Humidifiers and Dehumidifiers - fresh air intake (minnesota) source of humidity

I have a 2 year old new construction in Minnesota.

My problem is the fresh air intake draws in humid outside air, and raises the humidity level inside my home. This fresh air intake is located in my furnace room. There is an attic fan that runs 24x7 to draw in fresh air through out the house. Not sure how common this fresh air requirement is in other states?

Anyway, I have a dehumdifier in the finished part of my basement and it works fine maintaining humidity level at 50-55% RH.
I'm concerned about the furnace room where the fresh air intake is. The humidity in there has been around 60-70% RH lately with all the hot weather.

I have a vent in the furnace room, which is slighly cracked to allow some cool air to flow into the room, but I don't have a return. Should I add a return?

Anyway, I would like some recommendations on how to remedy my problem.

Thanks,
jasper

Id look in to HRV's and ERV's

or a thermo-stor dehumidifier!

Hi Jasper,

making it alive with our 101 degree heat today?

This fresh air intake should be open in the winter to bring fresh air into the home in the winter when the furnace runs.

Your attic fan shouldn't have any affect on this unless you have a whole house fan or this one of those bathroom exhuast with a remote blower in the attic?



DO NOT put a return into your furnace in the furnace room.

Hi Jay.
yeah, glad we're getting some relief today.

I have a whole house exhaust fan in the ceiling in the hallway on my 2nd floor. I was told by the builder this fan runs 24x7 to ensure fresh air is drawn in the house via the fresh air intake. I think this is a good thing.

I'm just concerned about the humidy level in the furnace room now. I wasn't thinking about putting a return on the furnace box itself. I was thinking I could cut one into the return duct for the adjacent room. Would this be OK?

I would be curious to know what other Minnesotans are doing about this?

Airmain, thanks for the tip. I've heard of HRV/ERVs. I guess I should investigate.

thanks,
jasper

How big is this fan? (model/cfm) Sized like a bath fan or bigger? Are you running this when you run your central air?

yes, you can put a return in the room next to the furnace room. Just as long it's not in the furnace room itself. Is your basement finshed? It will help alot in the winter if you do have a return in the familyroom near the floor to pull the cold air off the floor.

OK, understood. It's a big "No go" for putting a return in the furnace room.

Yes, my basement is finished, and registers/returns were added appropriately by a licensed HVAC contractor. Also, the furnace room is separated from the finished space with a solid door. Theres probably a 2" gap underneath though.

I haven't actually looked at the fan motor closely. I would guess its similar to a bath fan judging by the grille though? I would have to look at it more closely when I get home this evening. Again, it runs constantly, even when the furnace/AC is off. Its very quiet. The only shutoff I'm aware of is at the breaker box. Also, the fresh air intake is never closed, basically a 7" diameter hose coming from the outside to my furnace room. Yes, it adds to my heating/AC bill! Here's more info if needed http://www.extension.umn.edu/distribution/housingandclothing/DK7284.html.

thanks for your help.
-jasper

As long you already have a return added in the basement, you are good.


As for the exhaust fan, A couple of friends of mine has something like this.. one has a timer, they said the only run it maybe twice a week and turns the timer over to about 45 min in the winter, never in the summer Other friend they have a speed control to turn on high, med, low. They said the quit running it, just run it when they are having house full of company or order in the home.

otherwise, I think it's just a waste of power running this 24/7 like you said, it tax onto your heating/cooling bills.

If you really need fresh air into the home, Look into the HRV system.

Hi Jay. Enjoying the rain?

Yeah, this is good to know. Seems like this fresh air thing may be overkill, esp during the summer as you indicated. It's just like an open window, and aids in bringing more humidity into your home. I guess this is where a HRV/ERV would help.

Also, fyi. I verified my exhaust fan is just a panasonic bathroom fan.

thanks again,
jasper

Yes, I am enjoying the rain! I don't know what we got down here so far. We did have a down pour before I went to bed.

I'd just turn off the fan, and use it only as needed. Like house full of company, orders, and when the house been closed up too long in the winter. Otherwise, airwill come in on it's own when you run the dryer, range hood, baths fan, and water heater are running.