Retrofit isolation
A boundary drawn around the equipment the measure changed; IPMVP options A and B.
Best for one plant item: a chiller, a lighting circuit.Software · energy efficiency, cited
Energy efficiency software: proving a saving is real
Energy efficiency software finds savings, tracks the measures that deliver them and shows the result in kWh.
In the UK that proof now has a legal shape: ESOS asks for planned and achieved savings in kWh, and SECR asks directors to describe the measures they took. This page sets out what a tool must carry, and the trap a falling grid factor sets for every dashboard.
What it does
What does energy efficiency software actually do?
It carries an energy saving from the moment it is spotted to the moment someone signs a report that says it happened.
The ESOS action plan sets the format: each measure, the date, the estimated total saving in kWh, the saving per organisational purpose and the method, under reg 34A(3).
Since 22 July 2026, regulation 27D also asks for the savings actually achieved in the compliance period, in kWh, measure by measure.
So the core test of a tool is whether a measure keeps its identity from plan to result, rather than living in a project tracker on one side and a meter dashboard on the other.
- 1
Find
Audit findings, meter patterns and site surveys turned into a list of candidate measures.
- 2
Plan
Each measure with a date, an estimated saving in kWh and the method behind it.
- 3
Implement
Owners, dates and evidence that the measure went in.
- 4
Verify
The saving measured against a baseline, with the factor effect kept apart.
- 5
Report
ESOS savings achieved, the SECR narrative and progress against targets.
ESOS
What does ESOS ask a tool to carry?
ESOS is an energy scheme, so everything it asks for is in energy units, not carbon.
An ESOS audit must cover assets and activities that together make up not less than 95% of total energy consumption, under reg 25(2), which replaced the original 90% in 2023.
Each of the four organisational purposes needs at least one energy intensity ratio, under reg 25C, where a SECR report needs only one ratio, and that one an emissions ratio.
The Environment Agency’s Phase 4 guidance puts the Phase 4 action plan due date at 5 December 2028, covering 6 December 2027 to 5 December 2031, with annual progress updates after it.
Read the penalties and what is not penalised
The penalties in Part 8 cover failures such as not notifying compliance or not carrying out an energy audit.
None of them attaches to the action plan or progress updates, so the action plan is a duty without a penalty, which makes a tool’s value there managerial rather than defensive.
The audit itself is covered on energy audit software, and the scheme on ESOS.
ESOS, in kWhExplore
ESOS, in kWh
Audit coverage
Assets and activities making up not less than 95% of total energy consumption.
ESOS, in kWh
Four purposes
Transport, industrial process, buildings and any other purpose, each with an intensity ratio.
ESOS, in kWh
Savings achieved
Measured savings in the compliance period, in kWh, per measure and purpose.
ESOS, in kWh
Progress updates
Annual updates on the action plan, owed even where it proposed no measures.
The 2026 trap
Did we save energy, or did the grid factor fall?
Both can be true, and a tool has to show them apart.
The UK consumed electricity factor fell from 0.19553 kgCO2e/kWh in the 2025 set to 0.14396 in the 2026 set, according to Table 9 of the DESNZ methodology papers.
DESNZ attributes most of that to grid decarbonisation and 6 to 7 percentage points to a methodology change, with the data lag cut from two years to one in the major changes report.
The calculator beside this splits your own fall in electricity emissions into the part from using fewer kWh and the part from the factor alone.
An efficiency claim belongs to the first part only, and ESOS measures savings in kWh for exactly that reason.
Efficiency or factor? Split the fall
| 2025 emissions (0.19553) | 97.8 tCO2e |
|---|---|
| 2026 emissions (0.14396) | 67.7 tCO2e |
| Change from the kWh you used | 4.3 tCO2e |
| Change from the factor alone | 25.8 tCO2e |
Of a 30.1 tCO2e fall, about 14% is the company using less electricity; the rest is the grid factor.
Factors: DESNZ methodology papers, Table 9, consumed electricity including losses. The kWh effect is valued on the 2026 factor and the factor effect on 2025 kWh, so the two parts add to the total.
Not anyone’s SECR figure. Nothing is stored or sent.
Measurement and verification
How should a saving be measured?
No UK rule prescribes a method, so the method has to be stated.
The ESOS action plan asks for “the method used to calculate the estimate” under reg 34A(3)(a)(vi), which a tool should store beside every saving.
The most common reference is IPMVP, owned by the Efficiency Valuation Organization, which sets four options: retrofit isolation with key-parameter or all-parameter measurement, whole facility, and calibrated simulation.
A tool that adjusts the baseline for weather or occupancy should show the adjustment, because an unexplained baseline is the easiest place for a saving to be overstated.
One
measure
measure
Whole facility
The site’s main meters before and after; IPMVP option C.
Best for several measures that interact; noisier for small savings.SECR
What does SECR ask about efficiency?
