13 August 2025

Beating the Heat and Humidity: How to Manage your Collections in a Coastal Climate by Cassandra Knoppel

Late last month, at the onset of the terrible heatwave we had in Beaufort, my home's air conditioning went out. My husband and I came home from work on a Friday evening to find the temperature in our house climbing above 85° F, and the HVAC repairmen said we'd have to wait until at least 8:30 that night before someone could get out to take a look at it. My husband's first concern was the health of his wife and dog in the heat (and the safety of the homemade hot sauce he was fermenting). My first concern? Aside from the health of our poor old dog, I was bombarded with thoughts like "How soon until the walls grow mold?" and "Do we have any precious documents and photos that might get damaged in the high heat?" My reaction was admittedly a little more extreme, but that's because I have to keep these things in mind at work as we try to preserve our historic collections in a hot and humid climate. 

Heat and humidity are two of the worst enemies of preservation, and given where the BDC is located, some might think that we are fighting a losing battle. ASHRAE designated Beaufort County as being within Zone 2-A: Hot-Humid, but any local knows that fact just by stepping outside in the months between April and October. Living in such a climate makes things difficult, not just in terms of staying comfortable but in keeping things safe from creatures and critters who thrive in muggy conditions. In the Getty Conservation Institute's Managing Collection Environments: Technical Notes and Guidance (2023), the authors state that "...a Zone 2A Hot-Humid climate can be expected to host microorganisms and insects throughout the year" (p.60). Microorganisms like mold and insects of all varieties can damage collections, and hot and wet conditions on their own can also slowly degrade the integrity of cultural materials.

But, despite the clammy cards we've been dealt here in Beaufort County, the BDC follows guidelines and best practices that help us to conquer the threats to our collection, and we'd like to share some of these tips with those of you who might be worrying about the safety of your collections in this weather, too. We've adapted the 2023 CCAHA article "Hot and Humid Weather Preservation Tips from CCAHA's Preservation Services Office," which is geared more towards collections professionals, to make their 5-point list more relevant to at-home preservation of personal document and photograph collections (along with some additional advice).

1. Find a safe place to house your collection

Last year, I worked on a collection of records that had once been stored in a shed for many years. The members of the organization recognized this was probably not a great place to keep their records but were limited in places to store their materials. When the organization made the decision to give the BDC their records, they felt relieved that the collection would be a safe environment, and we felt that way too! However, those years of less-than-ideal storage conditions had taken their toll on some of the records. Materials bore signs of water damage, some pages had dormant mold, and photographs were stuck together from heat and water-caused delamination, which the BDC remediated as best we could.

To prevent something like this from happening to your personal collections, it is best to store materials somewhere safe from huge swings in temperature and humidity levels and away from potential sources of water or pest damage. Attics, basements, sheds, and garages are not safe storage areas because they are often not temperature or humidity controlled, can be pest "hot spots," are more likely to flood or experience leaks, and are less convenient for periodic monitoring (which is something we'll address later in this post!). Instead, find somewhere in your home that is climate controlled. Keeping collections off the floor is also ideal, as it can prevent damage caused by flooding if your roof leaks from one of the Lowcountry's furious mid-summer thunderstorms (or hurricanes!). It would be best not to store items in areas with known issues with leaks, mold, or pests either.

Collections Environment Infographic
by CCAHA   
2. Create and maintain the right "climate" for storage

Ideally, collections should be kept in an environment that is between 50° and 77° F. This can prevent some of the chemical reactions that can happen in high heat that causes materials to fade or yellow, become brittle and crack, or melt and stick to one another.

Maintaining a safe humidity level is also important, as the relative humidity is a big factor in mold growth. If your HVAC system allows for it, keeping the relative humidity below 65% can prevent mold from germinating and growing on your treasured documents and photographs. (If you're extra nerdy like me and would like to learn more about the most ideal environmental conditions for museums, archives, and historic houses, you can check out the chart provided by ASHRAE on page 117 of the Getty's Managing Collection Environments: Technical Notes and Guidance.) If you cannot monitor and adjust relative humidity through your HVAC system, you can also use a portable dehumidifier and set the relative humidity level to 75% or under. This can help keep both you and your collections comfortable in muggy weather. Using a fan to move air around your collection storage area also helps to lower the humidity and prevent mold from growing.

3. Periodically monitor your collections and their storage environment 

Once you set up your personal collection storage area, it is important to keep tabs on the space to see if any issues arise. In the BDC, we check the temperature and relative humidity level in our collection twice daily to ensure that we are operating within safe levels, but a less frequent check of your storage area can suffice, especially if the storage area is a bookshelf in a room that you frequently spend time in. If you don't otherwise frequent the storage area as often, it is best to check in periodically to ensure that the temperature and humidity levels are as they should be, that pests have not invaded the space in your absence, and that, perhaps, your HVAC drain pan in the attic has not backed up and created a ceiling leak that is dripping rusty water on your items (ask me where I came up with that example!). Staying abreast of any potential problems before they get out-of-hand and cause real damage to your collections is always a good idea.

You can create a routine of checking the environment weekly or even monthly, depending on your collection's needs and your schedule. If the weather is particularly rainy, or a large storm has just blown through town, it would be good to check your storage area in addition to your regularly planned "inspection" to see if any leaks in windows or ceilings have materialized. If a heatwave is affecting the area and you have multiple HVAC systems in your home, I would also suggest checking your storage area to ensure that the system in that area of your house has not failed or is struggling to keep up. 

Remember: Prevention and preservation are much easier (and cheaper) than remediation and restoration!

I hope these tips are helpful to those who are either getting started or in the midst of preserving your personal heritage items here in the Lowcountry. While it can be overwhelming to know that preserving materials is not a simple, one-time thing but more-so an ongoing and evolving process, doing so is vital to ensure that the things we value are available for future generations. 

References: 

ASHRAE. (2021). ANSI/ASHRAE Addendum a to ANSI/ASHRAE Standard 169-2020: Climatic data for building design standards. https://www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20addenda/169_2020_a_20211029.pdf
Conservation Center for Art & Historic Artifacts. (n.d.). Collections environment infographic. Conservation Center for Art & Historic Artifacts. Retrieved August 1, 2025, from https://ccaha.org/resources/collections-environment-infographic
Conservation Center for Art & Historic Artifacts. (2022, October 24). Temperature, relative humidity, and dew point for collections. Conservation Center for Art & Historic Artifacts. https://ccaha.org/resources/temperature-relative-humidity-and-dew-point-collections
Conservation Center for Art & Historic Artifacts. (2023, June 15). Hot and humid weather preservation tips from CCAHA’s preservation services office. Conservation Center for Art & Historic Artifacts. https://ccaha.org/news/hot-and-humid-weather-preservation-tips-ccahas-preservation-services-office
Core: Leadership, Infrastructure, Futures a division of American Library Association. (n.d.). Quick preservation tips. Preservation Week. Retrieved August 1, 2025, from https://preservationweek.org/resources/quick-preservation-tips/
Gaylord Archival. (n.d.). Agents of deterioration. Gaylord Archival. Retrieved August 1, 2025, from https://info.gaylord.com/resources/agents-of-deterioration
Taylor, J. T., & Beltran, V. L. (Eds.) (with Getty Conservation Institute). (2023). Managing collection environments: Technical notes and guidance. Getty Conservation Institute. https://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/mce-technical-notes-and-guidance.pdf

 

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