Frome, like most towns in the UK, has a serious affordable housing crisis. Is it possible to meet this challenge while building to low or zero carbon standards? Reports from COP26 and the IPCC, over 2021-22, suggest we cannot afford not to. According to the IPCC, Greenhouse gas emissions must peak by 2025 and should almost be halved by the end of the decade to give the world a chance of limiting future heating to 1.5C above pre-industrial levels. Any increase above 1.5C is likely to have catastrophic consequences for the stability of our climate.
The IPCC report said:
All sectors of the global economy, from energy and transport to buildings and food, must change dramatically and rapidly, and new technologies including hydrogen fuel and carbon capture and storage will be needed. In the case of building new homes, the ‘new technologies’ are already known and in use. Building homes that have zero carbon emissions once they are occupied is well established practice, but only a tiny percentage of new houses are built to this standard.
The overall strategy to reach this standard is to reduce the energy demand of the building, in use, to very low levels by preventing the heat inside from leaking or flowing out of the building. What energy is needed for cooking, heating and hot water should be provided from renewable resources. The construction operation itself is an energy intensive process so measures should be taken to keep this ‘embodied energy’ to a minimum. Prevention of heat loss in houses is achieved by installing high levels of insulation and air tightness (draught proofing), efficient glazing and a ventilation system that prevents cold air from entering the house. There is a very extensive knowledge-base about the construction methods and materials that can be used to minimise the carbon emissions in building new homes (and buildings across the spectrum of use). In the UK Building Regulations (BR) set the minimum levels of performance for the various criteria relating to carbon emissions and other factors such as fire and electrical safety, water use and waste disposal, site activity and safety. https://en.wikipedia.org/wiki/Building_regulations_in_the_United_Kingdom
Builders who wish to go beyond this level of carbon reduction can follow various paths to reach a zero (or even negative) carbon target. One of the earliest set of standards was the Code for Sustainable Homes (https://www.designingbuildings.co.uk/wiki/Code_for_Sustainable_Homes), introduced by the Building Research Establishment (BRE) in 2006 and, for a while, a mandatory requirement for newly built homes until the Conservative government abandoned a target, set by their predecessors, to require all new houses to be Carbon Zero from 2016. The code had 6 levels, 1 being the BR standard in 2006, and 6 being zero carbon. Current BR set energy requirements to code level 4.
Other standards include
· New Home Quality Mark (https://www.designingbuildings.co.uk/wiki/Home_quality_mark_HQM) · Active House https://www.designingbuildings.co.uk/wiki/Active_House · Akitvplus eV https://www.designingbuildings.co.uk/wiki/Aktivplus
A useful summation of how to build to these standards can be found at https://urbanistarchitecture.co.uk/how-to-design-eco-houses-passivhaus-and-zero-carbon-houses/
The Passivhaus is considered by some to be the ‘gold standard‘ of these schemes (https://www.designingbuildings.co.uk/wiki/Passivhaus)
All these schemes provide very detailed advice for all stages of design and construction and both the Code for Sustainable Homes and Passihaus provide assessment of these stages and certification of the finished building and handover to the occupants.
Readers who follow any of these links to find details of the methods and materials required to build to low carbon standards will realise that they present builders with great challenges, even to achieve the BR level. For example, to make a building sufficiently air tight to meet requirements involves creating an unbroken barrier within the fabric of the building. Membranes can be included in walls, floors and roofs and must be sealed at all the points at which these sheet materials are joined. And then when the services of water, gas, sewerage etc enter of leave the building and have to penetrate the membrane, this must be resealed. This work must be done with skill and attention to detail, checked by a supervisor and then tested at completion. A much fuller description of this process can be found here: https://www.zerocarbonhub.org/sites/default/files/resources/reports/A_Practical_Guide_to_Building_Air_Tight_Dwellings_NF16.pdf
All of the other factors involved in building low carbon homes have similar extensive lists and as the standards rise from BR to Passivhaus so the requirements and challenges increase. And, not surprisingly, the cost of building to these standards is raised. Some estimate that the increased cost is only 1 or 2% but others claim it to be as high as 25%.
