Where We Are in the Series

In Part 1, we set the audit mindset. In Part 2, we examined the chiller as a heat-removal system.

Now we’re at the step that decides whether your site visit will feel smooth and structured - or rushed and chaotic.

Before you visit the site, you need data.

The Mistake Most Auditors Make

Many auditors arrive on-site and start measuring straight away.

That’s a mistake.

Without pre-audit data, you don’t know what “normal” looks like, where the energy is going, or what truly deserves your attention. You end up measuring everything instead of focusing on what matters.

Strong audits start at the desk, not in the plant room.

The Three Data Sets You Must Have

Almost all useful pre-audit information falls into three buckets.

1️⃣ Energy Data - The Cost Baseline

Energy data tells you where the money is going. At a minimum, collect 6–12 months of electricity bills showing:

Energy consumption (kWh)
Demand (kW)
Tariffs
Basic operating hours

This lets you see seasonal trends, demand patterns, and the likely share of energy used by the chiller system.
Without this data, you can’t reliably quantify savings or justify your recommendations - no matter how good your technical findings are.

2️⃣ Equipment Data - What You’re Walking Into

Equipment data prepares you for what you’ll actually find on-site.
For the chiller, this includes:

Make
Model
Age
Capacity
Refrigerant type
and Efficiency ratings.

The overall system includes pumps, cooling towers, and major auxiliary equipment.

Having this information in advance lets you benchmark expected performance and avoid wasting time on-site hunting for nameplates or guessing capacities.

Arrive without equipment data, and your audit quickly becomes reactive instead of focused.

3️⃣ Operational Data - How It Actually Runs

Operational data often explains most of the energy waste.

You need to know:

When the system runs
When it’s supposed to run
How it’s controlled
What issues are already known

Operating schedules, occupancy hours, setpoints, maintenance history, and control strategies often reveal problems before you take a single measurement.

Many “inefficient” systems are simply running at the wrong time - or under weak control.

The One Question That Changes Everything

If you ask only one question before the audit, make it this:

“When is the chiller supposed to run?”

The answer immediately exposes scheduling waste, control gaps, and some of the biggest saving opportunities.

A chiller running 24/7 in a building used 10 hours a day is burning thousands of unnecessary operating hours every year - and you won’t see that clearly without pre-audit data.

What “Good Enough” Data Looks Like

At a minimum, you should have:

Several months of energy bills
Basic chiller specifications
A clear operating schedule

Ideally, you’ll also get maintenance records, control details, and any available historical trend data. You won’t always receive everything, but you should always ask.

Why This Step Matters

Without energy data, you can’t quantify savings.

Without equipment data, you waste time and miss performance benchmarks.

Without operational data, you chase hardware “problems” that are really control or scheduling issues.

Weak inputs lead to weak audits.

Key Takeaway

Data before measurement. Context before calculation.

The best audits are prepared, not improvised. A small amount of effort upfront leads to faster site visits, clearer findings, and recommendations that actually stick.

What’s Next?

In Part 4/8, we go on-site and walk through the inspection process - what to look for, what to document, and how to spot issues before you even pick up a meter.