“I needed to have my boiler flu repositioned and approached GMH ltd for advice. They attended site promptly to chat through the options and costs. Once agreed their engineers attended site punctually, on the agreed date and undertook the work. They kept me informed throughout, checking that any decisions had my approval before proceeding. By nature the work is messy, however the team worked to minimise this and did a great clean-up at the end. The engineers were both really nice chaps and couldn't have been more helpful. I'm really pleased with both the outcome and the quality of workmanship. I would certainly use them again and would not hesitate to recommend.”
Public evidence profile · Checked June 2026
GMH Gas Maintenance Heating Ltd
Credentials & registries
Which? Trusted Trader
Trust Score
50out of 100
- Rated 5.0 from 33 reviews
- 4 reviews in the last 12 months
How this score is worked out
Rating5.0 / 5
Review volume33
Independent sources2 independent public sources
Credentials1 credential shown
How this score is made up
What customers say32.8 of 60
Independent checks8.8 of 30
Track record8.5 of 10
See the independent checks
- Licences and credentials0.6 of 8.3
- Ways to reach them8.3 of 8.3
- Reviewed on more than one site0 of 6.2
- Registered company details0 of 4.1
- Photos of their work0 of 2.1
- Industry recognition0 of 1
Missing evidence lowers the score because we can't check it. It doesn't mean it doesn't exist. Claiming a profile never changes the score. Evidence context, not a guarantee of workmanship.
Trust at a glance
1 checkWhat we can verify about GMH Gas Maintenance Heating Ltd
Each card sums up one thing we can check from public sources. Open it for the full detail and the named source. This is evidence context, not a guarantee.
See the full verification checklist for GMH Gas Maintenance Heating Ltd →Reviews · public evidence
What customers say
These reviews are published independently on the named public source below, not testimonials this business chose to show. We bring them together and link each one back to where it appeared, so you can open the source and read it yourself.
5.0out of 5
Customers often mention
Where these reviews are published
- Which? Trusted Traders33 reviews · 5.0 avg
Highlights
“GMH recently dealt with a leak for me - this was the 2nd time I had engaged GMH on a job. From the initial investigation through to the resolution and required fixes Gary was excellent. The consistent communication and methodical approach from Gary on a very tricky job gave me confidence throughout and they did everything they said they would during the different stages of the work. I can absolutely recommend GMH.”
“I've use GMH Ltd for a few years now. They were originally recommended to us by a family member so when we needed a new combination boiler I thought we would try them out. Recently we have moved into a very old house which needed a complete overhaul of the water tanks as the house had no water pressure. With both jobs GMH were fantastic and the end result was faultless. The guys who did the fitting were friendly, knowledgeable and took time in explaining the process of the work. I would certainly recommend GMH LTD for any plumbing and heating work.”
Detailed reviews
These are the individual reviews we hold for GMH Gas Maintenance Heating Ltd, including the highlights above. The 33 headline total is the review volume reported across public review sources.
Everything done in an efficient, courteous and timely manner. Very polite engineers who worked well with the engineers who were installing new gas mains in the vicinity.(Could easily have been a difficult situation.) Overall we are very, very pleased and now have a new boiler working very well indeed.
Yearly boiler service found our boiler needed several replacement parts. Gmh engineers went over and above, throughout the day to pick up the new boiler parts to insure by the end of the day we had hot water and fully functioning boiler. Thanks Gary and Harry as usual great service.
Gary Horton had serviced my back boiler for several years and I was impressed by his attention to detail and knowledge. I therefore had no hesitation in asking him for a quote to remove the old boiler and have a condensing boiler installed in the new position in the Garage. The work also involved replacing an old radiator in the Kitchen and also putting in an extra one in the Lounge. The system was power flushed and left running with an inhibitor. The team arrived promptly each day and worked well and efficiently. The installation went smoothly and the team was considerate and thoughtful throughout. I will be using them for the annual boiler service and I have no hesitation in recommending this company.
Used Which Trusted Traders to find a local CH company to replace a CH motorised valve with leaky connection and discovered GMH Ltd with great reviews. After exchanging a couple of emails with Mandy in the office and sending a photo of the problem, I received a competitive quote and an appointment was made for a couple of weeks later. Harry arrived promptly on the day with the parts and completed the job without faff or drama. I plan to use GMH for all future CH and plumbing work. I thoroughly recommend GMH Ltd. Which Trusted Traders is a great platform to find quality businesses.
GMH were amazing! On the days the new boiler was being installed, they arrived at the arranged time every day, minimal amount of mess and noise and fuss, very helpful information from the main engineer when installing the app, the boiler works beautifully and the installation work looks great.
