Cara, thank you for asking the question - your concern for your collections is wonderful to see, as well as your use of C2CC for exactly what it was designed for. I have been working with collections in the NorthEast for virtually all of my conservation career which spans more years than I care to think about. For the last 30+ I have focused on smaller institutions such as historical societies, historic house museums, and local history facilities, with a smattering of the nationally-known ones thrown in. Anyone who lives in this region has gone through power outages, often a number of days long, as one previous respondent mentioned. We all have also seen local institutions that have no heat at all in the winter, either in the house or in the outbuildings where collections are located. Some are not even open in the winter. As pointed out, rapid fluctuations are of most concern. Fluctuations are of two types, those that occur in the air of the rooms, and those of the objects themselves. Air changes can occur relatively quickly in standard building construction - think of normal day to night fluctuations outdoors. The building significantly slows those changes even when no HVAC systems are running. The tightness of the exterior doors and windows are a major factor affecting the speed, and every building will vary dependent on many other factors. A loss of heat for a day or two is on a relative basis fairly minor for most reasonably tight structures.
The second issue is how quickly the objects themselves respond to the changes in the air around them. This of course varies greatly from object to object. In general thinner items respond more quickly than thicker ones. Certain materials types respond more quickly than others. And some items are sensitive to a given amount of T and RH change and some are not, to the extreme of not responsive at all to these types of variations.
So in summary, first the room air T and RH have to change. Then the objects subjected to this different air will begin to change at different rates, or not at all depending on the material. And this takes time, it is not instantaneous. None of this is easy to assess in the whole of a building with collections. So we generally have to look at past experiences. The aforementioned power failures and fully unconditioned environments show that for short periods of time of a few days there is very little likelihood of perceptible damage to the collections. I use the word perceptible since I am unaware of any procedure or equipment that can quantitatively measure damage over such a short period of time in a real-world setting like an historic house. Over a year, yes. Or even over a few months, perhaps. So yes, isolate the upper levels from the first floor, which you would want to do for dust purposes anyway. Before you shut the door, make sure all shades, curtains and interior shutters, if you have them, are closed fully to provide the maximum insulation from the outdoors. Of course, verify that the windows are fully closed and storm windows if you have them are also fully closed. You would be surprised how many I have found in similar situations that were still open in the winter - no one had checked. And don't open doors into the isolated spaces unless necessary, including for a day or so after the work is completed. Then fully open them back up. In general, doors being open for air circulation prevents undesirable micro-climates in individual rooms. And don't use space heaters as the slightly cooler T and higher RH that will result will actually be better preservation conditions than a heated space.
These are the basics. With minimal effort you should be able to successfully weather your "power failure" for a few days.
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Marc Williams, AIC Fellow
American Conservation Consortium
Broad Brook, CT
acc@conservator.com------------------------------
Original Message:
Sent: 01-12-2026 13:56
From: Cara Kuball
Subject: climate control during renovations
Hi all, looking for thoughts/advice on how best to prepare for an upcoming daylong planned shutdown of our HVAC system. Our 2150 sqft building is well-insulated, and was constructed in 2008.
There will be a period (about one working day - the exact day is TBD) when the forced air heat in our house gallery will be turned off, because contractors will be jackhammering concrete in the downstairs bathroom and creating very fine dust that could circulate through the heat system if it were on. Heat will be shut off in January in NY state (outside temperatures expected to be anywhere between 20-50 degrees F).
All artworks on the lower level have been removed. Upstairs, spread across 3 rooms there are 2 large color photos mounted to dibond, one framed and glazed (plexi) inkjet print, glazed stoneware, unframed wool felt quilted textile, and aluminum sculptures. This small house museum is usually temperature controlled, but not climate controlled. My biggest concern is for the photographs -- though of course those do well in low temperatures, I can't anticipate how gradual the temperature drop will be.
The question is whether we request contractors install one or more space heaters on the main floor (1300 sqft), or whether this might create dangerous pockets of dry, hot air. I am conflicted: would be better to leave the upstairs completely closed to the contractors, anticipating a slow drop in temperature over a day without heat? The risk of course is that this work might take more than one day.
Thank you all so much for your help making this decision--I am a bit stumped!
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Cara Kuball
Contract Registrar
Forge Project
Stone Ridge
United States
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