Measurement & Verification: A Guide for Energy Projects
How to calculate the energy and carbon savings attributable to your projects and programmes
What Is Measurement & Verification (M&V)?
The cheapest and cleanest unit of energy is the one you never use. But proving you didn’t use it is harder than it sounds, because you’re trying to measure something that, by definition, never happened.
This is where Measurement & Verification (M&V) comes in. M&V is the process used to plan, quantify and report the energy, cost and carbon savings attributable to an energy efficiency or decarbonisation project or programme.
The best practice standard for M&V - and the basis for this guide - is the International Performance Measurement & Verification Protocol (IPMVP).
This guide explains why M&V matters, and how IPMVP works in practice, alongside real-world use cases and practical applications - so whether you're commissioning M&V or reviewing someone else's numbers, you know what 'good' M&V looks like.
*IPMVP® is a registered trademark of the Efficiency Valuation Organization (EVO).
The Problem M&V Solves
Your project is complete. The invoices have been paid, the equipment is operational and the business case says you should be saving a healthy amount each year. Then your Finance Director asks: how much are we actually saving?
It sounds like a straightforward question. In practice, it isn't.
The problem is that you cannot directly measure energy you have saved. 'Savings' are the energy no longer being used as a result of the project, so they don't appear on a meter or in an energy bill. To determine them, you need to answer a different question: how much energy would we have used if the project hadn't happened? This is known as the counterfactual — the business-as-usual level of consumption that would have occurred without the project.
M&V exists to answer that question in a structured, standardised way. Rather than simply comparing energy consumption before and after a project, it uses measured energy data alongside the factors that influence consumption — weather, occupancy, operating hours, production volumes — to build a robust counterfactual baseline: what energy use would have looked like under the same conditions if the project hadn't happened. Actual post-project consumption is then compared against that baseline, and the difference is the saving attributable to the project.
This matters because a simple before-and-after comparison of meter data can be misleading. Energy consumption changes for plenty of reasons that have nothing to do with an efficiency project — weather, occupancy, operating hours, production levels, how a building is used. A building might use more energy after an efficiency project than before, but that doesn't mean the project failed — it may simply mean consumption would have been even higher without it.
That's the core purpose of M&V: to separate the impact of a specific project from everything else that influences energy consumption, and provide credible evidence of the savings actually achieved.
How Energy Savings Are Calculated
Below is a step-by-step illustration of the basic M&V process. Click through steps 1 to 7, or press play:
Meter the site for a full annual cycle before the project starts, capturing every season and pattern of use — this is what the blue bars show.
Total Energy Savings
≈181,700 kWh (~16%)
A saving against the counterfactual — this is the total of the shaded area above: the gap between the model and the metered bars, added up month by month across the reporting period.
Illustrative only. Bars show metered monthly consumption. The line is the baseline model calculated from that data — carried forward into the reporting period to estimate the counterfactual: what the site would have used if the project had never happened.
The International Performance Measurement and Verification Protocol (IPMVP) is the global best practice framework for measuring and verifying energy savings, developed and maintained by the Efficiency Valuation Organization (EVO).
IPMVP is not a detailed ‘how to’ guide, but sets out the standardised good practice principles, processes and procedures that should be followed so that savings calculations are transparent, comparable and trusted.
Six key principles underpin an IPMVP-quality M&V approach:
■ Accuracy. Use an appropriate level of measurement and analysis for the value and complexity of the project.
■ Completeness. Account for all material factors affecting energy performance within the measurement boundary.
■ Conservativism. Where uncertainty exists, avoid overstating savings.
■ Consistency. Use a methodology that allows performance to be compared fairly over time and between projects.
■ Relevance. Focus measurement and analysis on the factors that actually influence the project’s performance.
■ Transparency. Document the data, assumptions, calculations and judgements so another party can understand and reproduce the result.
M&V versus Monitoring
It is important to point out that M&V is not the same as monitoring. Energy monitoring tells you what energy consumption is doing. M&V goes further - it uses measured data and an agreed methodology to determine how much of the change in monitored energy use can reasonably be attributed to a particular project. Monitoring is therefore an important input to M&V, but it isn't M&V itself.
