Indoor Air Quality Operating Tips

Sabre Plumbing, Heating & Air Conditioning is one of the leading heating, cooling, and ventilation contractors in Plymouth, Minnesota, serving the suburban Twin Cities areas. For better operation and efficiency of your indoor air quality equipment, see our operating tips below:


  • Humidifiers are automatic now, meaning they automatically adjust humidity percentage based on outside temperature. The control has levels one through seven with level one being low humidity and seven being high humidity. Start in the middle and adjust accordingly until you find the correct setting for your comfort. Once you find the correct setting, it will automatically adjust and you shouldn’t need to touch the control again. The digital readout on the control will read the relative humidity in the house, not the percentage of humidity. The percentage of humidity will go up when the outside temperature is warmer (35 percent at 40 degrees Farenheit) and will go down (10 percent at -10 degrees Farenheit) when the outside temperature is lower. Examples of percentage versus temperature are estimates.
  • There is a fine line in the humidity setting between having your wood floors affected due to low humidity and having your windows collect moisture. Leaving your curtains open and running your furnace fan will help reduce moisture build-up on the windows. The humidifier control will not allow you to over-humidify your home, but it is still possible to have moisture on your windows.
  • It is common to have more moisture build-up on windows when the outside temperature drops dramatically. This is caused by the indoor humidity level not falling fast enough to adjust for the outside temperature drop. The humidifier is not running during this time, and no adjustment is needed on the control. Dropping the humidity during this time can be accelerated by running a bath fan or range hood fan, or cracking a window open. Eventually the humidity will drop when the ventilation system (continuous fan or HRV) catches up to changing conditions.
  • Your humidifier filter needs to be changed once a year. Having an old humidifier filter can possibly create a water leak. Filters are available through Sabre or any home improvement store.


  • Run your heating recovery ventilator (HRV) on high at all times. Your HRV is installed to provide fresh air ventilation to your home. If you shut off the HRV or drop it too low, you shut off or reduce the ventilation to your home, which could cause mold and other issues.
  • Running an HRV will dry out your home during the heating season. Control the humidity in your home with the humidifier. You do not want to shut off your HRV to control humidity. The humidifier will provide enough humidity to overcome the dryness caused by the HRV.
  • Running the HRV in the summer is necessary—ventilation is also needed in the summer months. The humidity added to your home will be taken out by the air conditioning system.
  • The two HRV filters inside the HRV need to be cleaned every three months. The best way to wash them is with water. Failure to clean filters causes the blower motor to fail, which is not a cheap fix.
  • Clean the HRV fresh air intake on the outside of the home. There is a screen on the intake that gets dirty and needs to be cleaned. A dirty intake will reduce air intake which will cause a reduction in ventilation and also cause blower failure.