36+ years. 1,000+ boiler installations. Gas Safe registration No. 575142.
Those numbers matter. But they are not the only things to check before inviting a gas engineer into your home.
Whether you need a gas boiler service, a repair, or a complete replacement, the right engineer should give you more than a cheap headline price. They should provide proper qualifications, clear paperwork, honest advice, and work you can rely on.
We are Boilers On-Demand. We have served homeowners across Sussex and Surrey since 1988. We are not a national call centre. We are a local team that believes gas work should be done safely, clearly, and properly.
Here are the ten checks we recommend making before you book.
1. Check the Business Is Gas Safe Registered
This is the first check. Do not skip it.
Any business carrying out gas work in Great Britain must be registered with the official Gas Safe Register. You can search for a company by name, registration number, or location.
Our business is registered as Boilers On-Demand / Coventry Plumbing Ltd, Gas Safe registration No. 575142.
Registration means a business is legally permitted to carry out gas work. It does not mean you should stop checking there. You also need to confirm that the individual engineer attending your property is qualified for the work you need.
2. Ask to See the Engineer’s Gas Safe ID Card
A genuine engineer should be happy to show you their Gas Safe ID card. Ask to see it before work starts.
Check:
- The engineer’s name and photograph
- The licence number
- The start and expiry dates
- The Gas Safe logo and security details
- The types of gas work and appliances they are qualified to handle
A company’s registration number and an engineer’s personal licence number are not the same thing. The company registration confirms the business. The card confirms the individual’s qualifications.
There is no awkwardness in asking. A professional engineer will expect it.
3. Confirm They Are Qualified for Your Specific Appliance
Not every gas engineer is qualified to work on every appliance.
For example, someone qualified to work on domestic boilers may not be qualified for commercial systems or LPG appliances. If you need a boiler service, repair, or installation, check that the engineer’s card covers domestic natural gas boilers.
You should also ask whether they have experience with your boiler type:
- Combi boilers
- System boilers
- Regular or heat-only boilers
- Older central heating systems
- Modern high-efficiency appliances
This is particularly important if your boiler is older, has an unusual fault, or is still under warranty.
4. Look for a Real Local Track Record
A local phone number does not always mean a local business.
Ask how long the company has operated in the area and whether they regularly work in your town. A local engineer should understand the housing stock, common heating systems, parking restrictions, and practical issues that affect homes in the area.
We work across Sussex and Surrey, including Horsham, Billingshurst, Petworth, Storrington, Findon, Worthing, Crawley, Brighton, Chichester, Arundel, Littlehampton, and the surrounding towns and villages.
We have been working in Sussex and Surrey since 1988. That means local customers, local recommendations, and a reputation built the old way: by turning up, doing the job properly, and letting word-of-mouth do the rest.
5. Check Independent Reviews and Completed Work
Reviews can tell you what a company is like after the sale.
Look for comments about:
- Punctuality
- Communication
- Cleanliness
- Quality of workmanship
- Whether the final price matched the quote
- How the company handled problems
Be cautious of businesses with only vague testimonials or reviews that all sound identical. Look for specific customer experiences.
Boilers On-Demand has more than 30 five-star Google reviews and has installed over 1,000 boilers. We are proud of that record, but we still believe each job has to earn the next recommendation.
6. Get a Written Quote With the Full Scope of Work
A verbal estimate is not enough for most boiler work.
Before agreeing, ask for a written quote that explains exactly what is included. It should state:
- The boiler make and model
- Labour costs
- Materials and additional components
- Flue or pipework changes
- Removal of the old boiler
- System cleaning or flushing, if required
- Commissioning and testing
- VAT
- Any certificate or registration fees
For a repair, ask whether the price includes diagnosis, labour, and parts. If the engineer cannot identify the fault until they inspect the boiler, ask how diagnostic charges work.
A clear quote protects both sides. It also makes it easier to compare like with like.
7. Ask About Call-Out Charges and Hidden Fees
A low advertised price can become much higher once extra charges are added.
Ask directly:
- Is there a call-out fee?
- Is there a separate diagnostic charge?
- Are evenings or weekends charged differently?
- Is labour charged by the hour?
- Are parking or mileage costs added?
- Will I be contacted before extra work is carried out?
There is nothing wrong with a company charging for its time. The problem is being surprised by charges you were never told about.
We believe in clear pricing before work begins. If something unexpected is found, we explain the issue and the options before carrying out additional work.
8. Check the Guarantee and Aftercare
A boiler installation is a major purchase. Ask what protection you receive after the engineer leaves.