IPMVP: The Foundation of Good M&V
| IPMVP Option | In plain English | How energy is typically measured | Typical use |
|---|---|---|---|
| A Key Parameter Measurement |
You measure the most important performance factors and estimate the others. | Existing meter data, combined with spot measurements or checks of key parameters such as equipment output, operating hours or load. | Simple projects such as lighting upgrades or straightforward equipment replacements. |
| B All Parameter Measurement |
You measure all the important energy-related parameters before and after the project. | Dedicated meters, submeters or temporary measurement equipment such as clamp meters, flow meters or temperature sensors. | Projects involving boilers, chillers, pumps, fans, variable speed drives and other equipment where performance can be measured directly. |
| C Whole Facility |
You look at overall energy use and analyse how it changes over time. | Main utility or fiscal meters, smart meters, BMS data and other whole-building energy data. | Multi-measure building retrofits and projects where several measures affect overall energy consumption. |
| D Calibrated Simulation |
You use a computer model to estimate energy performance where direct measurement isn’t practical. | Model inputs from design information, building characteristics, measured data and utility consumption. | New buildings, major refurbishments or projects where there isn’t enough reliable historical data for another approach. |
IPMVP provides four recognised approaches for determining a project’s savings. The appropriate approach depends on what you are trying to measure, where the measurement boundary is drawn, the data available and the level of confidence required.
The underlying principle is the same for all four: establish what energy use would have been without the project, then compare it with what actually happened.
The difference between the options is in what you measure and where you draw the measurement boundary. Selecting the right Option - A, B, C or D - depends on the type of project, the data available and how easily the impact of the project can be separated from other changes.
Table 1: The IPMVP Options
IPMVP’s Four Options
Diagram 1: Example Measurement Boundaries
Which Option should you use?
As a basic rule of thumb:
If you are installing one clearly defined energy saving measure (e.g. a lighting upgrade) - Option A or B will often be appropriate.
A piece of equipment where you can measure its performance directly - Option B may be the best choice.
Several measures across a building or site - Option C is often appropriate, particularly where good whole-building energy data is available (e.g. via half-hourly AMR meters).
A new building or major refurbishment where there isn't enough historical data - Option D may be appropriate.
These are only rules of thumb - there is no single ‘best’ M&V option. The approach should be chosen to suit the project and provide a reliable, practical and cost-effective way of determining the savings.
Your M&V provider should be able to explain why the chosen option is appropriate for your project. If they cannot explain it clearly, ask them to explain the approach, the data required and how it will demonstrate the savings.
A note on metering
IPMVP does not prescribe a particular type of meter for each Option. The appropriate meter or data source depends on what needs to be measured, the accuracy required and the M&V approach. Depending on the project, this could include:
Fiscal or utility meters for whole-building or site energy consumption
Smart meters providing more frequent consumption data
Submeters measuring individual systems or areas
BMS data for equipment operation and building conditions
Temporary measurement equipment, such as clamp meters, flow meters or temperature sensors
Existing operational data, where it is sufficiently reliable for the M&V purpose
The objective isn't to install as many meters as possible. It is to collect the right data, at the right level of accuracy, to provide credible evidence of the savings.
How M&V Works: The Seven-Step Process
In accordance with IPMVP, every credible M&V exercise should follow the same broad sequence, whether it is a single lighting upgrade or a multi-site Energy Performance Contract (EPC).
1. Develop an M&V Plan Sets out how the savings will be calculated and reported, before the project is implemented.
A crucial reference document setting out the agreed ‘rules of the game’: the scope of the project, the IPMVP Option to be used, the baseline, the metering and data that will be used, how changes will be treated, and how savings will be quantified, verified and reported. Because savings are calculated using a mathematical model, rather than being measured directly, this agreement helps to build certainty around the modelling process and helps stop the parties reaching different conclusions from the same data later on. For anything linked to contractual payments or funding decisions, ensure the M&V Plan is independently verified (to IPMVP standards) and signed off by all parties before it is written into the contract.
2. Collect and Validate Data Assemble the evidence needed for robust analysis.
Good M&V depends on more than meter readings. You may also need weather data, occupancy and operating hours data, Building Management System (BMS) data, and a record of anything unusual that happened on site — e.g. power cuts, generator tests or one-off events. Before analysis starts, check the data is complete, uses the right meters, and reflects normal operation. Poor-quality data creates baseline errors that are hard to fix later. Modern metering and analytics tools can flag that consumption has changed far faster than a monthly bill ever could, but they cannot tell you why. That still takes someone who knows what happened on site.
