Outside Air Kit

[Chas0218]

Just backing up to the original post, you say your house is relatively air tight, then say that one of the rooms in your house has no drywall on the ceiling and your attic is full of frost.

The issue here is that your house is really, really, really leaky. If you do a really good job of air ceiling your house - mean caulking electrical boxes to the drywall, caulking all the holes and where the electrical wire comes in, your humidity issues will go away.

A direct air source to the wood stove isn't going to do anything.

The frost was last year when I didn't have the drywall on the ceiling of the bathroom and didn't have the living room area of the upstairs ceiling sealed. This season I have both sealed and humidity is 30% also all electrical boxes on exterior walls are sealed with spray foam. All rim joists for the 2nd floor are spray foamed. Everything is pretty tight now and the humidity is still low. I wouldn't consider my house to be as tight as someone with all spray foamed walls and ceiling but I would think it should be pretty tight. I can't find any drafts with my IR thermometer around windows or doors.

 

[Nateums]

The frost was last year when I didn't have the drywall on the ceiling of the bathroom and didn't have the living room area of the upstairs ceiling sealed. This season I have both sealed and humidity is 30% also all electrical boxes on exterior walls are sealed with spray foam. All rim joists for the 2nd floor are spray foamed. Everything is pretty tight now and the humidity is still low. I wouldn't consider my house to be as tight as someone with all spray foamed walls and ceiling but I would think it should be pretty tight. I can't find any drafts with my IR thermometer around windows or doors.

That sounds way better.

30% still seems pretty low at this time of year to me if everything is sealed up. The electrical boxes must have been spray foamed before putting up drywall? I would still consider caulking the electrical box itself to the drywall.

What is the basement situation? What about the attic hatch?

Only sharing this info to help you benchmark, when I was building my house I was very diligent with air tightness. We have roxul in the walls and 3" of exterior rigid foam.. so super insulated too. But anyway, we are sitting at 48% RH right now, and when the real cold in Jan/Feb hits I will have to crack a window downstairs and run the bathroom upstairs to lower the RH, otherwise we float in the 48-52% range all winter at around 68-70F

 

[Chas0218]

That sounds way better.

30% still seems pretty low at this time of year to me if everything is sealed up. The electrical boxes must have been spray foamed before putting up drywall? I would still consider caulking the electrical box itself to the drywall.

What is the basement situation? What about the attic hatch?

Only sharing this info to help you benchmark, when I was building my house I was very diligent with air tightness. We have roxul in the walls and 3" of exterior rigid foam.. so super insulated too. But anyway, we are sitting at 48% RH right now, and when the real cold in Jan/Feb hits I will have to crack a window downstairs and run the bathroom upstairs to lower the RH, otherwise we float in the 48-52% range all winter at around 68-70F

Thanks, I really appreciate any help. I have 2 young boys and their health is my biggest concern I don't want them to have sinus issues as it makes mom and dad's lives harder too.

Electrical boxes were foamed using the canned stuff (Great Stuff) around the exterior of the box, i had just enough room between the drywall and the boxes to get the straw in after flattening it with a hammer.

No attic hatch(s) but I do have 2 bathroom vents.

Basement under the old house doesn't have any insulation and has a de-humidifier. It has the automatic shut off at 45% it hasn't hit that yet this year. It usually has pretty good moisture with out the furnace running.The addition has the 2" foam from 1st floor to footer.

Addition walls are 2x6 R21 fiberglass insulation with exterior house wrap. All 2nd story rim joist have been spray foamed, prior to the spray foam you could feel the draft. The old house is cinder block to the 2nd story floor with 1" foam (R5) on the exterior with 2x4 r15 interior walls with 80# felt paper as the barrier. According to NYSECC the cinder block has an r value of 10. All exterior electrical boxes are sealed prior to insulation in the walls.

All in all the house is sealed as tight as I think I can get short of full spray foam on all exterior walls and roof.

 

[Nateums]

I have a little girl and the mindset sure does change when they come along.

So the basement is at 45+% RH? I wonder what would happen if you shut that off. What is the air temperature in your basement?

One possibility is that as temperature drops, the capacity for air to hold water also drops, which means if you have 30% RH @ 70F, the same amount of water in the air @55F will give a relative humidity of 51%. It is possible the dehumidifier is drying out your house.

Also just to add, anything cementitious can be considered to have an R-value of 0.

 

[Ludlow]

I'm at 45% RH @ 72* right now and at night I see sparks when I russle the blankets. I wouldnt try to go lower than 40%. When it gets in the 30's RH later in the winter I purposely shower with the fan off and bathroom door open. Under 40% is just too uncomfy IMO.

 

[Chas0218]

I have a little girl and the mindset sure does change when they come along.

So the basement is at 45+% RH? I wonder what would happen if you shut that off. What is the air temperature in your basement?

