Advice on improving indoor air quality!

[Kari D.]

Seeking ideas and advice on how to improve indoor air quality. We have a cinderblock home built on a concrete slab from 1952. Have had IAQ tested twice and readings showed higher levels of Co2 (house was closed up prior to testing), as well as slightly elevated humidity and slightly elevated levels of VoCs. No mold showed up in testing, however mold was recently discovered in bathroom and remediated. The levels weren’t alarming per say, but home has been known for “feeling stuffy”. There is no ducted heating. Was originally baseboard heating when we purchased and was recently replaced with ductless heat units. Windows are newer vinyl from the past 10 years. Attic insulation was cleaned out and replaced in the past few months with light and chimney futures being insulated in attic beforehand, Gable vents were added in addition to extra soffit vents to bring house up to code. Panasonic vent was added in bathroom and is basically running all the time at 100cfu to help exhale air from home. There is a microwave kitchen vent above stove that is always being used when cooking (electric), as well as turned on through the day to help exhale more air from home. After all this work has been done, the home still remains “stuffy”. We have a Co2 monitor plugged in that most of the time stays off under 800, but at times throughout the day it can alarm when levels reach over 800. At this point we are scratching our heads wondering what the next step is to do to improve IAQ in home. House is in WA state so it is difficult to leave windows open for ventilating given the weather. Worried if we put even more ventilating in that it will counteract the heat being produced from the ductless units. Another theory is that because it is a cinderblock home that possibly this may be another reason house isn’t breathing well. If anyone has experience with this I would appreciate your thoughts and advice!

[Mike Reynolds]

Originally posted by @Kari D.:

Seeking ideas and advice on how to improve indoor air quality. We have a cinderblock home built on a concrete slab from 1952. Have had IAQ tested twice and readings showed higher levels of Co2 (house was closed up prior to testing), as well as slightly elevated humidity and slightly elevated levels of VoCs. No mold showed up in testing, however mold was recently discovered in bathroom and remediated. The levels weren’t alarming per say, but home has been known for “feeling stuffy”. There is no ducted heating. Was originally baseboard heating when we purchased and was recently replaced with ductless heat units. Windows are newer vinyl from the past 10 years. Attic insulation was cleaned out and replaced in the past few months with light and chimney futures being insulated in attic beforehand, Gable vents were added in addition to extra soffit vents to bring house up to code. Panasonic vent was added in bathroom and is basically running all the time at 100cfu to help exhale air from home. There is a microwave kitchen vent above stove that is always being used when cooking (electric), as well as turned on through the day to help exhale more air from home. After all this work has been done, the home still remains “stuffy”. We have a Co2 monitor plugged in that most of the time stays off under 800, but at times throughout the day it can alarm when levels reach over 800. At this point we are scratching our heads wondering what the next step is to do to improve IAQ in home. House is in WA state so it is difficult to leave windows open for ventilating given the weather. Worried if we put even more ventilating in that it will counteract the heat being produced from the ductless units. Another theory is that because it is a cinderblock home that possibly this may be another reason house isn’t breathing well. If anyone has experience with this I would appreciate your thoughts and advice! 

In another life I was a HERS rater. The CO would be gases that are unwanted mostly. basically every heating appliance that "burns" gas will cause CO. Stove, heater or water heater equals a level of 3. Then you calculate the occupants. 2 occupants equal a level of 2.  If both of you smoke in the house that's 2 more full occupants. If you have a dog over 50 lbs that is another occupant. Kids count 1 each. 

So, for a house with 2 adult smokers would be 4 occupants. Add a gas stove and WH that makes 6. Add a Rottweiler makes 7. CO2 is what we breath out and not toxic unless you are a politician. CO is carbon monoxide and deadly in the right doses. So you need so many interchanges of outside fresh air per hour per occupant to be safe. Usually 1 to 3. If your unit doesn't use fresh air then you need to get with a local HERS rater and see what you need.

 Sounds to me like you are too tight being a block wall construction and need some fresh air. You need a blower door test done and proper guidance.