan is the Manrose MF100S which can achieve 68l/s (though only 30 is necessary at the cooker position). I already have a MF100T in the loft and have fitted them for others, and know they're reliable quiet fans. Is this possible for this length of ductwork? Do I need to uprate the fan for the length of ductwork? Should I use 125 or even 150mm ductwork and fan?
My plan is to remove the motor from the cooker hood and simply duct the loft fan to the cooker hood, possibly using the cooker hood switch to turn on the fan in the loft (I'm an electrician and the cooker hood is long out of warranty).
Thanks!
My idea is to use an in line fan in the loft and vent out of the gable end. The house is two storey, but I do have access to the bedroom above and can build box work around the duct. The main issue with this would be the length of the duct. It would be around 3 metres to the loft floor, then another 8-9 metres to the discharge point on the gable wall. I would do it all in rigid duct, would only need 3 x 90 degree bends. My preferred fan is the Manrose MF100S which can achieve 68l/s (though only 30 is necessary at the cooker position). I already have a MF100T in the loft and have fitted them for others, and know they're reliable quiet fans. Is this possible for this length of ductwork? Do I need to uprate the fan for the length of ductwork? Should I use 125 or even 150mm ductwork and fan?
My plan is to remove the motor from the cooker hood and simply duct the loft fan to the cooker hood, possibly using the cooker hood switch to turn on the fan in the loft (I'm an electrician and the cooker hood is long out of warranty).
Thanks!