One possibility is that as temperature drops, the capacity for air to hold water also drops, which means if you have 30% RH @ 70F, the same amount of water in the air @55F will give a relative humidity of 51%. It is possible the dehumidifier is drying out your house.

Also just to add, anything cementitious can be considered to have an R-value of 0.

I usually turn off the humidifier in the winter as I thought it would dry out the house but the wife complained of a musty smell so it stayed on so far. I have no problem shutting it off as I don't smell anything musty. The basement stays right around 60* and the stove room hovers between 69* and 74* with a 30% humidity. I have noticed that the humidity has been going up when the room is cooler but I think that has more to do with the exchange of warm and cool air. FWIW I don't like to count the cinder blocks as any R value although the dead air space supposedly has an R value. I can't imagine much but we are taking down all the old drywall and adding batt insulation in all the old framing that originally had none.

I'm at 45% RH @ 72* right now and at night I see sparks when I russle the blankets. I wouldnt try to go lower than 40%. When it gets in the 30's RH later in the winter I purposely shower with the fan off and bathroom door open. Under 40% is just too uncomfy IMO.

We aren't getting the static yet but that is one of my tell tale signs we are getting too dry.

Right now our Nest thermostat is reading a humidity of 38% @ 69* for the upstairs, our cheap weather station downstairs is reading 29% @ 74* (in the stove room) and 50% @ 62* in the basement. I think the cheap weather station downstairs is off a little probably by at least 5% lower than it really is. I would think with that low of humidity I would get the static and such with the boys wrestling around on the carpet and such. Either way I think we are going to start the humidifier and see if I can seal up some things and get that humidity higher with an OAK.

 

[Ludlow]

I only notice a little flash when moving the blanket around. Not going to get shocked at 45%.
When I stick my finger at the cats nose and lightning jumps the gap I know its too low, and so does the cat.

 

[Chas0218]

I haven't added the OAK yet but I did shut down the dehumidifier on Monday. The house is hovering right around 30% goes up to 32% in the stove room when it isn't running and 38% upstairs. I haven't seen it drop below 35% upstairs yet. We are going to try and run the whole home humidifier and see if that helps and how long it holds the humidity to see if the OAK is needed. I'm also in the process of sealing up as many air leaks as possible. I've found a few but I don't think the are substantial enough to make a difference.

 

[Highbeam]

I rebuilt my OAK a couple years ago with 4" rigid duct and the last piece is a 4" dryer vent. It is called semi rigid since it is all metal but flexes. Perfect for an OAK.

The old was 3" semi rigid dryer vent and it was fine too.

 

[Highbeam]

Of course, on the NC30, the OAK connection only feeds one of 4 air inlets to the stove so it's not quite as effective as the stoves that are 100% OAK fed.

 

[Chas0218]

Of course, on the NC30, the OAK connection only feeds one of 4 air inlets to the stove so it's not quite as effective as the stoves that are 100% OAK fed.

Yeah i think mine is the same way. Thanks for the photos i grabbed some 4" semi rigid and a couple galvanized pieces my plan is to paint it in the basement so it blends in a little.

With the humidifier running it's a little higher but i think the OAK is needed.

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[Highbeam]

Yeah i think mine is the same way. Thanks for the photos i grabbed some 4" semi rigid and a couple galvanized pieces my plan is to paint it in the basement so it blends in a little.

With the humidifier running it's a little higher but i think the OAK is needed.View attachment 235329View attachment 235330

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So many factors. Even with 100% outside air for my stove, this 1963 built house is cruising at 35% rh in wet western Washington. Yes, it’s raining.

 

[Lewisthepilgrim]

Just backing up to the original post, you say your house is relatively air tight, then say that one of the rooms in your house has no drywall on the ceiling and your attic is full of frost.

The issue here is that your house is really, really, really leaky. If you do a really good job of air ceiling your house - mean caulking electrical boxes to the drywall, caulking all the holes and where the electrical wire comes in, your humidity issues will go away.

A direct air source to the wood stove isn't going to do anything.

This is a good idea. I might go around the house and do that

 

[Chas0218]

So many factors. Even with 100% outside air for my stove, this 1963 built house is cruising at 35% rh in wet western Washington. Yes, it’s raining.

The old part is a 1952 build i know there are a few air leaks still but those will get addressed once i pull out the kitchen.

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[Highbeam]

I suppose my point is that the stove connection is just one of the problems in most cases. Didn’t want anybody to assume connecting a proper oak will always be the fix for low humidity.

 

[Chas0218]

I suppose my point is that the stove connection is just one of the problems in most cases. Didn’t want anybody to assume connecting a proper oak will always be the fix for low humidity.

I can't imagine it would hurt humidity levels might help might not. If not I will save the pieces of wood and reinstall and be out $20. I've spent a lot more than that on crap that i only used once just to make life easier.