Best CP12 Software for Gas Engineers (UK Guide)

What a CP12 Is and What the Law Actually Says

A CP12, formally called a Landlord Gas Safety Record, is the written record produced after a gas safety check on a property rented out to tenants. The duty to carry out that check and issue the record sits in Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998. Regulation 36(3) places the obligation squarely on the landlord, but it is the Gas Safe registered engineer who carries out the check and signs the record. If you sign a CP12, you are certifying that the appliances, flues, and associated pipework have been inspected and found safe, or that any unsafe items have been identified and the appropriate action taken.

The term CP12 is not a statutory term. It is industry shorthand for the certificate format historically associated with CORGI and carried over into Gas Safe registration. What the Regulations actually require, under Regulation 36(3)(c), is that a record be made in writing containing specific prescribed information including the address of the property, the date of inspection, the appliances checked, any defects identified, and the name and Gas Safe registration number of the engineer. The document you hand over must contain all of that. If your software produces a PDF missing any of those fields, it is not compliant regardless of how professional it looks.

It is worth being clear about who is liable for what. The landlord commits an offence under Regulation 36 if they fail to have the check done or fail to provide the record to tenants. But an engineer who issues a CP12 that does not accurately reflect what was found, or who signs off on a check that was not carried out properly, faces separate and serious consequences under Regulation 3 of the same Regulations, which covers work on gas fittings, and potentially under the Health and Safety at Work etc. Act 1974. The software question is about making sure the record itself is accurate and complete, not about whether you have done the job properly. Both matter.

• •Regulation 36(3) of the Gas Safety (Installation and Use) Regulations 1998 is the specific legal basis
• •Required fields include: property address, inspection date, appliances checked, defects found, engineer name and Gas Safe registration number
• •CP12 is industry terminology, not a statutory term, but the prescribed content is statutory
• •The engineer signing the record has independent legal exposure, separate from the landlord's obligations

When You Must Issue a CP12 and Who Must Receive It

The gas safety check must be carried out every 12 months. Regulation 36(3) requires that the check is done at least once in every 12-month period for every gas appliance and flue in a property let under a tenancy agreement. That 12-month clock runs from the date of the previous check, not from the anniversary of the tenancy. If a landlord has their check done in March one year and lets the following year's check slip to the following May, they are already in breach for the two months in between.

Once the check is done and the CP12 is completed, Regulation 36(6) requires that the landlord gives a copy of the record to each existing tenant within 28 days of the check. For new tenants, a copy must be provided before they move in, or at the point the tenancy begins. If you are producing the CP12 through software, this means having the ability to either hand over a printed copy or email a PDF on the day. A system where records sit in a dashboard and have to be manually downloaded and forwarded later introduces unnecessary lag and the risk that the landlord simply does not bother.

Owner-occupiers are not covered by Regulation 36. If a homeowner asks you to check their boiler, the output of that visit is a service record or an inspection note, not a CP12. Issuing something labelled as a CP12 to an owner-occupier is technically inaccurate and could cause confusion about their legal obligations. Most decent software will let you select the document type at the start of the job, which avoids this problem.

• •Check must be carried out every 12 months, per Regulation 36(3)
• •Existing tenants must receive a copy within 28 days of the check, per Regulation 36(6)
• •New tenants must receive their copy before or at the start of the tenancy
• •CP12 applies only to rented residential properties, not owner-occupied homes
• •The landlord must also keep a copy of each record for at least two years

What Happens If You Get It Wrong: Real Penalty Figures

The penalties for gas safety failures are not administrative fines. They are criminal offences. Under Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998, a breach is a criminal offence under Section 33 of the Health and Safety at Work etc. Act 1974. On summary conviction in the Magistrates' Court, the maximum fine is £20,000 per offence. Cases can also be referred to the Crown Court, where fines are unlimited. In cases involving fatalities or serious injury, custodial sentences are not unusual.