Find out:
- How long the boiler manufacturer’s guarantee lasts
- Whether the boiler must be registered after installation
- What workmanship guarantee is provided
- Who deals with guarantee claims
- Whether servicing is required to keep the guarantee valid
- Who you contact if something goes wrong
We install leading brands including Vaillant, Glow-worm, and Baxi. Depending on the model and installation terms, manufacturer guarantees of up to 12 years may be available.
Our guarantee is simple: clear advice, proper installation, and support after the job is finished.
For customers looking for Vaillant boiler installers, our team regularly installs Vaillant systems, including the Vaillant ecoTEC range. We will recommend a boiler based on your home, hot water demand, and budget — not simply the model with the highest price.
9. Ask What Safety Checks and Paperwork Are Included
Gas work is not finished when the boiler fires up.
A competent engineer should carry out the necessary safety and commissioning checks. Depending on the job, these may include:
- Gas tightness checks
- Operating and standing pressure checks
- Flue and combustion checks
- Ventilation checks
- Carbon monoxide safety checks
- Controls and safety device checks
- Boiler commissioning
- Explanation of the system to the homeowner
You should also ask what paperwork you will receive. For a new installation, this may include the installation and commissioning documents, manufacturer registration details, and guarantee information.
For a landlord property, you need the correct annual gas safety record, commonly called a CP12. We provide landlord gas safety certificates across Sussex and Surrey, with clear documentation for landlords and tenants.
10. Check How They Treat Your Home
Technical ability matters. So does basic respect.
A good engineer should:
- Arrive when agreed
- Protect flooring and work surfaces
- Keep disruption to a minimum
- Explain what they are doing
- Dispose of old equipment responsibly
- Test the system before leaving
- Show you how to use the controls
- Leave the work area clean
This sounds basic. It should be. But homeowners remember the engineer who communicated clearly, took their shoes off, and cleaned up just as much as they remember the boiler brand.
We work in people’s homes every day. We know that punctual, tidy service is not an optional extra.
Looking for a Gas Boiler Service Near You?
Annual servicing can help identify faults before they become breakdowns. It also gives you the opportunity to check that the boiler is operating safely and efficiently.
If you are searching for a gas boiler service in Sussex or Surrey, use the same checks above:
- Confirm Gas Safe registration
- Check the engineer’s appliance qualifications
- Ask what the service includes
- Confirm the full price
- Make sure you receive the relevant paperwork
You can find out more about our boiler servicing and repair service.
Why Homeowners Choose Boilers On-Demand
We are not the biggest heating company in Sussex. We are a local team focused on doing reliable work for local homeowners.
Our customers choose us because we offer:
- 36+ years of local experience
- 1,000+ boilers installed
- Gas Safe registration No. 575142
- Vaillant, Glow-worm, and Baxi installations
- Manufacturer guarantees of up to 12 years
- Clear, upfront quotes
- Clean and punctual service
- Boiler servicing, repairs, installations, and plumbing
- Coverage across Sussex and Surrey
If you need a new system, our boiler installation service includes a survey, clear recommendation, written quote, professional installation, and handover.
Frequently Asked Questions
- How do I check if a gas engineer is Gas Safe registered?
- Search the official Gas Safe Register by business name, registration number, or location. Boilers On-Demand (Coventry Plumbing Ltd) is registered under No. 575142. Registration confirms a business is legally permitted to carry out gas work.
- What is the difference between a company registration number and an engineer’s ID card?
- The company registration confirms the business is Gas Safe registered. The engineer’s ID card confirms that individual’s qualifications, including the start and expiry dates and which types of gas appliance they are qualified to work on.
- Should a gas engineer show ID before starting work?
- Yes. A professional engineer will expect it. Ask to see their Gas Safe ID card and check the name, photo, licence number, expiry date, security details, and the appliance categories they are qualified for.
- What paperwork should I receive after boiler work?
- For a new installation you should receive installation and commissioning documents, manufacturer registration details, and guarantee information. For a rental property, a landlord needs the annual gas safety record, commonly called a CP12.
- Do you cover my area in Sussex or Surrey?
- Yes. We work across Sussex and Surrey, including Horsham, Billingshurst, Petworth, Storrington, Worthing, Crawley, Brighton, Chichester, Arundel, Littlehampton, and surrounding towns and villages, and have done since 1988.
The Bottom Line
Do not choose a gas engineer on price alone.
Check the registration. Check the individual ID card. Confirm the qualifications. Get the quote in writing. Ask about guarantees, paperwork, safety checks, and extra charges.
Those ten questions can save you money, prevent avoidable problems, and give you confidence that the work is being done safely.
If you need a Gas Safe engineer in Sussex or Surrey, call Boilers On-Demand on 01903 802395 or email info@on-demand-group.co.uk. No hard sell — just a straight conversation about what your home needs.