Alectrona
Commercial guidePAS 2038:2021 is the BSI specification for retrofitting non-domestic buildings for improved energy efficiency. It is a whole-building framework rather than a solar install standard, and a rooftop PV array sits inside it as one of the renewable measures it covers.
These are representative example reviews, not yet-collected customer feedback. They are written to illustrate the kind of feedback Alectrona aims to earn and are shown as design placeholders while we gather and verify reviews from our first commercial clients. Alectrona is the commercial solar trading brand of RVTC LTD.
What set Alectrona apart was the documented design pack. We had quotes from three installers, but only Alectrona handed us a full set of drawings, a single-line diagram and a design referencing BS 7671 and the G99 connection process. The whole thing read like an engineering submission rather than a sales brochure. Our M&E consultant reviewed it and signed it off without a single query. That gave the board the confidence to release the capital.
Other firms priced our roof off a satellite image and a desktop guess. Alectrona flew an in-house drone survey, fully insured and flown by a qualified commercial drone pilot, and built a 3D model of the actual roof. It picked up plant, vents and a parapet line that a flat aerial photo had completely missed, which changed the panel layout. I would rather find that out at design stage than on the day the scaffold goes up. The accuracy of that survey is the reason I trusted everything that followed.
As a finance director I was wary of being oversold a system bigger than we could use. Alectrona modelled the array against our actual half-hourly consumption data rather than an annual total, so it is sized to what we genuinely draw on site during the day. They were honest that exporting surplus is worth far less than self-consumption, and built the design around that. The capital case stacked up because the engineering was honest, not because the numbers were inflated.
We were undecided between buying outright, leasing and a PPA. Alectrona laid out all three side by side with the pros and cons of each against our balance sheet, instead of pushing the one that pays them best. They were clear about where a PPA makes sense and where capex wins, and pointed us at our own accountant for the tax treatment. The survey and design took a little longer than I expected, but the thoroughness was worth the wait. Genuinely consultative.
The install crew were tidy and well run, and worked to a clear CDM 2015 plan with a proper site induction and RAMS. What impressed me most was the handover. We received a full commissioning pack with the IEC 62446-1 test results, certification, O&M documentation and an as-built record for our maintenance team. As the people who have to live with this asset for the next twenty years, having that paperwork in order matters enormously. Nothing was left loose.
I expected the usual hard sell and got the opposite. After surveying our site Alectrona told us one roof section was not worth covering because of shading, and that a smaller, well-sited array was the better investment than filling every square metre. There was no commission-driven upselling and no pressure. For a six-figure capital project, that straight talk is exactly what you want from the people advising you. We will be using them again on our second site.
OrientationThis is a plain-English orientation to PAS 2038, not formal advice; confirm the current status of the specification and whether it applies to your project with the relevant body or a qualified adviser before relying on it.
PAS 2038 is a publicly available specification published by BSI in 2021. In one sentence: it sets out how to retrofit a non-domestic building for better energy efficiency, working from a whole-building assessment first and then designing the measures around it. Solar photovoltaics, including inverters and batteries, are among the renewable measures it covers, so a commercial rooftop array legitimately sits within its scope.
It is worth being precise about what PAS 2038 is and is not. It is not a solar-specific installation standard, and it does not replace the electrical and grid-code standards a PV system is built to. It is the governance and assessment wrapper around the whole project: who does what, in what order, and with what documented trail of responsibility. For a commercial buyer over 50 kWp, outside the domestic MCS scheme, that process discipline is a useful reference point. This is a plain-English orientation, not formal advice; we confirm what applies to your project.
PAS 2038:2021 is titled, in full, the specification for retrofitting non-domestic buildings for improved energy efficiency. It was published by BSI in 2021 and remains current. A PAS, or publicly available specification, is a fast-track standards document developed under BSI process; it is a recognised reference rather than a statute, and following it is voluntary unless a funder or client makes it a condition.
Its central idea is to assess the whole building before specifying any measure. Rather than bolting on individual upgrades in isolation, PAS 2038 asks for an energy audit of the building first, so that each measure is chosen in the context of the fabric, the services and how the building is actually used. It is the non-domestic counterpart to PAS 2035, which covers domestic retrofit. Its scope is buildings other than private dwellings, and it explicitly reaches multi-residential buildings with shared facilities such as hotels, hostels and student accommodation.
Renewable energy systems are within the scope of PAS 2038 as retrofit measures. That includes solar photovoltaics and solar thermal, together with their inverters, batteries and heat stores. So a commercial rooftop PV array, with or without battery storage, is one of the measures the specification is designed to govern.
