The price is a bit rich - but would one of these work for me?

http://www.foursevenfive.com/index.php?main_page=product_info&cPath=70_71_98_99&products_id=239&zenid=c280c6095be550faf3b069003118ad07

I could not tell from the literature if you can set a desired humidity level - the only humidity info mentioned was "Humidity recovery: 20-30%"

-Rosalinda

Thats a lot of plants. Must be nice and comfy in there on a cold winters day!

The lunos e2 unit looks pretty neat. Never knew one of those existed. It says only 22 CFM and it also recovers 20-30% of the moisture. With that slow flow and some vapor recovery, I'm not sure you would make a significant dent on your humitidy situation. I wonder if the intake filter would become a burdon due to the small size, but I am not sure. Its a neat concept nontheless.

I think you may need a HRV with more flow and no vapor recovery to get the numbers down. Is there a space you could add an HRV to your house?

Can you switch to glazed or plastic pots and use soil covers to limit moisture to the house?

Posted By Rosalinda on 27 Feb 2013 07:27 PM
The price is a bit rich - but would one of these work for me?

http://www.foursevenfive.com/index.php?main_page=product_info&cPath=70_71_98_99&products_id=239&zenid=c280c6095be550faf3b069003118ad07

I could not tell from the literature if you can set a desired humidity level - the only humidity info mentioned was "Humidity recovery: 20-30%"

-Rosalinda

It doesn't have dehumidistat control, and it's has an ERV core which returns some (apparently 20-30%) of the humidity in the heat exchanger.  It's CFM rates are pretty low for a whole house, but with the dryness of your outdoor air that might not matter very much.

A whole house ERV would have many more features, and cost 2-3x as much.

The Panasonic FV-04VE1 ERV is about ~$700, and has comparable cfm ratings as the, but has frost damage issues in very-cold climates.  There's a recommended location map of the US in the manual.

The Lunos looks like it would be easier to install, and with lower moisture recovery, would have slightly better drying capacity that you're looking for.

What's your ZIP code or nearest city? (For weather data purposes.)

Chrisbiker - My plants are not in clay pots. As I repot, I will add a layer of mulch to those plants that don't already have it, that is a good idea for keeping water in the soil, though of course wont do much about transpiration.

Zip is 13065 - elevation at my location 600 ft

I only need this for winter use so I don't think the Panasonic ERV is what I need. I am in Zone B and on the edge of zone C according to their chart, and I need it to work Nov through March which is the opposite of what they suggest. If I got something like the Lunos, I would use it in conjunction with my current system, on the winter days my current system is least effective, and at night. At least it sounds as if it is both quiet enough, and has good enough heat recovery to let it run all the time.

I have no intention of installing a standard ducted HRV system. I don't want any duct work in the house. I will create some kind of dry air heat source so that I can run my current system more frequently.

As of now, running the system on cloudy days based on dew point seems to be helping. The humidity in the house is low enough so that there is no condensation on the windows, hovering around 60% on my hygrometers, and without having to run my dehumidifier.

I appreciate all the input

-Rosalinda

Getting it to under 40% RH would be nicer to the house, since even through 5" of cc foam even a 60% interior RH is enough moisture drive to be an issue in a zip code 13065 (US zone-6) climate. You would have to run a WUFI simulation on your exact stackup to know just how much of an issue. Ideally you would be keeping the interior air dew point below 45F (40% RH @ 70F) during the winter months, and under 55F even during the summers.

The Lumos system looks pretty good, but I don't have much feedback on it. It looks dead-simple to install.

All heat sources (other than a pot of water boiling on the stove dumping water vapor into the air) are "dry air heat sources". Heating the air does not change it's absolute humidity level (measured by dew-point). Heating system neither add or remove moisture from the air. The dew point temperature relative to the air temperature determines it's relative humidity (it's not simple-arithmetic model)- but the amount of moisture in the air and the temperature at which condensation would occur does not change, no matter how that air was heated. Only by exchanging the air with drier outdoor air or mechanical dehumidification will you be able to lower the absolute humidity in the interior air, and that's not a heating-system function.

Thanks Dana,

I got the message about all the outside air being dry, as long as the dew point is below 45 degrees. I appreciate the education. The idea would be to heat the outside air via burning wood, and then use that air as a makeup air source whilst running the ventilation system. Not quite sure how I am going to do that yet, but I am starting to foment some ideas.

In the meantime I will use what I have, my dehumidifier and my ventilation system, based on outside dew point, and try to get the humidity level down as much as possible.

Thanks again,
Rosalinda

Any suggestions for a reasonably priced instrument that will more accurately measure the actual RH in my house?

Thanks
-Rosalinda

On the cheap you could buy or make a web bulb thermometer. Compare wet to dry and look up on a table to get RH. Or get a higjer priced instrument.

Chris is right. Old school way to get the data you seek would be to get a kitchen thermometer with a remote probe (Walmart, $15), and then strap a small bit of wet sponge to the tip of the probe and spin it rapidly using the probe cable. The thermometer will then display wet bulb temperature. Enter wet bulb and dry bulb temps into one of any number of internet psychrometric calculators and RH will pop out.

Honeywell thermostats (8000 series) do a respectable job of displaying RH.

That looks more affordable than this fancy baby -
http://www.amazon.com/GSI-Handheld-Hygrometer-Psychrometer-Thermometers/dp/B004HM85Y0

-Rosalinda

The bottom of the line $10 battery operated AccuRite humidity & temp monitor (some box stores, even Wal-Mart carries them) are really not bad in the middle ranges. Don't put them outside or in anyplace so damp that it pegs the end of it's range or any place that might freeze, or they go off calibration but indoors in a conditioned space they track pretty well- close enough for the kind of thing you are doing here. They wouldn't cut it in a greenhouse where it might hit the dew point overnight, but in your house-house it's fine between 20% RH & 80%, 50F & 90F. I have several kicking around the house, and even after 3-4 years they still agree with one other within 1F & 2%RH, and agree within a couple of degrees of a wet-bulb thermometer. (The one I left outside went way off calibration within a month, and they're not re-settable.)

eg:

http://www.homedepot.com/p/AcuRite-Digital-Humidity-and-Temperature-Comfort-Monitor-00619HDCSA2/202260980#.UTY4eVeBCwc

http://www.walmart.com/ip/AcuRite-Digital-Humidity-and-Temperature-Monitor/16888914

Thanks Dana,
All the ones I have are AccuRite, so maybe my readings are not too far off.

-Rosalinda

It's easy to verify the mid-range accuracy of your cheapie AcuRites with a home-made wet-bulb thermometer and an online psychrometric calculator, eh?

http://www.sugartech.co.za/psychro/index.php

There's nothing that makes you look more serious about your environment than swinging the sling psychrometer. Just don't bust your thermometer.