This is an interesting topic, to me at least. Lots of good information so far, but some that is not quite correct. I'll try my best to explain from our (DC's) point of view what could be done.
Undercovers do, for a certainty, help with maintaining the environment under the piano, especially in high air movement situations. They are beneficial in virtually all situations, but due to the fact that they're a bit of a pain to install, an extra cost, and not necessarily a cosmetic plus, they often are not installed. The wider the range of humidity the piano is subjected to, the greater the benefit.
A full System will almost always be the best solution to humidify fluctuations. There are two common exceptions to this rule though. Areas, like Florida, where the RH is never dangerously low is the first exception. The second one is absentee piano owners. If there is nobody available to add water to the PLSS, there's not much point in having a full System.
If the people are not going to be around for extended periods of time and the heat will be considerably lower during that time, I would NOT recommend a "heater" to keep the piano warm. The ambient RH in the house with the heat set low will be
relatively high due to the low temperature. While low temp will affect the tuning, it will not be harmful to the structure of the piano. If you incorporate a heater under a blanket, you're going to lower the RH pretty significantly, which could harm the piano. If you installed a dehumidify-only System with an H-D Humidistat and a 48-50A Dehumidifier, it will respond to low RH levels by adding heat, but it will not respond to low temperatures at all. I just looked up the weather in Hathaway Pines. 77° and RH of 13%. Wowzers. These numbers equate to a dew point of 22°. If we assume a similar dew point during colder weather and lower the temperature to 50°, the RH level climbs to 35%. It would appear that this is typical for the area conditions. In a situation like this, if the Dehumidifier is plugged into a Humidistat, it would likely never come on.
My conclusion, therefore, is that adding any heat to this situation without some way of adding humidity as well would be dangerous to the piano. If you tune the piano when it has been sitting in a stable temperature environment for long enough to equalize, and then it goes for a month in the cold, when it gets warmed up again, it will be relatively close to where it started. Concert stage perfect? No. I think the customer has to have realistic expectations though. Make them aware, if they aren't already, that this is not an ideal situation.
A dehumidify-only System that would safeguard against ultra-low temperature-induced condensation in the piano is likely your best bet. No cover, no added heat.
P.S. For anyone interesting in the relationship between RH, Temp, and Dew Point, go to a website called Dew Point Calculator. They have a very handy interactive tool that makes it easy to see how each reacts to a change in the other. Unfortunately, it is not mobile-friendly, so you'll have to do it from an actual computer, no phones or tablets.
If anyone has questions about any of my rambling you can put them here or call or email me if you want.
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Charles Rempel
Dampp-Chaser Corporation
Hendersonville NC
828-692-8271
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Original Message:
Sent: 10-23-2019 11:57
From: Keith Roberts
Subject: piano warmer
Peter, you are in New Hampshire. That explains a lot.
The east coast doesn't have the same problems and NH is,,, well I made it through two winters there.
When you have cold drafts the air is dry. When we have cold drafts the air is wet. The condensation aspects of the vinyl are different. East coast summer you turn on central AC and dry the air. Evaporative coolers are used a lot out here. The air is dry.
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Keith Roberts
owner
Hathaway Pines CA
209-770-4312
Original Message:
Sent: 10-23-2019 11:45
From: Peter Grey
Subject: piano warmer
Maggie,
I would be interested in whatever pointers you have for undercover installation. I think I want to start adding this on standard installs. Have one to do next week.
Oddly enough, I've been putting vinyl-like covers on grands for several years now with very good (and no bad) results. Increases stability significantly.
Pwg
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Peter Grey
Stratham NH
603-686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 10-22-2019 14:17
From: Margaret Jusiel
Subject: piano warmer
Aside -
Terry said, "(Dog-gone, where is the emoji button?!?!?!? Margaret?)"
Maggie replies in Richard West style:
BAHAHAHAHA!!! 😂
I've been told there are some browsers that support emojis and you can insert them, but I use either Firefox or Ghostery and have never found this feature if it exists on those. 😳 See if your browser has that option. 🤔 Phones typically have them available from their keyboard by default. 📱 If not, you can copy paste from sites like this: https://coolsymbol.com/emojis/emoji-for-copy-and-paste.html
I've always wanted them plus a "like" button, but...meh...too many of us would get carried away with them. 😉 Copying and pasting is typically too much trouble for me to bother with. 😜
Later 🐊
Maggie
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Maggie Jusiel
Athens, WV
(304)952-8615
mags@timandmaggie.net
Original Message:
Sent: 10-22-2019 09:21
From: Terrence Farrell
Subject: piano warmer
Tim C. wrote: "In conversation with Dampp-Chaser's main engineer I was told the unit needs to breath."
Very interesting. I'm not going to try to argue that point because I am not an expert with the Dampp-Chaser system - I think I am knowledgeable, but by no means any sort of expert. I do have a strong science educational background and hence reasonable - I think - opinions. I'm curious why a Dampp-Chaser system would "need to breathe". I wonder if it stems from use of the humidification portion of the system (which I don't used here in central Florida). I could see where having the water tank under the piano could result in excess water vapor in a small enclosed environment. I guess if you think of it, you enclose the piano in a good floor-length cover or a box with an ever-present water source, water is going to evaporate until it come to equilibrium with its environment - which, yes, would certainly result in a too-high-humidity environment for the piano regardless of how many dehumidification heater rods one might install (like if a box offered a 100% seal, we're talking 100% relative humidity at equilibrium regardless of the temperature!!!). So yeah, I do see how a sealed environment wouldn't work with the full system. I do think it would work great with just the dehumidification system. But a floor-length cover - I do have to admit that I cannot envision a cover like that isolating the environment enough that an excess of water vapor would be retained in the environment. But it is certainly true that if one has a adequately sized/configured full Dampp-Chaser system on the piano, there would indeed be NO need for the more full enclosures I have described. So perhaps a good point.