What this means in practice is that the array is not treated as a standalone purchase but as part of a building's energy strategy. PAS 2038 would have the generation sized and designed against the building's assessed demand and the other measures in the plan, rather than against roof area alone. That sits comfortably with how a commercial system should be sized in any case, from the building's actual half-hourly load. The point to hold onto is that PAS 2038 covers the assessment and design discipline around the array; the array's own electrical engineering still comes from the standards written for it.
PAS 2038 sets out a sequence of project stages: a whole-building assessment, a retrofit strategy with clear objectives, design, installation, commissioning and testing, then monitoring and evaluation after handover. The assessment comes first by design, and the specification asks for a documented thread of building information and responsibility, sometimes called a golden thread, running through the project, with risk management and a risk register among its deliverables.
It also names the roles that carry the work. A retrofit lead, or lead professional, oversees the process and manages risk and the competence of the team. A lead assessor carries out the assessment and builds the evidence base. Lead designers, contractors and installers deliver the measures, and a commissioning sign-off confirms that they perform as intended. The purpose of naming these roles in writing is to assign accountability at every stage, so it is always clear who is responsible from the first assessment through to the monitoring that follows handover.
A commercial array over 50 kWp sits outside the MCS scheme, because the MCS solar PV standard applies up to 50 kWp of DC output and no further. So the question of what assures the work is a real one, and PAS 2038 is sometimes raised as part of the answer. It is helpful to be clear about how it fits, because it is a governance wrapper rather than a technical substitute.
PAS 2038 wraps assessment and process governance around that technical stack; it does not replace any part of it. Funders and grant bodies increasingly reference it for non-domestic works, so it can matter to a project's eligibility as well as its rigour. This page is orientation rather than formal advice; we confirm whether PAS 2038 applies to your project and which standards govern the install before any work begins.
PAS 2038 did not appear in isolation. It is part of a retrofit standards framework that grew out of the 2016 Each Home Counts review, the government-commissioned report led by Peter Bonfield that examined consumer protection and standards in home energy efficiency. That review produced the framework BSI then built out: PAS 2035 for domestic retrofit, published first, and PAS 2038 as the non-domestic counterpart published in 2021. Both sit under a quality regime that TrustMark administers for the schemes that adopt it, and both share the same philosophy of assessing the whole building before specifying any single measure. For a commercial buyer the practical point is that PAS 2038 is the recognised non-domestic member of a deliberately structured family of standards, which is part of why funders reach for it. BSI has continued to develop this framework, but the recent additions sit on the domestic side: BS 40104, published in 2025, is a retrofit-assessment standard for domestic dwellings and replaces parts of PAS 2035, so it does not govern non-domestic work. PAS 2038 remains the current non-domestic specification. Because standards in this area are revised, we confirm the current document and version a funder relies on with the relevant body rather than assume, and we set out how it sits alongside the wider non-MCS assurance picture for a system over 50 kWp.
The whole-building energy audit that PAS 2038 puts first is not a new obligation invented by the specification. It overlaps heavily with assessments a large organisation may already be doing, so much of the evidence can be reused rather than gathered twice. If your organisation is in scope for the Energy Savings Opportunity Scheme, the mandatory four-yearly energy audit the Environment Agency administers, much of the building and energy-use evidence PAS 2038 wants will already exist in that ESOS report. The same is true of a commercial Energy Performance Certificate and its recommendation report, which the Department for Energy Security and Net Zero oversees. Drawing on that existing evidence base avoids paying twice for the same survey work, and it means the solar array is sized against demand that has already been characterised rather than a fresh guess. Our guides on the ESOS and SECR overlap and on EPC obligations under MEES set out where that prior evidence comes from and how it feeds a retrofit assessment.
The part of PAS 2038 most often overlooked is the end of it. The specification does not stop at commissioning; it asks for monitoring and evaluation after handover, so the building is checked against the performance the retrofit strategy set out to achieve. This is the specification's answer to the performance gap, the well-documented difference between how a building was modelled to perform and how it actually performs once occupied. For a solar array that discipline is straightforward to honour, because a generation meter records exactly what the array produced and how much was used on site. That metered record is the same evidence a carbon or SECR claim rests on, so the monitoring PAS 2038 expects and the reporting a finance director needs are served by one well-specified setup. The documented thread of decisions and responsibilities the specification keeps running through the project, sometimes called the golden thread, is also what lets a later owner, insurer or auditor see who assessed, designed and signed off each measure. Where storage is added, the same monitoring confirms the battery is earning its modelled self-consumption rather than sitting idle, which our maintenance guidance covers as part of operating the system.
