Basement humidity

[tp4tissue]

The basement is only ~300 cubic meters.  Dehumidifier running 8 hours removed ~6 liters of water, measured in the bucket.

This morning the meter read 73 F @ 75% humidity

Now, it reads 75 F @ 63% humidity

The difference should be ~477ml of water, ~0.5 Liter.


How does this work ?  is the humidity meter just busted ?

[fohat.digs]

I think that there will be a base line or latent humidity that will not allow accurate measurement below some threshold.

My guess is that the device sucked out quite a bit of water in an initial (initiation?) draw down but can't easily get much lower.

A dozen of the machines working full time probably could not achieve a level below maybe 20%-30% in basement air because there is a near infinite supply of moisture in the soil behind the walls that can be pulled through continuously.

[tp4tissue]

The system must be extremely open, with more water coming in constantly, otherwise I can't understand how there's this much of it.

[jamster]

Isn't the whole reason that damp basements are such a typical problem is that they're underground and subject to moisture coming in from the ground?

You've got 4 walls and a floors worth of surface area for ingress.

Regarding the achievable RH comment above. iirc standard compressor based dehumidifiers won't effectively work below about 50%. Dessicant/hybrid ones will go lower but are less energy efficient.

You could also supplement with a $5 temperature and humidity sensor as a second check.

[noisyturtle]

This is why people get sump pumps in their basement, because water obeys the laws of gravity

[fohat.digs]

Sump pumps handle liquid water in a pool.

This concept is about water vapor passing through concrete.

[Maledicted]

I invested in one of these when I moved my room into the basement. I forget the specs, but it was one of the better ones (on paper). I have a hose running from its reservoir directly to the drain in the floor (not all dehumidifiers have this feature, unfortunately), since we've run one of these things before and I knew the sheer volume of water it could accumulate in a relatively short amount of time.

I set the thing to about 45% humidity, just because I want a margin of error to keep it roughly around 50%. During the summer, it runs almost entirely constantly. It is rare for me to go into the laundry room and not hear a trickle of water dripping from it into the drain.

That basement was gross before. It smelled, it was musty, everything in it would accumulate some sort of grunge/film over time. Steel would literally rust down there. Yes, this is all in spite of a functional central air system. I'm glad I invested in a decent one, because the difference is night and day.

Without the humidifier on, in the summer, I'm pretty sure that basement can reach upwards of 75-80% humidity.