A domestic EPC assessor should check three things before paying for software: that the exact product and version are on the government's approved list, that the accreditation scheme will accept its lodgements, and how quickly the supplier ships updates when the methodology changes. AI helps with client emails and wording, never with the rating calculation or lodgement.
The order matters. Scheme membership comes first, because the scheme runs the quality checks on your work, sets out how you lodge and may supply or support particular software, and software bought before that conversation can turn out to be the wrong product. Everything below is a checklist to run with your scheme's current rules in hand, because those rules are what count and they change.
Why the scheme comes before the software
The government's guide to EPCs for dwellings sets out the chain in plain terms. Energy assessors must be members of a government-approved accreditation scheme, and the schemes manage their assessors and make sure they are competent. Assessment data is fed into government-approved software. Only an approved energy assessor can lodge data on the domestic EPC register, and a certificate is valid only if it was generated from lodged data. It also says assessors must take part in their scheme's quality assurance procedures, work with reasonable care and skill, and handle complaints first themselves and then through the scheme.
That chain gives you a sensible buying order. First confirm which scheme you belong to or will join. Then ask it a short list of questions, in writing, before you look at any software demo:
- Which assessor software does the scheme publish or recommend, and which third-party products does it support for lodgement?
- What does lodgement cost per certificate, and what else do I pay the scheme each year?
- How do you tell members about methodology updates, and how much notice do you usually give?
- What quality assurance do you carry out on my work, and what evidence do you expect me to keep?
- How long do I need to keep site notes, photos and floor plans after lodgement?
- If I use software from another supplier, who supports me when something fails at lodgement?
The answers shape the checks that follow. If your scheme supplies software, you are comparing it with outside products. If it only supports third-party packages, you are comparing those and the scheme's lodgement route.
Eight checks to run before you pay
Is this exact product and version on the approved list?
Approved software is listed per methodology version. The published lists carry dates in their file names, September 2025 for the RdSAP 10 list and March 2026 for the SAP 10.3 list, and the government's methodology page, updated in June 2026, says the current RdSAP version is 10.0.1 and that SAP 10.3 is the only approved SAP methodology. RdSAP is the simpler method for existing homes; SAP is the full method.
Why it matters: an unapproved product cannot be used to produce a certificate. How to verify: ask the supplier for the product name and version number in writing, find that entry on the current list yourself, and confirm with your scheme that the update after the list's date is also approved.
Will your scheme accept its lodgements, and by what route?
Approved is necessary but not enough. Ask whether the software lodges directly or through your scheme's own portal, whether lodgement is included in your scheme fees or billed per certificate, and whether the scheme has tested the product. A supplier saying "we work with all schemes" has not answered the question. Ask for the scheme's name in the reply.
How fast do approved updates arrive when the method changes?
This check does the most to separate good suppliers from poor ones. When RdSAP 10 went live in June 2025, one scheme's member checklist said the previous version would no longer be available and all assessments had to be lodged with RdSAP 10. A bulletin about the 10.0.1 update said the scheme was targeting the first week of June 2026 and that the date might change. The government's methodology page adds that the launch of a new Home Energy Model has been delayed and is expected in the coming months, so another change is likely. So ask:
- How many days passed between the last methodology release and the supplier's approved update?
- Are updates included in the licence, or do they cost extra?
- What happens to a survey half-entered when the version switches?
- Do you warn customers in advance, and where?
- When the conventions change, do the in-app help and warnings change with them, and how soon?
That last question matters because the methodology is not the only thing that moves. The conventions, the rules on how an assessor records awkward features such as a loft room or an extension of mixed construction, are revised between versions: the RdSAP 10 conventions reached version 12.2 in August 2026. Software that still prompts you with last year's interpretation invites a quality query on work you did carefully.
A supplier that cannot name the date of the last update has not done one under pressure.
Does it work on site, offline, on the device you carry?
Many surveys happen in lofts, basements and rural houses with no signal. Test the app on the phone or tablet you will really use, with the signal turned off, on a real property. Check that photos attach to the right room, that the room-by-room entry is quick, and that copying a window or a wall type to another room works without retyping. Time one full survey; setup differences of five or ten minutes a job add up over a year.
