Replies

1. 
   erik_brewster | Feb 12, 2020 06:39pm | #1

   If cracking the windows and turning on the bathroom fan does the trick, an HRV will work for you. I have a 1000 sq. ft house with a mini split for cooling and heat. I had humidity problems in the winter until I installed a Broan HRV80S. It's not fancy, but it does the job. I needed to duct it, but was able to hide the ducts pretty well. Sweating windows completely stopped after this. I don't think I ever got down to 30% humidity, but I'm in California, so it isn't super dry here in the winter. The energy usage was a lot less than the dehumidifier it replaced. It also makes sure we have regular air replacement, which makes the house feel noticeably fresher.

2. Expert Member
   BILL WICHERS | Feb 12, 2020 06:46pm | #2

   +1 for an HRV, but it’s probably worth checking to see where all that extra moisture is coming from. Do you have a lot of plants or fish tanks? Things like those can add moisture to the air. The other possibility is something coming in the basement, but that’s much less likely assuming you’re basement was prepared properly prior to being finished.

   Note that many of the portable dehumidifiers have garden hose connectors inside so that a drain hose can be connected so that you don’t have to constantly empty them. I have a unit like this in my own basement, with the hose going to a nearby floor drain.

   Bill

3. Expert Member
   Dana Dorsett | Feb 12, 2020 06:47pm | #3

   The outdoor air in MA in winter is usually pretty dry, with dew points averaging in the 20s or lower. This winter it's more like the 30s, which is still dry enough to dehumidify by active ventilation. Heat recovery ventilation allows you to run fairly high ventilation rates with only a minimum heating energy use penalty.

   I have a single pair of Lunos E2 ductless HRV (22 cfm at max speed) running constantly in my insulated but not fully finished 1600' basement in Worcester, which is enough to keep the basement humidity in the 30% RH @ 68F range in winter, but adds a bit to the mechanical dehumidification load in summer. Unless you have a major humidity source (like a clothes dryer venting into the basement) that would probably be sufficient for your basement too.

   If you have an electric water heater, swapping it out for a heat pump water heater will also provide a lot of "free" dehumidification, turning the latent heat of the moisture it's pulling from the air into sensible heat in the water inside the insulated tank. Heat pump water heaters are also subsidized with a significant rebate in a wide swath of MA under the MassSave program.

4. 
   cjohnsen89 | Feb 22, 2020 06:24pm | #4

   Thank you for the responses.

   I do not have any sources of humility. The washer/dryer are in the basement and correctly vented. The basement is very dry and is very well insulated both below and on the sides.

   I recently visited a friend in Vermont who just built a house and he was talking about his moisture issues with a tight house. He installed a HRV in the attic and it made it like a completely new house.

   I took a few pictures of his setup and I think I will be going that route. I plan on installing it in the lofted are to pull air from the bathroom, bedroom, and cathedral ceiling portion of the house. I will return air to the cathedral portion of the house. It will be an easy hook up to get fresh air and to vent to the outside up there. Thanks again for the comments

5. 
   maine_tyler | Feb 23, 2020 08:54am | #5

   This might help a bit too: https://www.greenbuildingadvisor.com/article/designing-a-good-ventilation-system

   I don't say this to be pedantic, but you DO have humidity sources if you're humidity is higher than environmental. But, seeing as your house is small and tight, these sources may be as commonplace and unavoidable as cooking, showering, and breathing. But it's still worth considering what these sources are since running your specific systems to deal with them will be the most effective (i.e. bath fan when showering, stove fan when cooking, water recovery respirator when breathing). Alright the last one was a joke. Any Frank Herbert 'Dune' fans out there familiar with the stillsuit? (sweat recovery).

6. 
   walta100 | Feb 23, 2020 10:39am | #6

   It would not be unexpected for newly constructed home to have high humidity thru the first year. All the wood concrete and drywall all are full of water that will be release into your house in the first year.

   Running a dehumidifier in the first year is not a bad idea. It is wasteful to buy one knowing you will only use it for a few months.

   How tight is your house? Until you measure with a blower door test you are only guessing at how tight any house is and builder are often surprised. Rarely pleasantly and often no so much.

   In my opinion if your house tests very tight (less than 1 ACH occupant) you need to add ventilation.

   Walta

7. 
   cjohnsen89 | Feb 24, 2020 09:43pm | #7

   I know there has to be humidity coming from somewhere because like what you said it’s higher than outside. I don’t have a washer/dryer installed in the house yet. My shower fan does an amazing job getting the steam out and the bathroom seems dryer than the living room when I come out. I have no plants or aquariums. I think it’s mostly from breathing. When I cook I crack the window next to the stove and turn the hood on. Which actually helps the humidity issue.

   I’ve been wondering if it’s from new construction but I got the Sheetrock and plaster put up last June. I had the air conditioning running since late July until the colder months started.

   After spending hours reading about air exchange even if I didn’t have the humidity issues I think I need an HRV. When I come hold from work it smells like stale air.

   I haven’t gotten a blower test done. I live on an island and it’s mostly tendered towards rich people building huge houses. Sub contractors are booked longer than you would think and I’ve called around a bunch and there is so much money building for the rich people that the sub contractors just won’t call me back.

   In Massachusetts you need a licenced HVAC installer to do any duct work so you can get your CO. I called every company I could find and only 1 called me back and he was straight forward and said he was too busy to take on a house as small as mine. Therefor I was forced to do my ducting for my stove hood, bathroom venting, and the duct work for my eventual dryer. I’m just hoping I can BS my way through getting my CO when that time comes.

   Luckily there are forums like this where I can ask questions and get some good advise

   Edit: I also did run a humidifier full time (Along side the mini splits) from late July until mid September to try and get some moisture out from the new plaster and whatever moisture was still in the concrete slab in the basement floor. Maybe I didn’t run it long enough

1. 
   CMObuilds | Feb 24, 2020 11:54pm | #8

   Setup the dehumid up to go directly into a drain, set it at 40 and let it go. It can take a month, it can take a year and a half.