The Great Winter Coop Humidity/Ventilation Experiment! Post Your Results Here!

[Beekissed]

That's nigh perfect! I've always wanted to visit Montana and if I was to ever live anywhere but WV, I always wanted it to be Montana. When I was a teenager I used to dream of working on a dude ranch in Montana, wrangling the horses.

 

[MollySunshine]

Beekissed, fabulous explanation...as usual. Your example of ventilation echos what I have going on in my coops. The construction type of both are board and baton (if I recall hubby's words when preparing to build). The type of construction lends itself gaps between each board. Normally, with this type of construction another slimmer board would be placed where the gaps are, to dress it up, in other words. It was inching towards summer when the original coop was built and I, realizing he benefits

of these gaps told hubby to leave it as it is, don't add the slim boards, it will aid in ventilation. Fast forward to winter and now both coops, same design. I placed plastic on the outside of both structures to close off some of the "ventilation". As was described on these threads, on either side I left an entire top portion of opposite sides, one higher than the other uncovered, for cross ventilation. I figured if I need more ventilation, it's an easy fix. All I have to do is cut off more of the plastic exposing a larger section of the gaped framing. I do have normal house type windows I open in the summer.

Now on to the humidity portion. While checking and closing the coops after work the other day, I noticed my coops humidity rose to 85%! It was dark out and I didn't want to drag out a ladder etc. to increase ventilation. Instead, I opened the windows. The plastic is merely tacked on with staples so air still circulates through. This was sufficient. My humidity is back down to 67% in both coops. I closed the windows last night because it was going to get colder overnight. I figured I would see if I still need to keep the windows open, my own experiment. Humidity is still holding at 67% both coops. The skirt I placed around the bottom of the coop, to limit the amount of wind that is able to move under the coop, seems to be working also. The outdoor temp. this morning was 20F and inside both coops was 35F. And yes, I am one of those that uses the Sweeter heater (don't be hatin') but my temps. prior to the skirt was usually that of the outdoors. So I'm able to hold in the heat a bit better. The good news for me was I didn't have frozen water buckets this morning. I didn't have to switch to plan B.

 

[centrarchid]

@mobius

How do you setup heat / humidity recorders so they do not interfere with each other? I brand model important please indicate. I am going to sort of replicate with a bunch of game chickens.

 

[mobius]

@mobius

How do you setup heat / humidity recorders so they do not interfere with each other? I brand model important please indicate. I am going to sort of replicate with a bunch of game chickens.

Good question! I have a Homdox remote thermo/hygrometer with only one separate remote, although I think I could get extra remotes and set them up elsewhere. http://www.ebay.com/itm/172353225312?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I also found helpful answers here:

https://www.backyardchickens.com/t/...station-do-you-use-to-monitor-coop-conditions

So the one remote is in the coop. Other people like Acu-Rite which seems more common. Min-max helps although I haven't incorporated that reading yet.

The only interference I note is the instructions say to make sure that cell phones and computers are not near the readers. It doesn't say anything about using with multiple remotes, so I would guess the same 10 foot rule could apply, not sure. So i keep my instruments at least ten feet away from other electronics. I keep the remote at about beak level to where the chickens roost.

Others may weigh in and know more about how to set up multiples, or abut electronic interference. Glad to hear you want to replicate!

 

[mobius]

Beekissed, fabulous explanation...as usual. Your example of ventilation echos what I have going on in my coops. The construction type of both are board and baton (if I recall hubby's words when preparing to build). The type of construction lends itself gaps between each board. Normally, with this type of construction another slimmer board would be placed where the gaps are, to dress it up, in other words. It was inching towards summer when the original coop was built and I, realizing he benefits

of these gaps told hubby to leave it as it is, don't add the slim boards, it will aid in ventilation. Fast forward to winter and now both coops, same design. I placed plastic on the outside of both structures to close off some of the "ventilation". As was described on these threads, on either side I left an entire top portion of opposite sides, one higher than the other uncovered, for cross ventilation. I figured if I need more ventilation, it's an easy fix. All I have to do is cut off more of the plastic exposing a larger section of the gaped framing. I do have normal house type windows I open in the summer.

