Humidity Levels?

Naturally aspirated tech and talk
dr bob
Moderator
Posts: 627
Joined: Thu Jul 08, 2021 9:30 pm
Location: Central Oregon
Has thanked: 255 times
Been thanked: 248 times
Amen! Salt is hygroscopic, and if not cleared regularly will gather humidity on its own if left in a space, even when there's otherwise non-condensing humidity.

I found myself in northern Ohio in the winter a decade or two ago, and marveled at the see-through doors where rust had completely removed the bottom skin and structure.
dr bob

1989 928 S4, black with cashmere/black inside
SoCal 928 Group Cofounder
928 Owner's Club Charter Member
Former Ex Bend Yacht Club Commodore Emeritus

Free Advice and Commentary. Use At Your Own Risk!

#11

User avatar
EuroFighter2003
Posts: 30
Joined: Mon Mar 03, 2025 2:19 pm
Has thanked: 20 times
Been thanked: 2 times
The 944 is definitely going to be properly garage stored over the winter months, I am lucky enough to have another car to tackle salted roads. It sounds like I might have another project to add to the ever expanding list...redo the insulation of my garage doors! Thanks all for the info.

#12

Bearhawg
Posts: 1
Joined: Mon Jul 24, 2023 11:11 am
Been thanked: 1 time
I can add a personal experience. When I purchased my 944 I was forced to store my ‘70 C10 truck in a non-climate controlled storage unit. I thought I was in good shape because it was well sealed and insulated and over the winter so lower humidity here in Georgia. After 30 days of storage I returned to find that any surface that was not sealed or painted was covered with “flash” rust. The master cylinder, calipers, fittings, unpainted areas of the engine block, you name it and it was covered. I was heartbroken to see what I had spent 3 years restoring go from nearly new to rust covered in only 30 days.

For me, the lesson was air circulation/exchange is just as important as temperature and humidity levels. Maybe more so. One gut wrenching lesson.

#13

User avatar
PSU_Crash
Posts: 283
Joined: Sun Apr 06, 2025 4:34 pm
Location: Decatur, Tennessee
Has thanked: 191 times
Been thanked: 111 times
I run 2 dehumidifiers with auto set to 45 and 50% and a hose drain. Plus the Minisplit runs AC all day this time of year, which pulls a LOT of water out. This keeps levels under 55% no matter how nasty it is here in SE TN and it has been brutal this year.
'86 Zermatt Silver 944 N/A :thumbup:
'86 Mitsubishi Starion - Purpose built SM class Autocross car
'87 Chrysler Conquest - Mid LS Swap

#14

User avatar
blueline
Moderator
Posts: 6120
Joined: Mon Sep 26, 2022 12:22 pm
Location: Middle Tennessee
Has thanked: 4461 times
Been thanked: 2422 times
PSU_Crash wrote: Mon Jul 07, 2025 4:23 pm I run 2 dehumidifiers with auto set to 45 and 50% and a hose drain. Plus the Minisplit runs AC all day this time of year, which pulls a LOT of water out. This keeps levels under 55% no matter how nasty it is here in SE TN and it has been brutal this year.
Same here for me in Mid TN! Two dehumidifiers plus the mini split keep my well-sealed and well-insulated garage in fine shape. I also run a couple of fans in the hot months, mainly overnight, to help circulate the air. All performs wonderfully!
Tim
Current:
'26 911 Carrera S - PTS Verde British Racing Green
'24 Cayenne S - Algarve Blue Metallic
'21 718 Cayman GTS - Black
'22 911 Turbo S - Carmine Red
'21 718 Cayman GT4 - White
'11 GMC 1500 Quad Cab 4x4 - Black

Musik-Stadt Region

#15

User avatar
Tom
Site Admin
Posts: 8965
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 941 times
Been thanked: 4027 times
Contact:
I struggled with heat (less so humidity) in my old garage, which has a split unit, but the garage was too big and drafty for it to really work as designed. The guy who spec'd that unit went by the book in terms of sizing and didn't really understand the unique needs of a drafty old garage. It was a constant struggle and one of the things I was determined to 'fix' in the new garage. The high ceiling added to the challenge, but our contractor 'got it' and fought fire with fire...

p.s., my nephew works for Milwaukee :)


duct.jpg
duct.jpg (819.94 KiB) Viewed 212 times

#16

User avatar
PSU_Crash
Posts: 283
Joined: Sun Apr 06, 2025 4:34 pm
Location: Decatur, Tennessee
Has thanked: 191 times
Been thanked: 111 times
blueline wrote: Mon Jul 07, 2025 4:43 pm Same here for me in Mid TN! Two dehumidifiers plus the mini split keep my well-sealed and well-insulated garage in fine shape. I also run a couple of fans in the hot months, mainly overnight, to help circulate the air. All performs wonderfully!
I also have a 14" louvered fan on a thermostat to pull hot air from the peak. My shop is 25x52' with 14ft peak metal building. It has been spray foam insulated and most walls finished in either metal roofing material or plywood. i didn't spray foam the ceiling because it had that reflective bubble stuff on it and I though, that's good enough for now. It is not. Plus the 4 roll up 10' doors with zero insulation. It can be tough to heat and cool, but the dedicated 6.4kW solar system with 200aH battery keep it running free of charge :)
'86 Zermatt Silver 944 N/A :thumbup:
'86 Mitsubishi Starion - Purpose built SM class Autocross car
'87 Chrysler Conquest - Mid LS Swap

#17

dr bob
Moderator
Posts: 627
Joined: Thu Jul 08, 2021 9:30 pm
Location: Central Oregon
Has thanked: 255 times
Been thanked: 248 times
PSU_Crash wrote: Thu Jul 10, 2025 7:45 am .... It can be tough to heat and cool, but the dedicated 6.4kW solar system with 200aH battery keep it running free of charge :)
A battery free of charge. I see what ya did there!
dr bob

1989 928 S4, black with cashmere/black inside
SoCal 928 Group Cofounder
928 Owner's Club Charter Member
Former Ex Bend Yacht Club Commodore Emeritus

Free Advice and Commentary. Use At Your Own Risk!

#18

Post Reply