Designing energy efficient homes

In a bid to create highly energy efficient homes, architects are employing 21st century technologies. TiC reports on one project that could lead the way for designing renewables into housing.

AS architects are increasingly pushed to create more energy efficient buildings, they are forced to come up with novel designs and to take a more holistic view of the buildings they create.

The Code for Sustainable Homes (CSH), for example, encourages a “whole house” approach to design as it takes nine elements into account in order to produce an overall carbon rating for the building.

When designing energy efficient buildings, the most important element is the roof, as this is where the greatest energy savings can be made. Architects are now talking about integrating the roof into the rest of the building to work with other elements to create a more energy efficient buildings.

The roofing element isn’t just about including sufficient insulation to stop the house leaking heat in the winter and becoming an oven in the summer months, it is at the centre of the debate on including renewable energy in house designs.

Taking an holistic approach
Mark Elton of ECD Architects says the construction industry will not be able to achieve energy efficiency targets without paying close attention to building design.

“A challenge for the industry is finding the level of insulation we need to achieve targets on low levels of heat loss,” he says. “How do we address it without taking up more land? If the only answer is to increase the amount of insulation, we will end up with walls half a metre thick.”

ECD has worked on energy efficient housing projects such as 154 new houses for the Peabody Trust at Coopers Road, Southwark, and a CSH Level 5 project for Leeds Jewish Housing Association to build a community of 400 homes.

The architect was also behind building the pioneering Radoon house in Rock, Cornwall, which brought different building elements together in a complimentary way to create an energy efficient house.

The roof of the Radoon house also plays an important part in improving the energy efficiency by creating solar shading. The house features large windows, so ECD created large overhangs to shade its south-facing rooms and reduce overheating in the summer.

The proof of the roof
However, ECD wanted the roof to play more than just a passive role in the building’s overall energy performance.

The company used an holistic approach to design on the building’s microrenewables and connected the building’s solar thermal water heater with its groundsource heat pump.

The building’s roof features a solid flat solar thermal panel to produce hot water and a photovoltaic panel, which creates electricity. ECD joined together the different technologies. The company decided to reduce energy costs and connect the photovoltaic panel to power the groundsource heat pump.

The pump creates warm water by storing large quantities of water underground, in a network of pipes beneath the front lawn in the case of the Radoon house. The temperature below ground is more than that of the surface and this is used to warm the water in the pipes, which is then fed back into the house and added to its hot water supply.

ECD found it could save on the building’s overall heating bill by feeding the water warmed by the sun in the solar thermal panel on the roof to the heat pump, which would then be stored beneath the lawn. “We talked about connecting it up to the ground source heat pump,” says Elton.

“The pump works much more efficiently when you’re not putting cold water into the ground as the ground has to work that much harder to heat it up. By installing solar thermal into the loop it makes it that much more efficient.”

Although it is not in the same energy efficiency league as, for example, the Kingspan Lighthouse showed off at Offsite 2007, the Radoon house raised some interesting questions about how to integrate design with technology to create a “whole house” energy saving.

When integrating microrenewable technologies such as photovoltaic and solar thermal panels, its architects have given forward-looking designers another string to their bow in the fight against climate change.