W/C ventilation

[Thedreamer]

I would be grateful for any help with this question.

 

I have small WC upstairs which is approximately 1.34m x 1.5m. 

 

I have large U04 velux which cover the width of the room. 

 

If the regulation states that 1/30th of floor area does this mean that if the size of the velux ventilator is 30th of the floor area this would be compliant with the requirement below? 

 

Toilet

either: a ventilator with an opening area of at least 1/30th of the floor area it serves, or mechanical extraction capable of at least 3 air changes per hour.

10,000mm

 

Thanks

 

 

 

[Jeremy Harris]

Are you fitting MVHR?

 

If so, then that should meet the requirement.

[Thedreamer]

No currently due to fit a Joules Aero system it like an hybrid because MHVR and Air Source heat pump to provide hot water.

 

Plans show a duct in our ensuite, bathroom and one in a airing cupboard which is where our stove pipe will run through.

 

In this W/C the plans show just a standard electronic fan, I have a similar fan here in a small bathroom in our loft conversion it pretty hopeless at ventilating the space. We just open our velux window and this provides ventilation.

 

 

[Jeremy Harris]

But, if you're using an MVHR with a built-in exhaust air heat pump then you still need the house to be airtight, so fitting a fan or vent in the WC will pretty much negate the benefit of the MVHR part, as well as create an imbalance.  Why not just include and extract in the WC, as would be normal practice when fitting MVHR?