Measure Life in the 2026 PA TRM, by Project Type

Most Pennsylvania efficiency projects are described as earning credits for fifteen years. That is true for about two-thirds of measures, and wrong for the rest.

Across the commercial and industrial measures in the 2026 Pennsylvania Technical Reference Manual, measure life runs from 3 years to 23 years — close to an eightfold spread. An HVAC tune-up and a ground source heat pump can be sold into the same building, in the same year, by the same contractor. One earns for three years. The other earns for twenty-three.

That range sits directly underneath the number that matters most in an AEC transaction: how many credits a project produces over its life.

Where the fifteen-year figure actually comes from

This is the part worth getting right, because the shorthand has a specific origin and it is not the AEPS.

TRM Volume 1, Section 1.9 states that AECs and savings "will apply in equal annual amounts corresponding to either PJM planning years or calendar years, beginning with the year deemed appropriate by the Administrator and lasting for the approved life of the measure for AEPS Credits. Energy efficiency and demand response savings associated with Act 129 can claim savings for up to 15 years."

Read that twice. The fifteen-year ceiling is written against Act 129 — the utility energy efficiency and conservation programs. For AEPS credits, the manual says the approved life of the measure. Those are two different clocks, and the 15-year number belongs to the other one.

So a 20-year economizer or a 23-year ground source heat pump is not automatically truncated at 15 for AEPS purposes by this sentence. What the Program Administrator approves in practice for any specific measure is a question to put to them in writing before a project is modelled — but the manual does not impose a flat 15-year AEPS cap, and any project economics built on the assumption that it does should be re-checked.

What measure life is

Measure life — Effective Useful Life, or EUL — is defined in Volume 1, Section 1.4 of the Pennsylvania Technical Reference Manual. It is the number of years an installed measure is assumed to keep delivering its savings for the purpose of claiming those savings.

Two things about the TRM are routinely conflated and are worth separating.

First, the TRM is the shared measurement standard. Volume 1, Section 1.2 states the manual "serves a dual purpose: to determine compliance with the AEPS Act, 73 P.S. §§ 1648.1-1648.8, and to determine compliance with the energy efficiency and conservation requirements of Act 129 of 2008," and that it "provides guidance to the Administrator responsible for awarding Alternative Energy Credits (AECs)." One manual, two programs.

Second, the 2026 TRM is a Phase V document, adopted 12 September 2024. Earlier phases carry different values for some measures. A project is measured against the TRM in effect for its program year, not the newest one. For a full picture of Phase V, see our overview of Act 129 Phase V.

Why measure life sets your lifetime credit volume

Alternative Energy Credits are issued against energy savings at one credit per megawatt-hour. TRM Volume 1 defines an AEC as a tradable instrument where "One credit is earned for each 1,000 kWh of electricity generated (or saved from energy efficiency or conservation measures) at a qualified alternative energy facility." 52 Pa. Code § 75.63(b) puts it in regulation: a credit "may be certified by the Commission for each MWh of electricity conserved."

Credits accrue as savings accrue. They are not awarded as a lump sum at project completion. Under the GATS Operating Rules, certificates "are created monthly, on the last business day of the month following the month of generation."

That produces a relationship most project economics ignore: lifetime credit volume ≈ annual kWh savings × measure life ÷ 1,000.

First-year savings is the number that appears on every proposal. It is half the equation.

A worked comparison

Take two projects, each modelled at 200,000 kWh of annual savings.

Same first-year performance. Roughly 4,000 additional credits on one side of the table. Whatever an AEC is worth in the year it is sold, that gap is the single largest variable in the project's credit economics — larger than most price movement in the market.

It is also why registration timing matters unevenly. Because credits are not issued retroactively, every month a qualifying measure runs unregistered is volume that cannot be recovered. On a 3-year measure, a six-month delay costs one-sixth of the total. On a 23-year measure it costs proportionally little. Short-life measures are where administrative delay is genuinely expensive.

Measure life by project type

The values below are taken from the 2026 PA TRM, Volume 3 (Commercial and Industrial Measures). Nothing here is estimated or interpolated. Sections we could not extract clean values from are named at the end and are deliberately absent rather than guessed.

Lighting — TRM Section 3.1

Two things stand out. Permanent de-lamping earns for 11 years, not 15 — a distinction that disappears when a project is described generically as a retrofit. And controls carry an 8-year life, roughly half the life of the fixtures they control. A combined fixture-and-controls project is two measures on two clocks, and should be modelled that way rather than blended.

HVAC — TRM Section 3.2

HVAC is where the spread is widest — every value from 3 to 23 years appears in this one section.

The envelope and distribution measures sit at the top. Duct sealing, pipe insulation and economizers all carry 20 years, longer than the equipment they serve. Insulation is usually a minor line item on an HVAC proposal. On a credit-volume basis it is one of the better-earning things in the section, and it is rarely presented that way.

At the other end, tune-up at 3 years is the shortest life in the entire commercial and industrial set. Tune-ups are a legitimate savings measure and often the right first move in a building. They are simply not a durable credit asset, and a project built around them should be priced on that basis.

Motors and variable frequency drives — TRM Section 3.3

Uniform at 15 years across the measures extracted. For a facility weighing where to deploy capital, this is the most predictable category in the manual — no short-life exceptions to model around. Our guide to variable frequency drives and Tier II credits covers the qualification side.

Compressed air — TRM Section 3.10

Also uniform at 15 years. Compressed air deserves a specific flag for industrial sites: leak reduction and control measures often carry high annual savings relative to installed cost, and a 15-year life means that annual figure compounds across a long window. For a plant running compressors continuously, this is frequently the highest lifetime-credit category available.

