Listen to this article
In times gone by, homes both grand and modest were of necessity built on the assumption of limited heating or power supplies. Until relatively recently, most households were distinctively “off grid”.
For architects today, and particularly in urban settings, power supplies are one of the factors that signify modern living.
But are we moving back to an era where household heating or cooling uses little or no energy, yet offers the best in modern standards of comfort?
Gavin Killip, senior researcher at Oxford university’s Environmental Change Institute (ECI), argues that there are few technological barriers to achieving sharp reductions in the energy consumption of households and non-residential buildings in the coming decades. “A lot of technologies are available out there. It’s not a technological problem but a societal one.”
He estimates that energy used and lost through buildings accounts for about half of the UK’s overall carbon dioxide emissions. More than half is accounted for by domestic use, suggesting that household consumption accounts for 25-30 per cent of the UK’s carbon dioxide emissions.
Within a typical home, 60 per cent of energy is used for heating, 20 per cent for hot water, and the remaining 20 per cent for lights and appliances.
While much in the short term can be done to encourage improved energy efficiency in the home and public buildings – through replacing old boilers, for example – Dr Killip argues that policy should encourage improved designs of new houses and refitting of old houses to drive down energy demand to a fraction of what is consumed at present.
“The Victorians and Edwardians were fresh air fanatics,” he says. Much of the UK’s and northern Europe’s housing was designed with the need for plentiful circulation of air demanded by the burning of fossil fuels.
Beyond improved insulation, the main imperative for achieving substantial reductions in energy demand for heating now is “make it tight, ventilate right”, says Dr Killip.
At its most basic – but perhaps also most elegant – the notion of using design to control temperatures was exemplified by the Italian classical architect Palladio, whose villas were designed to moderate interior temperatures across the extremes of winter and summer.
The Passivhaus – or Passive House – movement that began in the 1980s, has led to a wave of new houses designed to achieve a 90 per cent drop or more in usual energy use compared with the typical central European home.
High specification insulation, heat exchange systems controlling air flow and even recouping energy from warm water, along with other efficiency measures, are combining to drive down energy consumption in workplaces and homes.
In a Passivhaus, human bodies and the odd electrical appliance provide enough heat for comfort. Though more common in Germany and Scandinavia, the Passivhaus template has been used in a growing number of construction projects in North America and the UK.
But what of the remaining housing stock? Dr Killip argues that the biggest contribution to energy demand management in the home can be made through refitting of old housing stock.
Not all housing is suitable for the highest specification of energy-saving measures, such as the ducting of air to prevent the unnecessary loss of ambient heat.
Even so, he argues that a suite of refitting measures for most buildings, even if not capable of meeting the Passivhaus targets, could still achieve 60-65 per cent falls in typical energy use.
Even if the house of the future may include such items as solar panels, air ducting, biomass burners or CHP (combined heat and power) units instead of boilers, “it doesn’t have to look that different”, he argues.
However, research conducted by the ECI examining the potential and constraints of refitting in France and the UK suggests low uptake of the most modern energy-saving measures available.
“In both countries, the current market for low carbon refurbishment is extremely small, and it needs to grow significantly and at a considerable rate if the housing sector is to make its contribution to national and international carbon reduction targets”, the research concluded.
The Institute’s Katy Janda, who is also involved in the project says: “I see deep renovation as very much of a ‘chicken and egg’ question.
“It is about both supply of expertise as well as the demand for it. This is certainly true with new housing ... The skill involved in building a passive house is not the same thing as building a ‘normal’ house.”
Another factor that prevents refitting along Passivhaus lines is the passivity of consumers themselves.
A study recently conducted by academics at the University of East Anglia (UEA), funded by the British Energy Research Council, suggested that energy efficiency was rarely the main motivating factor for people’s decisions to renovate their homes.
Instead, the biggest motive was to improve the comforts of domestic life by extending or adapting space. Other triggers might include specific events such as the need to replace a boiler or window.
According to George Chryssochoidis, leader of the university team: “The fundamental insight from this research is that home renovations have to be understood through the lens of normal, routine domestic life.
“Decisions to renovate are rooted in a need to improve the quality of life at home, rather than any burning desire to be energy efficient,” Mr Chryssochoidis adds.
Rising energy costs though, argues Dr Killip, alongside enlightened public subsidies for refitting, could accelerate the emergence of the low-carbon house – and the human body as a key supplier of ambient warmth.