Does it catch mistakes before you lodge?
Your scheme runs quality assurance on your work, and the data is yours. So the best software warns you about missing and inconsistent inputs, and lets you review every field before lodgement. Test it deliberately: leave a required field empty, enter a window larger than its wall, give a heating system that does not match the fuel, and see whether the software warns you or lets you through.
Can you produce the evidence if a job is audited?
An audit or a complaint may arrive months after the visit. Check that the software keeps your photos, notes and floor plan with the job record, that you can export a complete job file, and that the record stays available after you stop paying. The government's guide says the register keeps data for 20 years, so a question about a certificate can appear long after you have forgotten the house. Ask your scheme how long its rules expect you to keep your own evidence.
A filled-in evidence set for one illustrative job, a three-bedroom house with a loft conversion, shows what the software must hold together: the sketch floor plan with room dimensions; photos of the boiler data plate, the heating controls and the hot water cylinder; a photo of the loft insulation depth with a ruler in frame; a photo of each window type showing the glazing; a photo of the wall thickness measured at a door or window reveal; one photo of each elevation; and a note explaining how the loft room was recorded. That is about 20 photos and two pages of notes. Your scheme's evidence list is the one that counts, but the test is the same: open the job a week later on a different device and check that every item is still attached to the right room.
What does it cost per assessment, all in?
Costs come in buckets: scheme membership, the software licence, any per-lodgement charge, extra users and training. Ask which buckets apply and add them up for a year. Divide by your expected certificates to get a cost per assessment, then add the time cost of data entry, which is often larger than the licence gap between two products. The worked comparison later in this checklist shows how that sum can reverse a decision.
Who answers when it breaks mid-survey?
A homeowner is waiting, so support hours and response time matter more than they do for office software. Send a real support question during any trial and time the reply. Ask who owns a fault if the software rejects a lodgement that looks correct, and read the supplier's terms on liability, with a qualified adviser if the contract is long.
Reading a supplier's reply: dodges and good answers
Suppliers answer in sales language unless you ask for specifics. Put the key questions in an email so you can keep the replies, and compare what comes back with these example pairs:
| You ask | A dodge | A good answer |
|---|---|---|
| Is this version on the approved list? | "We are fully compliant and our users love us." | "Version 10.0.1, listed under RdSAP 10; here is the entry and the date we shipped it." |
| Which schemes accept your lodgements? | "All the major ones." | "Two accept direct lodgement; a third takes an export file. Here are their written confirmations." |
| How long did the last update take? | "We are always quick." | "The method changed on the 3rd and approved software shipped on the 14th, which is 11 days." |
| What if a version change lands mid-survey? | "That rarely happens." | "Open surveys stay on the old version until you lodge them, and we tell you the cut-off date by email." |
A message you can adapt and send to every supplier on your shortlist:
Hello [name], I am choosing assessor software and would like written answers to six questions. 1) The product name, version and its entry on the current approved list. 2) The accreditation schemes that accept your lodgements, with how each lodgement works. 3) How many days your last approved update took after the methodology change. 4) What the all-in cost is for one assessor lodging about [number] certificates a year, including updates. 5) Whether I can export a complete job file with photos and notes. 6) Your support hours and the usual reply time. Thank you, [your name].
Replies that arrive quickly and answer all six in order tell you something about support. Replies that skip questions 3 and 5 tell you something about the product.
Filled-in answers for three packages
Here is how a completed grid might look for a solo assessor lodging 180 domestic certificates a year. The three packages are hypothetical: A is a scheme-supplied bundle, B is a third-party product, C is a low-cost tablet app. Prices are invented to show the method, in dollars; use your own currency and real quotes.
