You always want to avoid 80 percent at a gypsum board surface to avoid capillary condensation via adsorbed water to control mold. That is the reason that for many decades ASHRAE and others recommended no higher than 60 percent in the air to avoid 80 percent at the surface. In terms of health Stephanie Taylor is the only one who has done work that I trust and she recommends 30 to 40 percent to help deal with issues relating to the alveoli function in the lower respiratory system. In cold climates during winter months I typically recommend 30 percent. In hot humid climates I recommend 60 percent. Note that this is for residential/commercial occupancy. For special use occupancies such as art galleries, swimming pools, ice rinks, data processing centers, hospitals things are very different. Here is the "warning"...in many cold climate residences/commercial occupancies even 30 percent will get the enclosure into trouble....and wait till we retrofit these places listening to activists rather than folks who actually know math and physics...and you already know how I feel about humidifiers...you have to used distilled water and clean them every week or they act like bioweapons...pay attention to the Mayo Clinic not those other folks...
@@garrettscott4094 Fluctuate with the seasons...except in special use occupancies such as hospitals, art galleries, data processing centers, chip manufacturing factories, you get the idea..
Joseph Lstiburek is without a doubt the most notable individual in regards to everything regarding Building Science. That being said it's the Smithsonian not Smithstonian.
Rrminds me of a cooking story. You always cut the end of the hambone off before cooking it in the oven.... Grandma didn't have a pan long enough. Context matters
A gentleman would rescue a man trapped in a well, but he would not jump in himself. He is not perfect, but he is not stupid, either. - Confucius, Spring and Autumn Period Good advice from Dr. Joseph Lstiburek: The Harvard School of Public Health is recommending that we maintain interior relative humidity between 40 and 60 percent during the winter. I’m not arguing with the health science basis for this, just the building science basis for this: Relative humidities this high in houses are going to be a killer in cold places where we have winter. Yes, bad pun…
I guess a better question would be , "Joe, what is your preferred RH in residential applications and why?"
You always want to avoid 80 percent at a gypsum board surface to avoid capillary condensation via adsorbed water to control mold. That is the reason that for many decades ASHRAE and others recommended no higher than 60 percent in the air to avoid 80 percent at the surface. In terms of health Stephanie Taylor is the only one who has done work that I trust and she recommends 30 to 40 percent to help deal with issues relating to the alveoli function in the lower respiratory system. In cold climates during winter months I typically recommend 30 percent. In hot humid climates I recommend 60 percent. Note that this is for residential/commercial occupancy. For special use occupancies such as art galleries, swimming pools, ice rinks, data processing centers, hospitals things are very different. Here is the "warning"...in many cold climate residences/commercial occupancies even 30 percent will get the enclosure into trouble....and wait till we retrofit these places listening to activists rather than folks who actually know math and physics...and you already know how I feel about humidifiers...you have to used distilled water and clean them every week or they act like bioweapons...pay attention to the Mayo Clinic not those other folks...
@JoeLstiburek Would you say that RH needs to be constant, or fluctuat with the seasons?
@@garrettscott4094 Fluctuate with the seasons...except in special use occupancies such as hospitals, art galleries, data processing centers, chip manufacturing factories, you get the idea..
Awesome, I'm gonna go read that study you mentioned now. Hahaha
Joseph Lstiburek is without a doubt the most notable individual in regards to everything regarding Building Science. That being said it's the Smithsonian not Smithstonian.
My big time language error...LOL...sones vs stones...
It’s also “in regard to”, not “in regards to”. 🙂
Rrminds me of a cooking story. You always cut the end of the hambone off before cooking it in the oven.... Grandma didn't have a pan long enough. Context matters
I'm left with more questions than answers!
It doesn't matter... just keep it where you feel yourself comfortable (inbetween 35 and 75%).
about 50% more questions? :)
@@koenraadprincen7212 Fair enough!
A gentleman would rescue a man trapped in a well, but he would not jump in himself. He is not perfect, but he is not stupid, either. - Confucius, Spring and Autumn Period
Good advice from Dr. Joseph Lstiburek:
The Harvard School of Public Health is recommending that we maintain interior relative humidity between 40 and 60 percent during the winter. I’m not arguing with the health science basis for this, just the building science basis for this: Relative humidities this high in houses are going to be a killer in cold places where we have winter. Yes, bad pun…