email: . tel: 00 44 (0)1481 200388


Technical Services

Our Technical Services Capability

As a company we have 17 years of working in the residential construction industry. We have professionals who have worked in a variety of industries including residential, but including the army and merchant navy, giving us unparalleled experience and technical insight. The business is strongly technically driven, almost to the point of being geeky about it. Yet we have to translate highly technical and technological concepts to be appreciated and understood by the homeowner. This is a major challenge. On these pages we home to provide greater insight to the workings of advanced renewable energy concepts, starting with the fundamental basics to systems that power our modern global society.

We are at your service and provide customer care for electrical, heating and water systems around the home. We service oil boilers, heat pumps, solar systems, electrical and hydronics systems. Because we've seen a lot of things go wrong, we know how to make it right! Because we have tried every type of solar system, heat pump and boiler, we know which manufacturers, which equipment works and which does not.

We design, provide schematics, quality control, pre-commission and commission all our systems and installations in-house. By keeping all our services in-house we have control over the quality of install, service and maintenance. See About Tech for more information.

Our Tech Talk pages are meant to be educational, entertaining, useful and designed to promote discussion, inspire you and create 'different thinking'. Here at E-Si we pride ourselves in thinking differently. Its a way of life for us.

tech image

Call or email for service and maintenance:

Dave Thomas, Chief Renewable Energy Engineer, (Electrical & Electronics), Technical Services. Email: Mobile: 07781 135 227

E-Si Limited, Guernsey Hub: Dyson House, Southside, The Bridge, St Sampsons, Guernsey, Channel Islands, GY2 4QJ Web:

UK/local: 01481 200388 / International: 0044 1481 200388
Registered in Guernsey.
Company Registration No: 27380

About Tech

Our Technical Services aims and remit.

Tech Team

Meet the Tech Team: photos, profiles, blogs.

Tech Talk

FAQs and E-Si Academy Articles


Find out about the fundamentals of energy, Renewables, sustainability, atoms and quarks.


Find out about the practical aspects of Renewables.


Regulations and boring important stuff.


Homeowners fault finding guide.