How to Get a Replacement Boiler Certificate

How do I get a replacement boiler certificate in the UK?

You can get a replacement boiler certificate by contacting the Gas Safe Register, your local council, or the boiler manufacturer, depending on the certificate you’ve lost. There are different types of certificates, like the Building Regulations Compliance Certificate which proves a boiler was installed properly, the Gas Safe Certificate also known as a CP12 for annual safety checks, and the Benchmark Certificate from the manufacturer. Each plays a different role, and getting a new one is usually straightforward with the right details to hand.

What is a boiler certificate?

A boiler certificate is an official document confirming that a gas boiler has been installed or maintained by a qualified engineer. In the United Kingdom, this document ensures legal compliance with gas safety regulations and confirms that the work meets the requirements of the Building Regulations.

You might have one or more of the following:

Building Regulations Compliance Certificate

This certificate is issued after a Gas Safe registered engineer installs a new boiler. It confirms that the installation complies with Part L of the Building Regulations. The certificate is posted to the property address shortly after the installation is registered.

Gas Safe Certificate (CP12)

This certificate is a legal requirement for landlords and must be renewed every twelve months. It confirms that all gas appliances, pipework, and flues in a rental property have been inspected and deemed safe.

Benchmark Certificate

Provided by the boiler manufacturer, the Benchmark Certificate is completed during commissioning. It plays a key role in activating the boiler warranty and confirms the appliance has been fitted to the manufacturer’s technical specifications.

These certificates are not just paperwork. They prove that gas appliances are safe, compliant, and handled by certified professionals. Keeping them up to date helps protect you, your tenants, and your property.

CP12 vs Boiler Installation Certificate

Although often confused, these certificates serve different purposes. The CP12, or Gas Safety Record, is a yearly requirement for rental properties. It documents a full check of all gas appliances and ventilation systems.

The Boiler Installation Certificate, formally known as the Building Regulations Compliance Certificate, is only issued once after a new or replacement boiler is installed. If you are a homeowner selling your house or a landlord proving that the boiler was properly installed, this is the certificate you will need.

If you are unsure whether you need a CP12 or a Building Regulations Certificate, it depends on your situation. Homeowners usually need the installation certificate for legal records. Landlords must ensure annual gas safety inspections are carried out and properly documented.

Why would you need a replacement boiler certificate?

There are several situations where a replacement certificate might be necessary. Documents can be lost during property renovations or house moves. The installation might not have been registered correctly. In many cases, homeowners discover the missing certificate when they prepare to sell their property or during conveyancing checks.

Here are some of the most common reasons:

• Preparing for a property sale

• Letting a property to tenants

• Submitting an insurance claim

• Complying with local council safety checks

• Replacing documentation that was never received or has gone missing

Having accurate records provides peace of mind and helps speed up legal and property transactions. It also prevents delays that could affect tenancy agreements or mortgage approvals.

How do I replace a missing Gas Safe Certificate (CP12)?

If you are missing a CP12, also called a Gas Safety Record, the solution depends on whether you still use the same engineer.

Step 1: Contact the original engineer

Gas Safe engineers are required to keep records of the certificates they issue. If you know who inspected the property previously, contact them directly. Many will be able to issue a duplicate.

Step 2: Arrange a new inspection

If the original engineer is not available, you will need to schedule a new safety check with another Gas Safe registered professional. They will inspect the boiler, gas meter, pipework, and any other gas appliances before issuing a new CP12.

You can use the Gas Safe Register search tool to find a qualified engineer in your area.

Step 3: Keep a secure copy of the new certificate

Store the certificate in a digital folder linked to your property documentation. Landlords should also provide a copy to tenants within 28 days of the inspection.

How to get a replacement Building Regulations Compliance Certificate

This certificate is important when proving that a boiler installation meets current building standards. It is also required during property sales, so it is worth checking whether yours is on record.

Step 1: Use the Gas Safe Register online check

Visit the Gas Safe Register’s certificate checker and enter your property address to see if the boiler installation was notified.

Step 2: Request a duplicate certificate

If the installation was properly registered, you can order a replacement directly from the Gas Safe Register. As of 2025, the fee is £6 including VAT. You will receive it by email or post, depending on your preference.

Step 3: What if there is no record?

