Years ago, when I worked as a home inspector, I was hired to perform a capital needs assessment at a Buddhist retreat center in rural Vermont. In an obscure mechanical closet I discovered a heat-recovery ventilator that the facilities manager didn’t even know existed.
The HRV had been installed at least a dozen years before. The filter, which had never been changed since the day it was installed, was totally clogged. The HRV was no longer working — perhaps the motor had burned out years ago. I advised the owners to call an HVAC contractor to have the unit serviced.
When a furnace or water heater stops working in January, it only takes a few hours for the homeowners to notice that something is wrong. However, when an HRV stops working, the owners rarely notice.
The HRV failure at the Buddhist center raises several questions:
I don’t have any ready answers to these questions, but I welcome comments from readers.
Memories of the clogged filters at the Buddhist center came flooding back to me recently when energy consultant Joe Nagan sent me an amusing series of photos by e-mail.
Here’s the story: Joe was walking by his local nature center in Wisconsin — a “green” building equipped with a rooftop PV array — and noticed that the building had a large, commercial-sized energy-recovery ventilator (ERV) mounted on an outdoor slab. Although he could hear the Venmar unit’s three motors humming along, he was surprised to notice that there wasn’t any air flow at the intake or exhaust grilles.
Leaping into action like any good energy consultant, Joe decided to respond to this ERV emergency. “I took a quarter out of my pocket and removed a door panel,” Joe told me. The problem was clear: every belt was broken.…