Earlier this spring we posted an article on Pre-certified Passive Components: ERV or energy recovery ventilators. We fielded a couple of great questions following that post and want to answer them here:
The “fresh air machine” of passive homes, including those built by EkoBuilt, ERVs are a vital component and worthy of close inspection. The unit we recommend is the Jablotron Futura Passive ERV and it’s pre-certified by the IPHA.
If the ERV is frost-protected down to -20, what happens in areas where the temperature can go down to -30 or -35?
Anytime there are frost conditions, the machines will enter a re-circulation mode to “warm up” the core as required. There will still be incoming fresh air, just less depending on the machine’s efficiency level in extreme cold.
Have you looked at the Panasonic Intellibalance ERV for cold climates? Model FV-10VEC2.
We actually hadn’t installed one of these units before, but at the time this question came in on Facebook we found ourselves on a job where this is what the owner wanted to install, mainly because of cost. They are good units because they are frost protected in the same way that the passive units that we recommend are, however, they consume almost double the electricity and aren’t as efficient. Below we include a side by side comparison at a glance.
Why does the Futura documentation call it an HRV?
Although the documentation (shown below) actually lists the unit as an HRV, it does in fact function as an ERV. As noted in the Futura technical specifications on its website, the unit’s heat exchanger “enthalpy counter-current exchanger with humidity recovery control” means it operates as an ERV.
Jablotron Futura Passive ERV
Power consumption: 0.44 watts/cfm = 44 watts @ 100 cfm
Efficiency rating: 90% at -10°C
We love the dialogue with home owners, please keep the questions coming!