A small manufacturing company in Illinois called Build Equinox has developed a new ventilation appliance called the Conditioning Energy Recovery Ventilator, or CERV. Build Equinox was founded by an engineer, Ty Newell, and his son Ben Newell. (Ty Newell designed and built the Equinox House, which was described in a GBA article published in 2011.)
The CERV is a balanced ventilation system that includes an integrated air-source heat pump — a type of appliance that has been dubbed a “magic box” by Passivhaus designers. According to Ty Newell, Build Equinox has sold about 50 CERV units.
There is just one model of the appliance; Ty Newell told me that “one size fits all.” The CERV is unlike any other appliance sold in the U.S.:
Operating the CERV
When the CERV is commissioned, the user has to choose the sensitivity of the CO2 and VOC sensors. Even though the human health effects of 1,000 ppm of CO2 are not really comparable to the human health effects of 1,000 ppm of VOCs, the manufacturer of the CERV requires CERV users to choose a single setpoint (in parts per million) for CO2 and VOCs. While this setpoint can be raised or lowered, the CO2 setpoint and the VOC setpoint move in lock-step.
Peter Schneider, a senior project manager at the Vermont Energy Investment Corporation in Burlington, Vermont, has specified several CERV systems. “I set them at 1,000 ppm,” says Schneider.
According to the CERV owner’s manual, “In general, a lower air quality setpoint will result in better quality air and higher energy consumption, while a higher air quality setpoint will result in lower quality air and lower energy consumption. On one hand, you do not want to be overventilating your house and producing unneeded conditioning demands on your systems, while on…