It is clear that moving air is not efficient for heating/cooling due to the low heat capacity of air; water is much more efficient.
On the one hand, the principle of decoupling heating/cooling from ventilation (HRV/ERV) is gaining ground. This is also enabled by having a more energy efficient building envelope (air tight & well insulated) with reduced need for heating/cooling.
On the other hand, the PassivHaus compact system integrates ventilation (HRV/ERV) with heating, supplemented with a small heat pump or solar. The compact system saves money and space and is supposed to pay for the super-efficient building envelope.
Question: are the HRV drains really problematic? I also understand that ERVs are much more expensive…
Interesting points:
It is clear that moving air is not efficient for heating/cooling due to the low heat capacity of air; water is much more efficient.
On the one hand, the principle of decoupling heating/cooling from ventilation (HRV/ERV) is gaining ground. This is also enabled by having a more energy efficient building envelope (air tight & well insulated) with reduced need for heating/cooling.
On the other hand, the PassivHaus compact system integrates ventilation (HRV/ERV) with heating, supplemented with a small heat pump or solar. The compact system saves money and space and is supposed to pay for the super-efficient building envelope.
Question: are the HRV drains really problematic? I also understand that ERVs are much more expensive…
A related article:
http://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system
Another related article HRV (Heat Recovery Ventilator) or ERV (Energy Recovery Ventilator):
http://www.greenbuildingadvisor.com/blogs/dept/musings/hrv-or-erv
My summary:
Need HRV or ERV?
– Air tight house: OK
– Leaky house: KO (fresh air through the cracks)
– Cold climate: OK (save energy)
– Mild climate: KO (open the windows)
– Hot/hot-humid climate: OK (save energy)
– Very cold climate (winter): HRV (if indoor moisture loads are high), ERV (if indoor moisture loads are low)
– Marine climate (winter): HRV (less humid incoming air is good)
– Hot-humid climate (summer): ERV (less harm than HRV)
Cold climate: in summer?
Hot climate: shoulder seasons?
..one size does not fit all.