Spirits were high at last week’s Global Passive House Happy Hour after President Joe Biden recommitted the United States to the Paris Climate Agreement on his first day in office. In addition to the good news, we also got the opportunity to watch a video from Tom Bassett-Dilley on energy modeling for low-carbon architecture (see below) and to hear from one of the luminaries of the Passive House world, Lois Arena, the Director of Passive House Services at Steven Winter Associates. Lois has worked on some of the largest and most ambitious Passive House developments in North America and described the pros and cons of using variable refrigerant flow (VRF) systems in these projects.
Lois goes over the pros and cons of VRF systems.
Some of the specific lessons learned that Lois touched on include:
1. Sizing is very important. Currently, the smallest systems start at 4500 BTUs, which is way too big for a small apartment built to Passive House standards. That will likely have a heat load closer to 500 BTUs.
2. Change the settings on the units to shut off the fan when heat is not required. The default setting on these units is to keep the fan going even when there isn’t a call for heat, which can lead to waste and overheating.
3. You can increase the efficiency of a system in a heating dominant climate by using floor-mounted units.
4. Avoid placing the condensing units in an area that will likely get hit with considerable snow and ice. This can damage the units.
To hear more from Lois, check out the video here: