On Feb 11, 5:01*pm, mike wrote:
On 2/11/2013 10:23 AM, wrote:





On Mon, 11 Feb 2013 06:01:45 -0800, *wrote:

On 2/10/2013 5:42 PM, wrote:
On Sun, 10 Feb 2013 19:34:25 -0600, Dean Hoffman
" * wrote:

* * * * * We have the basic problem of too much moisture in the basement
of Mom's farmhouse. * We have a dehumidifier which helps a lot. * Are
air to air exchangers a better alternative?

* * * * * * * * * * * * *Thanks muchly gentlemen
* *Sometimes a sump-pump works better - but air to air heat exchangers
(heat recovery devices) ARE quite effective.

Effective at what?

Effective at lowering interior relative humidity in the winter.
Possibly more effective than his present dehumidifier. But like I said
- a sump pump MAY be more effective.

The problem statement is so vague that it's hard to say what is happening,
much less how to fix it.

1)fix the way the moisture is getting in.
2)depends a LOT on the conditions.

IN the case of humidity,
there's an interesting online calculator that relates
humidity, temperature and the probability of mold growth.

http://www.dpcalc.org/default.asp

Depending on the problem you're trying to solve...if
it ain't broke, don't fix it.

We need more info.
I have a lot to say about HRV's and use a homemade one myself.
But it's pointless to discuss if it's not in the solution set.

A basic HRV does nothing zero, nada to reduce humidity.

Of course it can reduce humidity in the basement. It
depends on the humidity levels and temperatures of the
air being exchanged.




A fan can reduce humidity by blowing out wet air and replacing it
with drier air. And that only works if the outside dew point is
significantly lower than the inside dew point...and in particular
if the dew point is below the surfaces in the basement.

Which contradicts what was said above, no?



That's why I linked the dpcalc site. *It saves you the trouble
of navigating the psychrometric chart and also gives you some idea
of whether mold is likely to grow.

You MUST keep all the surfaces in the basement above the dew point
of the inside air...and that's often higher than the dew point
of the outside air...unless you use a dehumidifier.

AFTER you determine that exchanging air solves the problem,
you can employ the features of the heat exchanger to reclaim
some of the lost energy.

http://ecorenovator.org/forum/conser...ilation-heat-e...

If you can't arrange it so that venting solves the problem
with passive thermodynamics,
you don't have much choice other than a dehumidifier...AND
preventing air influx to the greatest extent possible.

And all this assumes that water isn't seeping in somewhere.
It's not a simple problem.- Hide quoted text -

- Show quoted text -