Read the other 10 detailed reviews on this pageShow fewer reviews
GMH gave a clear and detailed quotation for installation of combi boiler to replace conventional central heating boiler. Quote was prompt and replies to a couple of queries were also very quickly responded to. Work involved removal of hot water tank/and associated pipework as well as draining of cold water tank and removal of pipes in loft. New pipework was installed to adapt central heating and hot water to new system. Gary and his team arrived promptly, worked solidly over the two days, gave clear explanation if I had any questions. A really efficient team. I have now booked them for a smaller job and will use them for annual service. I would recommend them highly.
We required a boiler update. Gary from GMH visited to assess our old boiler and gave advice on suitable products. GMH sent an email with a quote and the agreed date and time that the work would begin. The work commenced at the agreed time and date. The guys worked in a considerate and thoughtful manner. The work was completed in a timely way and upon completion, everything was tidied away. What's not to like? 10/10
After having a water leak to a mains pipe in the hall. The plumber sent by the insurance company could not stop, the leak the only advice he could give me was to "call the water supplier". I called GMH they arrived quickly were courteous, friendly and fixed the leak within the hour even helping me to clean up the mess. Would highly recommend will definitely be using them again.
Gary Horton has been servicing my boiler for many years and I have always been more than satisfied. He and his employees are courteous and helpful, clean and tidy and totally reliable. They are pleasant and friendly and highly professional both on the phone and in the house. This recent job was not urgent but very annoying as the heating system was very noisy due to air in the pipes. It is now quieter than it has ever been and I am very pleased. Gary was very cooperative about the social distancing and is happy to discuss these situations alongside the work needed. I have previously recommended him to another family member who is also extremely satisfied with his work. I have no hesitation in rated him highly.
I have used Gary for many years for various gas safety checks for rental properties and he's always proven to be prompt at both replying to emails and attending the property and he's extremely personable with good, friendly advice. On the last occasion, we had a bad smell in our bathroom which had been a problem for some time. Gary had a look, made a recommendation to fix it and within 3 days had the required part and had installed it! All for very reasonable pricing. We wouldn't go elsewhere for our gas or plumbing needs and would recommend Gary for anyone looking for a great, local service.
We've used GMH for many years and know lots of people who use the company locally. Had new boiler fitted 3 years ago by them and had services each year since. Workmanship is excellent. They are well organised and all the guys in the small team are just brilliant to deal with, always offering solutions and advice. Tidy workers too, taking care to make sure you're 100% happy on every call. A really motivated group of technicians with a good office organisation behind them. Really recommend this company.
GMH attended to provide my annual boiler service Gary attended on time and was courteous and polite All work completed to a high and competitive standard I have used GMH for over 10 years and they have installed new Worcester Bosch boiler systems in my 3 previous properties
GMH responded promptly to a boiler breakdown in my 95 year old Mother's house. They were alerted early in the morning and the heating was back on by mid afternoon. The service was personal, responsive and efficient. I cannot praise them enough. We have had a 8 years of regular boiler servicing before this. I would recommend this company to everyone.
We’ve used GMH for our annual boiler service for a few years now, always very reliable with quality work and reasonable pricing. More recently Gary’s team completed some plumbing repairs for us, they have done a great job and have been very good in coming back to make some necessary adjustments. Recommended to us and would also highly recommend them.
Company relatively small, courteous. Very good job for a day and a half. Pleased with work.
Local context
Rated 5.0, in line with the local average for plumbers in Banstead
Across 15 plumbers in Banstead, the typical rating is 5.0 out of 5. We compare against the same businesses a homeowner would find searching for this trade locally.
From customer reviews
What customers consistently say
Recurring themes from 25 customer reviews on Which? Trusted Traders.
Customers who keep coming back: “Gary Horton has been servicing my boiler for many years” · Which? Trusted Traders, 30 May 2020
“They attended site promptly” · Which? Trusted Traders, 6 Mar 2026
“The team arrived promptly each day” · Which? Trusted Traders, 1 Mar 2024
“Gary and his team arrived promptly” · Which? Trusted Traders, 13 Aug 2023
Credentials and associations
1Credentials and memberships
These credentials and memberships are attributed to named public sources. Check the source before relying on them.
- Source checked
- 25 Jun 2026
Source-listed gallery
11 photosPhotos listed on Which? Trusted Traders
These sources do not label every image as completed work. The gallery may include projects, people, logos or certificates, so it does not count as completed-work evidence.
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From Which? Trusted Traders
Opening hours
The hours this business publishes online, handy for knowing when to call. Confirm before you set off.
- Monday–Friday
- 8am–5:30pm
Sources
2 named public sourcesWhere this information comes from
Everything on this page is drawn from named public sources. Where a source provides a public link, you can open the original and dig deeper.
