At some point, every board asks the same question:
“We spent £200,000 on the project. Where’s the saving?”
Fair question.
Unfortunately, most organisations cannot answer it with anything stronger than, “The bills look a bit better.”
That will not survive contact with a finance director.
Measurement and verification, usually shortened to M&V, is how you prove whether an energy project has delivered what it was supposed to deliver. It turns energy data from a collection of charts into evidence that supports decisions, reporting and accountability.
This is not about creating another dashboard nobody opens. It's about establishing the truth before work starts, tracking what changes, and reporting it in a form boards, finance and operations can actually use.
The principle is simple:
Evidence then action.
It is the same measurement-first principle we set out in Measure Before You Change: Why Energy Monitoring Comes First for Every Business. That article explains why monitoring comes before behaviour change, technology and renewables. This one goes a level deeper: how you prove the result once the work is done.
Measurement and verification: savings are calculated, not directly measured
You can measure electricity consumption. You can measure gas consumption. You can measure demand, operating hours, temperature and production.
You cannot directly measure the energy you did not use.
That means savings are calculated by comparing actual performance with a properly defined baseline:
Savings = adjusted baseline energy use minus reporting-period energy use
The word “adjusted” is doing a lot of work there.
If energy use falls after a project, the reason might be the project. It might also be warmer weather, lower occupancy, reduced production, shorter operating hours or a building that was partly closed.
A simple before-and-after bill comparison cannot separate those factors. It can show a change. It cannot reliably explain the change.
That is why an IPMVP-style approach is useful. The Efficiency Valuation Organization’s IPMVP Core Concepts 2022 sets out a recognised framework for defining the measurement boundary, baseline, adjustments, calculations and reporting requirements.
It is an international protocol rather than a UK one, but UK practice is built on it. UK government guidance on energy performance contracting recommends basing the M&V approach on IPMVP, agreeing the measurement plan before the contract is signed, and tailoring it to the specific project. Government evaluations of the Electricity Demand Reduction pilot, run by what was then the Department of Energy and Climate Change, assessed IPMVP as suitable for the UK context and applied it as the framework for verifying metered electricity savings.
In UK buildings, the protocol sits alongside CIBSE guidance. CIBSE TM22 provides the energy assessment and reporting method for assessing the performance of an occupied building from metered energy use. CIBSE TM39: Building Metering and Monitoring (2026), the current edition published in May 2026, is the good-practice guide for designing, specifying and commissioning metering systems in non-domestic buildings, and includes guidance on data validation, reconciling submeter data against utility meters and reporting.
That is the difference between “we think it saved money” and “here is the evidence”.
Baselines: the work has to start before installation
The most important M&V work often happens before anyone installs anything.
Once the old system has been removed, you cannot go back and measure its real operating condition. You can estimate it. You can use nameplate data. You can ask somebody what it used to do.
But the original evidence has gone.
A proper baseline should set out:
- The equipment and systems included in the project
- The measurement boundary
- Energy sources and meters being used
- Operating hours and schedules
- Occupancy, production or throughput
- Weather variables where relevant
- Existing controls and setpoints
- Equipment condition and performance
- Data quality, gaps and exclusions
- The calculation method to be used afterwards
- Who owns each part of the data and verification process
For a whole-building project, the baseline may use utility bills, interval data, weather and operational information. For a specific motor, chiller or lighting system, it may be more sensible to measure the affected equipment directly.
A useful baseline is not necessarily the biggest spreadsheet. It is the one that reflects how the building actually operated before the intervention.
That matters because M&V should be proportionate. A small, straightforward lighting upgrade does not need the same level of analysis as a multi-building HVAC and controls project.
But every project needs enough evidence to answer the question being asked.
IPMVP options: choosing the right level of proof
“Estimated operating hours” should not quietly become “measured operating hours” in the final report. That single slippage is the most common way a defensible savings claim becomes an indefensible one, and it is what the IPMVP options exist to prevent.
The traditional IPMVP options are useful shorthand for thinking about the measurement approach.
Option A: measure the key parameters
This suits simpler projects where a few factors drive most of the savings.
A lighting project might measure fixture power and establish operating hours. Some parameters may be measured while others are based on documented assumptions or agreed values.
It can be practical and cost-effective, but the assumptions need to be visible, and labelled as assumptions.
Option B: measure the affected system properly
Option B uses measurement of all relevant energy and operating parameters.
This might suit a variable speed drive on a pump, where power, runtime, flow and pressure all affect the result. It generally provides more detail, but it also requires more metering, data handling and analysis.
Option C: analyse whole-facility performance
Option C looks at whole-building or whole-site energy use.
This is often appropriate where several measures interact or where the project affects the wider building. Utility and interval meter data can be analysed alongside variables such as weather, occupancy, production and operating hours.
A regression model may estimate what the building would have used under the actual conditions experienced during the reporting period.
That is more defensible than comparing two annual bills, particularly when buildings lie about what is driving demand.
Option D: use calibrated simulation
Option D involves a calibrated energy model. It suits complex projects or where no reliable existing baseline exists. It is powerful, but not a magic box: it needs good inputs, proper calibration and clear documentation.
The method should match the question, the investment and the risk. More complexity is not automatically better.
