Anton, I’m not an IT guy so I

Anton, I’m not an IT guy so I don’t know the answer to your first question.  Which means I don’t know the second either.  I can answer the third one, though.  We used to have the blog on a different platform and after a while I started closing comments after one year.  Most of the comments on earlier articles seemed to be spam, so it made managing that easier.  In 2016, we changed to a different platform and since then, all new articles still have comments open.  The cutoff for commenting on old articles is probably around 2015.

Feel free to ask your question here.

Jeff, sorry for the delayed

Jeff, sorry for the delayed response here.  It’s certainly possible to add spray foam insulation to the attic of an existing home, but putting it in the walls usually requires having the walls opened up.  There are some foams that can be installed in closed cavities, but you need a really good installer to do that right.

Jim, your information is

Jim, your information is seriously out of date.  So tell me, how does it improve the indoor air quality to allow musty, moldy air from the crawl space to come in through random leaks that should have been sealed?  How many people have been made more healthy by breathing gasoline fumes, car exhaust, and pesticides from the garage?  How does extra dirt in the air that got sucked through that dead squirrel in the attic help anyone breathe better?  The answers are (i) it doesn’t, (ii) zero, and (iii) it doesn’t.

Now, you almost had the right answer when you said “if you do not bring in outside air.”  But then you went and prescribed massive overventilation.  To “fully exchange the indoor air many times per hour” would be ridiculously expensive for homeowners, either in buying a lot more mechanical equipment than they really need (and paying the energy bills) or in creating new indoor air quality and health problems by losing control of humidity and temperature.  That’s a recipe for mold.

Your knowledge of residential building codes isn’t accurate either.  You wrote that “all new home building code require outside air intakes,” and that’s simply not true.  Yes, the model codes have requirements for mechanical ventilation, and they’re tied to the infiltration rate of the house.  In some places, meeting the air leakage code requirement means you’re also required to put in ventilation, but not everywhere.  And there’s the actual codes as adopted by states and local jurisdictions.  Here in Georgia, for example, new homes must test below 5 ACH50 but they don’t need ventilation unless they’re below 3 ACH50.  I agree with you, though, that all new homes should be airtight enough to be required to have mechancial ventilation.  Ventilation rates haven’t been specified in air changes per hour for a long time now, but the current rates in the code would come out as a few tenths of an air change per hour and not anywhere near the “many” air changes you suggest.

But airtightness and whole-house mechanical ventilation are only one aspect of good indoor air quality.  Local ventilation, especially with the kitchen range hood, is really important.  Filtration with high-MERV filters helps tremendously, especially with PM2.5.  And above all, source control keeps bad stuff out from the beginning.

Now, you’re in luck, Jim, because I’m writing a book this topic, and it’ll be out next year.  Click the banner at the top of this page to subscribe to updates, and you’ll be one of the first to know when it’s available. 

What about older homes that
What about older homes that are being restored, rather than wholesale renovated? My house was built in 1930, and has no insulation and the original windows. We pulled the 1950s-era furnace a couple of years ago, and have been heating with the wood-stove in the basement, and we’re constantly battling humidity problems in the winter. Have you any articles that might help chart a good middle course; we really don’t want to gut the house and try to make it modern, but I’m getting tired of scrubbing the walls behind bookshelves as part of spring cleaning. Part of what makes us nervous is understanding that a lot of old houses weren’t nearly as tightly built as new ones, and I’m loath to do something like blow insulation into the wall cavities if water is infiltrating anywhere…

Ken, there’s nothing wrong

Ken, there’s nothing wrong with touching cellulose or open-cell spray polyurethane foam (SPF) insulation.  If you damage the SPF, yes, it can create problems by allowing air leakage and not insulating as well as it should.  Likewise, if you disturb the cellulose so it’s not thick enough in some places, you’ll have excess heat flow in that area.

Sam, yes, I’ve got to finish

Sam, yes, I’ve got to finish writing the book and then go through the publishing process.  My plan is to have it available by the end of 2020.  If you subscribe on the Publishizer page for the book (link below), you’ll get all the updates about the status of the book and be alerted when it’s available.  You’ll also find out here in the Energy Vanguard Blog.

A House Needs to Breathe…Or Does It?