I am becoming obsessed with my home Rh. I want a meter as accurate as I can get without buying the $200+ ones.
The meter by P3 International “claims” Rh +- 3% accuracy and Temperature +-1%.
http://www.p3international.com/products/weather/p0270.html
I can live with these numbers but have to order it online.
Does anyone know a good accurate meter I can buy at the stores. The $8 Acurite that I bought from Wal-Mart makes me feel uneasy.
I want one good one that I know is very good and then a couple of more cheaper ones that are maybe +-5% for other rooms.
For my couple of cheaper ones I’m looking at the Honeywell TM005X but they don’t list accuracy. I figure it can’t be too far off being Honeywell. If I knew 100% that is was very very accurate, I could live with it as my main unit.
http://www.honeywellweatherstations.com/TM005X.html
I prefer digital and thanks in advance helping me find the right meter to beat my obsession.
Now there is a multi-room monitor by Oregon Scientific that would be great.
http://www2.oregonscientific.com/shop/product.asp?cid=2&scid=5&pid=885
It says “Humidity Resolution” is 1%. If that mean accuracy, then this would be perfect unit for me, but I worry about accuracy of remote sensors.
Edited 2/1/2009 3:53 pm by CoreyIL
Edited 2/1/2009 4:11 pm by CoreyIL
Replies
There is always analog ones.
http://www.drillspot.com/products/66851/Taylor_1330PJ_Sling_Psychrometer
William the Geezer, the sequel to Billy the Kid - Shoe
Like anything ... you want accuracy (i.e. quality) you'll likely have to pay for it. A sling psychrometer will be accurate ... but it ain't digital. Don't know the price. Sensors for humidity are inherently 'touchy' in that they can get screwed up easily (not a very scientific description, but it gets the point across, I think) ... unlike a standard thermometer/sensible temperature sensor. The exception is the sling psychrometer. Used properly, it has no issues and is 'durable'.
May we ask why you have this obsession? What's it all about? Maybe revealing that may allow us to help you get the answers you might be looking for.
Common ... you can tell us ... we won't tell anyone else. Anything you say here is 'confidential' ... it won't leave this website. ;)
Yeah, been nagging at me all day, what the human threshold is for sensing RH.
IIRC, pressure sesnitivity is around 1/4" WC; temperature sensitivity in the 2-3ºF--but, that's off the top of my head, too.
And non-contact, too. Contact changes all sorts of things. Finger tip is 1.75x over palm, 6x over skin on the back; has vibration sensitivity around 1-200 microns, but depends heavily on the frequency of the vibration, too, 15Hz different than 15kHz.
Occupational hazard of my occupation not being around (sorry Bubba)
> Yeah, been nagging at me all day, what the human threshold is for sensing RH.It's relative. The body adapts to a given RH and temperature scenario and detects as abnormal anything significantly different. Even your skin will get dry early in winter, then not so dry later, as you adapt to the lowered RH.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
It's relative. The body adapts
Well, that's what complicates this sort of thing.
But, I'm betting somebody measured human sensitivity/sensory responce to humidity changes (since every other sense is measured).
Just too lazy to go search the psycho-physiological ergonomics of it.
And, that info is probably stuck into the ASHRAE psychrometric chart, which likely means somebody has a research paper out there to read (since I'm not feeling like interpolative calculations on multi-order lines <lazy sigh>).Occupational hazard of my occupation not being around (sorry Bubba)
Yeah, I'm sure the info's out there. But you gotta pay a $500/year subscription fee to some journal to read it.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
But you gotta pay a $500/year subscription fee to some journal to read it.
Makes lunch and a few beers with a mechanical engineer seem cheap, don't it ?<g>
Only thing better is to have a research prof move in on a person's street <g>.Occupational hazard of my occupation not being around (sorry Bubba)
"that info is probably stuck into the ASHRAE psychrometric chart"
Absolutely. Figure 5 in the ASHRAE Fundamentals (p 8.12 in the 2005) has ranges of human comfort for summer and winter, plotted on a psychrometric chart.
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i use a sling psychrometer for RH..... and a moisture meter for wood
I don't have a recommendation, but if you are obsessed with the RH conditions in the house, and want to make reasonable comparisons from multiple locations, you might want to stick with using the same make/model throughout the house. Initially, put them all together in the same room and see how they compare to each other. Any differences in the baseline readings should be taken into account when comparing your data from around the house. While absolute accuracy would be nice, I'd think it's the relative differences from room to room that will have the most bearing on your corrective measures/ventilation adjustments.
I bought a $30 unit at the hardware store, it is digital and has a remote sensor so that it can display indoors and outdoors. I use it entirely indoors, one upstairs and one down. No doubt it is not highly accurate, but what real use can you make of highly accurate information? For me it's good enough to know that it's approx. 68 degrees and 40% RH. I use units like this to know when I need to humidify or dehumidify during projects. Close counts...
in RH ...and horseshoesMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
use hair, blonde or brunette, your choice .. fix down one end (the hair not the blond) tie the other end to a needle on a fulcrum .. grade 4 science experiment ... we did other things later on ...
Generally, you hit the nail on the head, IMO. Precision is generally not warranted while accuracy is important ... is it 40% or is it 80%? Just get me in the ballpark. We ain't in the science classroom where small differences may mean a lot.
That's why I don't pay $150 to calibrate my digital thermometer w/ thermistors attached. It ain't rocket science ... just getting an idea ... is it relatively hot or cold ... that's it.