SECR asks for a description, not a number.
A quoted company describes the principal measures taken to increase energy efficiency under ¶15(3D) of Schedule 7, and an unquoted company or LLP under ¶20D(4).
The directors write it; a tool can hold the measures, dates and evidence that make the description true.
In DESNZ’s evaluation, 56% of compliers reported better tracking of energy efficiency projects, and 25% said SECR led to a reduction in energy use, on their own account.
The full SECR line list is on SECR reporting software.
SECR and efficiencyExplore
SECR and efficiency
Quoted companies
The principal measures taken to increase energy efficiency in the year.
SECR and efficiency
What compliers said
56% reported better tracking of efficiency projects; 25% said energy use fell, on their own account.
Let buildings
When does efficiency become a legal duty for a building?
Current MEES minimum
Band EEngland and Wales, SI 2015/962 reg 22Payback test
7 yearsNon-domestic improvements, reg 28EPC B, over 1,000 m²
2031, proposedDESNZ interim response, 18 June 20262027 EPC C milestone
DroppedNot taken forwardFor a let non-domestic building in England and Wales, the minimum energy efficiency standard is band E, under the Energy Efficiency (Private Rented Property) Regulations 2015.
An improvement is required only if it passes the seven-year simple payback test in regulation 28: seven years of bill savings at least equal to cost, excluding VAT, times an interest factor.
DESNZ’s interim response of 18 June 2026 dropped the 2027 EPC C milestone and proposed EPC B from 2031 for private rented buildings over 1,000 m², only after secondary legislation passes.
The building-side duties, including DECs and air-conditioning inspections, are on building energy software.
Before you sign
Which questions separate a good tool from a dashboard?
Each question beside this names the provision it comes from and what a passing answer looks like.
Run them on your own sites, because a demonstration dataset never has an interacting set of measures or a factor year to cross.
The metering side, which most savings depend on, is covered on energy monitoring software, and the wider operating system on energy management software.
This site has tested no products
Nothing on this page is a rating, ranking or recommendation of any product.
Energy efficiency demo questions · tick the ones you need
The pass tests are our reading of the cited provisions.
Nothing you tick is stored or sent.
An order of work
Where should an organisation start?
- 01 / Baseline01
Fix the baseline year
kWh by site and purpose, with the factor set stored on every emissions figure. - 02 / Measures02
List the measures
From the ESOS audit and site surveys, each with a kWh estimate and its method. - 03 / Method03
- 04 / Evidence04
- 05 / Report05
Report savings, not factors
ESOS savings in kWh; the SECR narrative; targets on a like-for-like basis.
One saving, four usesExplore
One saving, four uses
MEES improvement
Evidence that a let building passed or failed the payback test.
One saving, four uses
Target progress
Progress against a company’s own target, with measurement changes disclosed.
In short
What should a board take from this?
A saving counts when it is measured in kWh and kept apart from the grid factor.
| What is true | What it means for a tool |
|---|---|
| ESOS action plans and savings achieved are stated in kWh. | Every measure carries a kWh estimate, a method and a result. |
| No penalty attaches to the action plan. | The tool’s value is in managing measures, not avoiding fines. |
| The UK electricity factor fell by about 26% between the 2025 and 2026 sets. | Emissions falls are split into use and factor before anyone calls them savings. |
| SECR asks for a narrative of measures, with no target. | The tool holds the evidence; the directors write the words. |
| MEES is band E today; EPC B 2031 is a proposal. | Let buildings need payback evidence, not a 2027 deadline. |
Next, check which energy figures you owe with the tool on energy reporting software.
Frequently asked
Energy efficiency software, answered
What is energy efficiency software?
Software that finds energy saving opportunities, tracks the measures a company carries out, and shows the saving in kWh.
For a UK reporter the useful test is whether it can carry a measure from an ESOS recommendation to an action plan line, then to a saving achieved, then into the SECR efficiency narrative.
Is energy efficiency software the same as energy management software?
They overlap.
Energy management software runs the estate day to day, often inside an ISO 50001 system; energy efficiency software focuses on the measures and the proof that they saved energy.
Many products do both.
What does ESOS require an action plan to contain?
Each measure the participant proposes to implement before the end of the compliance period, whether an audit recommended it, the date, the estimated total saving in kWh, the saving per organisational purpose in kWh and the method used, or a statement that no measure is proposed.
There is no statutory investment or cost line.
Is there a penalty for not submitting an ESOS action plan?
No penalty in the ESOS Regulations attaches to the action plan or progress updates.
That is different from the duty itself, which still exists; the penalties in Part 8 cover failures such as not notifying compliance or not carrying out an energy audit.
Does ESOS make me report savings achieved?
Yes, since Phase 4.
Regulation 27D, inserted by SI 2026/701, requires the savings achieved during the compliance period, in kWh, by measure and organisational purpose.
