Harvesting ground heat for your HRV

Zehnder ComfoAir 350 with ComfoFond-L

Zehnder ComfoAir 350 with ComfoFond-L

A great way to harvest ground heat to pre-heat your incoming air to the HRV is with a brine loop - which is essentially a salt water solution running through a buried hose. Zehnder has developed a special preheater, the ComfoFond-L, to make use of the ground heat.

This system is the one that benchmarks up to 99% recovery (Apparent Sensible Recovery) mentioned here.

I'm often asked about the details of the loop. If you are interested in such a system, simply download this PDF. There are instructions about the design of the loop on pages 9 and 10.

Make sure you consider this long before you dig your foundation, so you can incorporate the loop at the same time and have the materials on hand that you need.