The wall control beside our kitchen light had three markings and no explanation. I had been turning it down whenever the house felt chilly. My partner had been turning it up whenever the windows misted. We were both certain the other person was interfering with the heating.
The label inside our household folder finally settled one point: it belonged to the heat recovery ventilator. It wasn't the furnace thermostat. Before changing anything else, I photographed the model number and found the matching control instructions.
First identify what the setting controls
Source: Health Canada: ventilation and the indoor environment
Some ventilation controls set a humidity threshold; others choose continuous, intermittent or boosted operation. Those choices do different jobs. Health Canada's ventilation guidance explains that bringing in dry outdoor air in winter can lower indoor humidity. Turning ventilation up indefinitely can therefore leave a house unnecessarily dry.
Our useful questions were modest: which mode should normally run, what triggers a boost, and how does this particular controller respond to humidity? I wrote the answers beside the manual. I left the equipment's balancing adjustments alone.
Give a small change a fair comparison
We noted the original setting, room humidity, outdoor weather and whether the windows were wet. Then we followed the manual's winter guidance and watched several ordinary days. A dinner party and a quiet weekday were poor comparisons; so were a thaw and a sharp cold snap.
Persistent condensation, excessive dryness or a fan that seems never to change speed deserves a ventilation check. A technician can confirm actual airflow and control operation. I brought our short record to that conversation.
We still use the kitchen switch several times a day. Now the ventilation dial next to it has a small paper label, and neither of us mistakes it for another heating control.