For the gas engineer specifically, Gas Safe Register can and does revoke registration where there is evidence of incompetent or fraudulent work. Losing your Gas Safe card means you cannot legally work on gas as a self-employed engineer, which for most sole traders means the complete loss of their income. The Health and Safety Executive also has powers under the Health and Safety at Work etc. Act 1974 to issue Improvement Notices and Prohibition Notices, both of which can halt your business immediately.

In terms of the paperwork specifically, the most common failure that leads to enforcement is not a missed appliance or an incorrect reading. It is incomplete records. An HSE inspector who finds that a landlord cannot produce CP12 records going back two years, or that the engineer's copy does not contain a Gas Safe registration number, can treat that as evidence of a broader failure to comply. If you are producing records manually on paper or with a basic template, the risk of missing a mandatory field increases significantly with every job. Software that locks required fields and will not let you generate the PDF until they are completed removes that specific risk.

• •Maximum fine of £20,000 per offence on summary conviction in the Magistrates' Court
• •Crown Court prosecutions carry unlimited fines
• •Custodial sentences are possible in fatality cases
• •Gas Safe Register can revoke registration, which ends your ability to trade legally
• •HSE can issue Prohibition Notices that stop your business immediately
• •Incomplete records are a specific enforcement trigger, not just a paperwork inconvenience

How Long Records Must Be Kept

Regulation 36(3)(e) requires that the landlord keeps a copy of each CP12 for at least two years from the date of the inspection. That is the landlord's obligation. For the gas engineer, there is no equivalent statutory minimum in the Regulations themselves, but Gas Safe Register's own conditions of registration require that you keep copies of certificates you have issued. The practical standard across the industry is a minimum of two years to match the landlord requirement, with most insurers and professional bodies recommending longer.

From a pure liability perspective, keeping records for six years is sensible. If a fault develops in a property you have inspected, and a civil claim is brought against you or the landlord, your ability to produce the original CP12 showing what you checked and what you found is your primary defence. The Limitation Act 1980 allows contract claims to be brought up to six years after the event in England and Wales, so that is the window during which records might be needed. Software that offers cloud storage and retrieval for several years is worth more than software that emails you a PDF and then forgets it ever existed.

Paper records are legally acceptable. The Regulations do not require digital storage. However, paper records stored in a van or a home office are vulnerable to fire, flood, and simple loss. If you cannot produce a record when it is needed, you cannot prove you did the job correctly. That is the practical argument for software with cloud storage, not a legal requirement but a sensible risk management decision.

• •Landlord must keep CP12 records for a minimum of two years under Regulation 36(3)(e)
• •No statutory minimum for engineers, but Gas Safe conditions of registration require copies to be kept
• •Industry practice and insurer guidance suggests a minimum of two years, with six years recommended
• •Six years aligns with the civil claim window under the Limitation Act 1980
• •Digital cloud storage is not legally required but is significantly more reliable than paper

What the Software Actually Needs to Do

Before comparing specific products, it is worth being clear about the minimum functional requirements for CP12 software that is genuinely fit for purpose. The software must produce a document that contains every prescribed field under Regulation 36. That means: landlord details, tenant details, property address, date of inspection, a list of every appliance and flue inspected, the results of each inspection, details of any defects identified and what action was taken or advised, the engineer's name, and their Gas Safe registration number. If the software leaves any of those fields optional, it is possible to produce a non-compliant certificate without realising it.

Beyond compliance, the practical features that matter for a sole trader doing multiple CP12s a week are: speed of data entry, the ability to save landlord and property details so you are not retyping the same address every time, a clear PDF output that looks professional and is readable by landlords and tenants, and a way to send or share the document immediately on site. If you are waiting until you get back to a laptop to process and send records, you are adding unnecessary admin time and creating a gap between the job and the paperwork.

Storage and retrieval is the third pillar. You need to be able to find a specific CP12 from eighteen months ago within a couple of minutes if asked. That means either a searchable cloud database or a well-organised local filing system. Most decent software handles this. What you want to avoid is a system where records are emailed to you as PDFs and stored in a generic email inbox with no tagging or search functionality.