3. Develop the Baseline Model Predict expected energy use as if the project hadn’t happened.
The baseline model predicts what the building (or equipment) would have consumed without the project. Since savings cannot be measured directly, they are calculated as the gap between this prediction and what was actually metered. For simple projects this may just be a pre-installation measurement; for whole-building projects (Option C) it is usually built with regression analysis, modelling daily energy consumption against variables like daily temperature (via degree days), occupancy or production. A well-built baseline model is representative, accounts for the key variables, is transparent enough to reproduce, and is documented in the M&V Plan.
A baseline model should not just be built; it should be tested. Good practice checks it two ways: does it make engineering sense (heating use, for example, should clearly track outside temperature), and does it perform well against statistical checks such as how much of past energy use it explains, how accurately it predicts, and whether it is biased toward over or under-predicting. A model that passes the statistical tests but does not reflect how the building actually operates should still be treated with caution.
4. Implement the Project And verify it was correctly installed and commissioned.
Installing new equipment does not automatically deliver savings — an operational verification step means confirming the installation matches the specification, checking control strategies and schedules, and verifying meters and sensors are working correctly.
5. Monitor Performance Collect energy and operational data throughout the reporting period.
Throughout the agreed reporting period (as defined in the M&V Plan), energy and operational data is collected to compare against the baseline, and, just as importantly, anything that changes on site is recorded. M&V is an ongoing process, not a single calculation at the end. Regular monitoring catches problems early and builds the evidence base for the final numbers.
6. Calculate Savings Apply the agreed M&V methodology to determine the savings.
The methodology set out in the M&V Plan is applied to the reporting-period data, with routine adjustments (for predictable factors like weather) and non-routine adjustments (for one-off changes, like extended opening hours, power cuts etc) applied so the result reflects only the project’s impact. A careful analyst will also sanity-check the baseline model itself at this stage, reviewing how well it fits the data before relying on it to defend a savings figure. Where payments or guarantees are at stake, this is where independent verification can be used to check that the methodology was correctly applied and the savings accurately reported without error.
7. Report Savings Communicate results and use the findings to optimise future performance.
A good M&V report does not just state a savings figure, it shows how that figure was derived: the methodology and IPMVP Option used, the baseline and any adjustments applied, measured consumption, and the resulting verified savings, alongside key assumptions and any uncertainty. A figure that cannot be explained should not be treated as verified. Beyond proving the project worked, comparing actual against expected performance over time also flags opportunities to optimise further, which is why M&V is as useful for improving a project as it is for judging it.
Measurement & Verification is intended to provide an objective assessment of the savings delivered by an energy or decarbonisation project. Where the results determine supplier payments, performance guarantees, funding releases, investment decisions or other significant commercial outcomes, having an independent party involved can provide an important additional layer of confidence.
There are two ways an independent M&V provider can add value:
Independent M&V means the M&V process is designed and delivered independently of the organisation or supplier responsible for implementing the project. The independent M&V provider can develop the M&V Plan, establish the baseline, define the measurement and analysis approach, collect and assess the data, calculate the savings and report the results.
Independent Verification is narrower. In this case, the supplier or project team undertakes the M&V calculations, and an independent specialist reviews the methodology, calculations, data and supporting evidence to confirm that the results are reasonable and consistent with the agreed approach.
In both cases, independence helps reduce the potential for commercial interests to influence the outcome.
Why independent M&V matters
Building trust in reported savings
M&V involves professional judgement. Establishing a baseline requires decisions about the appropriate baseline period, which variables influence energy consumption, how changes in operating conditions should be accounted for and how unusual events should be treated. Different reasonable assumptions can sometimes produce materially different estimates of savings.
Where the party calculating the savings also has a financial interest in the result, there is an inherent potential for conflict of interest. Independent M&V provides greater separation between the project outcome and the organisation responsible for determining or reporting the savings.
For customers and funders, this can provide:
Greater confidence that reported savings are credible and independently assessed
Reduced risk when payments or investment decisions depend on project performance
Greater transparency around assumptions, calculations and evidence
A defensible evidence base for boards, auditors, funders and other stakeholders
Consistency in how savings are calculated and reported
For suppliers and project developers, independent M&V can also strengthen credibility of their performance claims. A saving verified by an independent specialist is more readily trusted than a saving that has simply been self-reported.
