Humidity vs. Layout - Are You Tracking It?

[Scottl]

Most research grade electronic RH sensors are +-5%, most retail grade are +-20%.

[learmoia]

Most research grade electronic RH sensors are +-5%, most retail grade are +-20%.

Yeah, I get that.. But I'm guessing Ecobee isn't using the best components for their sensors either...

EDIT: That was wierd... I averaged the readings of the 2 accurites.. (73deg/48%).. Then I adjusted my Ecobee to match.. Temp +5.. Humidity -10.. then Humidity dropped from 60 to 42.. the. I sent humidity back to 0 and it's at 51% (instead of 60%)


It already feels better in here!
~Ian

[C855B]

Hmm. Well, that's frustrating. So, in essence, the sensors in the Ecobee are very rough approximations at best. Ugh. My takeaway on this should simply be when the humidity gets higher, there might be problems.

What bothers me is that the Ecobee is supposed be an integrated climate systems controller, and we should be able to depend on it for controlling a dehumidifier, humidifier OR external air exchange apparatus. If the humidistat is that far off and has that much apparent hysteresis, then we're not controlling much. If I add dehumidification to the central system this leaves me sort of hanging on how to control the HVAC blower on humidity demand. I can do it through relays, but apparently it's not going to be a simple on/off pair from the Ecobee. Probably ought to toss this dilemma out in the Ecobee forum.

[learmoia]

Hmm. Well, that's frustrating. So, in essence, the sensors in the Ecobee are very rough approximations at best. Ugh. My takeaway on this should simply be when the humidity gets higher, there might be problems.

What bothers me is that the Ecobee is supposed be an integrated climate systems controller, and we should be able to depend on it for controlling a dehumidifier, humidifier OR external air exchange apparatus. If the humidistat is that far off and has that much apparent hysteresis, then we're not controlling much. If I add dehumidification to the central system this leaves me sort of hanging on how to control the HVAC blower on humidity demand. I can do it through relays, but apparently it's not going to be a simple on/off pair from the Ecobee. Probably ought to toss this dilemma out in the Ecobee forum.

If you take it to the Ecobee forum, I'd be curious how that turns out..

The Ecobee has the means to adjust the reading of both temp and humidity.. (manual calibration..)  After 24 hours and a few tweaks.. We are getting pretty close..

The wife says things seem much more comfortable.. (We had ours set to 68 to keep it comfortable.. A now "68" feels like an ice box), so I think we can adjust things to be a bit more reasonable (72/68ish).

Not to say that any of the gizmos I'm using are 'accurate' to any means..  But I've got  4 Temp humidity readings and a Dehumidifier reading generally the same numbers.. and Ecobee was out in left field..

~Ian

[Chris333]

Thought I read (maybe here) that the only way to accurately measure humidity is by using a human hair. 

I remember seeing a photo of about 20 digital aquarium thermometers in the same bucket of water. No two had the same reading on them. 

[peteski]

Thought I read (maybe here) that the only way to accurately measure humidity is by using a human hair. 

That is true. Well, that is one of the ways. I own an old-fashion graphing hygrometer/thermometer and it does use a bundle of human hair for measuring RH.  I did believe the specs so I took it apart. It really has a bundle of blond hair in there!. 

[Scottl]

Yes, original accurate RH instruments used human hair and the most precise still do.

Remember that RH is temperature dependent, what really matters is specific humidity which is what many electronic sensors measure but is converted into RH to make it understandable for the masses.  Our sense of humidity relates to saturation so RH is best suited to represent that.  The RH relationship is exponential, and as you get to higher (room) temperatures, you get a larger RH change for a given temperature.  This is why data from Ecobee or similar looks so variable.  The specific humidity is almost certainly much less so.

[John]

I would use one of these

[Scottl]

LOL.

[C855B]

I would use one of these ...

Yeah. You ever whack yourself in the face with one? Not fun.   

[Scottl]

The lecture begins 

 

[C855B]

The suggested videos at the end included a similar lecture in Hindi. I summoned our kid to translate. "He says use a wet cloth wrapped around the bulb... wait a minute!", followed by his stomping out of the room, "Everything on the board is in English! You know what he's saying! Nice try."

[John]

Yeah. You ever whack yourself in the face with one? Not fun.   

As a certified and trained Navy meteorologist -- I would never do that, but I did break a few

[Hornwrecker]

I watched them doing the sling thing in the Engineering spaces on the Prise, when we were in the IO.  A small crowd gathered to watch while the HMs went to take readings near the Main Steam stops over the Reactor Compartments.  They didn't last long, as it was about 180*F ambient right there.  We were amused, as we all knew that when you went through that area, you held your breath and ran through it.  At least it got some of the watchstations cut down to two hours or less before relief.

[Cajonpassfan]

The lecture sure got my attention; at first I thought she had a psychometer
I could have used of those during my dating days, before I was fortunate enough to meet my lovely wife
Otto K.