DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   HVAC (
-   -   Humidity Reading (

Jerry8C 11-10-2011 04:24 PM

Humidity Reading
Humidity Reading
My hygrometer reads about 60% in my house throughout the winter. I have a humidifier on my furnace, but do not seem to require its use due to my house reading. I was curious as to my high house reading so I placed my hygrometer inside the duct work going into my humidifier. My reading there was about 30%. I also have a humidistat mounted directly above the humidifier that when I adjust it I can hear a click when the dial is about 30 to 35%.
1. Why do the two readings differ?
2. Which reading should I use to determine if I should use my humidifier?

yuri 11-10-2011 04:43 PM

I have compared my customers hygrometers to my Pro unit and have found them to be out 10-20%. Probably yours is too. Those cheap table top units are usually inaccurate. If you want accurate readings try order a UEI one online. Especially important if you have hardwood floors.

Jerry8C 11-10-2011 05:09 PM

I understand your comments. However, I checked the accuracy of my readings as follows:
1. Although my hygrometer is store purchased, it did agree with another store purchased unit.
2. I have a wet-dry bulb hygrometer, which should be accurate, and it agrees with the hygrometer I used.
3. And, although the furnace mounted humidistat is not a professional reading device, when I heard it click on and off at about 30 to 35%, that seem to me another confirmation of my duct readings.
And finally, a 50% difference seem to me more of an issue than accuracy.

Also, my hygrometer read about 60% next to my humidifier when it was reading about 30% inside the duct work going to the humidifier.

yuri 11-10-2011 05:23 PM

Depends where you live. I can guarantee you that most peoples windows will sweat like crazy at 40% RH when it is below -5 deg C or 23 F for the US. Anybody in the Great White North where I live can attest to that. Seems rather unlikely that you could ever get the humidity that high. Impossible to get it over 40% here unless you have a large steam humidifier. Seems to me like your duct humidistat is accurate and not the one you are using upstairs.

Jerry8C 11-10-2011 09:12 PM

Thanks for your reply. I may need to do more checking.


beenthere 11-11-2011 04:31 AM

Post pics of your duct work, where the humidistat is.

Marty S. 11-11-2011 05:49 AM

Is there a fresh air pipe bringing in outside air into the return?

jfrotten 11-11-2011 06:51 AM


how 11-11-2011 01:32 PM

In "never stop raining" Vancouver with coat rooms dripping with wet gortex, live musicians with fine wood instruments who run there furnace humidyfyers at max 24/7 and never get over 40%.

yuri 11-11-2011 02:15 PM

Yep, at least in Wpg. aka Winterpeg it is a "dry" cold. -60 with a windchill but what the heck the Sun is shining.:laughing::thumbup:

how 11-11-2011 03:33 PM

Yes Yuri
Makes ya wonder why all my relatives from Winni have now moved out here. I'd show them your sunny posting if I thought it might make em reconsider.

yuri 11-11-2011 03:36 PM

Kinda wonder what those occupy the **** protesters are thinkin. Sleepin in a tent in the Peg is goin to get mighty miserable soon.:whistling2:

All times are GMT -5. The time now is 08:59 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1