My Indoor Air Quality Project

I've recently started tackling my indoor air quality project - I have a number of issues that I've been working on solving since moving into and renovating a 2500 square foot home with finished basement and two levels, and I'll post about the various solutions as I work through them.

Honeywell Prestige Thermostat
What are my issues?
  • Very dry air in the winter (dropping to the 20 to 24% range in the middle of winter on cold days;
  • Very humid air in the summer - getting up over 60% relative humidity
  • A musty odour on some days in the summer time, which tends to correspond with high humidity; 
  • Optmizing the HVAC performance, especially since one of the household members has Asthma, and seasonal allergies. For this reason, we rarely open the windows to the house, and rely on a Venmar ERV (energy recovery ventilator) for fresh air exchange.
The solution selected for the dry air in the winter was to install a whole house humidifier. I've been tracking humidity levels for the past two heating seasons, and I've been getting down to 24 or 25% relative humidity, and all the problems that go with humidity this low. Cracks opening up in hardwood floor, nosebleeds and dry throats, dry coughs, and the like. The installation of a Honeywell TrueEase central humidifier has solved the problem nicely. 

I suspect that my problem with high humidity levels in the summertime have been caused by two separate issues i) a blocked condensate pan drain, which keeps condensate water removed from the indoor air from the air conditioning evaporator recirculating in the indoor air stream, and ii) my Venmar ERV furnace fan interlock - which keeps the furnace fan running even when the air conditioner cycles end, not allowing the evaporator coil condensation enough time to drip down into the condensate pan and into the floor drain. Consequently, this condensate water just gets re-evaporated into the fan coil airstream, and back into the indoor air. Net result - buildup of humidity inside the house. The solution here was to correct the drain slopes, and to add unions to the condensate drain trap, to allow for easy removal and cleaning of the trap. I needed a way to independently control the ventilation ERV, the furnace fan, and timed with the air conditioning cycles, and the only thermostat that I found that would do that, and also independantly control humidifying, is the Honeywell Prestige 2.0 IAQ thermostat.

I also require central control of the humidifier in the winter time. This lead me to look at the latest generation of smart thermostats - in an attempt to get better control over the HVAC in my home, and address my air quality issues. I found that the Nest thermostat doesn't have the capability to intelligently control ventilation, has a single output to control humidification, and has the ability to control the air conditioning to control de-humidification. Similar situation with the Ecobee 3 thermostat. Finally, I found the Honeywell Prestige 2.0 IAQ thermostat - with the equipment interface module, it has three user outputs that can control ventilation (ERV/HRV), humidificationa and dehumidification. So - part of this plan included upgrading my thermostat and ERV control to the Honeywell Prestige IAQ thermostat.

I'll update this post as I work my way through this project.

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