In cases where the engineer did not register the installation, you will need to apply for a retrospective Building Regulations Compliance Certificate. This involves a qualified Gas Safe engineer visiting the property to assess the installation. They will check the flue, ventilation, and gas pipework to ensure everything complies with regulations.

What is a retrospective boiler certificate?

A retrospective boiler certificate is issued after a gas installation is checked and approved following the original work. This is necessary if the initial installation was not notified or if documentation was never completed.

Inspection process

The engineer will inspect the boiler, flue, ventilation, and connections. If the installation is safe and meets the standards, the engineer will submit a notification, and the Gas Safe Register will issue a new certificate. If there are any safety concerns, repairs or upgrades may be required before the certificate is granted.

Costs

Retrospective certificates usually cost between £200 and £400, depending on the complexity of the inspection. If major work is needed to bring the installation up to standard, the total cost could exceed £1000.

Not all engineers offer this service

Not every Gas Safe engineer is willing to certify another person’s work due to the responsibility involved. Use the Gas Safe Register’s search function and ask specifically whether they handle retrospective certifications.

What is boiler indemnity insurance and when should you use it?

Boiler indemnity insurance is a legal workaround used during the sale of a property when the installation certificate is missing and cannot be replaced. It provides financial cover if the local authority challenges the legality of the boiler installation in the future.

It does not replace certification, nor does it confirm safety or compliance. It simply protects the buyer from enforcement costs. Premiums usually range between £180 and £500 depending on the insurer and the value of the property. This option is often used when time is limited, and retrospective certification is not possible before exchange.

Can you sell a property without a boiler installation certificate?

While it is not illegal to sell a home without a Building Regulations Compliance Certificate, it often complicates the process. Most solicitors and buyers will expect this certificate as part of the property file.

If it is missing, your options are:

• Apply for a retrospective boiler certificate

• Provide boiler indemnity insurance

• Arrange a new Gas Safe inspection to show current compliance

These steps will reassure the buyer and reduce the chance of delays or renegotiation.

Best practices for storing boiler certificates

Keeping boiler paperwork in order can prevent last minute stress during sales or inspections. Use both physical and digital copies and label them by date and certificate type. For landlords, include certificates in your compliance file and renew your CP12 annually.

If you’re working with a managing agent, make sure they also keep a record. This avoids situations where tenants are left without proper documentation or inspections are delayed.

Frequently asked questions about replacement boiler certificates

What certificate do I need for a new boiler?

You will need a Building Regulations Compliance Certificate. This proves that a Gas Safe registered engineer installed the boiler correctly and that the work complies with Part L of the Building Regulations. The certificate is essential if you sell your property or if a solicitor requests proof of compliance.

Can I get a boiler certificate if the boiler was installed years ago?

Yes, but it depends on the situation. If the installation was registered, you can still request a copy from the Gas Safe Register. If not, you may need a retrospective boiler certificate, which involves an engineer assessing the installation before issuing documentation.

Is it a legal requirement to have a CP12 certificate?

If you are a landlord in the UK, you are legally required to have a CP12 certificate issued every twelve months. This certificate shows that all gas appliances in the rental property have been checked for safety.

What if the engineer did not register the boiler?

If your boiler installation is not listed on the Gas Safe Register, it is possible the installer did not notify them. You will need to hire another Gas Safe engineer to assess the boiler and apply for a retrospective Building Regulations Compliance Certificate.

Can I get insurance without a boiler certificate?

You may be able to get boiler indemnity insurance if the certificate is missing. This is often used during property transactions. However, it is not a substitute for having a proper installation certificate, and it does not guarantee the safety or compliance of the boiler.

Internal guidance and next steps

To find a Gas Safe registered engineer in your area, visit the Gas Safe Register’s engineer search page. You can also read more about landlord responsibilities on our Gas Safety Services Page, which includes advice on annual checks and document handling.

If you need support with retrospective certification, gas safety inspections, or document recovery, Landlord Building Certificates can help. Our experienced team handles everything from inspections to direct liaising with the Gas Safe Register to get your paperwork sorted quickly and correctly.

Final thoughts

Replacing a lost boiler certificate is a straightforward process if you know which type of certificate you need and where to look. Whether you are a homeowner or a landlord, keeping these documents in order ensures that your property remains safe, compliant, and ready for sale or tenancy.

If you are unsure what to do next or need an urgent inspection, speak with a trusted engineer or visit our website for more information.