Over the last 10 years the UK has built between 135,000 (2013) and 243,000 (2020) new homes each year. The vast majority of these are built to BR standards with a comparatively tiny number built to higher standards. For example, by 2020 there were a total of 1300 homes built to Passivhaus standards. Approximately 50% of new homes are built by the large volume house builders (Barratt, Wimpey etc), 30% by smaller construction companies and the remainder by Housing Associations (HAs). The primary motive for building about 80% of new homes is therefore that of making a profit and so it is unsurprising that the challenges of cost and difficulty lead to almost all new homes in the uk being built to the lowest carbon standards permissible. A truly devastating report by the government Committee for Climate Change entitled UK Housing: Fit for the future? was issued in 2019. https://www.theccc.org.uk/publication/uk-housing-fit-for-the-future/. The committees answer to their own question was a resound No! and it is essential reading for all who are interested in the topic of New Homes and Carbon Footprint.
It says
We cannot meet our climate objectives without a major improvement in UK housing.
We will not meet our targets for emissions reduction without near complete decarbonisation of the housing stock.
The housing stock is not well-adapted for the current or future climate.
It makes 36 recommendations for policy and planning measures and notes that many of these will also increase the comfort and well being of occupants and reduce their running costs – thus making them more affordable.
Some of these have been included in the Future Homes Standard which will be the new Building Regulations operating from 2025 that the government says will reduce carbon emission of new homes by about 30% from the current BR levels.
Corporations in general, and the house building industry in particular, are largely risk-averse and conservative and have only reluctantly moved to the zero carbon future when driven by government policy and regulation. But there is a shift in the corporate world as the non-financial principles of Environmental, Social and
Governance (ESG) are being applied by investors to their analysis of risk and growth opportunities. An important element of this is the Race to Zero initiative launched by the UN in 2020 https://unfccc.int/climate-action/race-to-zero-campaign ‘Race To Zero is a global campaign to rally leadership and support from businesses, cities, regions, investors for a healthy, resilient, zero carbon recovery that prevents future threats, creates decent jobs, and unlocks inclusive, sustainable growth.’
The UN and partner organisations provide benchmarking for the strategies that companies put forward to reach their targets. Companies can sign up for verification, and 7 of the 12 largest UK builders have done so. This is a positive step towards tackling the climate emergency, although there may still be a considerable gap between aspirations and outcomes, which will emerge in the coming years.
And beacons of hope have already emerged. Exeter City Council has built 103 Passivhaus homes for social rent and retrofitted a further 300 homes for substantial carbon reductions. https://www.apse.org.uk/apse/index.cfm/news/articles/20181/passivhaus-exeter-city-council-leading-by-example/
https://news.exeter.gov.uk/council-to-retrofit-all-its-homes-to-reduce-carbon-and-lower-fuel-bills/
Norwich City Council built the the Goldsmith street development, abs award winning scheme of 105 Passivhaus homes for social rent. https://ggbec.co.uk/portfolio/ambitious-me-design-for-uks-largest-passivhaus-social-housing-scheme/
Curo have built 4 Passivhaus homes in Bath to be let for social rent. https://www.curo-group.co.uk/news/news-stories/curo-to-deliver-first-passivhaus-homes-in-bnes/
Bournemouth plans 3 developments for social renting
Camden claims to be building the largest Passivhaus development with 216 Council homes of which 37 are for Camden Living rent
https://cip.camden.gov.uk/agar-grove
Building new homes to low carbon standards is achievable, but the challenges involved mean that without the motivation of concern for the environment or the spur of regulation, the necessity that ALL new houses are zero carbon has been fulfilled in a tiny proportion of new homes completed in the UK. Local Authorities like Exeter and Norwich have been amongst those leading the way and it is to be hoped that government policy and regulation will now bring the whole industry into line. FACLT is working hard with Housing Associations and our Local Authorities to provide more homes for social rent and we very much hope that Frome can be added to the growing list of places with new affordable homes built to zero carbon standards.
by Tim Cutting and Paul Horton – FACLT directors