• •Mandatory fields must all be present: appliances, flues, defects, engineer name, Gas Safe number, dates
• •Saved landlord and property profiles avoid repeated data entry
• •On-site PDF generation and immediate sending saves time and closes the paperwork gap
• •Searchable record storage is essential for retrieval during inspections or disputes
• •Software should prevent certificate generation if mandatory fields are empty

The Main Software Options and Who They Suit

Gas Engineer Software (GES) is the longest-established dedicated product in this market. It was built specifically for Regulation 36 compliance and covers CP12s, service records, and a range of other gas certificates. The interface is functional rather than sleek, but it is well understood by engineers who have been in the trade for a long time. Pricing is subscription-based at around £20 to £30 per month depending on the tier, with a cap on certificates per month on lower plans. For a sole trader doing a moderate volume of landlord checks, GES works well. It does not do scheduling, job management, or invoicing to any meaningful degree.

Powered Now is a broader job management platform that includes gas certificate generation as one feature among many. If you want one app that handles quotes, invoices, job scheduling, and certificates, Powered Now is a reasonable option. The trade-off is that it costs more, the gas-specific features are less developed than in a dedicated product, and the interface is designed for general trades rather than specifically for gas work. Pricing typically starts around £25 to £40 per month.

Commusoft and BigChange are enterprise-leaning platforms aimed at larger operations with employed engineers and fleet vehicles. As a sole trader, you will be paying for features you will never use. They are not the right fit unless you are planning to grow to a multi-engineer operation within a year or two. At the other end, some engineers still use Microsoft Word or Excel templates, which are legally acceptable but require discipline to maintain compliance and are highly vulnerable to human error on required fields.

• •Gas Engineer Software: dedicated product, strong compliance features, limited job management
• •Powered Now: broad job management with certificate generation, higher cost, less gas-specific depth
• •Commusoft and BigChange: enterprise platforms, overcomplicated and overpriced for sole traders
• •Word and Excel templates: legal but risky on mandatory field compliance, no cloud storage
• •Any software used must produce a Regulation 36 compliant output, regardless of how it looks

A Worked Example: One Landlord, Four Properties, One Year

Take a sole trader gas engineer, registered with Gas Safe, who manages landlord safety checks for a portfolio landlord with four properties in the same town. Each property has a boiler and a gas hob. The landlord books all four checks in the same week in March to keep the renewals aligned. The engineer completes all four properties across two days, producing four CP12 certificates.

Under Regulation 36(6), the landlord must give a copy to each existing tenant within 28 days of the check. If the engineer emails all four PDFs to the landlord on the day each check is completed, the landlord has everything they need and has no excuse for a late handover. If the engineer instead batches all four and emails them at the weekend, the 28-day clock is already ticking and the landlord has less time. In this scenario, software that allows on-site PDF generation and one-tap email to the landlord saves time and removes ambiguity about when the record was provided.

Now assume one of the four certificates contains an error: the Gas Safe registration number is missing because the engineer used a template that did not flag the empty field. Eleven months later, a tenant in that property reports a gas smell. The HSE opens an inspection. The landlord produces three compliant CP12s and one that is missing the engineer's registration number. That is not just an administrative issue. It is evidence that the record does not meet the requirements of Regulation 36 and raises questions about whether the check was carried out at all. The landlord faces potential prosecution. The engineer faces Gas Safe investigation and possible revocation. The financial and professional consequences of one missing field on one certificate are disproportionate to the two seconds it would have taken to fill it in. Software that validates mandatory fields before allowing the certificate to be generated prevents this entirely.