“Just as financial auditors protect the integrity of a set of accounts, independent M&V protects the integrity of a reported energy saving — creating trust precisely where the customer’s and the supplier’s interests diverge. In practice that means acting as referee, fact-checker, and often the glue that holds a performance relationship together once real money is riding on the number.”
Ian Jeffries
Managing Director, EEVS
Expertise in M&V
Measurement & Verification is a specialist discipline, and the quality of the people carrying it out can have a significant impact on the reliability of the results. EVO oversees two professional M&V qualifications, providing a recognised framework for developing M&V knowledge and expertise:
PMVA (Performance Measurement & Verification Analyst).A foundation-level qualification covering the principles and practical application of M&V. It is particularly relevant to energy managers, engineers and other professionals involved in energy performance projects.
PMVE (Performance Measurement & Verification Expert).An advanced qualification for professionals who develop M&V Plans, undertake detailed analysis and lead more complex M&V assignments.
What qualification should you look for?
A qualification is useful evidence of M&V knowledge and competence, but it is not a guarantee of the quality of an individual assignment. When appointing an M&V professional, you should also consider their practical experience, understanding of your project, approach to data and analysis, and ability to explain and defend their methodology.
For more complex projects, it is particularly important that the person responsible for the M&V has the appropriate level of experience to develop and justify the methodology, rather than simply holding a qualification.
As well as offering both PMVA and PMVE training courses, all EEVS M&V specialists hold PMVA or PMVE certification, alongside practical experience in applying M&V to real energy and decarbonisation projects.
Common Challenges in M&V
Buildings are dynamic, and energy use is influenced by many factors beyond the measures themselves. Good M&V recognises this, accounts for them transparently, and makes sure reported savings fairly represent the project’s impact. For example:
Weather and Operational Changes
Buildings do not operate under identical conditions year to year. A colder winter can increase heating demand despite a successful boiler upgrade; extended operating hours can increase electricity use even though equipment has become more efficient. Good M&V adjusts the baseline for these changes so reported savings reflect the project, not how the building happened to be used.
The same logic applies to a leisure centre pool hall: bather numbers, pool covers and even a change in water-temperature setpoint can shift energy use by more than any efficiency measure, which is exactly why the baseline needs to account for these factors rather than just the season.
Data Quality
Reliable savings calculations depend on reliable data. Missing meter readings, estimated bills, faulty meters or gaps in BMS data all reduce confidence in the result, as does a poor record of the operating conditions during the baseline period. Validating data before analysis begins is one of the simplest ways to improve the credibility of an M&V exercise.
Multiple Measures Implemented Together
Many projects install several measures at once, which often maximises savings but makes it harder to attribute the contribution of each. Improvements can also interact: reducing lighting energy, for instance, can reduce cooling demand too. A well-developed M&V Plan identifies these interactions up front and defines how savings will be attributed.
Changes Unrelated to the Project
Buildings keep evolving after a project completes: equipment gets replaced, occupancy changes, spaces get refurbished for reasons that have nothing to do with the energy measure. Left unaccounted for, these changes get mistaken for project savings, or mask savings that were genuinely achieved. IPMVP’s routine and non-routine adjustments exist specifically to strip these effects out.
Capital retrofit projects are one of the most common applications of M&V. They include projects such as boiler and HVAC replacement, heat pumps, lighting, controls, building fabric improvements and whole-building decarbonisation programmes.
The equipment installed is not, by itself, the measure of success. The important question is whether the project has delivered the energy, carbon and financial benefits expected when the investment was made.
M&V can provide evidence of actual performance and help organisations understand whether their investment is delivering the expected return.
Typical applications include:
- Heat pumps and low-carbon heating
- LED and street-lighting upgrades
- BEMS and controls optimisation
- HVAC replacement
- Building fabric improvements
- Solar PV and other on-site generation
- Multi-measure and multi-building retrofit programmes
For larger or more complex projects, independent M&V can provide additional confidence that savings have been calculated fairly and consistently with the agreed methodology.
M&V becomes particularly important where payment or financial performance is linked to energy savings.
Energy Performance Contracts (EPCs), guaranteed-savings arrangements, gain-share and shared-savings contracts can all involve financial consequences if the savings achieved differ from those expected.
