RE: Moisture readings . . . well actually humidity readings

40-50 much more makes for good mold growing conditions

55% is smack dab in the middle of the normal range on my RH meter but I am lucky to get it to 40%.

We keep ours at 60% and have not had problems (that we know of) with mold.

For every 5% that you lower the humidistat setting it increases humidifier run time quite a bit.

Depends on the outside air temperature. I just installed a whole house humidifier and it adjusts the set point based on outside air temp. I know it would be annoying to adjust it all the time but here is a good example of how you can set it.

+40°F 45%
+30°F 40%
+20°F 35%
+10°F 30%
0°F 25%
– 10°F 20%
– 20°F 15%

firefighterjake said:

What humidity level inside a home would most folks consider to be optimal? My wife bought a humidifier this year and we're still working on getting the humidity dialed in to the ideal level . . . whatever that may be.

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I have my dehumidifier maxed out in the basement (35%), I had some problems with water condensing on pipes in a false ceiling... but call me crazy, does having humidity set too low make it feel colder? I'm constantly freezing in the basement, no matter how high I set the thermostat. Walk over to thermostat and see the temperature is 75 degrees.

Either I'm going nuts or the humidity is too low?

How you "feel" humidity depends on the temperature. In cold temperatures, high humidity will make you feel colder, and in warm temperatures, will make you feel hotter. Higher humidity air has more thermal mass, so it will take more heating or cooling to change temperature. High humidity also slows evaporation of sweat, which makes you even hotter, conversely low humidity will speed evaporation and make you colder. Very low humidity at 75F could easily feel much colder than moderate humidity at 70F.

It's important to understand the "relative" part of relative humidity too. RH is the amount of moisture in the air relative to the maximum amount of moisture air can hold at that temperature. Hot air can hold exponentially more moisture, so heating air just a few degrees will significantly reduce the RH, even though you haven't actually removed any water. This is why we say a stove dries out the air, although it doesn't do this any more than a furnace or baseboard, a stove-heated room is usually hotter, so the RH is lower. Kerosene or propane space heaters actually add moisture to the air in addition to heat, and so can make a room feel even warmer.

TE

Weird tolkienish figure, do you have that condensation problem in summer or winter? If you have a basement at 75F in winter, you may be adding to the problem by having it so warm. If you have moisture entering the basement, warmer temperatures will hold more of that moisture, creating more work for the de-humidifier.

75F in summer, look at how you can airseal that basement better.

TE

TradEddie said:

Weird tolkienish figure, do you have that condensation problem in summer or winter? If you have a basement at 75F in winter, you may be adding to the problem by having it so warm. If you have moisture entering the basement, warmer temperatures will hold more of that moisture, creating more work for the de-humidifier.

75F in summer, look at how you can airseal that basement better.

TE

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It was the winter, just a few weeks ago. I shut off the dehumidifier, condensation built up and started dripping a few hours later.

One factor I never thought about was the temperature during this time.

The problem is comfounding, let me tell ya'. I swear to God, I get cold, get up and look at the temperature and it says "75". Same temperature upstairs would mean I could barely stand it, from being too hot.

I don't get it.

What is heating the basement to 75? To get condensation on pipes in winter, you must be adding moisture to the air somewhere, deal with that and you will solve your problem. Do you have a humidifier somewhere else in the house (not de-humidifer), propane/kreosene space heater, or leaking dryer vent?

Back to the original question, I've never seen or felt a noticeable effect of indoor humidity in winter. I agree with the suggestion above to use saline spray. It would probably help more, and cost much less.

TE

TradEddie said:

What is heating the basement to 75? To get condensation on pipes in winter, you must be adding moisture to the air somewhere, deal with that and you will solve your problem. Do you have a humidifier somewhere else in the house (not de-humidifer), propane/kreosene space heater, or leaking dryer vent?

Back to the original question, I've never seen or felt a noticeable effect of indoor humidity in winter. I agree with the suggestion above to use saline spray. It would probably help more, and cost much less.

TE

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I have a baseboard heater. It's possible that the moisture was coming from a washing machine drain that was flooding before we noticed it. I snaked the drain a few weeks ago now it empties without any overflow.

Keeping a basement at 75F sounds expensive, that's up to you, but you may get better results without spending nearly so much on electricity by having the basement at 70F and running the dehumidifier less.

This may sound obvious, but are you sure you have a de-humidifier, not a humidifier? Is 35% what you set it at, or what you get when running flat out? 35% at 75F will condense about 48F, but you will not get humidity that high in winter unless you, or the building are adding water to the air (such as leaking washing machine).

TE

TradEddie said:

Keeping a basement at 75F sounds expensive, that's up to you, but you may get better results without spending nearly so much on electricity by having the basement at 70F and running the dehumidifier less.

This may sound obvious, but are you sure you have a de-humidifier, not a humidifier? Is 35% what you set it at, or what you get when running flat out? 35% at 75F will condense about 48F, but you will not get humidity that high in winter unless you, or the building are adding water to the air (such as leaking washing machine).

TE

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Lol, I"m pretty sure it's a dehumidifier, unless it's magically filling up with water.

I set it at 35%, yes, as opposed to "continuous" run. I don't keep the temperature at 75, I just end up setting it at that temperature to warm up. Usually the heat is completely off. Totally. It never gets below 60F.

I have more problems with the washing machine. Sigh...