[Greenbuilding] first certified Passive House in Canada

[elitalking]

John Daglish and list

I am interested in how an air source heat pump is set up that would use the 
exhausting HRV air for the air heat source.  Intuitively this makes sense, 
because the exhausted air is much warmer than the ambient air during heating 
season.  Do you have manufacturers with equipment that does this?  Can we 
see a diagram or picture of an installation?  It seems to me, this would be 
another layer of heat recovery.  However, I have never seen this.

Eli

John Daglish writes:
The certified Passivhaus quite often uses a heat pump in a
combined HRV ventilation unit. The air to air heat pump extracts the heat 
from the
outgoing ventilation air after the HRV heat exchanger and heats the
incoming air after the heat exchanger of the HRV.
Very few (if any?) use a convential heat pump air to air external or ground
sourced heat pump. Its less costly to simply use the HRV "waste air"
combined/compact unit for both air heating and domestic hot water
heating than install a ground sourced heat pump.
External air to air heat pumps decline markedly in performance when 
temperatures
get very cold less than 0C.