In these situations, M&V provides the agreed mechanism for determining performance and can be used for:
- Calculating guaranteed savings
- Determining performance payments
- Assessing shortfalls or over-performance
- Releasing retention or other payments
- Monitoring performance throughout the contract
- Resolving disagreements about savings
- Demonstrating value for money to funders and stakeholders
Where the supplier is also responsible for calculating its own performance, independent M&V or independent verification can provide an important additional layer of confidence for both parties.
The earlier M&V is incorporated into the contract, the better. The M&V Plan should establish the methodology, baseline, measurement approach and treatment of changes before the project begins, rather than leaving these decisions until savings are being claimed.
Not all energy savings come from replacing equipment or making large capital investments.
Energy optimisation programmes can improve the performance of existing buildings and systems through measures such as:
- BEMS optimisation
- Changes to operating schedules
- Continuous commissioning
- Heating and cooling control strategies
- Setpoint optimisation
- Behavioural or operational changes
- Ongoing energy management
These programmes can be particularly challenging to evaluate because performance may change continuously throughout the contract rather than following a single installation.
Where providers are paid through gain-share, shared-savings or other performance-based arrangements, M&V provides the evidence needed to distinguish genuine project savings from changes caused by weather, occupancy, operating hours or other factors.
For longer-term optimisation programmes, M&V is an ongoing discipline rather than a calculation performed once at the end of a project.
Public-sector organisations have particular reasons for using M&V. Energy and decarbonisation projects can involve significant public investment, while buildings often have complex and changing patterns of occupancy and use.
M&V provides an evidence base for understanding whether projects have delivered the energy, carbon and financial benefits expected, and whether public money has been invested effectively.
Typical applications include:
- NHS estates
- Local authority buildings
- Schools and colleges
- Universities
- Government estates
- Leisure centres
- Street lighting
- Social housing
- Multi-building public-sector programmes
Public-sector procurement frameworks and funding programmes may also include specific requirements for measuring and reporting savings. M&V should therefore be considered alongside the procurement and funding arrangements, rather than added once a project is already underway.
For organisations managing multiple projects, consistent M&V can provide value beyond proving individual savings. It can help build an evidence base showing which interventions are working, where performance is falling short and where future investment is likely to have the greatest impact.
The challenge becomes more complex when M&V is applied across an entire estate rather than a single building or project.
Large organisations may have hundreds of buildings, different building types, multiple energy suppliers and varying levels of metering and data quality. Projects may also be delivered at different times and by different suppliers.
A consistent M&V framework can provide a common basis for measuring performance across the portfolio. This can enable organisations to:
- Compare performance across similar buildings
- Track savings from multiple projects
- Identify underperforming assets
- Understand which interventions deliver the best results
- Prioritise future investment
- Monitor performance over time
- Build a stronger evidence base for decarbonisation strategies
At this scale, consistency and data quality become particularly important. The objective is not necessarily to apply exactly the same M&V methodology to every building, but to establish a proportionate framework that produces useful and comparable information across the portfolio.
M&V is not limited to existing buildings.
For new buildings and major refurbishments, there may be little or no historical energy consumption against which to establish a conventional baseline. In these circumstances, energy modelling and calibrated simulation may form an important part of the M&V approach, and IPMVP Option D may be appropriate.
M&V can help determine whether the completed building performs as expected and identify significant differences between predicted and actual energy performance.
This can be particularly valuable where a building has ambitious energy performance targets or where operational performance forms an important part of the business case.
The earlier M&V requirements are considered, the better. Metering, data collection, commissioning and operational arrangements can be designed into the project from the outset rather than added retrospectively.
M&V can also be applied to individual technologies or systems where their performance can be measured relatively directly.
Common examples include:
Heating and cooling
- Heat pumps
- Boilers
- Chillers
- Heating and cooling controls
Electrical systems
- Lighting
- Variable speed drives
- Fans and pumps
- Compressed air
- Refrigeration
Renewable energy
- Solar PV
- Other on-site generation
The important consideration is the measurement boundary. Measuring the electricity consumption of a new heat pump, for example, does not by itself establish its energy saving. You may also need to consider the heat delivered, the performance of the system it replaced and changes in the building’s heating demand.
The appropriate M&V approach therefore depends on what you are trying to demonstrate, what can be measured reliably and how important the resulting savings figure is.
