What is the ideal basement humidity?

[henny penny]

I'm getting our damp basement in order and installed a dehumidifier. We use the basement for storage and laundry exclusively so I don't need a "comfort" level humidity, just a "maintenance" level. I'd like to have it set just low enough to prevent mildew and mold and to keep a healthy air quality. The current "untreated" humidity is 69% which is better than I thought it would be. What should I set my dehumidifier on?

[SleeplessMommy]

less than 60% is the common expert opinion -- but I would use comfort as a determining factor.

[tine1973]

ours is set to 55% - keeps it pretty comfortable without wasting too much energy.

[ASusan]

Be careful that you don't go too low, as you can pull water out of/through the basement walls from the ground. I did this for a while before a contractor allerted me to it. (I was getting wet/mildew-y walls and the dehumidifier was running a LOT.)

[Ola_]

When we had our hardwood floors installed last year the installer told us that we should aim to keep the humidity level between 40-50%. Obviously this was for the floor's benefit but if I recall correctly the recommendation is similar to what I've heard elsewhere. We currently have our dehumidifier set to 40% in the basement.