22 November 2017

In December 2006 the government made an ambitious pledge. It was a pledge that would have ensured that within a decade every new home would be a 'zero carbon' home.

Britain was the first country ever to have made such a commitment and the plans dictated that come 2016 all new homes would be expected to generate as much energy on-site through renewable tech - such as wind turbines and solar panels - so to cancel out their overall emission of greenhouse gases.

A code for sustainable homes was drawn up to facilitate sustainability benchmarking. A tax break was put in place to encourage development of more eco-friendly domiciles. There were even stamp duty exemptions for eco-friendly abodes.

At first things seemed to be going well. In 2007 government proposed tightening building regulations to achieve the target- first by 25% in 2010, and then by 44% three years later. The 2008 budget extended the plans still further citing that all new non-domestic buildings should also be zero carbon come 2019.

2008 saw the introduction of the Climate Change Act. Its aim to reduce carbon emissions (compared to 1990 levels) by 34% come 2020 and 80% come 2050 with The Carbon Plan setting out how this would be achieved.

Yet nine years after the ambitious pledge, in 2015, a Treasury paper - Fixing the foundations: Creating a more prosperous nation - jettisoned the requirements for zero carbon buildings...

The government does not intend to proceed with the zero carbon Allowable Solutions carbon offsetting scheme, or the proposed 2016 increase in on-site energy efficiency standards, but will keep energy efficiency standards under review, recognising that existing measures to increase energy efficiency of new buildings should be allowed time to become established.

Speaking at the time Julie Hirigoyen, Chief Executive of the UK Green Building Council said the move sounded "the death knell" for the zero carbon homes policy and environmentalists, house builders and energy leaders were also quick to criticise the move.

Why did the push for zero carbon homes fail?

With no consultation it's fair to say it came as something of a surprise to much of the industry. So why the retreat? Concerns over whether it would ever be possible to build a carbon-neutral home cost-efficiently were certainly evident in some quarters.

The lack of a shared understanding over just what constituted a ‘zero carbon’ home anyway surely didn’t help - with a definite focus on operating rather than capital emissions. An additional fear being that developers might find it easier to adopt off-site 'allowable solutions' over compliance with carbon standards on the project at hand - measures that the owner/occupiers wouldn't directly benefit from.

There was also a lack of clarity about how maintenance or alterations would be regulated to ensure zero carbon ambitions continued beyond any initial build.

There were also doubts on whether the industry could deliver step-change in a decade and, even if it could, with the focus of the policy squarely on new homes the measures would arguably have taken a long time to have any meaningful impact. There were also concerns over whether, at a time of housing shortage, the measures would reduce the number of new homes being built.

What is a zero carbon home anyway?

The code for sustainable homes  provided an initial definition - with the expectation that such a home would achieve Level 6 in terms of emissions of regulated (heating, lighting, ventilation) and unregulated energy (appliances). Unregulated energy was removed from the definition in 2011.

In England the concept became aligned to an idea of a home where CO2 emissions from regulated energy use were limited or mitigated by developers focussing on combinations of three carbon compliance standards:

  • Achieving Fabric Energy Efficiency Standards (FEES) via space heating and cooling (39 kWh/m^2/year for apartments and mid-terraced houses, 46 kWh/m^2/year for end of terrace, semi-detached and detached houses.)
  • Using low and zero carbon technologies and connected heat networks to limit built emissions on site. (10 kg CO2(eq)/m^2/year for detached houses, 11kg for attached, 14kg for low-rise apartments)
  • Using off-site solutions to mitigate any remaining carbon emissions. Following consultation allowable solutions were confirmed as being abatement on site, abatement off site, third party abatement off-site or payment into a price-capped fund.

Is it possible to build a zero carbon home?

With housing responsible for almost a third of the UK's greenhouse gas emissions - a figure tipped to rise to 55% come 2050 - there's clearly scope for construction be ‘greener’ and allow people to live ‘greener’. However, the slashing of the feed-in tariff for domestic photovoltaic systems would appear to be a clear indication that low carbon technologies are not at the heart of the current political agenda. So, without the ‘stick’ of government policy, will we ever see eco-friendly abodes become the norm rather than a novelty?

Enter the team at Cardiff University’s Welsh School of Architecture and the SOLCER house, which took shape over 16 weeks in late 2014.

By using off-the-shelf tech the team delivered a highly insulated eco-friendly abode replete with a smattering of energy saving systems. Solar panels supply energy which is stored in a 6.9KWh battery, wall panels recover heat from the air. Heat is also stored in a water tank powering central heating and hot water. Across a year the creators reckon that the house generates 1.75 times more energy than it uses and as a result householders are likely to get an annual energy bill of just £200.

By using components and expertise present in the local supply chain it’s hoped that the house will be easy to maintain in the years ahead. The cost of construction? By integrating eco-efficiency from the outset as opposed to retrofitting the SOLCER house comes in at around £1,200/m2 which compares extremely favourably to ‘budget’ social housing. 

Another eco-friendly project has seen the construction of six homes in Pembrokeshire  – the Pentre Solar village. Solar panels are used to heat the space, while thermally efficient building materials, including locally sourced timber, aim to keep things toasty inside. The company behind the scheme, Western Solar, reckons that running costs will be in the region of £300 per year and construction costs work out at £1,100/m2 – around £100,000 all in. The firm hope to build 1,000 more across the UK in the next decade.

A reinterpretation of the traditional farmstead in rural Northumberland serves as an award-winning example of self-built eco-friendly design. Mark Siddall's Steel Farm features a solar thermal system for domestic hot water and a reed bed system for the treatment of foul waste water. A simple cost effective condensing LPG boiler provides the remaining heat. Mark's documentary provides more insight into the housebuilding process.

Will zero carbon homes ever get from niche to normal?

Just as one swallow does not a summer make, a handful of impressive projects doesn’t spur an industry to build green. They do, however, highlight working models that could be scaled to deliver. For now without a clear policy drive, such as a mandate to deliver a fixed percentage of eco-friendly dwellings, it would seem that there remains little incentive to change the status quo. And that inaction means constructors, tech innovators, society and the environment all stand to lose out.

We'd love to hear your take on what's needed to spur change, how eco technologies have benefited your projects and what lessons you've learnt from sustainable building. Get in touch and share your stories - drop us a line, or share your thoughts on social media.

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Video: Wimbish Passivhaus
Wimbish Passivhaus Project is a fourteen-dwelling Passivhaus-certified scheme in Wimbish, Essex. This programme looks at how the architect, Parsons + Whittley, and Bramall – the contractor, used Passivhaus design and construction methods to achieve both Passivhaus certification and Level 4 of the Code for Sustainable Homes.

Passivhaus projects recognised at Trust Awards
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