[Greenbuilding] indoor humidity levels and how to lower them without electricity?

Corwyn corwyn at midcoast.com
Thu Dec 29 15:38:13 PST 2011

On 12/29/2011 5:27 PM, Reuben Deumling wrote:
> Indoor humidity in my house this time of year fluctuates between about
> 50 and 60%. When we dry our laundry it briefly spikes to the
> mid-sixties. I've never thought of this range as humid/too moist, but
> reading a bit about this I see that below 50% is considered
> optimal/preferred. I am not inclined to run a dehumidifier. Are there
> other tricks for lowering humidity indoors?
> A few devices I don't have that come to mind are/fans for stove and
> showe/r. But I'm not sure where they'd get the makeup air.

Same place as everything else gets its makeup air.  The simplest way or 
reducing the humidity in the winter time (in cold regions), is by 
exchanging inside air with outside.  Basically there are then only two 
options, using a heat exchanger of some sort, or not.  All of the latter 
are functionally the same.

The RH of 50% preferred, does have some assumptions included in it. 
Figuring out the appropriate levels are IMHO tricky, and depend on the 
air leakage rate, wall construction, vapor barriers, etc.

Thank You Kindly,


Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
topher at greenfret.com
(207) 882-7652

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