Review sources
Business and public registers
Public evidence last checked June 2026
About
GMH Limited has been operating for 14 years with over 20 years experience in Heating and Plumbing. All of our Engineers are fully qualified and are Gas Safe registered as well as keeping up to date with Worcester Bosch Accredited Courses. We provide a polite friendly service where no job is too small, from the service of a boiler to a complete heating and hot water system. We also understand that reliability is key and work with people on all Budgets and aim to carry out work with the minimum of disruption for our customers at all times. Offering a professional experienced service the majority of our work comes through recommendations from existing customers and we are always happy to provide references of work carried out. For further information or if you need an estimate please contact us on 01737 216111 or by e-mail gmhltd33@gmail.com providing your name and contact details.
Services they list
Central heating systems (installation and servicing)Oil fired heating equipmentImmersion HeatersBoiler installationBoiler repairBoiler servicingGas safety testing and inspectionRadiators and central heatingUnderfloor heatingGas cooker installationGas emergenciesPower flushing
Listed on public sources or the business's own website; check directly that they cover your job before you book.
What this business says about itself
From their own website
What this business says about itself
- Services stated: Underfloor heating installation
Accreditations it displays. Confirm each is current on the official register before you hire:
- Gas Safe Register · verify (opens in new tab)
- OFTEC (oil heating) · verify (opens in new tab)
- Worcester Bosch Accredited Installer · verify (opens in new tab)
These are statements the business makes on its own website, worth confirming in writing (and on the official registers) before you hire, not independently verified by us.
Independent checks
About this business
Steadily reviewed4 reviews in the last 12 months, in line with their long-term review pace of about 5 a year.
Your own checks
What to check before you hire
Worth checking yourself
Always confirm credentials and quotes with the business directly before hiring.
Verify at the sourceCheck them yourself
Approved plumbers on the free WaterSafe register are vetted, qualified to the water regulations and insured. Check they're listed, or find a WaterSafe-approved plumber near you.
Check the WaterSafe registerAgree the call-out fee, the hourly or fixed rate, and whether parts are charged on top, in writing, before an emergency plumber starts. Out-of-hours overcharging and 'while I'm here' add-ons are common complaints.
Be wary of a plumber who, on a first visit, says your whole system or boiler must be replaced. Get a second opinion and an itemised quote (parts and labour separately) before agreeing to major work.
Gas and boiler work is a separate, regulated trade, not general plumbing. Make sure anyone working on a gas appliance is specifically registered to do gas work, and ask to see that registration before they start.
Want an extra legitimacy check? Run the Cowboy Checker on GMH Gas Maintenance Heating Ltd before you contact them.
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Common questions about GMH Gas Maintenance Heating Ltd
Is GMH Gas Maintenance Heating Ltd a legitimate business?
GMH Gas Maintenance Heating Ltd has 33 independent public reviews, rated 5 out of 5. This is independent public evidence gathered from named public sources (no ads, no paid placement), not a guarantee of workmanship. If anything here is out of date, the business can request a correction.
What do customers say about GMH Gas Maintenance Heating Ltd?
GMH Gas Maintenance Heating Ltd has 33 public reviews, averaging 5 out of 5. You can read the individual reviews and where each came from in the reviews section above.
How do I know GMH Gas Maintenance Heating Ltd's reviews are genuine?
GMH Gas Maintenance Heating Ltd's 33 public reviews come from a named public review source, and MyTrustedTraders links every one back to where it was published, so you can open the source and read them yourself rather than trusting a single curated page. MyTrustedTraders brings this public evidence together with no ads and no paid placement: we show where every review came from rather than selling rankings, so you can weigh the evidence for yourself.
Has GMH Gas Maintenance Heating Ltd had recent public reviews?
GMH Gas Maintenance Heating Ltd has 4 public reviews dated within the last 12 months. That shows their review history includes recent feedback; it does not prove current availability, so confirm capacity before hiring.
Is GMH Gas Maintenance Heating Ltd qualified and accredited?
We hold 1 independently sourced credential for GMH Gas Maintenance Heating Ltd, including Which? Trusted Trader. Each is attributed to the body that issued it in the credentials section. For example, Which? Trusted Trader is Which? Trusted Trader: an endorsement from the consumer champion Which?, given to traders who pass its assessment process.
What does GMH Gas Maintenance Heating Ltd specialise in?
GMH Gas Maintenance Heating Ltd lists specialist services including Central heating systems (installation and servicing), Oil fired heating equipment, Immersion Heaters, Boiler installation, Boiler repair, Boiler servicing. If your job is one of these, look for it in their listed services or ask them to confirm for your project.
How long has GMH Gas Maintenance Heating Ltd been trading?
GMH Gas Maintenance Heating Ltd has been reviewed on public sources since 2019.