Energy

Shoulder Season Strategies: Optimizing Building Schedules for Fall Efficiency

How to use the fall transition to cut waste, protect comfort, and set your systems up for winter

When outside temperatures drift into the not-too-hot, not-too-cold zone, many buildings keep running as if peak summer highs were still in effect. But the fall “shoulder season” – the transitional period between cooling- and heating-dominant weather – is one of the cheapest, lowest-risk windows to re-tune schedules, widen setpoint bands, and lock in efficiency before winter hits.

Fall optimization isn’t about massive capital projects or complex retrofits. It’s about cleaning up what’s already there: better aligning operations to actual occupancy, verifying that setback logic behaves as expected, and using milder conditions to stress-test your BAS logic and automation routines before winter arrives.

This post lays out a pragmatic playbook for facility teams and energy managers to use the fall shoulder season to optimize schedules, reduce runtime, and maximize system efficiency, without sacrificing comfort or indoor air quality.

Why Shoulder Season Matters

The shoulder season is a time of reduced heating and cooling demand, yet HVAC systems often continue running as if it’s still peak season. Occupancy schedules remain static, equipment settings go unchecked, and setpoints linger from summer, driving unnecessary energy use and causing wear on equipment. According to fault detection rules from Noda, common issues during this time may include AHUs operating while buildings are closed, unnecessary heating or cooling cycles, and fans running 24/7 despite mild outdoor conditions.

These inefficiencies are not just technical; they’re cultural. In many portfolios, building schedules remain on autopilot. Facilities and engineering teams may be too strapped to review them, or lack granular insight into when and where energy waste is occurring. However, with a bit of proactive attention during fall, building operators can catch these inefficiencies early, helping to reduce operating costs (a relief after high summer utility bills) and enhance the longevity of systems and equipment.

Schedule Optimization: A Missed Opportunity

One of the most common energy-saving opportunities missed during the shoulder season is schedule drift. Over time, operational schedules often fall out of sync with actual occupancy. A building might be set to occupied mode from 6am to 8pm daily, even though actual use has shifted to 9am to 5pm. Multiply that across a large portfolio and the energy waste is significant.

To address this, facilities and engineering teams can perform a schedule rationalization exercise. Start by comparing historical occupancy data (where available) to actual HVAC schedules. In the absence of occupancy sensors, even access control or Wi-Fi log data can serve as proxies. Aligning HVAC operation more tightly with these patterns can yield double-digit energy savings with no impact on tenant comfort.

Fall is also a prime time to audit setback temperatures, which are often conservative or based on outdated requirements. Adjusting setpoints by just 1-2°F in unoccupied hours can yield outsized returns during cooler months when systems cycle more frequently to maintain minimum thresholds.

What “Good” Looks Like in Shoulder Season

A well-managed building in fall typically shows:

Right-sized schedules that reflect actual occupancy.
Wider temperature deadbands to reduce simultaneous heating and cooling.
Reset strategies for air and water temperatures based on real-time conditions.
Verified economizer performance to maximize free cooling.
Optimal start/stop logic that actually adapts to zone drift rates.
Clear exceptions for holidays, cleaning crews, and after-hours use.
Monitoring for drift, like overrides, out-of-hours runtime, or setpoints reverting.

A step-by-step fall optimization playbook

1) Inventory and clean up schedules

Export current BAS schedules for AHUs, RTUs, plants, zone groups, and key terminal equipment.
Find and clear overrides. Identify points left in hand, safeties bypassed “temporarily,” or operators forcing valves/fans.
Compare to real occupancy. Pull access control, booking, or BMS trend data to validate whether spaces are used when systems are on.

Deliverable: a single source of truth “Schedule Matrix” that maps equipment → occupied hours → exceptions.

2) Widen temperature bands and tighten logic against simultaneous heating/cooling

Occupied band: consider moving from a narrow 1–2°F band to 3–4°F (or more) when comfort and process loads allow.
Unoccupied band: widen aggressively (e.g., 60–85°F / 15.5–29.5°C), with carve-outs for critical zones.
Lockout logic: ensure boiler and chiller lockouts are seasonal and temperature-informed, not fixed year-round.

3) Reset setpoints dynamically

Supply air temperature (SAT): reset upward as OAT drops or as average VAV damper positions fall.
Chilled water (CHW): consider higher CHW setpoints or full chiller lockout if loads are truly absent.
Hot water (HW): lower HW supply temperatures and disable secondary pumps on demand.
Static pressure: reset to the lowest value that still satisfies the “worst” served zone.