Buildings lie: the data needs a challenge process
Buildings do not lie deliberately. They simply produce numbers without explaining themselves.
A drop in electricity use may be a successful controls upgrade. It may also be a quiet production month. A rise in gas use may indicate poor boiler performance. It may be a colder winter or a change in operating hours.
This is where reactive effort becomes expensive. Teams respond to the latest alarming bill, urgent complaint or failed target without having a stable view of the underlying performance.
M&V helps move the organisation from reactive effort to controlled improvement.
Before installation, agree:
- What success means
- Which data will prove it
- What conditions need to be considered
- What changes will trigger an adjustment
- How often results will be reported
- Who reviews and approves the findings
Non-routine events must be logged too. A building extension, tenant change, production shift, equipment failure or operating-hours change can materially alter energy use.
Do not bury these changes in a footnote. Put them in an adjustment log with the reason, evidence, calculation and approval, and name the person who signs each adjustment off. A finance director wants to see that the log has an owner and a signatory, not just somewhere to file it.
A Finance Director will usually accept uncertainty when it is explained. They will not accept false precision.
“We saved 20%” is a weak statement if nobody can explain the baseline, the reporting period, the operating conditions or the margin of uncertainty.
To take an illustrative example:
“The adjusted baseline predicted 1.2 GWh for the reporting period. Actual consumption was 1.08 GWh. The estimated avoided consumption is 120 MWh, subject to the documented model uncertainty and the operating changes recorded during the period.”
That is a conversation finance can work with.
Reporting: the evidence has to reach the right people
M&V fails when the result is technically correct but operationally useless.
Boards need a concise view of:
- Investment made
- Project status
- Adjusted baseline
- Actual performance
- Estimated or verified energy impact
- Cost impact using the agreed rates
- Uncertainty and limitations
- Exceptions requiring a decision
- Next action and accountable owner
Facilities teams need something different. They need exceptions, drift, failed schedules, missing data and equipment that is not operating as intended.
Energy champions need a clear story they can share with colleagues. They need to see what changed, what worked and what still needs attention.
Same evidence. Different reporting.
This is where Enerlyse fits.
Enerlyse connects monitoring, invoice validation, carbon reporting, compliance and performance reporting into a usable account of what is happening across the estate. The point is not to admire the data. The point is to identify opportunities, act on them and check whether the intervention delivered.
If your organisation qualifies for ESOS, this evidence has a second job: it makes the audit easier to defend. Our ESOS Compliance Hub sets out what Phase 4 requires, from qualification and energy data through to director sign-off and Environment Agency notification, and walks through all ten stages step by step. The evidence trail that satisfies your board is the same one that survives an auditor's question, which is the reason to build it once rather than twice.
A good reporting cycle should flag:
- Missing or suspect meter data
- Changes in baseload power
- Unusual consumption patterns
- Variance from the adjusted baseline
- Equipment operating outside schedule
- Model residuals or unexplained changes
- Actions that have not been completed
- Projects that need further investigation
Reporting is not the final administrative step. It is part of the project delivery.
M&V and project delivery: prove the result, then keep it
Installation verification and savings verification are related, but they are not the same thing.
Installation verification asks:
- Was the specified equipment installed?
- Are the controls connected and programmed?
- Is the system operating safely?
- Are setpoints and schedules correct?
- Has commissioning been completed?
Savings verification asks:
- What energy use would have occurred without the project?
- What energy use occurred after installation?
- What conditions changed?
- What adjustments are needed?
- What level of uncertainty remains?
- Has the improvement persisted?
You need both.
A new control system can be installed correctly and still fail to reduce consumption if schedules are wrong. A building can show lower consumption while a project is not working because occupancy or production has fallen.
Our approach is built around connecting these questions: Enerlyse provides the evidence that identifies the opportunity, our Projects service turns it into a workable project, and the reporting shows what happened afterwards.
That is why our Projects service is designed to sit alongside energy intelligence rather than apart from it. Data should not end as a report and a to-do list.
The same principle applies to funding. Before borrowing capital for generation, storage or major infrastructure, look at the energy already being paid for without producing useful output.
The cheapest source of capital is the energy you are wasting.
That's not a telling-off. It's an opportunity. Better evidence can uncover operational improvements, strengthen a business case and help a board decide where capital should go next.
That is the argument we set out in The Cheapest Source of Capital, a practical walkthrough of finding that evidence before deciding which improvement deserves capital and attention.
Start with the evidence you already have
You do not need to begin with a perfect data estate.
Start with:
- Twelve months of bills, where available
- Meter coverage and meter ownership
- Operating hours and known site changes
- Existing submetering and BMS data
- Current projects and their stated success measures
- The reports currently going to the board
- The question finance is most likely to ask
Then test whether you could answer:
“We spent £200,000. What changed, compared with what would otherwise have happened, and how confident are we?”
If the answer is no, the next project should include the measurement plan before the installation plan.
Our Energy Health Check is a practical starting point for understanding where your organisation is today. It covers energy visibility, compliance, delivery and funding, so the next conversation is based on evidence rather than guesswork.
You can also email andrew@hawleyenergy.co.uk or call 01484 958761 to arrange a no-pressure 30-minute call. Bring the awkward question. They are usually the useful ones.
If you want to read more, click here: ESOS Compliance Hub