• •Four properties checked in March, four CP12s required
• •28-day clock for tenant delivery starts on the date of each check, not the date of email
• •One missing Gas Safe registration number on one certificate created enforcement risk for both landlord and engineer
• •Field validation in software prevents this class of error at the point of generation
• •Cost of software per month: £0 to £40. Cost of a CP12-related prosecution: potentially unlimited fine and loss of Gas Safe registration

MTD and Tax Admin for Gas Engineers Doing High Volume CP12 Work

This section is not about certificates. It is about the administrative context in which a busy sole-trader gas engineer operates. If your annual qualifying income from self-employment is above £50,000, you are required under Making Tax Digital for Income Tax Self Assessment to use MTD-compatible software for quarterly digital filing from 6 April 2026. The £30,000 threshold follows in April 2027. This matters in the context of CP12 software because some engineers are tempted to use a single all-in-one platform for certificates, invoicing, and tax records. That can work, but only if the platform is MTD-compatible for your income threshold.

Most dedicated gas certificate software is not MTD-compatible. GES, for example, is not an accounting product. If you are using it for certificates and a separate product such as QuickBooks, FreeAgent, or Xero for your accounts, the combination is fine as long as your accounting software is MTD-compliant. What you do not want is to assume that because you have one app for certificates and one for invoicing, your quarterly tax reporting obligation is covered. Check explicitly whether your accounting software is on HMRC's list of MTD-compatible products.

The quarterly filing requirement under MTD ITSA is separate from your Self Assessment return. It requires digital submission of income and expense summaries every quarter. Missing a quarterly submission is a penalty event under the points-based penalty system introduced alongside MTD. For a sole trader with straightforward self-employment income from gas work, the admin is not complex, but it has to be done through compatible software. Certificate apps are not that software.

• •MTD ITSA applies from 6 April 2026 for sole traders with qualifying income above £50,000
• •The £30,000 income threshold follows in April 2027
• •Gas certificate software is not MTD-compatible and does not replace accounting software
• •Confirm your accounting software appears on HMRC's approved MTD-compatible product list
• •Quarterly submissions are mandatory and missing them triggers the points-based penalty system

How to Evaluate Any CP12 Software Before You Commit

The most important test is simple: generate a sample CP12 and check every field against the requirements of Regulation 36(3). Print it out and go through it line by line. Does it include the property address, the date, every appliance inspected, any defects identified, the action taken, your name, and your Gas Safe registration number? If any of those fields are missing from the template, the software is not fit for the specific purpose of producing a Regulation 36 compliant record, regardless of what the sales material says.

The second test is retrieval. After generating five test certificates, can you find the third one in under a minute using only the property address or the landlord's name? If the search functionality is poor or the records are only stored as files in a folder, that is a practical problem. The third test is portability. If you cancel your subscription, can you export your historical records in a standard format such as PDF or CSV? Software that locks your records behind a paywall or loses them on cancellation is a significant risk if you ever want to switch products or need records after a dispute.

Free trials are standard in this market. Take them seriously. Run a real CP12 through the system on a real job before you commit to a subscription. Pay attention to how the app behaves on your mobile, not just on a laptop, because most engineers are filling in certificates on site from a phone or tablet. If the mobile interface is clunky or slow on a 4G connection, it will be a source of frustration on every single job.

• •Check every Regulation 36(3) required field is present in the template before committing
• •Test search and retrieval speed using only a property address or landlord name
• •Confirm you can export records in a standard format if you cancel your subscription
• •Test the mobile interface on a real job, on 4G, before you pay for anything
• •Ask the provider explicitly whether their output is described as Regulation 36 compliant

TradeDoc AI: Free CP12 Generation for Gas Engineers

TradeDoc AI generates a compliant CP12 in about two minutes. It is free for your first 100 documents a month, no card required at sign-up, and all four UK trades are covered in one place, so if you occasionally do gas and heating work across residential and light commercial, everything is in one account. If you want your logo on the PDF and one-tap email send to the customer or landlord, Pro is £15 per month.

The templates are built around the mandatory fields under Regulation 36(3), so required fields are locked, and the system will not produce the certificate until every prescribed field is completed. Records are stored in the cloud and searchable by property address, landlord name, or date. For a sole trader doing a moderate volume of CP12s each month, the free tier covers most working patterns without any cost at all.

You can start at tradedoc.co.uk, generate your first CP12 in about two minutes, and have it on the landlord's phone before you have packed your tools away.