Does outside temps affect indoor humidity levels?

[NYCPrincess]

My barometer is showing a 20% humidity level. Is that super low? I remember in Oct I had readings of 50-70%. I have a steamer on my stove so I figured that would generate more moisture. I would hate for my Windows to pop out. Thoughts?

 

[Hogwildz]

The heat inside the home dries the air out inside more than anything. A stove top steamer ain't gonna cut it. 20% is unhealthy, not to mention the static everywhere.
Any real dent to be made will take an actual humidifier. And it will also actually make the air feel warmer with higher humidity levels. Just keep it below 50%. I was in mid to high 20%, and could feel it. Installed new filters in the console humidifier, now low to mid 30% and much better on the house and me.

 

[nikolays]

As far as I know colder outside lower huminidy inside, plus you run your wood stove harder, that brings huminidy lower yet

 

[Woody Stover]

The actual amount of water vapor that air can hold decreases as the air temp drops. So if you have 90% RH outside, then bring air inside and heat it, indoor RH drops way down.

20% is unhealthy,

Hey, what about all the old folks (like me ) that move to the SW US to breathe all that healthy air (which, when I visit my Sis in NM, is 5-10%?) Be that as it may, I don't like the dusty boogers I get down there. This house doesn't seem to dry out as much. A cheapie plastic thermometer/RH gauge I have is showing 40%, a better antique one that also has barometric pressure is showing 50+ but I don't know if it's calibrated right.

 

[NYCPrincess]

Well, since I can't go out at this time to buy a humidifier, I put a mixing bowl at either side of the stove in addition to the steamer already on top of the stove. Let's hope this is enough for now.

Where is an ideal place to take this reading? Close to the stove, or in a room opposite the stove?

 

[Woody Stover]

I would hate for my Windows to pop out. Thoughts?

I don't think so.

 

[NYCPrincess]

What is RH?

 

[Dix]

I have a humidifier, it does wonders.

Also, hanging laundry up inside the house adds moisture, and I've been known to low simmer a pot of water on the gas stove in the kitchen.

My sinuses thank me

 

[hamsey]

What is RH?

Relative humidity

 

[NinjaTech]

As others have said, the stove top thing isn't going to cut it. I'm putting about 5 gallons a day in to the air to maintain 33-35%

 

[blacktail]

What is RH?

Relative humidity is the humidity relative to what the air can hold at its temperature. Air can hold more moisture as the temp increases.

 

[brant2000]

This is actually a very confusing subject that I believe is often misunderstood. It's true that the indoor humidity levels generally drop during the winter; however, it isn't due to the temps of the stove itself, but is instead a result of the introduced combustion air. Since the humidity levels at low temperature are extremely low, compared to desirable levels at room temperature, any introduction of outside air will lower the RH.

RH levels are very dependent on temperature, but even if the temps near your stove are extremely high, the water vapor still isn't leaving your house, rather just migrating. Any combustion appliance, regardless of fuel source, will reduce the indoor humidity levels, unless it has a dedicated outdoor air connection.

 

[NYCPrincess]

This has been all very helpful. Where is the ideal place to take this reading? Close to the stove, or far way from it?

 

[coaly]

I check mine about half way through the house away from stove. Open floor plan, stove is the only heat source. It has a 25 gallon water heating tank on the back, so when low, I remove one lid. Since it's the only heat source, I did not install the 3/4 stainless pipe coil in the firebox since they over humidify the air when not enough hot water is used to replentish tank and prevent boiling overnight. A bit low this morning at 30% at 66, 32%now at 72, will be 34% at 75 where I let temp top out. Normally keep it above that, but with the colder temps things dry out a bit more. This stove is designed for non electric households and the only hot water source. Can't tell you how much water is vaporized to humidify since we use it for hot water too.



A barometer measures air pressure. A hygrometer measures relative humidity, or the amount of water vapor that the air can hold at a given temperature.

 

[NYCPrincess]

For those that have stand alone humidifiers, how do you prevent it from wetting up your floor and furniture?

 

[rideau]

If you take a hot bath, leave the water in the tub and the bathroom door open for an hour or so, til the water cools down.
As noted above, hanging the clothes to dry helps too. Leaving hot water in the kitchen sink to cool. Letting water used for steaming vegetable or cooking pasta sit til it cools. All the little things combined can add to quite a lot of moisture.

I keep a large stewpot on the stove 24/7. It puts several gallons of water a day into the air. Can always add a second
stewpot and a smaller pot as well, if it gets too dry in here.

Plants in the house help too, I find.

 

[NinjaTech]

For those that have stand alone humidifiers, how do you prevent it from wetting up your floor and furniture?

I haven't had any issues with mine doing that. What kind of humidifier is it or do you know the model number?

 

[DickRussell]

This is actually a very confusing subject that I believe is often misunderstood. It's true that the indoor humidity levels generally drop during the winter; however, it isn't due to the temps of the stove itself, but is instead a result of the introduced combustion air. Since the humidity levels at low temperature are extremely low, compared to desirable levels at room temperature, any introduction of outside air will lower the RH.