| Check | Package A | Package B | Package C |
|---|---|---|---|
| Exact version on approved list | Yes, confirmed in writing | Yes, confirmed in writing | "Approval in progress" |
| Accepted by my scheme | Yes (scheme's own) | Yes, named in the reply | Not answered |
| Update after last method change | 11 days | 26 days | Could not say |
| Offline survey | Works, photos sync later | Works | Needs a signal |
| Warns on missing inputs | Yes | Some fields | No |
| Job file export | Yes | Yes | PDF only |
| All-in cost a year | $2,100 | $1,650 | $950 |
| Minutes per survey, data entry | 38 | 45 | 60 |
Package C fails the first two rows, so it is out before any price comparison, whatever its cost. That is the rule: approval and scheme acceptance are pass or fail, and only the survivors are compared. Between A and B, the licence gap looks like $450 a year in B's favour. Now add time. B takes 7 minutes longer a survey: 180 x 7 = 1,260 minutes, or 21 hours. At $35 an hour of your time, that is $735. So A costs $2,100 and B costs $1,650 + $735 = $2,385, which makes A the cheaper choice by $285 despite the higher price. Your numbers will differ, but run the sum with them rather than comparing licences alone.
Where AI helps an assessor, and where it stays out
AI is useful in the words around the job, not in the calculation. Treat the line as firm: the rating comes from approved software, using the data you gathered, and your scheme's quality assurance looks at that data. Anything that touches an input, a measurement or a conclusion stays with you.
Three messages worth drafting with AI
A booking confirmation that sets expectations. Give the assistant facts and forbid promises:
Write a short, friendly confirmation email for a home energy assessment visit.
Facts: visit on [date] at [time], about [x] minutes; I need access to the loft,
the boiler and heating controls, and every room; please have any recent
insulation or window paperwork to hand; I take photos of the building, not of
people; the certificate follows within [x] working days of the visit.
Do not promise any rating, savings or improvement. Use "[first name]".An illustrative first draft for a top-floor flat:
Hi [first name], this confirms your home energy assessment on [date] at [time]; the visit takes about [x] minutes. I'll need access to every room, the loft, the boiler and the heating controls, so please clear a path to the loft hatch. If you have paperwork for recent insulation or new windows, keep it to hand. I photograph the building only, never people. Your certificate will follow within [x] working days. Homes like yours usually score well, so there is nothing to worry about.
Two fixes before you send it. The last sentence is exactly the promise the prompt forbade, and a client who reads it will feel misled by a lower band, so delete it. And check the access list against the property: this flat's loft belongs to the building, so ask whether the hatch is in a shared hallway and who holds the key, rather than asking the client to clear a path.
An access chaser. Tenants and landlords often miss the first email. A short, polite second message that restates the date, asks for a named contact and offers a rebooking window cuts the number of wasted visits. A sample draft:
Hi [first name], a quick reminder that the energy assessment is booked for [date] at [time]. Could you confirm that someone will be there to give me access, and the best number to reach them on the day? If [date] no longer works, reply with two other times this week and I will rebook.
A complaint acknowledgement. The government's guide says complaints go first to the assessor and then to the accreditation scheme, so your acknowledgement can say so, accurately. A draft might read:
Thank you for raising this. I'll review my survey notes and photos for the visit and reply within [x] working days. If we cannot settle it between us, you can take the complaint to my accreditation scheme, which investigates complaints about its assessors.
Check the promised timescale against your scheme's rules, and keep the reply factual. For a sibling job, the home energy audit report tutorial shows how AI turns findings into a client report without altering the findings.
Explaining the finished certificate in plain English
After lodgement you can ask an assistant to turn the recommendations on the certificate into a plain-English note for the client. Paste only the recommendation text the certificate contains, and tell the assistant: "Explain each measure in one or two sentences, in the order given, and do not add costs, savings or advice that is not in the text." Before and after, as an example: the certificate line "Increase loft insulation to 270 mm" becomes "The loft has less insulation than current recommendations; adding more is usually one of the simpler improvements. A qualified installer can confirm what suits your roof." The second sentence is advice rather than fact from the certificate, so keep it only if you are happy to stand behind it. The insulation proposals tutorial covers wording that avoids promising savings.
What stays out of AI's hands
- Measurements and survey entries. A photo read by an assistant is not a measurement. Entering what it suggests as survey data is how a certificate ends up with an invented wall construction.
- The calculation and the rating. Only approved software produces these, from the data you enter.
- Statements about what you inspected. If an email says you inspected the loft, you must have done so.
