Plan to address IAQ
I'm hoping the experts here can help me lay out a plan for addressing IAQ of my Houston home.
I have a 4200sq ft 2-story home (2010 build) with 2 Carrier Infinity 2-stage systems and Infinity controls. Downstairs has 4 zones, upstairs has 1 zone. There is a fresh air inlet on the downstairs system. Filtering is currently achieved with 1" filters on each of the returns.
I want to add serious filtering to the system because of my wife's severe allergies and I want to add supplemental dehimidification because the system can't hit dehumidification target of 50% (Infinity T-stat is reading 60% but is set for comfort at 50%).
What testing / steps should I take to get the proper equipment installed? Blower door test for leakage, duct leakage testing, etc?
The house was built in 2010 but is not super-efficient. The blower is in the unconditioned attic and all runs are flexible ducting. The roof has techshield but is not conditioned and there is no spray foam. The builder used expanding foam (can style) on most of the exterior framing joints, but it's not a true spray-foam installation. The exterior walls all have normal pink insulation installed.
Windows are double paned low-e glass, but in the winter months I regularly get water buildup on the windows. I also can feel some air blowing past window sills.
The 2 primary drivers are the humidity level (houston is notorious for mold) and my wife's allergies.
We are in a bit of a unique situation in that we are not currently living in the house so we have about a year to do the research, planning, and testing before we move back in.
I'm thinking I need to do the following:
Blower door test to measure the house leakage - mainly to check if leakage is too high and address if necessary, but also to see if I even need any actual "fresh-air" intake on the main system.
Duct test to measure the duct leakage - address as necessary / possible
Install whole-house dehumidifier (April-aire or similar) and connect the existing fresh air inlet to this unit instead of the downstairs air handler (assume the fan would run on some sort of duty cycle with the de-humidification kicking in when necessary?) Any way to control this with the Infinity system?
Install some sort of allergen filter (carbon, thick pleated, electronic?)
I'd love to be able to install equipment that can be controlled by the existing Infinity controls, but it's not a necessity.
Sorry for all the details but I don't know much about filtration and humidity control and the contractors I've worked with here in Houston have been terrible to say the least. Even the Carrier rep was clueless about my Infinity system.
Thanks in advance for the discussion!