I think my thought of a floor-length cover originated from indoor environmental conditions here in central Florida. I only install dehumidification systems and oftenrecommend floor-length covers. I sure hope my recommendations are best practice. But I think that with the dehumidification-system-only there is not concern with excess humidity buildup (I mean like, what would be the source of water vapor?) and there is always some bit of circulation with the outside (outside of the piano cover) room environment. I think I am good with that recommendation.
Thoughts? Maybe I'm still out in left field...... :-( (Dog-gone, where is the emoji button?!?!?!? Margaret?)
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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
Original Message:
Sent: 10-22-2019 07:40
From: Tim Coates
Subject: piano warmer
Hi Terry,
Thank you for your information. The one area I have issue with is the cover. In conversation with Dampp-Chaser's main engineer I was told the unit needs to breath. He said a vinyl cover is not a good idea, nor is a floor length cover. For a grand a macintosh body length cover with an undercover is best according to him. I have tried his suggestion and found it to be true so far.
Thanks for all your insights.
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Tim Coates
Sioux Falls SD
Original Message:
Sent: 10-22-2019 07:23
From: Terrence Farrell
Subject: piano warmer
Keith R. wrote: "stabilizing the humidity will probably be better than stabilizing the temp." and Margaret J. wrote: "...one heater bar in a piano with a thermostat, then installed a full DC system...)"
Keith and Margaret have pretty much hit the nail on the head. Pianos are constructed of wood and metal. Changes in relative humidity affect wood expansion and contraction more than temperature. Temperature changes affect metal expansion and contraction more than humidity. I don't have any specific scientific knowledge of whether changes in wood or metal effect tuning stability more, but my anecdotal (and rumors!) suggest that relative humidity changes are the dominant effect on piano tuning stability. But both effect tuning stability.
So how to provide a stable environment for a piano. You basically have good, better and best options. Good would be to hermetically seal the piano in a water-vapor proof enclosure that is thermally stabilized. That is somewhat prohibitive to implement. Better would be to stabilize relative humidity for the piano environment. That is done by either installing a GOOD humidity-control system (adequate heat and water and a back/bottom cover - and a cover over piano if possible) on the piano itself, or better yet, whole room humidity control. Best would be to stabilize & optimize both relative humidity AND temperature. That would be done with an approach that Margaret J. described as "crazy and possibly stupid" - her idea is neither crazy nor stupid. If the piano environment (relative humidity and temperature) will not be under whole room control, then exactly as Margaret described - install a complete (and adequate) Damp-Chaser system, cover the piano, and install an adequate regulated heat source under the cover. I'm not sure it would be worth the effort, but one could construct a box to cover the piano from cardboard or insulation panels to isolate the piano environment. Of course, whole-room temperature and humidity control would be optimal, but the topic here is how to best work around that.
But installing a thermostat heater bar either in the piano or within a cover over the piano is a potential disaster for the piano. Different areas of the country have very different indoor environments. Much of the North American midwest has warm humid summers and cold winters. The outdoor humidity in those winters is often high, but indoor where the temperature is raised, the relative humidity often can be very low. In such a case, adding heat could dry out the wood in the piano even further. Folks tend to think that here in Florida we have a tortuous environment for piano. However, most pianos are indoors and most homes have air conditioning. The modern air-conditioned home in Florida is one of the kindest environments for pianos. During our hot humid summers, AC use keeps the indoor humidity at near optimal levels for pianos. It is during the winter that indoor relative humidity can very quite a bit. Sometimes it is relatively dry outside and indoors the humidity will tend to be near optimal. However, we can have some wet weather in the winter - and it doesn't get cold enough for home-owners to turn the heat on - it can get rather humid in homes during stretches like that.
I think the bottom line is to control relative humidity with a proper and adequate Damp-Chaser system (here in Florida we really do not have a pressing need for the humidifier portion of those systems - but elsewhere it is usually beneficial). Seal the piano us somehow - either with a back/bottom cover, quilted cover over the piano (to the floor), or a box of some sort over the piano. If one can add temperature control somehow, that would be great - but I think it would only be a workable option if one had some sort of insulated box over the piano. But whatever one does, do NOT regulate heat with a thermostat only!!!
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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
Original Message:
Sent: 10-21-2019 12:07
From: Keith Roberts
Subject: piano warmer
I got a call to tune a piano. I got there and it's a second/future home up in the mountains. He had just got there so the place was 50 degrees with the forced air blowing sort of warm air. I told him I should come back when the place was warm. We then got into a discussion about how to keep the piano stable.
He has a 7' 6" grand at his place in Sacramento so he got a P202 Yamaha for when he comes up. The place up the mountain doesn't get used enough for a full climate control system, it might sit for a month or more before being used.
My plan is to put a heat bar in that is controlled by a thermostat and have him blanket the piano. Trial and error is fine but I was wondering if there was any experience out there as to how effective this will be.
A 4 ft heat bar place as low to the pedals as possible.
A $20 Honeywell baseboard heater thermostat (amazon) hung on the side about 18 inches higher than the bar.
Wool blankets or Moving blankets?
Thanks
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Keith Roberts
owner
Hathaway Pines CA
209-770-4312
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