M&V can be applied to almost any energy efficiency or decarbonisation project where you need to understand what savings have actually been achieved.
The level of M&V should be proportionate to the size, complexity and commercial importance of the project. The following are some of the most common applications:
Practical Applications of M&V
Choosing the right approach
The examples above illustrate an important principle - there is no single M&V approach that is right for every project.
A simple technology replacement may need relatively straightforward measurement, while a multi-million-pound Energy Performance Contract may require detailed baseline modelling, ongoing monitoring and independent verification.
The M&V approach should be agreed before implementation, taking account of the value and complexity of the project, the data available, the level of confidence required and the consequences of getting the savings figure wrong.
A handful of habits separate M&V that holds up under scrutiny from M&V that does not.
Agree the M&V Plan before work starts, and write it into the contract, not just the tender documents.
Match the rigour to the value at stake. A £15k lighting upgrade does not need the scrutiny of a multi-million-pound energy performance contract.
Insist on independent verification wherever savings determine a payment or a claim your Board will rely on.
Keep a record of anything that changes during the reporting period: occupancy, opening hours, refurbishments. This is the single most common source of M&V disputes.
Build M&V into the tender or spec from the outset, not as an afterthought once a supplier is chosen.
Ensure suppliers confirm their approach - ask what IPMVP Option is being proposed, and why, and who is qualified (PMVA, PMVE or CMVP) to review it.
Six Things to Remember
Key Takeaways
Going back to the question this guide opened with: your Finance Director asking how much a project actually saved. There is no shortcut to that answer - savings can't be read off a meter, they have to be calculated. But with the right M&V approach in place from the start, it is always an answerable question. In summary:
Savings can't be measured directly.They only exist by comparison - actual consumption against a modelled counterfactual of what would have happened without the project. That's the problem M&V exists to solve.
IPMVP makes that comparison credible. Six principles (accurate, complete, conservative, consistent, relevant, transparent) and four measurement Options (A–D) give everyone - customer, supplier, funder - a shared, standardised way to calculate and check a savings figure.
The process is the same shape whatever the scale. Plan, collect data, build the baseline, implement, monitor, calculate, report. Get the M&V Plan agreed before the project starts, and most later disputes never happen.
Independence builds trust precisely where commercial interests diverge. Wherever a saving determines a payment, a guarantee, or a number your board will rely on, independent M&V (or independent verification of a supplier's own numbers) is what turns a claimed saving into a defensible one.
There's no single ‘right’ approach - only the approach that's proportionate to what's at stake, and robust enough to survive being challenged.
-
Not always to the same rigour as a multi-million-pound EPC. But even a simple lighting upgrade benefits from a lightweight M&V approach (Option A). A basic pre/post comparison with a documented methodology is usually enough to justify the spend, without the cost of a full independent review.
-
For straightforward projects, an energy manager with a good grasp of IPMVP principles (and ideally a PMVA qualification) can often run the M&V process in-house. Bring in independent expertise wherever a supplier is being paid against the numbers, a funder needs assurance, or the project is complex enough that a second opinion is worth the cost.
-
It will scale with project value and complexity. A simple Option A exercise might be a few days’ work, while ongoing Option C verification on a multi-site performance contract is a recurring cost over the term. As a basic rule of thumb, it should be proportionate to what is at stake and, for energy and cost saving schemes, never more than 10% of a project’s projected savings.
-
M&V planning should commence before the project starts. The reporting period should be sufficient to provide a robust assessment of long term savings. For many schemes this is typically 12 months, to capture a full seasonal cycle. Optimisation contracts often report savings quarterly or biannually across a much longer term.
-
A bill comparison shows that usage changed. It cannot tell you why, or how much of that change is down to your project versus the weather, occupancy or operating hours or other changes on site. M&V isolates the project’s contribution from everything else that also changed.
-
Start with a baseline of energy use before installation, under known conditions, then meter consumption afterwards and adjust for factors such as weather and occupancy changes.
Depending on the size of the saving and the metering available, this typically means IPMVP Option B (measuring the heat pump directly) or Option C (looking at the whole building). The verified saving is the adjusted baseline minus actual metered consumption — and wherever a supplier’s savings claim is being relied on, independent verification can confirm the result is robust.
-
Ask for the M&V process to adhere to IPMVP; the proposed IPMVP Option that they will use and why it is appropriate; who will develop, and if relevant independently review, the M&V Plan, what data and information they will need from you, and how and how often savings will be reported.