Now on to the humidity portion. While checking and closing the coops after work the other day, I noticed my coops humidity rose to 85%! It was dark out and I didn't want to drag out a ladder etc. to increase ventilation. Instead, I opened the windows. The plastic is merely tacked on with staples so air still circulates through. This was sufficient. My humidity is back down to 67% in both coops. I closed the windows last night because it was going to get colder overnight. I figured I would see if I still need to keep the windows open, my own experiment. Humidity is still holding at 67% both coops. The skirt I placed around the bottom of the coop, to limit the amount of wind that is able to move under the coop, seems to be working also. The outdoor temp. this morning was 20F and inside both coops was 35F. And yes, I am one of those that uses the Sweeter heater (don't be hatin') but my temps. prior to the skirt was usually that of the outdoors. So I'm able to hold in the heat a bit better. The good news for me was I didn't have frozen water buckets this morning. I didn't have to switch to plan B.

Nice work, Molly...since everyone's situation is so different, we have to find our own tweaks and what you described is so significant re: dropping humidity! Hurrah! Glad you were inspired to do this AND test it!

 

[mobius]

Copy and pasted this post here with @Howard E 's permission!

Do a Google search for "reducing condensation in buildings" and some nearly universal causes and solutions will materialize. This is one example, but the Internet has tons of information just like it:

https://www.designingbuildings.co.uk/wiki/Condensation_in_buildings

Bottom line is they will all say to reduce moisture in the buildings, solution is to a), reduce moisture generated in the building, b) provide heat to allow air to hold more moisture, which is felt as a lower relative humidity and c), increase ventilation to move moisture laden air to the outside.

Most of us see this all the time in our bathrooms. Take a long hot shower with the door closed and the vent fan off and you will step out into a warm, sauna like room, with moisture condensing on everything in sight. Mirrors fogged up, windows fogged up, and just about anything metal dripping wet. But turn off the hot water, open the door, turn on the vent fan or do both and all that will instantly go away. Temp will drop, but all the fog and condensation will go away and the room will start to dry out.

Basic condition is that in any building where air and moisture can move freely back and forth, such as an open sided shed, temp and relative humidity levels will tend to be the same, inside and out. Even closed up, the laws of physics suggest that pressure, heat and moisture levels will try to equalize, only slowed by any barriers that are in place (closed doors, closed windows, vapor barriers, insulation, etc). Managing the movement of heat and moisture is huge issue in virtually all buildings that make an attempt at some form of environmental control.

Think of a chicken house as being like a bathroom. Once we populate a building with birds, things are no longer the same inside and out. The birds themselves are the source of two things......heat and moisture, both of which are going to move to the outside.

So if we could just add heat from the birds or another source, the ability of the warmer air to hold more moisture goes up and the relative humidity level goes down, leading to evaporation of moisture from any wet surfaces. One free and easy way of doing this is in winter is to include lots of window space on south facing walls to allow sunshine to stream in resulting in heat gain from solar radiation. This even helps during the day when the birds are out and about and not in the building. If the house interior heats up any at all relative to the outside temps, it starts drying out. So windows not only add beneficial winter light, but also heat. But they need to face south into the winter sun to allow this to happen.

But in addition to the radiant heat given off by the birds, they also bring in moisture. From their breath, from their droppings and if we have waterers, etc. inside the coop, any spilt water has to evaporate. Also, if the coop has a dirt floor and moisture is being drawn up from the soil, that goes in the air too. These are all sources of water that if not vented, or if enough heat is not added to allow the air to hold it all, will build to the saturation point and start to condense out. In the extreme, moisture will condense on just about everything, including on the birds, will then evaporate from the heat generated by the birds, leading to that cooling effect. They are being chilled. This is really felt at night, when the air is cooling. The cooling effect, taken to the extreme is what causes frostbite. Do a google search on "causes of frostbite in chickens" and almost all of them will make some sort of reference to excessive moisture in the building, combined with zero or sub zero temps. So somewhere around 0F is where the bird's natural ability to ward off frostbite fails. A dry bird can go below that. A wet bird will likely suffer some damage.

So to house birds in zero to sub zero temps, without the need for supplemental heat, two things need to happen. Any heat from the birds and/or solar gain from sunshine streaming in through windows will lower the relative humidity level to help avoid condensation, but the moisture being generated by the birds and other sources is still building. If that moisture is not vented, as soon as the air cools just a little bit, humidity level goes to 100%, the dew point is hit and moisture starts to condense. Think wet bathroom. So there needs to be a controlled level of put and take. A controlled level of warm moist air moving out as it naturally wants to do and being replaced by cooler make up air, which when warmed just a little bit takes up the moisture being generated by the various sources found within the house. In short, a conveyor is setup moving the moisture out but at a controlled rate such that the heat level always stays above the outside temp. That elevated temp is the engine that runs the conveyor. A bathroom vent fan does about the same thing if you run it while taking a hot shower.

