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New homeowner--question on high cold weather humidity levels and HRV

Good morning,

I'm a new homeowner who just relocated from South Korea to Alaska (military move).

I have a 4 year old house (build in 2012) that's approximately 2600 sq-ft and there are two adults and three children living in the house.

The house has a Lifebreath 200 MAX HRV with what I believe is installed as a partially dedicated system. There are these air inlets in various rooms in the house, such as the bathrooms, kitchen, laundry room, etc.

It has been extremely cold out lately, with highs being between 7-10 degrees F.

My question/concern relates to my HRV and the indoor humidity levels. The indoor humidity has been running about 40% in the morning, and 35%-37% later in the day, despite me running the HRV on high speed with venting for the past several days. I had thought that due to the cold weather outside that it would be pretty easy to dry the house out, but that hasn't been the case. Due to the cold weather and indoor humidity levels I have had condensation on the windows every morning and I'd like to avoid that. As part of the purchase, the seller arranged to have the furnace, HRV, etc inspected and cleaned by a HVAC contractor. I doubt that they did any kind of balancing on the HRV however.

A few more facts--the house was empty for several months and now is full of 5 people and all of our stuff. Is the humidity due to high humidity levels in our furniture and stuff and do I need to just wait for everything to dry out or is there something else going on? It was very humid in Korea where we lived, so maybe our stuff just soaked up a bunch of humidity?

Also..let me add that while the house sat empty for a few months I'm not sure anyone was keeping an eye on the humidity. Maybe the house just soaked up some moisture and now it's taking some time to get it out of the house?

Any advice? I've attached a few pictures as well to help the discussion.

Thank you!

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Asked by jtludwig
Posted Mar 5, 2017 1:40 PM ET

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6 Answers

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1.

Also..it's Anchorage, AK so climate zone 7. Thanks!

Answered by jtludwig
Posted Mar 5, 2017 1:41 PM ET

2.

Open the windows a little, it'll drop the humidity fast, then you can reevaluate your situation.

Also, depending on the model, HRV/ERV goes into recirculation mode when it's too cold outside so they won't drop your humidity much at all.

Answered by Anon3
Posted Mar 5, 2017 2:11 PM ET
Edited Mar 5, 2017 2:15 PM ET.

3.

Start with the basics: Verify that your indoor RH readings are correct by installing more than one hygrometer (and ideally, more than one type of hygrometer). For more information on RH readings, see Measuring (and Understanding) Humidity.

Then verify that air is flowing through the HRV: Go outdoors and put your hand near the HRV exhaust port (to see if you can feel air blowing out) and put a T-shirt against the HRV fresh air inlet (to see if the T-shirt is sucked in).

Answered by Martin Holladay
Posted Mar 5, 2017 4:49 PM ET

4.

I am not an Alaska person but 45% does not seem excessive.

If it is 68° and 45% RH you will have a dew point of 46°. My dual pane windows often get sum condensation, when it gets below 0°. Do you have triple pane windows?

Are you operating any unvented fuel burning appliances? Unvented gas fireplace, kerosene heater, dryer vented indoors?

Have you opened the cover the EVR?

Walta

Answered by Walter Ahlgrim
Posted Mar 6, 2017 12:33 AM ET

5.

What is your goal relative humidity? Why?

It's my understanding that 40% is normally considered to be a perfectly fine RH.

Answered by Brendan Albano
Posted Mar 6, 2017 11:51 AM ET

6.

In a cold climate 40% RH @ 68F is on the high-side of normal for cold weather, in a reasonably ventilated house. A daily mean humidity in the 35-40% range is an indication that you may have higher than average indoor humidity sources.

Answered by Dana Dorsett
Posted Mar 6, 2017 2:45 PM ET

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