Measurement and Verification
How the effect of PECO Powersaver is measured on a working facility — and why we report the method rather than a number.
We Do Not Publish a Saving Percentage
Energy savings depend on load composition, operating hours, phase balance, harmonic content and the condition of the existing distribution system. These differ at every site.
A supplier publishing one guaranteed figure for all installations is not describing a measurable engineering result. In this industry, that figure is usually a warning sign rather than a credential.
What we commit to is the method by which savings are measured, and the discipline with which the resulting data is handled.
Accumulated kWh, at the Billing Meter
The customer pays for kilowatt-hours. Verification is therefore performed in kilowatt-hours, at the metering point that determines the electricity bill.
Not instantaneous kW. Not a modelled estimate. Not a laboratory figure. Accumulated energy, over periods long enough for the comparison to mean something.
A measurement expressed in average kW can be correct and still be misleading. Accumulated kWh is what appears on the invoice.
Two Ways to Measure
Which method applies depends on the facility. Both are agreed with the customer before measurement begins.
Method A
Continuous Monitoring — Before and After Installation
Consumption is logged continuously at the facility meter, beginning before PECO Powersaver is installed and continuing afterwards. In markets where our partners operate remote metering equipment, this data is collected automatically and reported to the customer on an agreed schedule.
This is the method we recommend for most installations. It requires only one change to the system — the installation itself — and it produces a long, uninterrupted record.
- Baseline recorded under normal operation, before installation
- Continuous post-installation logging, without manual intervention
- Data suitable for the customer’s own energy management review
- No additional switching or planned outage required
Method B
Saving vs By-pass — Same Site, Same Meter
PECO Powersaver includes an automatic transfer switch. The facility can therefore be operated alternately through the Saving path and the By-pass path, and the two periods compared directly.
The comparison is made on the same installation, on the same meter, with the same connected equipment, in the same season. No reference facility, no modelled baseline and no external benchmark is required.
Transfer between the two paths is performed at no load, during a window scheduled with the facility’s maintenance team. Measurement periods are therefore planned together with the customer in advance.
- Same site, same meter, same connected load
- Direct comparison rather than estimation
- Number and timing of transfers agreed with the facility
- Available where the facility can accommodate scheduled transfer windows
Most passive energy-saving equipment cannot be evaluated by Method B, because it cannot be taken out of circuit without disconnecting the supply. The transfer capability that protects PECO under overload is also what makes direct comparison possible.
The Conditions That Make a Comparison Valid
A facility is not a laboratory. Load changes with occupancy, production and weather. These conditions are agreed and recorded before measurement begins.
| Period matching | Same days of the week, same time blocks |
|---|---|
| Logging interval | 15 or 30 minutes, over full 24-hour cycles |
| Duration | Minimum one full week per period; longer where load varies |
| Operating conditions | Stable load periods; occupancy or production volume recorded |
| Ambient conditions | Outdoor temperature recorded for both periods |
| Transfer windows (Method B) | Scheduled at no load, coordinated with facility maintenance |
| Sequence (Method B) | Where more than one transfer window is available, an alternating sequence is used to cancel seasonal drift |
| Reporting | Both the complete data set and the filtered data set |
An Optional Measurement for Rectifier-Heavy Sites
Where a facility’s load is dominated by six-pulse rectifier front ends — variable-speed drives, large inverter-driven motors, induction heating, forging plant — a harmonic spectrum can be recorded at the same metering point before and after installation, alongside the energy measurement.
This is offered as an option, not as a performance claim. PECO is not a harmonic filter and we do not publish harmonic reduction figures. The measurement is included where a customer’s engineering team wants the record.
| Quantity | Individual harmonic orders and total harmonic distortion of current (THD-I) |
|---|---|
| Measurement point | The same point used for the energy measurement, stated by phase |
| Instrument | Make, model, serial number and accuracy class recorded |
| Load condition | Plant output or drive loading recorded for both measurements, and matched as closely as the facility allows |
| Timing | Before installation and after, under comparable operating conditions |
Unlike the energy measurement, which needs weeks of accumulated data, a harmonic spectrum is recorded in a single session. Results are available on the day.
Where Measurement Is Most Easily Distorted
Any measurement taken on a working facility contains anomalies: metering dropouts, unplanned shutdowns, exceptional operating days. Deciding what to exclude is the point at which energy-saving measurements are most often distorted — usually without any intention to deceive.
Our rule is simple.
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The exclusion criteria are defined before measurement begins.
Not after the results are seen. The criteria are written into the measurement plan and agreed with the customer.
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They are applied identically to both periods.
An interval excluded from one period is excluded from the matching interval in the other.
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Both data sets are reported.
The complete record, and the filtered record, side by side.
If a result depends on which data was selected, it is not a result.
Reporting both is how we demonstrate that it does not.
The Verification Report
Each project produces a written report containing:
- Metering point, instrument and logging interval
- Measurement periods, and the conditions applied to each
- The complete recorded data set
- The filtered data set, with the exclusion rule stated
- Accumulated kWh for each period
- Comparison result, expressed in kWh and as a percentage
- Ambient and operating conditions recorded during each period
- Harmonic spectrum before and after, where that option was included
- A statement of the limitations of the measurement
The report is written to be read by your own engineers, and to be checked by them.
We Do Not Publish Customer Results
Facility names, site locations, consumption data and verification reports belong to the customer, not to us. They do not appear on this website, in our brochures, or in our presentations.
Reference information is provided only under a non-disclosure agreement, at the customer’s discretion, during technical review.
Many of our installations are in hotels operated by international groups, where energy and occupancy data is treated as commercially sensitive. We work on that basis by default.
Supporting Energy-Efficiency Incentive Applications
In some markets, customers have used verified savings documentation to support applications to national energy-efficiency incentive schemes.
Eligibility, procedures, calculation rules and approval are determined solely by the relevant national authority. We provide the measurement data and report; we do not administer applications or guarantee outcomes.
Before Any Proposal, a Technical Review
Suitability is confirmed by reviewing your single-line diagram, transformer rating, nominal voltage and frequency, maximum load current and load composition. If PECO is not a good fit for your system, we will tell you at that stage.