Blower door test and HRV

gears

Just wondering about when you're getting a final blower door test done and the HRV has been completely installed how should the room vents be treated. I'm wondering should they be sealed shut with tape for the test?

soldsold

Thats correct, all vents are sealed during the test. That way you are measuring unwanted ventilation with the blower door test, and you can fix any leaks before opening the wall vents for normal use

sydthebeat

just remember that its simply the face of the vents that are covered....

if there are infiltration gaps around the pipes these should be discovered and fixed...

gears

sydthebeat wrote: »

just remember that its simply the face of the vents that are covered....

if there are infiltration gaps around the pipes these should be discovered and fixed...

Thanks for this, the housing for the fittings are taped to the air-tight membrane so it should (fingers crossed) be ok.

MicktheMan

When I do air tightness testing in a house with hrv installed, I generally carryout two tests. The first is as described by soldsold above (lets call this the official test).
I then remove the temporary seals from the hrv vents on the inside and temporarily seal the intake and exhaust vents on the outside.
I then repressurise the house to 50 Pa and compare this reading with the official test result. Why? To determine how airtight the hrv system is. Can lead to very interesting results (not quantitative but qualitative)

beyondpassive

Mick,

do you increase the volume, to include the duct area. The HRV when off, isnt air sealed, so do you seal the exhaust and frsh air supply plenums

MicktheMan

beyondpassive wrote: »

Mick,

do you increase the volume, to include the duct area. The HRV when off, isnt air sealed, so do you seal the exhaust and frsh air supply plenums

Yes, extra volume is estimated based on approx duct lenght/diameter.
I seal the supply/extract ducts at entry / exit to house - yes there can be leakage through the hrv unit (I don't like to tamper with installed systems) and this need to be discounted. The reason I do it is to determine if there may be an issue with the ducting leaking air. This is more of an issue where a significant proportion of the ducting is installed outside the thermal envelope.

doorhanger

Hi All Is there a specification on the gap under the door to allow the balancing of the rooms around the house for a Heat Recovery system as each room has its own supply either extractor or supply
Thanks
DH