Much has been writen about the swings in basement temperatures and humidity during the different seasons of the year particularly here in the midwest, but I do not recall anyone stating what the ideal range of humidity should be kept at assuming you are using a dehumidifier. Anyone willing to take on this subject???
The “Harven”
We aim at 50% in the summer and 70% in the winter, but that is because of expensive pianos and musical instruments. It is also nice for trains and train makers. Many will say that 65% is plenty good enough, though may put frost on the windows, 70% sure does, but windows cost less than pianos. We have central air and a small dehumidifyer in the basement seems to work fine. We also have a humidifyer in the furnace and that works hard all winter keeping the numbers up.
I’ll try we just got a new dehumidifier in a new house, I’m from out west now we are down east, I’m used to under 10% humidity, here we have 90%( I’m going to pass out) the DEhumidifier works like a charm, it holds 50 U.S. pints, which at first I emptied 2 times a day (New house–concrete–dry wall–lumber) needs to dry out, eventually it slows down on the amount of water taken out of the air, relative humidity is a bit complicated, it’s not just the humidity in the air(there is a certain formula) but here it seems to be @ 50% to 60% and that is a comfortable number, I’d say if you can keep @ 50% you will be all right, also these figures vary dramatically depending where you are in North America, hope this helps.
I don’t try to control humidity in my train room (which has open vents to the dessicated desert, where 2% is normal and 10% is rare) nor do I worry much about the house. (Unlike Arthill I don’t have any musical instruments to protect.) The trick is to take things which may react to the humidity into the train room and let them acclimatize themselves for a couple of months before using them. This applies especially to anything made of wood, and to wood itself.
Of course, my major construction material, galvanized steel (aka steel studs,) is totally impervious to humidity changes. That simplifies life.
Chuck (modeling Central Japan in September, 1964)
I try to keep my train room dry, not an easy task when we have spring well coming up in the basement… It really annoys me that my track nails were rusted out and all my tools were to so im gonna try to run my dehumdifer more once I get the trains going
Warmer air can hold more water content. So, as you let temps rise in an enclosed area, the air is capable of holding more water. Still, though, the relative humidity does not have to be an issue until it rises above 66%. Once it gets past that figure, you can expect to see changes in dimensions in milled lumber and in manufactured sheeting. Also, once temps fall below about 50 deg F, relative humidity higher than 66% (give or take 5%) can see condensation and mildew forming on surfaces and in textiles that have had contact with human fluids and tissues or with spilled drinks and food, even garden soil tramped in on shoes or slippers. That means your rugs may start to “grow”, or curtains and drapes where you have touched them, even wood can start to turn green or grey or black.
Bottom line is that, regardless of temperature, you should do what you can/must to keep RH below 66%.
I prefer Humidity to be about 45% regarless of temperature. Anything less is taking water out of the body and anything more simply adds unnecessary moisture.
When it is 80 degrees and 100% humidty outside as it is right now… it’s WET! Too wet to do anything with paints, sprays etc.
I have been out west in trucking where humidity levels are basically zero. Perfect for maintaining those old cars that I love so much but it is not my accustomed environment.
We like to use houseplants to generate humidity when it gets too dry inside; the airconditoning removes any excess water when it runs. A simple circut of each room and it’s plant with a tin of water in the very dry winter time generates a nice quality of air inside the home for about a week.
When you are down near the airport and the water vapor is coming off the wingtips… it’s WAy too humid. LOL. I get alot of airtraffic courtesy of the United States Airforce at or below 300 feet all day and night and they are useful. I have been told that the transports might have 90 degrees tropical air up front and 33 degrees with frost in the back.
Using a dehumidifier in the summer and humidifiers in the winter, I keep the RH floating near 50% (actually runs about 45% in the winter to 60% in the summer). A few days of high or low humidity (like if the dehumidifier drain clogs and I don’t go into the basement for a few days) doesn’t have much impact, since wood, homasote and such don’t absorb / lose the moisture very fast, but overall stable humidity level is very important, at whatever level you set it.
I am in Ohio and I keep a dehumidifier running in my train room from about May through Sept to keep it at 45%-50%. I also use our central air conditioner. The rest of the year it seems to stay around those levels without help.
Enjoy your modeling. Hal