ERV Systems Developing Mold

Crissie

Has anyone had experience with an ERV system developing mold because of the difference in temp's and humidity moving through it?

STEVEusaPA

How many threads are you going to start about one heating system?

Crissie

I don't have but need to get an ERV. It is not related to the boiler sizing questions.

Jamie Hall

There are two types of energy recovery ventilators. Sensible heat recovery systems and latent heat recovery systems. Furthermore, some are ducted to be counter current and some parallel flow.

OK. That out of the way. Latent heat recovery systems all recover not just the sensible heat in the air, but the latent heat -- the excess moisture in the indoor air leaving is condensed in the heat exchanger, and then evaporated in the intake air stream. While these do recover much more of the energy in the indoor air, and are thus rated t have a much higher efficiency, they also recycle into the incoming air most of the contaminants and bacteria and virus which is in the exhaust air -- and as such they don't improve indoor air quality significantly. They can and do grow mold on the heat exchange medium.

My recommendation is to avoid them like the plague.

The sensible heat recovery units are simple heat exchangers. At some point in the heat exchanger -- where depends on whether they are counter flow or parallel flow and the indoor dew point and the outdoor air temperature -- they may condense, but only on the exhaust side of the heat exchanger. It is possible to get mold growth on the exhaust side, but not on the intake air side, and thus it won't affect the incoming air quality.

Crissie

@Jamie Hall I'm trying to move to hydronic heat, easier said than done. Still need AC and ventilation. Thanks for the above, do you have any preferred brands?