Climate Control

The context 

Climate-controlled environments are a relatively new concept. Until the 20th Century, artworks were stored and hung in unheated spaces. By the mid-20th Century, temperature and humidity controls became standardised after the advent of HVAC systems.

This technology inspired conservators to consider how climate impacts materials, and researchers at the National Gallery, London published guidelines offering advice on protecting their collection. This included ideal temperature and relative humidity settings for paintings, based on the capacity of the HVAC technology and London’s variable climate.

The research caught on and these guidelines were widely adopted: being applied across the world - from Australia to Argentina, despite obvious climatic differences (not to mention different types of collections and historical conditions).

In the last 20 years, cultural organisations have begun questioning the logic behind implementing these ‘standards’. After much research, we now have the scientific understanding to know that collections don’t require such strict conditions to keep them safe.

Where do we go from here?

Ki Culture recommends that the first step in updating your climate control is to identify the key stakeholders in your organisation - who needs to be a part of the conversation to incite change?

This may include:

• Facilities Management

• Collection Care Team / Conservators

• Registrars

• Lawyers / Legal Department

• Insurers

• Directors

Too often, especially in larger organisations, we work in silos. By breaking down the barriers between the key stakeholders in this conversation, we can better understand each other's motivations and concerns and can work together to overcome the obstacles to change.

Start the conversation by asking the relevant parties, “What are our climate control settings, and WHY?”

Museums could save around 24-25% on energy costs just by making minor adjustments to temperature and humidity

Key considerations

Ensure that you are considering the following elements when discussing changes to your climate control:

• Your collection (type of materials, historical conditions)

• Your geographic location and climate

• Your building and its equipment - what are the limitations and opportunities?

• Your loan agreements

Changing your climate control conditions is entirely possible - but does require collaboration and conversations. Make sure to include everyone from your organisation and make sure everyone is on the same page when making change!

Making changes

• Start by reviewing what’s guiding your decision-making about climate parameters. You may be able to reduce temperatures for some objects. Most old objects existed in a broader band of internal temperatures than we now try to maintain – but equally, more careful stewardship may well have extended their lives. The primary aim should be to avoid sharp temperature changes and dew points (when temperature change causes moisture in the air to condense as water).

• Gather accurate humidity and temperature data around your building (if you have no facilities team, a local building services engineer may be able to help with this, and data can be gathered through portable plug-in equipment). Plan the location of environmentally controlled areas so that natural conditions need as little modification as possible. 

• Plan services controls and airtight compartments – for storage and (where possible) for displays – to make sure you only maintain the controlled environment each group of objects needs. That way you avoid expending energy in creating controlled environments for objects which don’t need it. 

• Humidity controls may be more critical for exhibits than temperature but often require a lot of energy. If possible, store and display objects with onerous humidity requirements in separate, airtight spaces. Make sure you can separately control and measure the environment on both sides of the partition.

• Review ‘set-points’ for temperature (i.e. the temperatures that trigger heating or cooling to switch on). When people are moving around a gallery (rather than being seated in an auditorium, for example), they can generally cope with lower temperatures. They may still have coats on (or with them) on a winter’s day. One gallery tested this by turning the heat right down and asking visitors about their day. No one complained about being cold. CIBSE Environmental Design Guide recommends a winter set point as low as 13°C for circulation spaces and foyers in places of public assembly and 19°C for museums.

• If the collection doesn’t have specific environmental needs, target heat (or coolth) at people, not spaces. In large spaces, focus heat at low level and on visitor paths. For example, underfloor heating can keep people comfortable without wasting energy on empty air. 

• Don’t run ventilation systems harder than you need. Carbon dioxide (CO2) sensors can optimise the amount of fresh air supplied to larger galleries. Aim to keep the fresh air supply to achieve no more than 800 ppm CO2.

• In-flows of air through entrance doors make it hard to maintain internal conditions – which are consequently achieved only through intense input of energy. Set temperatures for lobbies and entrance halls to an interim level, midway between external and internal temperatures, so as to provide greater stability at lower energy cost. 

• Where possible, consolidate storage into fewer buildings.

• Where possible, locate storage in buildings which can naturally support the climate requirements of the objects stored there. Using energy to maintain climate parameters in inappropriate buildings can have a huge carbon impact. In the right building, even onerous requirements can be achieved with little energy. A new-build example is the Imperial War Museum’s paper store at Duxford. 

Refrigerants

By refrigerants, we mean the coolant chemicals commonly used in air conditioning systems and fridges, with names like R-22 or R-134a. Many of these are significant greenhouse gases in their own right, with a warming effect hundreds or even thousands of times more powerful than carbon dioxide. This means that when they leak from cooling systems and evaporate into the air, they are directly adding to global heating – and just a few kilograms of leaked refrigerant can have the same climate impact as several tonnes of carbon dioxide.

Whenever new chemicals need to be added to an air conditioning or refrigeration system to top it up, this means an equivalent amount has previously leaked out into the air, creating a climate impact. This is what is being measured by the GCC carbon calculator, whenever you record a quantity of purchased refrigerant.

