February 27 , 2009
How DRY We Are…
All is not perfect in the world of green.
As we near our Nature Nurture Day open houses, the punch list of issues seems to be growing. Topping the list is humidity—or the lack there of. If the monitor we recently put in the home is accurate, we are at about 27% humidity which is very low. 50 to 55% is where we ought to be. Not only does extremely low humidity make for dry, itchy skin, it is wreaking havoc with our drywall, paint, and moldings. It can also damage flooring.
I have learned (although any construction professional knows) that houses naturally expand and contract as moisture levels in a home fluctuate. So, separation in crown molding joints at corners and the occasional cracking of paint is really quite common – although a bit startling to the homeowner who just committed herself to a pretty hefty mortgage. My builder, Don, typically lets a house “cure” for about a year after his homeowners move in and then returns to do touch up patching and painting. So all this is quite normal.
But the fact is, we have more than our share of cracks and separations as you can see by the pictures. It’s all cosmetic and none of it is going to be that difficult to repair…BUT that does not resolve the root of the problem which is overly dry conditions.
Having talked with at least a dozen people about this issue, including professional painters, builder, and green raters, and done some research on my own, I see now that none of this is not all that surprising. My home is wonderfully green and energy efficient but in making it so, we have unwittingly set ourselves up for desert like conditions.
- We have an extremely tight envelope. That’s a good thing – usually. It means we have an extremely well insulated, energy efficient home. My first fuel bill proved how efficient. However, what little humidity has been outdoors during this very cold, very dry winter has stayed outdoors.
- Enhanced automatic ventilation. Again, this is a good thing, but we are also quickly exhausting the moisture generated by showers, washing, cooking, and our own bodies.
- All hardwood floors. They’re beautiful BUT they soak up moisture in a home. While doing research on the web I found that a house that is carpeted will endure extremely low humidity better than a house with all wood floors. I never thought about this—and apparently no one else did either.
- It’s winter. Not only that, it has been an extremely cold, dry winter.
- Our haste to move in and our subsequent rush to complete our “Preoccupancy Flush” to achieve a LEED point under Indoor Air Quality. In order to achieve this point we had to log a total of 48 hours with the windows open and all the exhaust fans going prior to occupancy. Poor planning had us doing this in a hurry, logging hours right up until the time we moved in. At the same time, the painters were scrambling around making last minute touch-ups. As bad luck would have it, it was also rainy during this time, so I’m guessing the house was retaining a bit of water while those touch-ups were going on.
I also wonder if our beautiful, clay plaster walls (which I love) haven’t greedily sucked up what moisture we have had in the home. They remain in PERFECT condition by the way….
Ironically, we did all of these things to make our house more green. And thankfully, all of it can be repaired – albeit at some expense. The question is, what do we do about it?
I’m looking into some options, including installing a humidifier into our HVAC system. It’s not an uncommon practice, but there are pros and cons. I personally am hesitant to directly introduce moisture into my duct system. I would love to hear from others who might have experienced some of these issues themselves. Email me if you have at firstname.lastname@example.org. In the meantime, we’re running two room humidifiers 24/7 to try to boost our indoor humidity to 50%.