Extract Unit vs PIV

[Bemak]

Ok so bear with me on this. Existing 70s house, semi-detached, two-storey. Typical condensation issues associated with a house of this nature. I need to core a few extra wall vents to improve ventilation but I was tempted to add a PIV system to help move air also.

 

However my main concern with this kind of system is the potential for cold air/draughts etc. I'm also not keen on the heater element either as it drives the energy consumption way up.

 

As an alternative would it be completely mad to have a extract unit in the attic do the same thing in reverse? i.e. extract air from the house from a central location (first floor landing) which would have the effect of pulling air into the house from "all the nooks and crannys" and wall vents (as opposed to driving it out). That way the draughty element is reduced as it's warm air that's being moved out as opposed to cold air being drawn in?

 

Just putting it out there. Advice greatly appreciated!

Edited January 11, 2023 by Bemak

[PeterW]

9 hours ago, Bemak said:

As an alternative would it be completely mad to have a extract unit in the attic do the same thing in reverse?

If you’re doing that then seal up all the gaps etc and fit MVHR. You’ll find a draft from a window vent more annoying and colder than a centralised PIV. Either way you’re removing the same amount of heat from the building if you aren’t using either heat exchange to limit it or adding in heat using a post PIV heater.

 

 

[Bemak]

46 minutes ago, PeterW said:

If you’re doing that then seal up all the gaps etc and fit MVHR. You’ll find a draft from a window vent more annoying and colder than a centralised PIV. Either way you’re removing the same amount of heat from the building if you aren’t using either heat exchange to limit it or adding in heat using a post PIV heater.

 

 

 

Thanks Peter. Ideally yes but I looked into the ducting for MVHR but we can't make it work for the downstairs rooms. I appreciate that we would be losing the same amount of heat, but wouldn't that be distributed across the vents as opposed to one blast from a PIV system?

[Bemak]

The alternative is two or three dMVHR units in the vents, like the lunos e60 etc, which would work in tandem to extract/supply air into the house. These look great for completely airtight houses but I'd be curious to know how they work with standard levels of airtightness.