But how significant is this impact really? A 2021 study of 19 cultural institutions in Germany found that emissions from their building use were approximately 53% from heating, 44% from electricity, and 3.5% from refrigerant leakage. While this suggests that refrigerant use is only a small part of the total footprint of a typical arts institution, it is still worth measuring and including in action plans for a few important reasons:

• While the average footprint of refrigerant usage may be proportionally low, there are plenty of individual cases of leaky systems that have a much higher footprint than this. If you don’t investigate your own air conditioning/climate control system, you won’t know if you are one of them.
• On the flipside of this, there is the potential for an “easy win” if your system uses a refrigerant with a high climate impact that could be exchanged for a lower-impact chemical, or if you are replacing your climate control system and have the option of choosing a lower-impact refrigerant from the start.
• From a reporting and accounting perspective, refrigerants fall within Scope 1, and so are often considered to be mandatory in carbon reporting legislation.

How to find out the type and amount of your refrigerant

Your cooling system should have some accompanying documentation, or a plate or label of some kind, that will specify the type of refrigerant (e. g. R 134a). There should also be a record of past servicing of the system, which will say how much refrigerant has been added to top-up the system each year - whoever is in charge of your building/facilities/maintenance should have access to this.

If you can’t find information on the annual top-up amounts, you could instead look up the maximum capacity of your system, and assume that 3% of this total is leaking out every year (the typical leakage rate of an air conditioning system is 1 – 5% per year, so 3% is a reasonable midpoint). However, this should ideally just be used as a stopgap figure, to give you a sense of the scale of the climate impact, until you can gather information on the real top-up rate.

What are the impacts of different refrigerant chemicals?

To get a sense of the range of different refrigerant chemicals in use, and their very wide range of climate impacts, look at this list here. “GWP” stands for “Global Warming Potential”, or the average amount of warming that one kg of these chemicals can create in comparison to carbon dioxide (which has a GWP of 1). You’ll see that a kg of R-22 has the equivalent impact of 1810 kg of carbon dioxide (CO 2 ), while a kilo of R-134a is equivalent to 1430 kg of CO2 .

By contrast, newer chemicals in the “R1234” family, which have been specially developed to have a lower climate impact, have a GWP between 1 and 4. When purchasing or upgrading cooling equipment, you should ensure it is compatible with these lower-impact chemicals. However, these varieties are often incompatible with existing systems.

As an effective temporary measure, manufacturers have been developing new blends of coolant chemicals, that still work in existing systems but have a significantly lower GWP. For example R-513A, a mix of R-134a and R-1234yf, can often be used as a direct replacement for R-134a in existing equipment and has a GWP of 573, 60% lower than R-134a.

Of course, the refrigerants in your cooling system should only be handled by a qualified professional, and you should not make any decisions about changing the chemicals in your system without professional advice tailored to your specific circumstances.

Actions you can take to reduce the climate impact of your refrigerant

• Speak to whoever is responsible for maintaining and managing your air conditioning equipment. Find out if it’s possible to directly replace the refrigerant in your system with a lower-impact chemical (and ensure that the removed refrigerant is properly extracted and destroyed).
• Look at the total capacity of your system and how much refrigerant is being topped up each year. If you’re needing to add more than a few percent to the system each year, then you may have a leakage problem – speak to an expert practitioner to find out how to investigate this further and fix it.
• If you are installing a new system, or replacing an existing one, ensure that it uses the lowest-impact refrigerant available, and that any waste refrigerant is disposed of correctly.
• In the long term, investigate shifting towards more natural cooling/ventilation options and minimising the amount of artificial climate control you need.

The takeaways

Change is possible 

Not only this, but change is already happening. We're seeing leading institutions already updating their climate control ranges and saving large amounts of money, energy, and carbon.

Effective Actions

• Identify and Collaborate with Key Stakeholders: Engage departments such as Facilities Management, Collection Care, Legal, and Directors. Break silos to align goals and facilitate decision-making.

• Initiate dialogue by asking, “What are our climate control settings, and why?"

• Assess and Adjust Existing Practices: Evaluate current climate control settings and historical rationale behind them.

• Gather accurate humidity and temperature data for informed adjustments.

• Prioritise avoiding rapid temperature and humidity changes over strict adherence to rigid standards.

• Optimise Energy Usage: Lower set-points for temperatures where possible (e.g., 13°C for circulation spaces).

• Target heating or cooling at people, not spaces (e.g., underfloor heating for visitor paths).

• Use CO2 sensors to optimise ventilation systems and avoid overuse.

• Adapt Climate Control to Collection Needs

• Tailor conditions to specific materials and their historical tolerances.

• Implement microclimates for objects with strict requirements in airtight storage or display areas.

• Consolidate storage into energy-efficient buildings that naturally meet climate requirements.

• Invest in portable equipment for humidity and temperature monitoring if facilities teams are unavailable.

• Plan services and airtight compartments to control energy use and environmental needs effectively.

• Shift Terminology and Perspectives: Treat “guidelines” as flexible methodologies, not strict “standards.”

• Frame changes as “updating” or “upgrading” to align with modern professional practices.

• Share and adopt successful strategies from similar organisations.

• Ensure all departments are aligned on goals and processes.

• Create a culture of collaboration to overcome challenges and fears, particularly around loan agreements.

• Promote Systemic Change: Advocate for global collaboration in the cultural sector to build consensus and foster widespread adoption of updated practices.