-
A savings figure with no stated baseline, no mention of an IPMVP Option, no adjustment for weather or operating changes, or no way to trace the number back to metered data. If it cannot be explained and evidenced, it should be treated with caution.
-
Many public-sector funding and procurement routes, including RE:FIT and Salix-supported schemes, expect a documented approach to measuring and reporting savings. Check the specific funding conditions for your project, but building IPMVP-aligned M&V in from the outset will satisfy most of them.
-
Hospitals are complex, 24/7 sites with interacting systems, so the right approach depends on the specific measures and the contract.
Whole-facility analysis (Option C) often suits large Energy Performance Contract savings, while retrofit isolation (Option A or B) suits individual plant such as CHP or lighting.
Many NHS schemes are delivered under performance contracts - exactly the situation where independent M&V or independent verification matters most.
Frequently asked questions
Glossary of Terms
Quick definitions for the terms used throughout this guide. Tap any term to expand it.
AMR
Automatic Meter Reading: meters that transmit consumption data remotely at frequent intervals, rather than being read manually.
Baseline
The energy consumption a building or system would have had without the project, the reference point savings are measured against.
CV(RMSE)
Coefficient of Variation of the Root Mean Square Error: a measure of how accurately a baseline model predicts energy consumption.
Degree Days
A measure of how much colder or warmer a period was than a reference temperature (commonly 15.5°C), used to normalise energy consumption for weather when building or checking a baseline model. Heating degree days (HDD) and cooling degree days (CDD) are the two variants most often used in M&V.
ECM
Energy Conservation Measure, the general term for a project or intervention intended to reduce energy consumption, such as a boiler upgrade or lighting retrofit.
Fiscal meter
The meter used for billing purposes, often the main utility meter used as the data source for whole-building (Option C) M&V.
Gain-share
A commercial arrangement where savings, and sometimes the cost of achieving them, are shared between customer and supplier.
IPMVP Option
One of four standard IPMVP approaches (A to D) to calculating savings, chosen to match the project type and required accuracy.
Measurement boundary
The boundary drawn around what is actually being measured, narrower for single-measure projects (Options A/B), wider for whole-building approaches (Option C).
NMBE
Normalised Mean Bias Error: shows whether a baseline model consistently over or under-predicts energy use.
Non-routine adjustment
An adjustment for one-off or unplanned changes, such as extended opening hours or a temporary closure.
Operational verification
Confirming an installed measure is commissioned correctly and operating as intended, before savings are assessed.
P-value
A statistical test of whether a variable, such as temperature, genuinely relates to energy use, or whether the relationship could be due to chance. A low p-value indicates a meaningful relationship.
R² (Coefficient of Determination)
A statistic between 0 and 1 showing how much of the variation in historical energy use a baseline model explains. Closer to 1 means a better statistical fit.
Regression analysis
A statistical technique used to model the relationship between energy use and variables like temperature or occupancy, commonly used to build Option C baselines.
Routine adjustment
An adjustment for predictable, expected-to-vary factors, most commonly weather.
Get this guide as a PDF
Keep this guide for reference, or share it with your Finance Director, your Board, or a supplier who needs convincing. Enter your email and we'll send you the full PDF - plus, if you'd like them, occasional updates on M&V best practice. Nothing else.
Talk to an independent M&V expert
If you would like to discuss the contents of this Guide - or explore how good practice M&V could be applied to your projects - please do get in touch:
Ian Jeffries
Managing Director
Email meNick Keegan
Director
Email meEEVS is a global leader in Measurement & Verification. Our team holds PMVA and PMVE accreditations and brings over 40 years of combined experience across hundreds of energy and decarbonisation schemes. We are also wholly independent; we don't design, install or sell energy-saving measures. Our role is solely to objectively verify whether a project delivered the savings it promised.
This guide was written by Ian Jeffries, Managing Director of EEVS, drawing on the team's day-to-day M&V experience across public and private sector projects. If you'd like the same rigour applied to your own project, do get in touch.
Our Credentials
Disclaimer
This guide is intended as general information to help you understand M&V and does not constitute professional advice for any specific project. EEVS accepts no liability for any loss, damage, or decision arising from use of or reliance on this guide. For project-specific guidance, speak to an independent M&V specialist.