Hi Dennis,
Great question. In a vault setting like yours, it typically doesn't mean abandoning 70/50 altogether. It's more about how tightly and uniformly that target is applied. A couple of practical ways this shows up:
• Zoning by collection type – instead of one uniform setpoint across the entire vault, some institutions are starting to define slightly different "climate classes" depending on what's stored (e.g. more tolerant materials vs. more sensitive ones), and controlling those zones independently.
• Controlled setpoint bands vs. single point targets – rather than holding exactly 70/50 at all times, the system could allow a narrow, controlled range and focus on avoiding rapid corrections. That reduces the constant cycling you mentioned while still staying well within conservation-safe limits.
• Smoother control logic – instead of reacting every few minutes to hit a fixed number, the system would prioritize gradual adjustment and stability over time, so you don't get the continuous "chasing" behavior, which expends big energy.
In smaller volumes like your vault, you already have an advantage because control is easier. But it becomes interesting when you start asking: are all objects benefiting equally from the same level of tightness, or could some flexibility be introduced without increasing risk?
Out of curiosity-do you have a mix of object types in that vault? And if so, are you able to treat them differently from a control standpoint, or is everything currently managed as one uniform environment?
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Joseph Upjohn MBA
Museum Energy Consultant
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Original Message:
Sent: 04-21-2026 05:48 PM
From: Dennis Callahan
Subject: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Hi Joseph,
That's an interesting point. I understand it logically from a gardener's frame of reference and also from human behavior. I'm curious how that would be implemented in a commercial Art Vault.
Thank you for bringing it to my attention.
Best regards,
-- Dennis Callahan
Callahan art & Associates
Original Message:
Sent: 4/21/2026 3:26:00 PM
From: Joseph Upjohn
Subject: RE: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Hi Dennis,
One other aspect we've been looking at, separate from energy, is how objects respond mechanically over time under different control strategies.
When conditions are held very tightly at a fixed point like 70/50, materials aren't experiencing much day-to-day movement. That can feel "safe," but it also means the system is optimized for constancy rather than resilience.
In a number of cases, the bigger risk shows up during an unexpected event, equipment failure, a rapid weather shift, or loss of control, where conditions move quickly outside that narrow band.
What some of the newer research is suggesting is that when variation is introduced in a slow, controlled way (within safe boundaries), materials are less exposed to abrupt stress during those events compared to systems that are constantly correcting back to a fixed point and then suddenly lose control.
So it becomes less about allowing wide swings, and more about:
how to minimize harmful rates of change, especially in worst-case scenarios.
That's been an interesting angle in a few discussions lately. Curious if that aligns at all with what you've seen.
Also, thank you @Bruce, for the insights and research references!
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Joseph Upjohn MBA
Museum Energy Consultant
Original Message:
Sent: 04-21-2026 02:59 PM
From: Dennis Callahan
Subject: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Bruce,
You are absolutely correct. There is a lot of variance among objects and their needs.
Dennis Callahan
Callahan art & Associates
Original Message:
Sent: 4/21/2026 2:08:00 PM
From: Bruce MacLeish
Subject: RE: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Regarding practical approaches to environmental control in museums, we are fortunate to have a great deal of research and reporting to rely on beginning several decades ago at such august institutions as the Royal Ontario Museum, the Smithsonian's Conservation Analytical Lab, and the Shelburne Museum. These days, organizations such as the American Institute for Conservation (AIC) and the Canadian Conservation Institute (CCI) have also advanced this subject area, but the basic principles are still the same.
As I so often state at the start of any suggestions about care of collections, "It depends." A blanket recommendation for care of collections usually does not cover every possible variable such as: particularly delicate objects; objects that have always been in a very dry, or very damp environment; the museum building's envelope; climate control machinery and control system; financial resources... and one could go on like this for a very long time. It seems to me that the reasonable decisions are different in every museum.
Fortunately, current guidelines are available from sources such as the AIC, CCI, and other conservation organizations. A good starting place is the article available from the Getty Conservation Institute:
Richard Kerschner
"Providing Safe and Practical Environments for Cultural Property in Historic
Buildings-and Beyond"
Contribution to the Experts' Roundtable on Sustainable Climate Management
Strategies, held in April, 2007, in Tenerife, Spain
Happy researching!
A. Bruce MacLeish
Curator Emeritus
Newport Restoration Foundation
85 Lake Street
Cooperstown, NY 13326
Original Message:
Sent: 4/21/2026 9:52:00 AM
From: Dennis Callahan
Subject: RE: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Hi Joseph,
We maintain a 70/50 Vault at all times. Our system takes readings every 5 minutes and adjusts as needed. At only 36,000 cubic feet it is not difficult to maintain. I've been watching the conversation regarding energy conservation vs object safety for a few years but still feel safer with the older guidelines.
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Dennis Callahan
Callahan art & Associates
Chicago IL
[dennis@callahanartandassociates.comdennis@callahanartandassociates.comdennis@callahanartandassociates.comdennis@callahanartandassociates.com
Original Message:
Sent: 04-20-2026 08:07 PM
From: Joseph Upjohn
Subject: Rethinking "70/50": Practical Approaches to Climate Control Without Major System Changes
Are you still holding temperature and humidity constant everywhere? Curious how others are thinking about this…
I've been having a lot of conversations lately with facilities and conservation teams who feel a bit stuck between:
- Maintaining tightly controlled, constant conditions (typically around ~70°F / 50% RH)
- And the reality of rising energy costs + systems that are constantly "chasing" those setpoints
In a lot of cases, it's not that people want to change-it's that:
- There's uncertainty around risk to collections
- And it's not clear how to make changes without major system overhauls
There's an upcoming Cultural Facility Shared Practice Meeting that's digging into this topic, including:
- Research from TU Eindhoven on more flexible ("dynamic") climate control approaches
- Real-world examples where museums reduced energy use significantly while maintaining (or improving) stability
- How teams are approaching this without ripping out existing systems
They're also collecting a short questionnaire ahead of the session to get a sense of where institutions are today-should make for a more grounded discussion.
One thing I'm especially curious about:
Where are you on this spectrum right now?
- Keeping conditions constant across spaces?
- Starting to experiment with seasonal or more flexible ranges?
- Or somewhere in between but unsure how far to push it?
Would be great to hear how others are navigating this internally-especially between facilities and conservation teams.
If you want to join (or share your perspective in advance), here are the details:
April 28, 12pm ET / 9am PT
https://facilityissues.com/ci-sp-26-04/
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Joseph Upjohn
Museum Energy Consultant
Dyseco
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