Another stack effect question – this one relating to tight envelope
I’m in the early stages of a new residential development. The goal is to create a very tight building envelope, coupled with an ERV system.
An issue I’ve been grappling with in this high performance endeavor is the stack affect and how to minimize it. And perhaps, as much as I’ve spent hours on educating myself, I’ve decided to turn to the community to see if anyone well versed in the science can offer some insight and or solutions to my concern.
The key concern: Assuming that the ERV is in balance. The home is going to have a range hood for the kitchen, along with a pellet stove, perhaps even bathroom fans, though looking at maybe the ERV to replace them; all ducts will have the proper dampers on them. How is the home going to deal with negative pressure from the mentioned appliances?
At what point do you think we’ll see self adjusting ERV/HRV’s that detect changes in building pressure adjust accordingly?
Thank you!
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Replies
The bigger issue is not your ERV but the pellet stove.
An ERV with ECM blowers is not very sensitive to small pressure changes in the order of 0.1" WG, it takes a pretty tight house to get to there with reasonable range hood. Some like the Panasonic intellibalance or Venmar N series auto balance, so as long as the pressure change is within their operating range, the flow won't change.
Stove is a different beast tough, in a tight house an ERV can create enough pressure change to cause the stove to backdraft:
https://www.greenbuildingadvisor.com/article/flatrock-passive-winter-update
Wood burners are best avoided in a sealed house, otherwise opening a window and making sure the range hood or dryer is not running when stove is lit is a must.