Today Dee’s Electric completed the install of our Energy Recovery Ventilator (ERV). They installed two boost timer switches, one in the kitchen and one in the bathroom. This allows us to run the ventilator on high for a set period of time, while showering or cooking. There’s also a main dial switch that controls the speed of the fan, ranging from off to high.

Part of the commissioning process involves adjusting the airflow at each register to ensure the proper amount of air is being supplied and removed from each space. This also balances the system to ensure the same amount of air is introduced and removed from the house, so there is no pressurization or depressurization of the house.

They did this by first measuring the actual airflow at each register, then comparing that with the required airflow at that register. The required airflow at each register was determined by our energy consultants. The measuring is a bit like the blower door test, except the fan is the ventilator itself. The device measures airflow at the register in cubic feet per minute (CFM).

Since each register is a different distance from the ventilator with a different number of turns and elbows, it requires a little math and a few iterations of adjustments to get everything working as designed. Each vent outlet has an adjustable mechanism to control the amount of air flowing through that register.

After all was complete I ran the ventilator at different speeds and walked around the house to see what the noise levels were like. I could feel no vibration from the unit at all in the house. When the unit was running on the low setting I could barely hear the air movement. The air movement was very noticeable running on high, like in a house with a central air conditioned system. Medium speed was somewhere in between.

In practice, we will be running the unit continuously on low whenever the windows and doors are closed, and on high only for short periods of time when we’re cooking or showering.

That completes the installation of our mechanical systems. Next is finishing the electrical and plumbing. Tomorrow we’re taking a trip down to Ikea to buy our kitchen. And if the humidity in the house levels off tomorrow, we may get to start installing the wood floor this weekend.