My shop is a subterranean garage with poured councrete walls and ceiling. The ceiling is insulated with foam panels as is the garage door.
1 wall shares an interior wall with the basement, 2 are below grade, and one is an insulated garage door with about 1.5’ or poured concrete on each side.
There is no HVAC in there.
Summer it does not get much above 70* and I run a humidifier to keep humidity about 50% or a little lower and it is quite comfortable.
Prior to this year I rarely went in the shop in the winter but it stays around 45*-55* and around 30%-40% which is fine too.
But as we approach spring garage temps are about 55* but we have had tons of rain so I am looking at 87%-92% humidity and of course a dehumidifier only freezes coils in that ambient temp range.

How can I get the humidity down??

I have been looking to put a mini split in there so I guess I could regulate the temp to 65* and 50% humidity with the single unit.

Not sure I am ready to drop $1200 on that or not and certainly don’t want to run a space heater to keep the temps up as I am not in there for long periods of time.

Heat the space with a space heater and run the humidifier.

55 degrees is about the temp where humidity falls out of the air.

The dehumidifiers I have bought recently claim to work down to 41 degrees. It might be worth a try?

quote:

Originally posted by GA Gator:
Heat the space with a space heater and run the humidifier.

55 degrees is about the temp where humidity falls out of the air.

I do not trust unattended space heaters. I’ll deal with humidity before that.

quote:

Originally posted by maladat:
The dehumidifiers I have bought recently claim to work down to 41 degrees. It might be worth a try?

What did you buy??
I am using a hand me down Kenmore that is likely 25+ years old.
Works great in normal temps.

The last ones I bought were GE (because they are what I could get at Home Depot and I needed them immediately).

Frigidaire seems to be the best reviewed and theirs (at least the ones I looked at) claim to work down to 41 degrees as well.

Some dehumidifiers also have pumps built in so you can use a drain hose instead of having to go empty the bucket all the time. Just make sure the hose doesn't accidentally get pulled out of whatever drain you're using (ask me how I know this).

An older dehumidifier will not work below 55 degrees due to the buildup of ice on the coils. Many of the modern ones have a deicer built in.

Don't buy cheap - an industrial version would be advised. Also beware of brands that have recalls due to fire problems.

V.

I have one of these that we use in an uninsulated and poorly sealed concrete block cabin in Alabama (i.e. ranging from very to INCREDIBLY humid!). During the summer it easily keeps at 40% while we are there and we dial it up just a bit and leave it running when not there. We have a 10K window unit a/c, cabin is about 750 sq ft.

Also leave it on year-round and it has made a HUGE difference in the musty aroma that previously permeated the cabin. Based on our change in daily usage after starting that, I estimate it costs just under $1/day to run during winter time.

Frigidaire FAD504DWD Energy Star 50-pint Dehumidifier

They have one with slightly more capacity. If you have any sort of drain, it also has a hose connection on back that bypasses the storage tank. We use that in winter and just run into shower.

Their spec sheets show it will work fine in low temps. Honestly never considered that a concern and have been using it in the cabin even when it's sub-freezing. We turn it on, walk away and don't come back for 3-5 months.

specs

quote:

Originally posted by Georgeair:
I have one of these that we use in an uninsulated and poorly sealed concrete block cabin in Alabama (i.e. ranging from very to INCREDIBLY humid!). During the summer it easily keeps at 40% while we are there and we dial it up just a bit and leave it running when not there. We have a 10K window unit a/c, cabin is about 750 sq ft.

Also leave it on year-round and it has made a HUGE difference in the musty aroma that previously permeated the cabin. Based on our change in daily usage after starting that, I estimate it costs just under $1/day to run during winter time.

Frigidaire FAD504DWD Energy Star 50-pint Dehumidifier

They have one with slightly more capacity. If you have any sort of drain, it also has a hose connection on back that bypasses the storage tank. We use that in winter and just run into shower.

Their spec sheets show it will work fine in low temps. Honestly never considered that a concern and have been using it in the cabin even when it's sub-freezing. We turn it on, walk away and don't come back for 3-5 months.

specs

Thanks. I will take a peak at this.
I like the digital setting. I only have a utility tub with a drain in the shop so unless I elevate the humidifier it will be a pain to get the water up there.
I wanted to put it up on a mount above the tub and just drop a hose to the basin. My current unit while it works is very old and only has a high to low knob and does not keep a consistent level so I am always jockeying the knob.
With this having a digital setting I can just set it to 50% and be done, have the hose drop into the basin and no emptying the tub.

Do you have natural gas available? I installed 3 of these, work like a champion.

https://www.homedepot.com/p/Wi...at-1403822/100055560

quote:

With this having a digital setting I can just set it to 50% and be done, have the hose drop into the basin and no emptying the tub.

Yep. Only thing to be mindful of is keeping it somewhat accessible to be able to clean filter. In that setting I doubt it will pick up dirt/lint much unless you're using the area, but you have to pull out the drain bucket to access the filter which slides upward into a slot.

For example, I stopped by cabin yesterday for the first time since late November. Filter almost as clean as when I left it then.

Oh - it was also 60 degrees and raining outside. Humidity on my hygrometer inside was 44% in living area with the machine set on 45% in bathroom.

It's an additional cost and complexity but you can get dehumidifiers with a pump that automatically empties the collection bucket through a hose - that way the drain hose doesn't have to slope down to the drain the way the ones that passively drain do.

They use a pump that isn't very fast but has a lot of head so it can push the water up quite a bit of elevation (I think the main application is basements without drains).

When the bucket gets mostly full it triggers the pump and empties the bucket automatically.

quote:

Originally posted by 1967Goat:
Do you have natural gas available? I installed 3 of these, work like a champion.

https://www.homedepot.com/p/Wi...at-1403822/100055560

I have thought about those but if I spend $600 just for heat may as well spend the extra $600 on a minisplit and add A/C and dehumidifier all in one.

quote:

Originally posted by Georgeair:

quote:

With this having a digital setting I can just set it to 50% and be done, have the hose drop into the basin and no emptying the tub.

Yep. Only thing to be mindful of is keeping it somewhat accessible to be able to clean filter. In that setting I doubt it will pick up dirt/lint much unless you're using the area, but you have to pull out the drain bucket to access the filter which slides upward into a slot.

For example, I stopped by cabin yesterday for the first time since late November. Filter almost as clean as when I left it then.

Oh - it was also 60 degrees and raining outside. Humidity on my hygrometer inside was 44% in living area with the machine set on 45% in bathroom.

Just be a matter of climbing on a stool. No big deal but since I empty the tank almost daily in the spring and summer don’t feel like doing that at the moment.
But occasionally to clean the filter, no big deal.