A few weeks ago I posted about how we commissioned the Zehnder ventilation system. Our commissioning agent measured and adjusted all the airflows to ensure the system is delivering the proper amount of fresh air to each living space and exhausting correctly from the bathrooms and laundry rooms.
This last week we continued our certification testing as our LEED rater, Mark, came in to measure heating system airflows, room pressures, and water temperatures. These are all components of the LEED, ENERGY STAR, Indoor airPLUS, or Zero Energy Ready Home checklists.
First he took a balometer (device for measuring air flows) and verified that each register and return in the house was within tolerance of the design criteria from our HVAC system designer and installer, Boucher Energy Systems. Next was the differential pressure test, to ensure that all rooms remain at the same pressure when the doors are closed. If the ventilation system was unbalanced, a bedroom with a closed door and inadequate airflow could become overpressurized, with undesirable consequences for indoor air quality and interference with airflows in the rest of the system.
Finally we also tested the hot water delivery system. The LEED and ZERH certifications have guidelines for how long it should take to obtain hot water at a fixture: too much time means that there is a lot of water and energy wasted in the system. We tested this by timing the interval to get hot water at different locations around the house, and I’m glad to say the flow times were all significantly faster than the requirements!