A little off-topic for the OP but here goes:
Formaldehydes and etc. = don't bring stinky stuff into your house if you can help it, but if you can't, let it offgas outside your living space before bringing it into the house (new electronics, fabrics, etc.)
Try to avoid stinky building materials as much as possible. There are healthier products out there; may cost a little more...your health is worth it.
Fresh air ventilation requirements = Nobody is suggesting not to ventilate with fresh air. What is being offered is to more closely examine WHY ventilation is required. Human respiration and bodily function is primary, followed by dilution of indoor pollution, which may be best addressed by striking a reasonable balance between source control and ventilation (and supplemental filtration via hepa/carbon methods). An objection to this is that people won't stop bringing or keeping stinky stuff into their home, but how well do they understand what they're breathing when they purchase items that produce strong VOC offgassing?
If the buying public was more aware of this, and more concerned, mounting pressure upon manufacturers of building materials, furnishings, fabrics, etc. might be enough to convince the manufacturers that the stinky components need to go. You can build a cabinet without putting formaldehyde in it. You can floor a house without spreading out a mat of off-gassing toxic fumes throughout the entire house. And you don't need to douche yourself with gallons of deodorants/perfumes to not smell objectionable to someone else. The way some folk splash on the cologne or perfume, I'd almost rather settle for the odor of sweaty socks...read that ALMOST.
Bottom line: give source control more serious thought when considering ventilation needs.
As for
shoulder season ventilation, when little heating or cooling is required, this goes back to my earlier post regarding humidity levels, which is a primary concern when ventilating for any reason. Reducing infiltration of the building envelope not only reduces moisture and heat load gain or loss, it moves the introduction of outdoor air to a controlled source, be it the HVAC system or a
ventilating dehumidifier. Some regions of the country, or some residential configurations within any region, may warrant the latter, but for my own dwelling in my own neck of the woods, I can't justify the cost of buying and installing it, when the passive means coupled to my existing mechanical system does the job handily.
Generally, when I need cooling I need dehumidifying, and when I need heat I may need humidifying, depending on internal moisture generation levels. The house is by no means tight as a drum, but it has enough measures in place to reduce needless air exchange, funneling it down to a controllable level. It is not beyond my means to open a window or two when outdoor conditions permit to allow a really good purging of the interior spaces. This often can happen in "shoulder season weather" with no adverse comfort or IAQ effects. The rest of the time there appears to be enough remaining duct leakage on both supply and return side to assure a sufficient amount of make-up air so the house does not become a locker room.
The overall challenge for this discussion is to strike a balance between indoor air quality/human health requrements, human comfort requirements, and energy consumption management. The OP built a SIP house with hopes to address the third item - energy management - and got stuck with way too much HVAC capacity, putting his IAQ at risk. He's
NOT comfortable and his IAQ levels are
NOT good. The building envelope is in his favor, but his mechanical contractor is not. Until HVAC contractors get smarter about building science and heat transfer dynamics in dwellings, this kind of crap will continue happening. It should not. The OP should not have been placed in a posiiton where his above average dwelling design was met with below average mechanical design.
VALUED DISCUSSIONS - IAQ - LEARNING
Originally Posted by shophound
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