10 year guarantee



Central heating output
Solar compatible



Greenstar i System highlights

  • Simple boiler controls with clear information display
  • Suitable for homes where the heating system includes a hot water storage cylinder
  • Choice of controls enables greater comfort and economy
  • Can be used with Greenskies solar panels for energy and cost savings
  • Low energy pump reduces electrical usage
  • Large Condensesure style siphon built into the boiler - eliminates frost risk

Worcester Diamond Accredited

Worcester Bosch Accredited Installers (WAIs) are accredited to install Worcester Bosch boilers to the highest standards.

Worcester Bosch quote "We want to provide homeowners with peace of mind when they are upgrading their home heating system. We invite heating engineers who we deem as reputable, quality-conscious and representing value for money to join our Worcester Accredited Installer scheme.

The installers must have relevant Gas Safe approval to be a Worcester Accredited Installer.

We check the installers’ Gas Safe, accreditation on a regular basis."

What our clients are saying

W. Williams Boilers & Heating IconW. Williams Boilers & Heating

36 Hurst Road, Twyford, Reading

4.9 26 reviews

  • Avatar Emma-Jean Wells ★★★★★ a week ago
    After getting quotes from a few places for a new boiler we really liked Wesley and his approach. I had lots of random questions prior to confirming with him that we would use his services that he took the time to answer and explain.
    … More fitted us in for a new boiler the next week and we had Pete and Darren come and spend 2 days installing the boiler, new valves on our radiators and nest. These guys were so polite and friendly and super tidy!
    Even after I had paid the full amount Wesley still took the time to answer more random questions I had and we felt really valued as a customer.
    Would 100% recommend this company to anyone considering any boiler work.
    Invoice: 748223
  • Avatar Michael Davies ★★★★★ 2 weeks ago
    Wesley arrived promptly to carry out the annual service on the boiler, wearing the appropriate PPE and self distancing. He also fitted a new controller and cured the vibration on the cabinet. Delighted and will certainly ask him again. … More Thank you. Michael
  • Avatar Gerry Brittan ★★★★★ 3 weeks ago
    After initial difficulty in contacting W Williams, I think due to them being very busy, Wesley visited my home to discuss the proposed work. We agreed a plan which included a new boiler and I later received a very comprehensive estimate. … More I agreed the price and work was scheduled to start within ten days. Wesley and his brother arrived on time and began the work which involved replacing and lagging all the pipe work in the garage loft and repositioning other items next to the new boiler. Work was completed the next day and I was extremely pleased with the result. A very neat and tidy job. I would have no hesitation in recommending W Williams Boilers and Heating.
  • Avatar Neil Stewart ★★★★★ in the last week
    This company was recommended to me by a neighbour and I was very impressed - really good service, efficient and professional. Five stars from me :)
  • Avatar Kevin Harte ★★★★★ 2 weeks ago
    A very professional and courteous service, the quality of the work was excellent and a real can do attitude makes all the difference . I would highly recommend this company and compliment Wes and Darren for their very respectful approach … More . Invoice 748206
  • Avatar Tracy Lee ★★★★★ a month ago
    I recently had a warm air boiler replaced with a full central heating system, this was no easy task in my house. The engineers were brilliant, they were professional, friendly and nothing was too much trouble. I am very pleased with the … More end result and would have no hesitation in recommending this company.
  • Avatar Rob Hewison ★★★★★ a month ago
    Wesley Williams was one of three installers who quoted for our boiler and hot-water tank replacement. He was the most expensive of the three (though by only a small margin) but we chose him for his professional, knowledgable approach when … More he came to survey, his instant and detailed response whenever we asked questions about the quotation, and the fact that he could install the make of boiler we preferred, Worcester-Bosch.
    It was a good choice. His two engineers, Pete and Darren, were as pleasant, professional and competent as their boss. The job was completed in the two days quoted, the system works well, the installation is very neat, and they tidied up well at the end of each day.
    Who could ask for more?...
  • Avatar Penny Lowe ★★★★★ 2 months ago
    Superb service as usual from Wes - even in these extraordinary times. Replacement boiler fitted within a couple of days of getting called out. Highly recommended.