ploTS WiTH plaNNiNg pERMiSSioN

north, Scotland and northern ireland 47%

ould it make more sense to fit a boiler or a heat pump? Depending on

the property, in some instances, a heat pump does not make financial sense. One option here is to combine a heat pump with another heat source; this is known as a bivalent or hybrid system.

On smaller properties (up to three beds and one bathroom), a combination (combi) boiler might be just the ticket. However, until now, these systems have precluded any renewables (except as a pre-heat option), as heat pumps usually require stored hot water, larger radiators and space for the actual heat pump unit.

Sime (sime.co.uk) has introduced a technically advanced new hybrid product, the Murelle Revolution 30, that combines a traditional combi-type boiler (either natural gas or LPG) with a small heat pump to provide space heating and domestic hot water.

The unit is no bigger than a combi boiler with a reported effective combined seasonal heating performance of 134%, granting it A++ energy efficiency according to the ErP Ecodesign regulation. (The most effective combi boilers, by comparison, would be expected to achieve a performance of 91-95%.)

Unlike most hybrid heat pumps that share the heat load according to set conditions, this unit runs a 4kW

Low-energy construction supplier green building Store is holding its latest free open day in Huddersfield on 8 September at its Heath House mill base. the day will cover:

l an introduction to Passivhaus and radical retrofit

l Question and answer session on low-energy building and retrofits

l understanding mvHr systems, high-performance windows and airtightness

l Hands-on product demonstrations

l Children’s activities

to find out more, and to book your place, go to greenbuildingstore.co.uk.