Should I insulate my Spigot Box?

[ToughButterCup]

My distribution box for the MVHR  ( sometimes called spigot box or manifold) will sit beneath a flat roof , but above a ceiling.

The roof build up from top down is;

• Alvitra Avalon over
• 270mm of insulation on 
• some super expensive vapour stuff - forgotten the name - the price was so traumatic
• 22mm OSB3
• POSIs above the ceiling build up which is 
• Vapour control layer 
• 25mm insulation
• 12 mm plasterboard
• 2mm plaster skim.

 

There's enough space for  spigot boxes to  sit comfortably under the POSIs. That means they are outside the heated envelope. (just)

 

The supplier says not to worry : but they would wouldn't they? Everyone has that problem, said the rep,

 

What do you think?

 

[willbish]

I think, do you need the 25mm insulation? Is it going to be make a significant different to target Uvalue.

 

The supplier is probably right, the temperature in the void between the posi's will be very close to room temp. Chance of condensation very minimal I would have thought.

[ToughButterCup]

?