When organisations talk about reducing energy costs, they usually focus on the obvious: upgrading equipment, improving insulation or switching to LED lighting. Wasted energy in commercial buildings is often overlooked in these conversations.
But the biggest source of wasted energy is far simpler – and much more widespread.
Unnecessary out‑of‑hours operation is the number one hidden cost in commercial buildings.
And most businesses don’t even know it’s happening.
In this article, we break down why this issue is so widespread, how much it really costs and how Tyrrell Analytics help you tackle it with data‑driven precision.
What is out‑of‑hours energy waste?
Out‑of‑hours energy waste happens when building systems run outside of normal occupancy times. Typical culprits include:
- HVAC systems heating or cooling empty spaces
- Lighting left on overnight or during weekends
- Ventilation running at full capacity when no one is in the building
- Equipment and plant left running by default rather than by need
These issues often go unnoticed because they’re baked into schedules, legacy settings or assumptions about how the building should operate.
But the cost is far from invisible.
Why it’s the most expensive energy mistake
Out‑of‑hours operation is costly for three reasons:
1. It happens every day
Even small inefficiencies, a fan left running, a zone heated unnecessarily, accumulate into thousands of hours per year.
2. It’s rarely monitored
Most organisations track total consumption, not when or where it occurs.
That means waste hides in plain sight.
3. It’s completely avoidable
Unlike capital upgrades, fixing out‑of‑hours waste requires no major investment.
It’s a behavioural and operational issue, and that makes it the fastest win for energy savings.
How much does out‑of‑hours waste really cost?
For many buildings, 20-40% of total energy use occurs outside of occupancy hours.
That means a significant portion of your energy bill is spent conditioning, lighting and powering empty spaces, resulting in wasted energy in commercial buildings.
Across a portfolio, this can translate into:
- Tens of thousands of pounds in avoidable annual costs
- Higher carbon emissions (see how this contributes to carbon emissions reduction in the UK
- Reduced equipment lifespan due to unnecessary runtime
And because it’s not obvious, most organisations underestimate the scale of the problem.
Why most buildings don’t catch it
Even well‑managed facilities struggle to identify out‑of‑hours waste because:
- Schedules are outdated or misaligned with actual occupancy
- BMS data is overwhelming or incomplete
- Multiple contractors make changes without full visibility
- Manual audits only capture a moment in time
- Energy reports don’t show when waste occurs
This is precisely the gap Tyrrell Analytics was built to solve.
How Tyrrell Analytics eliminates hidden energy waste
Tyrrell Analytics gives you complete visibility into your building’s real‑world operation, not assumptions, not schedules, but actual performance.
With our platform, you can:
- Identify out‑of‑hours operation instantly
- Pinpoint the exact systems, zones, and times where waste occurs
- Compare expected vs. actual occupancy patterns
- Quantify the financial impact of every issue
- Prioritise actions that deliver the fastest ROI
Instead of guessing where energy is being wasted, you see it clearly and can take appropriate action.
The fastest way to cut energy costs and carbon emissions
If your organisation is under pressure to reduce energy spend, meet sustainability targets, or demonstrate operational efficiency, tackling out‑of‑hours waste is the smartest first step.
It’s fast.
It’s measurable.
And it delivers immediate savings.
Stop paying for energy you don’t use.
If you want to uncover hidden waste, reduce costs and optimise your building’s performance, Tyrrell Analytics can give you the clarity you’ve been missing.
Book a demo today and see exactly where your building is wasting energy, before it costs you another pound.
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