In cold climates, (my guess is this kicks in around Zone 5), insulation is needed in the walls and roof to help hold in the radiant heat generated by the birds to get that 10 to 15 degree temp spike of inside air over that on the outside. Without insulation in sub zero weather, the bare walls will suck the radiant heat out and in turn, radiate it to the outside vs. convection of the warm moist air to the outside. In short, in Zone 4 and colder climates, insulation is likely needed to help keep the conveyor running. We are hearing reports of birds kept in unheated houses down to -20F and colder, but temps inside these houses are about 0F and warmer and no frostbite.

Seriously tricky business getting ventilation right in cold weather climates!

Edited by Howard E - Yesterday at 8:59 am

IMHO, this needs to be an article! ~mobius

 

[Beekissed]

Take that same shower with the window over the shower open.

You won't see the same levels of moisture, heat and condensation in the bathroom. Even the vent fan won't move it out like that window will.

 

[Howard E]

Take that same shower with the window over the shower open.

You won't see the same levels of moisture, heat and condensation in the bathroom. Even the vent fan won't move it out like that window will.

I agree, but it would take someone made of better stuff than me to open a window above my shower when it's 0F outside!

Speaking of bathroom vents, and residential ventilation in general, this is a seriously complicated issue in our own homes, bathroom vents being #1 on the hit parade causing serious issues. We are mostly oblivious to it as we are not aware of it happening, but the whole thing is rife with problems.

So if we take that hot shower with the vent running, and moisture is drawn out, where does it go? Exhaust fans that vent into the ceiling and unheated attic space beyond are especially tricky. The moment this warm moist air clears the attic insulation into the cold, cold air, the water vapor we are venting instantly condenses into liquid water and in extreme conditions, may in fact freeze right in the vent hose.

CODE has evolved over the years, but current recommendations would have you attach a vent vent hose laid out on top of your insulation, running over to the nearest side wall and hopefully run over the top plate where it vents into the soffit area. This may arrive as water vapor or liquid water. With plywood soffits, those may get wet and start to mold. Metal soffits may condense it and in cold weather it freezes to the metal. Or it may simply freeze in place inside the vent hose. Unless the vent hose runs downhill from the start, you may end up with a huge chunk of ice in a hose above the attic insulation. Come spring or a warm spell, it thaws, dumping onto the insulation and onto a ceiling. If you have a black moldy stain in your bathroom ceiling, this may be why.

A better option might be to use the PVC rigid sewer pipe run to the outside wall so any liquid water is always flowing downhill. That presumes a riser is attached to the vent fan to get enough elevation in the pipe to allow enough slope so it will drain. But it still then dumps into the soffit.

Older homes may have simply vented the warm moist air directly into the attic, where hopefully, the attic was vented well enough to have it disperse before it condenses. Many are not that well vented, however, so moisture condenses on items within the attic, eventually leading to mold and rot. Not good. So all attics need to have a lot of natural ventilation to allow any moisture to escape as water vapor. They use the same principle of warm moist air rising, which is why you see those mushroom caps up high, along with triangle shaped gable vents up high under the roof peaks. Cooler make up air comes in through the soffits.

So back to the bathroom vents and what is the best plan. If I had it to do from scratch, I'd mount an exhaust fan in an exterior wall, and vent it about 6 inches or so to something like a dryer vent mounted directly outside. A travel distance of about 6 inches or less. Vent it straight to the outside like a dryer vent does.

 

[lazy gardener]

Copy and pasted this post here with @Howard E 's permission!

Do a Google search for "reducing condensation in buildings" and some nearly universal causes and solutions will materialize. This is one example, but the Internet has tons of information just like it:

https://www.designingbuildings.co.uk/wiki/Condensation_in_buildings

Bottom line is they will all say to reduce moisture in the buildings, solution is to a), reduce moisture generated in the building, b) provide heat to allow air to hold more moisture, which is felt as a lower relative humidity and c), increase ventilation to move moisture laden air to the outside.