- Client data in unmanaged tools. Use placeholders for names and addresses, and read the supplier's data terms before pasting anything personal.
Here is a slip, invented but realistic, that shows why the line is firm. An assessor photographs a combi boiler's data plate in poor light and asks an assistant to read it. The assistant returns a model name and an efficiency figure with total confidence, and the assessor enters both. The plate said something different, the scheme's quality check compared the entry with the photo, and the job came back for correction. The fix is dull: read the plate yourself, zoom the photo, and use the assistant only to tidy your notes about it afterwards.
A trial that never touches the live register
Ask for a trial that includes a way to practise without lodging, because a lodged certificate is a real record. Then take three of your own finished assessments, one simple and two awkward, and enter them in the trial. A rating that differs slightly from the lodged one is not a failure when the methodology version has moved since; ask the supplier to explain each difference. A difference of several bands is a warning about your own entry or the software.
Record four numbers for each package: minutes to enter, errors caught by the software, errors you caught yourself and minutes to recover from a deliberate mistake. Add the support reply time. Then score against the eight checks and apply the pass-or-fail rule from the comparison grid.
When you have a winner, negotiate before you sign. Ask for monthly rather than annual billing for the first quarter, so you can leave if an update arrives late. Ask for the update commitment in writing, with the number of days. Ask for your data export to be a named clause rather than a favour. And ask what the price will be next year, because a first-year discount can hide a larger renewal. If you also work in a neighbouring trade, the electrical certification apps checklist uses the same approach for a different set of certificates.
The first 50 lodgements: proof the choice was right
Once you are live, judge the software on your own record rather than the demo. Keep four running counts for the first 50 lodgements: minutes of data entry per survey, jobs your scheme's quality checks queried, lodgements that bounced back, and support tickets with their reply times. Set them against the figures you used in the comparison grid.
Say an assessor who chose Package A expected 38 minutes a survey and is averaging 46, with two quality queries in 50 jobs, both about heating controls. That pattern says the controls screen is slow or confusing and that the same screen is where the errors start. Eight extra minutes across 180 surveys is 24 hours a year, about $840 at the $35 rate, which is enough to wipe out the $285 advantage A had in the grid. Raise it with the supplier as a training question first; it becomes a reason to switch only if they cannot fix it before renewal.
Run the same count again after the next methodology update. That is when the promise about days to an approved release gets tested, and when you learn whether surveys in progress survived the switch.
Questions assessors ask about software and AI
Can AI produce an EPC rating or recommendations?
No. The rating comes from calculation in government-approved software, using the data you collected on site and lodged under your scheme's rules. AI can help you explain the finished certificate to a client in plain English, but it must not calculate, fill in survey fields or replace your inspection, because the responsibility stays with you.
Can I use my scheme's software and a third-party package together?
That depends on your scheme's rules, which vary. Some schemes publish their own assessor software, and the approved list names products from more than one supplier. Ask your scheme in writing which products it supports for lodgement, whether using a different one changes your fees, and who gives support when the two disagree.
How often will my software need to change?
Expect updates every year or so, and be ready for short notice. The reduced-data method for existing homes had a major version change in mid-2025, a minor update in 2026, and a new calculation model is expected to follow. Ask each supplier how fast approved updates arrive and whether they are included in the price.
Is it safe to paste client details into ChatGPT or Claude?
Treat client addresses, names and photos as personal data. Use first names or placeholders and leave addresses out when drafting emails. If you want to paste anything sensitive, use a business plan where training on your content is off by default, and read your scheme's and your own data-protection policies first. When unsure, ask a data-protection adviser.
Further reads
- Compliance Calendar: Track Licences, Insurance and Certificates — Tracking renewals, insurance and membership dates.
- AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.
Sources: the government's guide to energy performance certificates for dwellings; the government's SAP and RdSAP methodology page (updated June 2026); the published lists of approved RdSAP 10 and SAP 10.3 software; accreditation-scheme member bulletins on the 2025 RdSAP 10 switch and the 2026 RdSAP 10.0.1 update. Checked October 2026. Verify every rule with your own scheme.