RH levels are very dependent on temperature, but even if the temps near your stove are extremely high, the water vapor still isn't leaving your house, rather just migrating. Any combustion appliance, regardless of fuel source, will reduce the indoor humidity levels, unless it has a dedicated outdoor air connection.

Bear in mind that as outside air gets colder, it's density increases. Air at zero (F) is about 15% heavier than room temperature air. Just like floating a leaky boat will point out the leaks in a real hurry, a home full of room temperature air surrounded by cold air will see cold air leaking in down low and interior air leaking out up higher. This leakage is worst in cold, windy weather and practically nil in mild, windless weather. Leakage of dry outside air flushes out the moisture produced inside by human activity (cooking, showers, breathing, plants, fish aquariums, etc.). True, a combustion device inside (stove) will draw in a bit more leakage air, but that's peanuts compared with other leakage in winter for a typical house. Now an open hearth fireplace is a different story, as it sends far more room air up the chimney.

A house that is uncomfortably dry in winter almost always is one that leaks far too much air, flushing out human-produced moisture. It's interesting to note an observation made by Gene Leger, who built the first of the very tight superinsulated houses in the northeast back in the late 70s-early 80s. He moved into the first "Leger House" down in Peperell MA in January, and right away realized a design mistake. He said it was "like living in a baggie." It was so humid inside there was condensation running down all the windows. He quickly installed an early HRV, an air-to-air heat exchanger, through a hole cut in the wall. All his subsequent superinsulated houses he designed had an HRV. Mechanical ventilation is needed in a very tight house to keep humidity down, even in winter. The take-away lesson from this is that the proper thing to do for a house that is too dry in winter is a good air-sealing job to reduce leakage.

It should be noted, too, that excessive use of humidifiers in a heating climate is risky. For anyone interested, the December 2014 issue of JLC (Journal of Light Construction) has an article (pp.33-35) titled "Petri Dish House." It describes a house in Cleveland visited by a building performance consulting company. The occupants, from a South Asian climate, kept the temperature in the house in the upper 70s, with up to six humidifiers running at times, with resulting dew points above 70 F. The pictures of mold on walls, around windows, and in the attic are disgusting. All that moisture added to the house has to go somewhere, and it's condensing on cold surfaces it contacts, inside or where it leaks out.

 

[NYCPrincess]

I haven't had any issues with mine doing that. What kind of humidifier is it or do you know the model number?

I don't actually own one yet. But did a long time ago and I remember after a few hours there was evidence of water around it. (Did I say many years ago? I was a kid. )

 

[firefighterjake]

For those that have stand alone humidifiers, how do you prevent it from wetting up your floor and furniture?

Non issue.

 

[NinjaTech]

Just be sure to use the anti microbial stuff in the water. I ran out for a while and though I would be ok till I made it to the store. A few days later BAM! Entire house smelled like old socks and the top half of the evaporator pad was green.

 

[Dakotas Dad]

110 gallon reef aquarium in the dining room and basement.. during the winter I leave the light hood open most of the time, go trough 3 gallons or so of top off water a day.. Indoor RH is 44% right now.. 42% outside.

 

[elmoleaf]

A house that is uncomfortably dry in winter almost always is one that leaks far too much air, flushing out human-produced moisture.
...
Mechanical ventilation is needed in a very tight house to keep humidity down, even in winter. The take-away lesson from this is that the proper thing to do for a house that is too dry in winter is a good air-sealing job to reduce leakage.

Absolutely spot on.
I renovated exterior of 1965 home ( it consisted of 1980's vinyl installed over original wood shingles, building felt, plywood, 2x4 walls with 2" fiberglass). To all appearances, it seemed a relatively tight home, but when siding was stripped, we found lots of holes into my wall cavities....the seams between plywood sheets, sill plate/sheathing interface at foundation, electrical boxes cut in at exterior for light fixtures, etc. Lapped building felt doesn't do much to seal all those air leaks (and today neither does Tyvek as typically installed: flapping loose, often poorly taped, with staples ripping it). I spent a lot of time making sure all existing weak points (sill plate, conduit and pipe penetrations, penetrations at exterior light fixtures etc) were properly air-sealed. The house exterior got stripped to the sheathing and we installed fully adhered breathable air/moisture barrier, insulated vinyl and new windows. Inside, I gasketed all exterior wall receptacles/switches, sealed at baseboard heat where it connected into wall cavities, etc.

Wall and attic insulation remained untouched. The home now is much more comfortable, easier to heat, and humidity levels remain much higher....so much so that I'm considering buying a dehumidifier to reduce window condensation that occurs in bathrooms and kitchen.

Air sealing is the most inexpensive thing you can do that will drastically improve your comfort.

 

[rudysmallfry]

Get a cold mist humidifier. The warm mist ones almost always leak. The first few times you use it, but a cookie sheet or something under it just in case.

 

[Hogwildz]

A humidifier works wonders.
Last night's temp brought ice and condensation on the windows, with 30% humidity in the house. Never against air sealing. But below certain temps, most are going to get the ice & condensation, no matter how low the humidity.