Six Energy-Saving Strategies for Collections Environments

Cutting HVAC and lighting energy use doesn’t have to mean compromising preservation quality. In this guide, Christopher Cameron, Conserv’s Director of Conserv Services, walks through six risk-managed strategies adapted from the Image Permanence Institute’s field-tested methodology — work he contributed to during his nine years at IPI.

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Every strategy below follows the same risk-managed cycle. Change one variable at a time, and log both the mechanical system and the collection space throughout.

How to test any strategy

1. Document the current system.
2. Gather data on baseline conditions.
3. Analyse the data.
4. Test and implement — a two-week trial, per season.
5. Assess and maintain — repeat seasonally.

Strategy 1 — System shutdowns

Energy savings: roughly 33% on an eight-hour nightly shutdown.*

The goal is to turn HVAC off entirely during unoccupied hours — the single biggest energy win available — while keeping fluctuation within a safe range.

• Best for: well-insulated, low-occupancy storage such as high-density stacks and sub-grade spaces.
• Watch for: bigger swings in poorly insulated buildings, and slow recovery before opening.

Strategy 2 — System setbacks

Energy savings: cumulative across every unoccupied night, weekend, and closure.

The goal is to dial back temperature and RH overnight or at weekends for systems that can’t fully shut down — much like setting back a home thermostat.

• Best for: facilities without automated shutdown, and RH-tolerant collections in the 40–50% range.
• Watch for: it’s easy to forget restoring normal operations. Skip this one on summer subcool and reheat systems.

Strategy 3 — Adjusting fan speed

Energy savings: roughly 87% less fan horsepower at 50% speed.*

The goal is to use a variable speed or variable frequency drive to slow fans when full airflow isn’t needed, without changing downstream temperature or RH.

• Best for: zones with low or inconsistent occupancy that still meet required air changes.
• Watch for: this requires a VSD or VFD, and some fans can’t safely run at reduced speed.

Strategy 4 — Seasonal set points

Energy savings: lower HVAC load from wider seasonal tolerances, with a 150% preservation index gain in IPI’s winter test.*

The goal is to shift temperature and RH targets with the seasons instead of holding one year-round set point, using outdoor conditions to save energy and improve preservation together.

• Best for: any climate with a real seasonal swing, and mid-Atlantic and northern climates especially.
• Watch for: it’s easy to forget resetting for the next season, and comfort complaints if the space is occupied.

Strategy 5 — Outside air reductions

Energy savings: often the largest single reducible energy load on an air handling unit.

The goal is to bring in only the outside air needed for indoor air quality and off-gas management, rather than the design-minimum default most systems still run.

• Best for: collections storage with low daytime occupancy and minimal off-gassing.
• Watch for: reducing too far can affect air quality, and this requires balancing and pressurisation checks.

Strategy 6 — Light reduction

Energy savings: lighting accounts for roughly 18% of commercial building energy use.*

The goal is to cut lighting energy use and reduce the collection’s exposure to damaging UV, visible, and infrared light by adjusting how long, and what type of, lighting runs.

• Best for: spaces where lights are routinely left on when unoccupied.
• Watch for: new fixtures and sensors require investment, and savings are smaller than the HVAC strategies.

Before you test anything

• Change one variable at a time so cause and effect stay clear.
• Log both the mechanical system and the collection space throughout.
• Run an initial test for at least two weeks, repeated each season.
• If it works, write it into the system’s permanent sequence of operations.

Document your process

Every stage of the process needs to be documented. A strategy that works but never makes it into the building automation system’s sequence of operations is easy to lose — during a controls upgrade, a recommissioning cycle, or simply when staff turn over.

Retest seasonally

Each strategy should get an initial retest across seasons, since tuning that works well in one season may not hold up in another. Once a strategy’s limits have been validated for a given season, they can generally be reused going forward, but keep an eye on the data afterwards in case conditions shift.

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Adapted from the Image Permanence Institute’s Methodology for Implementing Sustainable Energy-Saving Strategies in Collections Environments (Image Permanence Institute, Rochester Institute of Technology, 2017), funded by the Institute of Museum and Library Services. Figures marked * are drawn directly from IPI’s field research and reflect typical, not guaranteed, results — savings vary by building, climate, and system.

The printable version of this guide, along with our full set of HVAC and facilities reference guides, is available in the Conserv resource library.