Only the combined saving is published.
Why did my electricity emissions fall when we used the same energy?
Because the UK electricity factor fell.
The consumed factor went from 0.19553 kgCO2e/kWh in the 2025 set to 0.14396 in the 2026 set, mostly grid decarbonisation with 6 to 7 percentage points from a methodology change, according to DESNZ.
The calculator on this page separates the two effects.
What is IPMVP?
The International Performance Measurement and Verification Protocol, owned by the Efficiency Valuation Organization.
It sets four options for determining savings: retrofit isolation with key parameter or all parameter measurement, whole facility, and calibrated simulation. It is a protocol, not a UK legal requirement.
Does SECR require energy efficiency targets?
No. SECR asks for a description of the principal measures taken to increase energy efficiency in the year, under ¶15(3D) for quoted companies and ¶20D(4) for unquoted companies and LLPs. It requires no target and no plan.
What is the MEES seven-year payback test?
For a let non-domestic building in England and Wales, an improvement is required only if seven years of energy bill savings are at least its cost, excluding VAT, multiplied by an interest rate factor based on the Bank of England base rate (SI 2015/962 reg 28).
There is no £3,500 cap for non-domestic property; that cap is domestic.
Is EPC C by 2027 required for commercial buildings?
No. DESNZ dropped the 2027 interim milestone in June 2026.
The current minimum is band E, and EPC B from 2031 is proposed only for private rented buildings over 1,000 m², where cost effective, after secondary legislation passes.
Does energy efficiency software help with UK SRS?
Indirectly.
UK SRS S2 asks for emissions, targets and transition plans; listed companies in UKLR 6, 14, 15, 16 and 22 apply it on a comply-or-explain basis for periods beginning on or after 1 January 2027 under FCA PS26/19.
Measured savings feed the progress a company reports against its own targets.
Has this site tested any energy efficiency software?
No. This page is built from ESOS, SECR, MEES, the DESNZ factors and IPMVP, each cited to its source. It names, ranks and prices no product.
Sources
Primary sources
Every test on this page traces to the provision listed here.
Checked against 20 sources fromlegislation.gov.ukEnvironment AgencyGOV.UKDepartment for Energy Security and Net ZeroEfficiency Valuation OrganizationDepartment for Business and Trade
- legislation.gov.ukESOS Regulations 2014 (SI 2014/1643), Part 6A, reg 34A(3)
The action plan: each measure, its date and its estimated saving in kWh.
- legislation.gov.ukESOS Regulations 2014, reg 34A
Action plan due dates and the period it covers.
- legislation.gov.ukESOS (Amendment) Regulations 2026 (SI 2026/701)
Reg 27D: savings achieved, in kWh, per measure and purpose; Table J.
- legislation.gov.ukESOS Regulations 2014, reg 25
Audit coverage: not less than 95% of total energy consumption.
- legislation.gov.ukESOS Regulations 2014, reg 25C
At least one energy intensity ratio per organisational purpose.
- legislation.gov.ukESOS Regulations 2014, Part 8
The penalties, none of which attaches to the action plan.
- Environment AgencyHow to comply with ESOS phase 4
Action plans and progress updates; what ESOS is estimated to save.
- GOV.UKEnergy Savings Opportunity Scheme (ESOS)
The scheme overview.
- legislation.gov.ukSI 2008/410, Schedule 7
SECR: ¶15(3D) and ¶20D(4), the principal energy efficiency measures.
- Department for Energy Security and Net ZeroSECR regulations: evaluation
What compliers said SECR changed.
- Department for Energy Security and Net Zero2026 post-implementation review of the SECR regulations
Retain with amendments; consultation areas not decided.
- Department for Energy Security and Net Zero2026 GHG conversion factors methodology paper, Table 9
UK electricity consumed: 0.19553 (2025 set) and 0.14396 (2026 set) kgCO2e/kWh.
- Department for Energy Security and Net Zero2026 GHG conversion factors: major changes report
The data lag cut from two years to one.
- Efficiency Valuation OrganizationInternational Performance Measurement and Verification Protocol (IPMVP)
Options A to D for determining savings; a protocol, not a law.
- legislation.gov.ukEnergy Efficiency (Private Rented Property) Regulations 2015, Part 3
MEES: band E is the current minimum.
- legislation.gov.ukSI 2015/962, regulation 28
The seven-year simple payback test.
- Department for Energy Security and Net ZeroNon-domestic MEES: interim response (18 June 2026)
EPC B from 2031 proposed for buildings over 1,000 m²; not yet law.
- Department for Business and TradeUK SRS S2 Climate-related Disclosures
Changes in measurement approach must be disclosed.
- Financial Conduct AuthorityPS26/19
Comply or explain against UK SRS for periods from 1 January 2027.
- ISOISO 50001 energy management
The energy management system standard and ESOS route.