Most of us see this all the time in our bathrooms. Take a long hot shower with the door closed and the vent fan off and you will step out into a warm, sauna like room, with moisture condensing on everything in sight. Mirrors fogged up, windows fogged up, and just about anything metal dripping wet. But turn off the hot water, open the door, turn on the vent fan or do both and all that will instantly go away. Temp will drop, but all the fog and condensation will go away and the room will start to dry out.

Basic condition is that in any building where air and moisture can move freely back and forth, such as an open sided shed, temp and relative humidity levels will tend to be the same, inside and out. Even closed up, the laws of physics suggest that pressure, heat and moisture levels will try to equalize, only slowed by any barriers that are in place (closed doors, closed windows, vapor barriers, insulation, etc). Managing the movement of heat and moisture is huge issue in virtually all buildings that make an attempt at some form of environmental control.

Think of a chicken house as being like a bathroom. Once we populate a building with birds, things are no longer the same inside and out. The birds themselves are the source of two things......heat and moisture, both of which are going to move to the outside.

So if we could just add heat from the birds or another source, the ability of the warmer air to hold more moisture goes up and the relative humidity level goes down, leading to evaporation of moisture from any wet surfaces. One free and easy way of doing this is in winter is to include lots of window space on south facing walls to allow sunshine to stream in resulting in heat gain from solar radiation. This even helps during the day when the birds are out and about and not in the building. If the house interior heats up any at all relative to the outside temps, it starts drying out. So windows not only add beneficial winter light, but also heat. But they need to face south into the winter sun to allow this to happen.

But in addition to the radiant heat given off by the birds, they also bring in moisture. From their breath, from their droppings and if we have waterers, etc. inside the coop, any spilt water has to evaporate. Also, if the coop has a dirt floor and moisture is being drawn up from the soil, that goes in the air too. These are all sources of water that if not vented, or if enough heat is not added to allow the air to hold it all, will build to the saturation point and start to condense out. In the extreme, moisture will condense on just about everything, including on the birds, will then evaporate from the heat generated by the birds, leading to that cooling effect. They are being chilled. This is really felt at night, when the air is cooling. The cooling effect, taken to the extreme is what causes frostbite. Do a google search on "causes of frostbite in chickens" and almost all of them will make some sort of reference to excessive moisture in the building, combined with zero or sub zero temps. So somewhere around 0F is where the bird's natural ability to ward off frostbite fails. A dry bird can go below that. A wet bird will likely suffer some damage.

So to house birds in zero to sub zero temps, without the need for supplemental heat, two things need to happen. Any heat from the birds and/or solar gain from sunshine streaming in through windows will lower the relative humidity level to help avoid condensation, but the moisture being generated by the birds and other sources is still building. If that moisture is not vented, as soon as the air cools just a little bit, humidity level goes to 100%, the dew point is hit and moisture starts to condense. Think wet bathroom. So there needs to be a controlled level of put and take. A controlled level of warm moist air moving out as it naturally wants to do and being replaced by cooler make up air, which when warmed just a little bit takes up the moisture being generated by the various sources found within the house. In short, a conveyor is setup moving the moisture out but at a controlled rate such that the heat level always stays above the outside temp. That elevated temp is the engine that runs the conveyor. A bathroom vent fan does about the same thing if you run it while taking a hot shower.

In cold climates, (my guess is this kicks in around Zone 5), insulation is needed in the walls and roof to help hold in the radiant heat generated by the birds to get that 10 to 15 degree temp spike of inside air over that on the outside. Without insulation in sub zero weather, the bare walls will suck the radiant heat out and in turn, radiate it to the outside vs. convection of the warm moist air to the outside. In short, in Zone 4 and colder climates, insulation is likely needed to help keep the conveyor running. We are hearing reports of birds kept in unheated houses down to -20F and colder, but temps inside these houses are about 0F and warmer and no frostbite.

Seriously tricky business getting ventilation right in cold weather climates!

Edited by Howard E - Yesterday at 8:59 am

IMHO, this needs to be an article! ~mobius

Awesome article mobius and Howard E.

 

[Beekissed]

Quote:
But in keeping with the analogy, the chickens have that open window...or at least, they should. With fresh intake down below, like what would happen at the bottom of a bathroom door~a vent or pop door, in the case of the coop. Combine those two elements in a bathroom~ or a coop~ and that humidity becomes less of an issue overall. Especially in the winter months. Smaller passive fresh air intake, large enough vents up above the roosts to create a positive~but slow~ airflow through the coop.