What the distribution actually looks like

Of the 41 measure entries extracted across those four sections:

• 27 carry a 15-year life — roughly two-thirds
• 4 carry 20 years, and 1 carries 23 years
• 9 carry less than 15 years — lives of 3, 8, 10 and 11 years

So "fifteen years" is a reasonable default and a poor assumption. It is right most of the time, and when it is wrong it is wrong by as much as 12 years in either direction.

Measure life is not the same as credit expiry

These two clocks get confused constantly, and they are unrelated.

Measure life governs how long a project keeps *creating* credits. Vintage and expiry govern how long a credit, once created, remains usable — AECs are eligible in the reporting year they were created and may be banked for either of the following two years. A 23-year measure does not produce a credit that lasts 23 years; it produces 23 years' worth of credits, each of which has its own three-year usable window. We cover that second clock in how long Tier II AECs last.

Where metering becomes mandatory

TRM Volume 1, Table 1-2 sets kWh savings thresholds above which measurement is required rather than optional. These are worth knowing before a project is designed, because they determine whether default values may be used at all.

For lighting, Volume 3 states that above the threshold "metering is required," that "installation of light loggers is the accepted method of metering, but trend data from BMS is an acceptable substitute," and that below the threshold metering "is encouraged for projects with expected savings below 750,000 kWh but have high uncertainty, i.e. where hours are unknown, variable, or difficult to verify."

Note the HVAC and motor thresholds are 250,000 kWh — a third of the lighting figure. A mid-size HVAC project crosses into mandatory measurement far earlier than most people expect. If a building management system is already trending the relevant equipment, that requirement is close to free. If it is not, the metering decision belongs in the project design, not in the closeout. See energy monitoring and M&V for how that data flows through, and M&V best practices for documentation standards.

What to do with this

• Model lifetime credits, not first-year savings. Every proposal should carry annual kWh, measure life, and the product of the two. A project summary showing only the first number is not describing the asset being created.
• Unbundle mixed projects. A retrofit combining fixtures, controls and a tune-up contains three different measure lives. Treated as one line, the short-life components quietly drag the blended figure down and nobody can see where.
• Register early, and register short-life measures first. Credits do not backdate. The measures with the least time on the clock are the ones where delay costs the most in percentage terms. Our enrollment process starts with a measure-by-measure screen for exactly this reason.

What we have not confirmed

We would rather name a gap than fill it with a plausible number.

Measure lives for several TRM sections are not included above: domestic hot water, refrigeration, appliances, food service, building shell, consumer electronics, miscellaneous, demand response and agricultural. Values for these did not surface cleanly and have deliberately been left out rather than estimated.

Separately, whether the Program Administrator approves an AEPS eligibility period identical to the TRM measure life for every measure is a question we put to the Administrator rather than answer ourselves. Volume 1 Section 1.9 distinguishes the AEPS "approved life of the measure" from the Act 129 15-year claim, which is the basis for this article, but the approval is measure-specific and administrative.

If you need a specific measure life confirmed for a project in flight, ask and we will pull the value from the TRM governing that project's program year rather than the current one.

Frequently Asked Questions

What is measure life in the Pennsylvania TRM?

Measure life, also called Effective Useful Life or EUL, is the number of years an installed efficiency measure is assumed to keep delivering savings. It is defined in Volume 1, Section 1.4 of the Pennsylvania Technical Reference Manual and is used to calculate the total savings a project may claim.

Is measure life always 15 years in Pennsylvania?

No. Of the 41 commercial and industrial measure entries extracted from the 2026 Pennsylvania TRM, 27 carry a 15-year life, but the full range runs from 3 years for an HVAC tune-up to 23 years for a ground source heat pump. Nine measures carry lives shorter than 15 years. The 15-year figure that circulates as a rule of thumb is written in the TRM against Act 129 claims, not against AEPS credits.

Which measure has the longest life in the PA TRM?

Among the commercial and industrial measures extracted, ground source and groundwater source heat pumps carry the longest measure life at 23 years. Electric chillers, economizers, duct sealing and insulation, and chilled water pipe insulation each carry 20 years.

Which measure has the shortest life?

HVAC tune up, at 3 years. Lighting controls, guest room occupancy sensors, programmable thermostat adjustment and LED refrigeration display case lighting each carry 8 years.

How does measure life affect how many AECs a project earns?

Alternative Energy Credits accrue against energy savings at one credit per 1,000 kWh and are not issued retroactively. Lifetime credit volume is therefore approximately annual kWh savings multiplied by measure life, divided by 1,000. Two projects with identical annual savings but different measure lives earn very different total credit volumes.

Does the Pennsylvania TRM apply to AEPS or only to Act 129?

Both. Volume 1, Section 1.2 of the Pennsylvania Technical Reference Manual states that it serves a dual purpose, determining compliance with the AEPS Act and with the energy efficiency and conservation requirements of Act 129 of 2008, and that it guides the Administrator responsible for awarding Alternative Energy Credits.

Which TRM version applies to my project?

The TRM in effect for the project's program year. The 2026 TRM is an Act 129 Phase V document adopted 12 September 2024. Projects from earlier phases are measured against earlier manuals, and some measure lives changed between phases. For new construction, the governing TRM is set by the date the building permit was issued.

*Source: 2026 Pennsylvania Technical Reference Manual, Volumes 1 and 3, Pennsylvania Public Utility Commission, adopted 12 September 2024; 52 Pa. Code § 75.63; PJM-GATS Operating Rules. Nothing in this article is legal, tax or investment advice.*