Design of domestic combined solar, biomass, gas heating system in 3 bedroom mid-terrace Victorian dwelling

October 10th, 2013 by

Design and project management of the installation of a combined solar, wood, and gas heating and hot water system in a three bedroom Victorian Terraced house.


October – December 2011

Project partner

Solarsense (UK) Ltd.

What was the project about?

The brief was to provide space and water heating in a 3 bedroom Victorian mid-terraced house using 100% renewable energy or with as little reliance on gas as possible given the constraints of the building, and occupants’ requirements.

How we approached this

We began by considering which renewable energy technologies could be used and which we would be appropriate. It became clear that wood heating and solar water heating were the most suitable options in this case. The property also had a cellar giving options for the bulk storage of wood pellets.

Wood for domestic heating

We examined the possibility of using a wood pellet boiler located in the cellar (with a bulk store) to provide all the space and water heating eliminating the need for gas altogether. This was ruled out due to poor access to the cellar. We also considered the option of using a wood pellet stove, in the living room, with back boiler to provide space and water heating. This was finally discounted on the grounds of cost and additional work needed to create a suitable space to accommodate the stove.

The final solution was to combine heat inputs from a log burner with back boiler, high efficiency gas boiler and solar water heating system all delivering heat to a thermal store. This was a compromise, in that gas would provide a proportion of the space and water heating, but it is also very flexible. Between April/May and September water heating is provided by a roof mounted, 20 evacuated tube, solar system.

In the winter the majority of space heating is provided by the (DEFRA compliant) log burner which uses a thermo-syphon to feed a thermal store installed in the room above. Logs are delivered in bulk once a year and stored in a purpose made store in the garden.Combined domestic, solar, biomass, & gas heating system

Top-up heating and hot water is provided by an unvented gas condensing boiler which also delivers heat to the 318 liter thermal store.

The system was installed in two phases with the solar system added two years after the main system. Gas consumption been cut by more than 75% and the clients are very pleased with the system which was installed by Solarsense UK Ltd.


Written by

Environmental consultant, facilitator, founder & Director of Climate Works Ltd.