Shop Humidity

[derek labian]

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.

[Phillip Mitchell]

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.

[Kevin Jenness]

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."

[Thomas Wilson]

Dehumidifier set to to 50%. It keeps the level below that.

[Scott Winners]

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.

[Andrew Seemann]

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:)

[Andrew Seemann]

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.

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).

[Kevin Jenness]

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.

[Alan Lightstone]

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.

[derek labian]

For those using a dehumidifier, what models are you using?

[Aaron Liebling]

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.

[Ole Anderson]

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.

[Bob Riefer]

For those using a dehumidifier, what models are you using?

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 (https://www.amazon.com/gp/product/B08N6C4GPP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) (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.

[glenn bradley]

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.

[Erik Loza]

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

[derek labian]

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

Hi Erik,

My problem is everything keeps rusting, and I'm tired of cleaning rust off tools. (I've tried waxing, etc) I'm sure it has more to do with the fact that tools will sit for weeks at a time un-touched. In a production shop, a rolling stone gathers no moss.

[Jamie Buxton]

My shop has no heat, no cooling, and no humidity control. The atmospheric humidity here runs 75-80% year-round.

[Anthony Whitesell]

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.

In the winter in my basement I have to run a dehumidifier almost 24/7. I have the coil connected to a temperature sensor. Once it drops below 35 the coil ices over it shuts it off until the temp is above 50.

In the summer the dehumidifier in combination with the summer heat there isn't enough temperature delta to get the dehumdifier to condense. I end up also running an air conditioner. The mechanics of an air conditioner and dehumidifier are the same, only the air flow is different. Once the A/C is running it condenses out some water and the dehumidifer kicks in. I usually pump out 70-80 pints per day (4-5 gallons) during the summer.

I don't know what the exact RH is, but if it feels humid to me then it probably is too humid for the tools.

[Jim Becker]

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 (https://www.amazon.com/gp/product/B08N6C4GPP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) (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.

Glad things worked out for you, Bob...I'm going to consider that unit for the basement here at the new place. It really needs attention to humidity for sure.

[Jack Frederick]

Until this weekends storm the humidity level 140mi east of our Bay Area respondents has consistently been in the 15% +/- range. Having received 15” of rain over the last week, yippee, I can joyfully report that it is a comfortable 74% this morning and time to go over the CI tool beds.

[Erik Loza]

Hi Erik,

My problem is everything keeps rusting, and I'm tired of cleaning rust off tools. (I've tried waxing, etc) I'm sure it has more to do with the fact that tools will sit for weeks at a time un-touched. In a production shop, a rolling stone gathers no moss.

Derek, you're 100% correct on the "why". Unless someone is running AC in your shop full-time Spring through Fall here in TX, there is gonna' be some rust. To varying degrees, but unavoidable. I've never seen a machine that doesn't have some level of rust to it. This being said, you shouldn't have any problems with rust on the cast iron tops so long as you are waxing them routinely. At least I never did.

Erik

[Thomas Wilson]

Several commenters on this thread mention that they do not monitor shop humidity. I do and find it useful to protect from rust. This monitor is only $10.99, has thermometer and hygrometer plus max/min function.

https://www.amazon.com/ThermoPro-TP50-Digital-Thermometer-Temperature/dp/B01H1R0K68/ref=mp_s_a_1_4?dchild=1&keywords=thermopro+thermometer+hygrometer&qid=1635355879&qsid=135-7878688-8494000&sr=8-4&sres=B07WCR5Y4B%2CB01H1R0K68%2CB075QBRR6S%2CB08J7V XPLV%2CB079N98K93%2CB08LKCLFR6%2CB07VHP217S%2CB07R L2LY1M%2CB06XTPTG1J%2CB06XKH666P%2CB07L82PF1Z%2CB0 7Y1Y9JGF%2CB09HKPV5G5%2CB0953GC4CG&srpt=THERMOMETER

[Erik Loza]

Something just popped into my head: Our edgebanders comes with several of these things stuck to the inside of the working compartment: https://www.zerust.com/products/vci-emitters-diffusers/vapor-capsule-diffusers/

I had no idea about them prior to coming back to Felder and haven't seen them used on any other machines (the glue fumes are probably corrosive to raw metal) but if someone was really worried, they're available on Amazon. Seems like the company offers a bunch of rust preventative solutions.

Erik

[Alan Lightstone]

Something just popped into my head: Our edgebanders comes with several of these things stuck to the inside of the working compartment: https://www.zerust.com/products/vci-emitters-diffusers/vapor-capsule-diffusers/

I had no idea about them prior to coming back to Felder and haven't seen them used on any other machines (the glue fumes are probably corrosive to raw metal) but if someone was really worried, they're available on Amazon. Seems like the company offers a bunch of rust preventative solutions.

Erik

I have a few of those that I throw into the drawers with tools and chisels/rasps/router bits, etc... Plus some rechargeable desiccant containers. Despite AC running essentially 14/7 in my workshop, it's impossible to really lower humidity to a level that would prevent rust.

Keeping the rust at a small but manageable level is my goal. It does bother me, but it is what it is living on the water.

[John Lifer]

My woodworking shop is not climate controlled other than it's insulated. It is way better up here than central MS where it would rain inside occasionally. My laser room is my basement and it's dry and stays between 25 and 40% like the house. I did install minisplit that I use mainly for heat and I could use to eliminate moisture if it was an issue.

[mike stenson]

Hi Erik,

My problem is everything keeps rusting, and I'm tired of cleaning rust off tools. (I've tried waxing, etc) I'm sure it has more to do with the fact that tools will sit for weeks at a time un-touched. In a production shop, a rolling stone gathers no moss.

Keep the dust off of it.