4) Recommission economizers and free cooling

Functional tests: verify that outdoor air dampers modulate as expected, high-limit logic is correct (temperature, enthalpy, or dew point), and sensors are calibrated.
Dehumidification/rehumidification guardrails: shoulder seasons can be humid in certain regions. Make sure economizer logic cooperates with humidity control to avoid counterproductive reheat.

5) Tune optimal start/stop and night setback

Data-drive it: use trend data (zone temp drift rates, preheat times) to set realistic optimal start parameters.
Night setbacks: let zones float during unoccupied hours and start equipment only as much as needed to hit the first occupied setpoint.

6) Re-align ventilation with occupancy and IAQ

Demand-controlled ventilation (DCV): ensure CO₂ (or occupancy proxy) actually drives OA rates during low loads.
After-hours ventilation policies: codify minimum OA and fan runtime for cleaning crews, server rooms, and 24/7 areas.

7) Plant sequencing and seasonal lockouts

Chillers: define the OAT/load thresholds where chillers are fully off; rely on economizers or waterside economizers where available.
Boilers: delay boiler enable until you truly need heat — and ramp HW temps based on OAT or return water temperature.
Heat pumps / VRF: verify mode-change logic to avoid simultaneous heating and cooling in mixed-mode periods.

8) Monitoring, measurement, and persistence

Post-change verification: track comfort (complaints, zone temps), IAQ, and energy against a pre-change baseline.
Alerting: instrument rules for out-of-hours runtime, unexpected valve positions, and reset schedules reverting to defaults.
Document & version: store the fall schedule matrix, reset curves, and lockouts in a version-controlled location.

Comfort, IAQ, and risk management — don’t cut blindly

Efficiency is not an excuse for poor air quality or thermal comfort. A few guardrails:

Track IAQ continuously (CO₂, RH, PM2.5 where relevant) to ensure ventilation reductions are safe and compliant.
Beware humidity in mild but moist climates. Maintain dew point limits and reheat only where necessary.
Document carve-outs for labs, data rooms, health spaces, or process-critical zones.
Monitor complaint channels (work orders, emails) post-change. A small bump in complaints may be acceptable if overall comfort stays inside ASHRAE 55/62.1 ranges — but measure it, don’t guess.

Common pitfalls to avoid

Leaving summer overrides in place: It’s the #1 reason savings don’t show up.
Simultaneous heating and cooling during mixed-mode days: Tighten lockouts and widen bands.
Not verifying economizer sensors: A failed OA temperature sensor can destroy your savings (and comfort) quietly.
Plant sequencing drift: Chillers or boilers left enabled “just in case” will run on standby losses and pumps.
Static pressure too high all season: Fans eat a disproportionate share of energy at part load; reset them.
No persistence layer: If you can’t see schedule drift and out-of-hours runtime, you’ll be back where you started next fall.

Make it stick: governance for schedules

Treat schedules as governed assets, not tribal knowledge:

Standardize templates (weekday/weekend/holiday; office/lab/retail; summer/shoulder/winter).
Version control changes with timestamps, authors, and rollback notes.
Automate checks that alert when a schedule is created with 24/7 occupancy or when equipment runs outside its assigned block.
Align with corporate carbon targets by converting saved kWh and therms into CO₂e and reporting it upstream

Final Thoughts: Don’t Let Shoulder Season Drift

Most buildings lose efficiency not from major failures but from drift — a setpoint that never reset, a fan that never shut off, a cooling valve that never closed. Fall is your chance to reset course.

Whether you’re running a Class A office tower, a school district, or a hospital campus, use the shoulder season as your annual systems tune-up. The effort is minimal, the costs are low, and the payoff — in savings, comfort, and system longevity — will carry you all the way through winter.

About Noda

Noda is a data and analytics company on a mission to make every building smarter, more efficient, and more sustainable. Recently ranked in the top 10 tech companies leading the charge on climate action, its AI-powered suite of products surface unique insights that empower real estate teams to reduce costs, decrease time spent on routine work, and find and act on opportunities to save energy and carbon. Discover how Noda's solutions can unlock the potential of your assets and accelerate the transition to net zero. Visit us at noda.ai to learn more.