Hi

I've been looking at the problem of condensation in heritage buildings.
I'm concluding that - especially in winter - best practice would be to
mechanically ventilate to a positive pressure (i.e. supply more than
extract).

My rationale is thus:
- The external air is heated, lowering it's RH.
- The positive pressure ensures this air with a more favourable (drier)
psychrometric is continually pushed from the inside out.

Doors and windows need to be reasonably well sealed for this to work.
Obviously, this is no guarantee against condensation build-up. Can
anybody see any error in my rationale? I would be grateful to hear of
alternative methods of control that have been successful.

Most commercially available building simulation codes can't model this:
- I'm uncertain as to what E+ can do at present.
- IES-VE can't
- ESP-r can but is very anachronistic (thar be dragons!)

Can any of the 1D Transient FEA packages model this positive ventilation
scenario? e.g. 1d-HAM, MOIST, WUFI

Best regards

Chris Yates