Sigma Plumbing & Heating
South West Wales's Dependable Heating Engineers

South West Wales's Dependable Heating Engineers

Gas Safe-registered boiler installations, servicing and 24/7 emergency call-outs across South West Wales. Manufacturer-backed installs from Navien, ATAG and Intergas with clear communication and safety-first workmanship.

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5.0 stars
69 verified reviews

Our Services


Expert heating services across Milford Haven

Why Choose Us

Certified & safe

Gas Safe registration and industry-standard safety checks on every job — your property and family remain protected throughout installation and repair work.

24/7 emergency response

Round‑the‑clock call-outs with fast local attendance in Milford Haven and nearby villages when boilers fail or leaks occur.

Manufacturer-approved installations

Approved experience with Navien, ATAG and Intergas means installations meet manufacturer requirements and unlock long warranty cover, including ATAG’s 18‑year option where applicable.

Local knowledge

Deep familiarity with Pembrokeshire properties and common regional heating issues leads to faster, more accurate diagnostics and less disruption.

Clear pricing & punctual service

Upfront quotes, punctual engineers and regular updates so you know the schedule and scope before work begins — no hidden surprises.

Ready to get started?

Get in touch today for a free, no-obligation quote.

Local, dependable heating specialists

Simon is a Gas Safe registered engineer serving Milford Haven and the surrounding communities. Sigma Plumbing & Heating focuses on manufacturer-backed installations, fast boiler repairs and straightforward communication so you always know what to expect. Safety, punctuality and clear pricing come first on every job.
All engineers Gas Safe registered for legal, safe gas work
24/7 emergency response for boiler breakdowns and leaks
Navien specialist, ATAG (18-year warranty partner), Intergas Xtend and Honeywell Evohome installer
Covering Milford Haven, Hakin, Johnston, Hubberston, Steynton and nearby villages
Local, dependable heating specialists

What Our Customers Say

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“Simon was prompt friendly and very competitively priced, boiler broke down in the night, rang before 9am and he was on site within the hour, returned at around midday with the parts to rectify the issue with my boiler. Absolutely brilliant service.”

Oscar DixonGoogle
“We have been so happy with the work that Simon has done for us. He has installed a new boiler, hot water tank and radiators. All work was done on time and very professionally. I couldn't recommend Sigma enough.”

Mark lloyd-radfordGoogle
“We used Simon from Sigma and cannot rate him highly enough. We had an issue with our boiler and were struggling to find local availability as was in the start of the winter period where many people were having issues. Simon responded quickly, identified the issue, sourced replacement parts and consulted the boiler supplier technical representatives to get the boiler up and running in a short space of time. Very happy with the service as Simon went out of his way to resolve the issue I would definately use him again in the future, highly recommended”

Gary RandallGoogle
“We needed a plumber asap and contacted Simon. He was with us within 24 hours and having looked at the job in hand, he knew immediately the cause of the problem and fixed it without hesitation. He was professional, experienced and knowledgeable. We cannot thank him enough for his prompt and exceptional work. His customer service is excellent and he wouldn’t leave the job until he was satisfied it was complete. If you are looking for a professional plumber then Simon Mayhew is your guy! We highly recommend and will definitely not hesitate to call him in the future.”

Bev ThomasGoogle
“Well Simon ⭐⭐⭐⭐ ⭐ what a complete life saver, highly recommend, my caravan boiler completely shut down on my, he unfortunately couldn't make it out to my today, but took the time to video call me and take me through it step by step and was so patient”

Cat ThomasGoogle
“A true gentleman and extremely good at his job. Called Simon regarding an intermittent fault on the boiler. He asked a few questions over the phone and requested a video be sent so he could gain an idea before coming out. Arrived the next morning at 06:45, boiler out, faults identified, components replaced, tested and recommissioned by 09:00. Couldn't do enough to help and prices very reasonable! Thanks, our go to plumber from now on.”

mi keGoogle

Need heating help today?

Call 07939 012 055 for same‑day response or email sgmayhew44@gmail.com to arrange a visit in Milford Haven.