Hello All.
In a previous iteration of my life, I did disaster restoration and repair which provided me valuable experience with thermo-hygrometers. The device we used was the Extech 445580. Why did my employer choose this device? Because of it's RANGE. It accurately displays the RH from 0-100%. Other, less expensive devices do not go down to 0% RH. They stop at 20-25% RH. A device that stops at 20% RH is fine for those that live in areas that do not get very dry but of you are in a desert or super cold/dry climate, you need something that goes lower.
When I go to the mountain communities I serve in Northern Utah, I frequently find RH in the single digits during the winter. The lowest I have recorded is 6.9% RH. (Side note: I verified that reading with a second device.)
These devices range from $60-$100 depending on where you find it. Amazon has typically been the cheapest.
Now to answer the other, REAL question.
Just how exact do you REALLY need to be?
The truth is, a one time reading does not matter. It only gives you a snapshot of the current conditions. It does not tell you if the RH is going up or going down. You must develop a series of readings over time to have any value to taking the readings. That way you can determine a trend that you may need to take into consideration when tuning a piano. (To float or not to float the pitch.)
A good rule of thumb to follow is this:
When humidity goes up, pitch goes up.
When humidity goes down, pitch goes down.
When temperature goes up, pitch goes down.
When temperature goes down, pitch goes up.
Humidity is slow acting.
Temperature is fast acting.
The wood has to soak the moisture into the wood or give off the moisture within the wood. That takes time. At least compared to the metal components in a piano. The metal components will generally stabilize at a new temperature in a few hours. Wood takes days or weeks to stabilize depending on the amount of change required.
Remember, That is a rule of thumb based on circumstances, environments, and individual instruments.
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Randi Ford
Ogden UT
(801) 645-5668
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Original Message:
Sent: 10-23-2022 22:07
From: Peter Grey
Subject: Best Piano Hygrometer
Yes, in fact an oversized AC unit does not run long enough to effectively dehumidify the air and ends up pumping cool MOIST air throughout the house.
It is counterintuitive, but I learned this from an HVAC installer in Virginia. He advised that it should actually be slightly undersized so as to work longer and remove more humidity. He was correct.
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 10-23-2022 10:34
From: James Kelly
Subject: Best Piano Hygrometer
I suggest you undergo an energy audit by your utility company or hire a person qualified and equipped to evaluate air flow, exchange rates , hvac efficiency, duct work.
70% rh is well above the danger zone for pianos - refer to the literature/booklet that Dampp-Chaser publishes. I am surprised you do not have a mold problem . The HVAC could be the problem and in need of full overhaul and the duct work could be leaking or not properly distributed to balance . I also think you need to get the chimney repaired/replaced/sealed. There must be a tremendous updraft sucking up the air conditioned air and letting in humid moisture laden air. How are your electric bills ?
Until you fix the environment a dampp chaser is useless
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James Kelly
Owner- Fur Elise Piano Service
Pawleys Island SC
(843) 325-4357
Original Message:
Sent: 10-23-2022 07:17
From: Jasm Charl
Subject: Best Piano Hygrometer
I have central a/c (oversized, it came with the house) as well as a dehumidifier that runs 24/7 but my concrete block house here in Florida is rarely below 70% RH in the summer. My tuner complained when he visited in August.
I've replaced the aluminum jalousie windows that didn't close all the way with double-hung vinyl that does.
I have a chimney that does not close, cracks under the door, and a mail slot for my front door as well as three large dogs who are constantly wanting to go in and out of the house.
A damp-chaser would be like putting a band-aid on a gaping wound.
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Jasm Charl
Original Message:
Sent: 10-18-2022 10:36
From: Andrew Warden
Subject: Best Piano Hygrometer
What is the best hygrometer to set on top of a customer's piano while you're tuning so you can jot down an accurate RH reading when you're done? I've always really trusted the one I have that cost about $10, but they don't make them anymore. It's gone years and years without a battery change. Does it make sense to spend more? Thanks
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Andrew Warden
Evanston IL
(224) 420-1773
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