I'm curious what people are trying to keep their shop humidity at. I read somewhere 40-50% humidity is ideal, but that would be very hard for me in South Texas.
I'm curious what people are trying to keep their shop humidity at. I read somewhere 40-50% humidity is ideal, but that would be very hard for me in South Texas.
My shop is in my walkout basement and I keep a commercial dehumidifier set to around 45% relative humidity all year round. In the warmer and moister months and it pretty much maintains that even on really humid days (80% + / 80* + outside) but basically runs near continuously; this time of year and winter is much less run time.
The downside is that I have to keep the door closed if I want to be proactive about maintaining that humidity level, but when I am in the middle of a project (which is pretty much always) and especially once I’ve final milled parts and before assembly I am vigilant about maintaining humidity in the shop.
The last handful of weeks has been really nice as the outside air has really dried out and is basically around 40-50% RH naturally and has cooled off so I’ve been keeping the door open, which is really nice, but it’s a short window of time through the whole year that I feel relaxed about doing that if I’m trying to keep my lumber stable and tools and machines rust free.
Still waters run deep.
Tough to maintain a really stable rh in my environment. I have a ductless heat pump and woodstove. In the summer the average is 45-50%, in the dead of winter more like 30% with a pan of water on top of the stove. Some days I can keep the doors open but as the fellow said of New England, "If you don't like the weather, wait a minute."
Dehumidifier set to to 50%. It keeps the level below that.
Mine is hopeless. I see 70% RH in the summer and 8-15% routinely in the winter. The good news is I am in the habit of keeping things oiled and waxed. I found jojoba oil cheap at my local hippie store.
I have a detached shop building in MN. In summer, outdoor temps can be in the 90s with dew points approaching 80. In the winter, outdoor temps can be -30, with dew points below -40. Basically a combination of Florida and Alaska; welcome to the extremes of Continental Climate.
In the shop, summer relative humidity can be easily be over 80% with the AC on. In the winter I don't now what it is, because my digital gauge stops at about 16%. Doing the math from the outside air, it probably is in the mid single digits.
The house isn't much better: 70%RH in summer isn't uncommon inside, and in the winter, around 20-25% is unpleasant, but common during cold snaps.
There really isn't much that can be done, 50% year-round is completely unrealistic in this climate, something they do in museums, not private residences. In the summer you would need to run the AC and heat at the same time to pull enough water out of the air, and in the winter you'd rot the building with the condensation on the windows.
It is a challenging environment, but I get by. Let's just say you get really good at dealing with wood movement in this environment
There is kind of no point in trying to get your shop that low, anything you make is going to into into a more humid environment. If you get it kind of close to what most people's houses are at, that would be ideal for your location (assuming you are making indoor items).
I think it's better to be on the low side of the range of in service moisture content. More serious issues typically come from finished pieces drying out in use (checking, joints opening up) than from gaining moisture. In my area interior woodwork mc may range from as low as 5% up to 11% depending on conditions. If pieces I make in the summer are around 8% in the shop that puts them in the middle of the range, if made in the winter they will be lower. If I didn't make any attempt to control the humidity in the shop the typical mc in summer would be around 10%, and that can cause problems during heating season. Plus, if the rh swings wildly during construction as it can around here, it can cause difficulty with work in progress. People in a more stable environment would not have as much concern.
I know of a couple of shops nearby who run humidifiers in the winter. The one I used to work at used to get down below 10% rh on really cold days. They still don't condition the shop in the summer. The design studio, on the other hand, is air conditioned. At least the paper doesn't curl up and the computers don't overheat.
Last edited by Kevin Jenness; 10-22-2021 at 9:35 AM.
Mine's usually 55-60%. But the mini-splits thermostats are just usually set to 74 or 75 F. I can measure the humidity, but I don't try to control it. It's a losing battle for me too in Florida on the Gulf of Mexico.
- After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
- It's above my pay grade. Mongo only pawn in game of life.
For those using a dehumidifier, what models are you using?
We use a consumer Frigidaire draining to a sink. It's run non-stop in our basement
for four years.
Without it, the basement would be damp and musty. With it, it's very pleasantly dry (this is coastal California).
I've been very impressed.
I see 30% in the winter with a furnace humidifier and 50% in the summer running the a/c when hot or a dehumidifier regardless.
NOW you tell me...
I saw in the other dehumidification thread that others are also using this model... We replaced a big box residential unit in our always-musty basement with this AlorAir HD55 unit (currently listed at $600, although I paid $500 about 5 months ago)
I arrived at this model mainly because:
- An episode of This Old House recommended a product that I traced back and found this to be a close "cousin" and readily available
- My HVAC guy recommended
- And, readily available
It's a beast. After years of struggling with our basement, just barely overcoming the worst of the dampness... it's dry and smell-free now. The unit runs non-stop in our case and I clean the filter about every 6 weeks or so.
Edit: In my outbuilding workshop, I just keep the mini-split running year-round. It feels "comfortable" and I suspect it's just "as good" (or bad) as my house (and most people's homes) so I have never measured the RH.
Last edited by Bob Riefer; 10-26-2021 at 10:26 AM.
- Bob R.
Collegeville PA (30 minutes west of Philly)
I selected "Do Nothing" since I do little to effect the humidity in the shop. SoCal, desert basin. Humidity in the 30's when it's low, 80's when it's high, but 90% of the time it is in the high 40's to low 50's where I live and therefor in my shop.
"A hen is only an egg's way of making another egg".
– Samuel Butler
90% of the shops in my part of Texas are totally open to the outside air. If they're running, the bay doors are up and whatever temp and humidity it is, outside, it is, inside. A few have mini-splits and the really big commercial shops have climate control but huge fans are the usually best you get. If I had a home shop, I'd get a mini-split but not worry too much about actual humidity. Seems like chasing a moving target here in TX.
Erik
Ex-SCM and Felder rep