Sustainability expert Nigel Griffiths investigates how effectively different renewable heat and power technologies can perform in conjunction with one another for a low-carbon setup

Build It readers Kevin Adams and Lucy Miller transformed an old stone building into a stunning new home, combining solar thermal panels on the roof and a Stovax (www.stovax.com) woodburning stove with back boiler for an energy-efficient heating setup

DAVID BARBOUR

Renewably sourced power and heat are becoming increasingly popular among self builders and renovators, as many homeowners are aiming to minimise their carbon footprint. However, it’s rare to be able to partner more than one source. Here, I explore which combinations of renewable power and heat are possible and what might work best for your project.

Combining sources of renewable heat

There are four possible sources of renewable heat:

● Biomass, biogas or biodiesel boiler

● Heat pump

● Wood burning stove

● Solar water heater

Heat pumps aren’t strictly speaking renewable, as electricity is required to power the pump, but they do boost that by concentrating warmth taken from the air or ground. There is a limited supply of green electricity at present – most green tariffs simply hoover up electricity produced by existing renewables.

Biomass, biogas and biodiesel boilers all operate independent of season or time of day, meaning they can produce low-carbon renewable heat whenever required. No backup is needed, so there is little point combining them with each other or with another heat source.