Ducting for a kitchen extractor
I live in a house built in 2016 which is still under the NHBC 10 year warranty. The kitchen extractor fan has never worked properly and completely died shortly after I moved in. When it did make some noise I found all cooking smoke ended up in the downstairs loo and the same happens when I do a test now by creating some paper smoke and sending it up the pipe. I have taken the hood off and put my hand inside and found that the kitchen extractor feeds into rigid ducting that points in the direction of the downstairs loo which is in an internal loo with no windows and has its own air circulation extraction fan. The kitchen extractor should surely (a) not be feeding into the downstairs loo and (b) be ducted to the outside which was entirely possible as the kitchen is at the front of the house where there could be an air vent. All my neighbours houses built on the same development have the same problem and all extractor fans are broken and no air extraction is possible which obviously is not good for the decor/air quality/damp issues within the houses. Am I correct that this installation is incorrect or are there any circumstances where the installation I described would be acceptable?
Advice from 3 local tradespeople
Yes, the installation is incorrect. A kitchen extractor fan must vent directly to the outside, not into an internal room or shared duct with a bathroom. This setup breaches Building Regulations (Part F – Ventilation) and likely falls under defects covered by your NHBC warranty. You should report it.
You’re correct—kitchen extractor fans should vent to the outside, not into an internal room like a downstairs loo. This installation is incorrect and can cause poor air quality and damp issues. You should contact NHBC to get this fixed under warranty.
Ducting for a Kitchen Extractor
Based on your description, the current setup of the kitchen extractor appears to be non-compliant with standard building and ventilation regulations. A kitchen extractor should be ducted directly to the outside, especially in a property where this is clearly possible (as in your case, with the kitchen located at the front of the house).
Ducting into an internal room, particularly one like a downstairs WC with its own separate extraction system, is highly unusual and likely to be incorrect. This setup could cause air and cooking fumes to circulate within the house, rather than being expelled—leading to poor air quality, damp issues, and even potential hygiene concerns.
There are no acceptable circumstances under standard UK Building Regulations where a kitchen extractor would be intentionally ducted into a bathroom or WC, especially not one without a window. It should always discharge externally.
Given that your house is still under the NHBC 10-year warranty, and this appears to be a systemic issue across multiple properties, this may qualify as a latent defect or poor workmanship. You should raise this with both NHBC and the developer as a matter of urgency.
In the meantime, a qualified ventilation engineer or kitchen installer could assess the system and confirm the fault officially, which would help support any claim you make.