Following PAS 2038 is voluntary in law, but it stops being optional the moment a funder makes it a condition. Public grant schemes for non-domestic decarbonisation, and the public-sector decarbonisation funding routes government departments run, increasingly reference the PAS retrofit framework as the assurance standard for the works they pay for, precisely because it gives them a documented, role-accountable trail rather than an installer's word. Private lenders and some insurers take a similar view on larger retrofit packages. So for a project that hopes to draw on grant funding, PAS 2038 can move from a nice-to-have to an eligibility gate, and the whole-building assessment it requires has to be in place before the works rather than reconstructed afterwards. This is one of the first things worth confirming during a feasibility study, because it shapes the order of the project. Where a funder names PAS 2038, we build the assessment and the documented thread into the programme from the start rather than bolting governance on at the end. Funder requirements and the standards they cite are revised over time, so we confirm the current condition with the funding body before relying on it.
Our own insured pilot flies your roof and captures the real geometry and shading, so the design starts from your building instead of a satellite guess.
Booked to suit your operating hours
We model the array in bankable-grade software, size it around your daytime load, and set out generation, savings and payback across three funding routes.
Modelled, not promised
Designed and installed to BS 7671, commissioned to IEC 62446-1, connected under G99 and run under CDM 2015. Alectrona is typically the Principal Contractor.
Outside MCS, assured by the non-MCS stack
A 12-month defects period backed by an Insurance-Backed Guarantee, then ongoing operations and maintenance so the asset keeps earning for its full working life.
Kept performing, year on year
Last updated June 2026
No. PAS 2038:2021 is the specification for retrofitting non-domestic buildings for improved energy efficiency. It is a whole-building framework that covers solar photovoltaics, along with solar thermal and their inverters and batteries, as one of the renewable measures within its scope. The technical detail of how a PV system is wired, tested and connected comes from other standards, not from PAS 2038 itself.
No. PAS 2038 is a voluntary publicly available specification, not a statute. A commercial solar project does not have to follow it to be lawful or compliant. It is, however, increasingly referenced as a benchmark for non-domestic retrofit, and funding or grant bodies sometimes require it for the works they support. Where it applies to your project, we confirm that with you rather than assuming it.
They are separate things. MCS is a certification scheme whose solar PV standard applies up to 50 kWp of DC output, so above that ceiling MCS does not apply. PAS 2038 is not an MCS replacement and does not pair with it as a higher tier. It is a voluntary retrofit-process specification that can apply to a non-domestic building of any size, sitting over the technical standards the array is actually engineered to.
No. PAS 2038 governs the assessment and process around a retrofit; it does not replace the standards the system is built to. Above 50 kWp the electrical work is still designed and tested to BS 7671, the PV side is still commissioned to IEC 62446-1, the Building Regulations still apply, and the grid connection still goes through the DNO under G99. PAS 2038 wraps governance around those; it does not stand in for them.
It names a retrofit lead or lead professional who oversees the process and manages risk and team competence, a lead assessor who builds the evidence base, lead designers, contractors and installers, and a commissioning sign-off on performance. Risk management and a risk register are among its deliverables. The purpose of naming the roles is to assign accountability in writing, so it is clear who is responsible for each stage from assessment through to monitoring after handover.
There is no set fee, because PAS 2038 is a process specification rather than a product, and the cost depends on how much assessment evidence your building already holds. Where an ESOS audit, a current EPC or a recent condition survey exists, much of the whole-building evidence is reusable and the added cost is modest. Where none exists, the energy audit and documentation are genuine extra work we scope after a feasibility visit. The array itself is survey-led and priced from your own consumption data; our commercial solar cost guide explains how that estimate is built.
Working to PAS 2038 lengthens the early stage rather than the install, because it puts the whole-building assessment first. Expect the assessment and documentation to add time before any design is fixed, typically weeks rather than days, and more where no prior ESOS or EPC evidence exists to draw on. The build and commissioning run to the same timescale as any commercial array of comparable size. A funder may require the assessment complete before works begin, so we confirm at feasibility whether PAS 2038 applies and plan its lead time in.
A guide can only take you so far. The figure you get is modelled from your own half-hourly load and a system sized from the on-site drone survey. No obligation, and systems this size sit outside the domestic MCS scheme, so the assurance is the engineering stack.