Written evidence submitted by the Centre for Alternative Technology (DHH0024)

  1. What has been the impact of past and current policies for low carbon heat, and what lessons can be learnt, including examples from devolved administrations and international comparators?

To explore the changes needed to rise to the climate emergency, Centre for Alternative Technology has been carrying out detailed Zero Carbon Britain (ZCB) research for the last 13 years. The inputs to the questions below include work from CAT’s latest report (www.cat.org.uk/zcb) uses hourly data over 10 years to model a zero carbon end-point for the UK.


The impact of past and current policies has been a long way below what is demanded by the climate emergency. Far too little use has been made of the combination of ambient heat and vastly improved insulation, draught exclusion, smart heating controls and heat recovery in our buildings. In 2017, 41% of the UK’s energy use was in buildings – houses, offices, shops and public buildings (BEIS, 2018). This energy was used for heating, cooling and ventilation, hot water, cooking, lighting and electrical appliances. The UK currently has an aged and poorly insulated building stock. Small improvements have been made to reduce heat loss from buildings, but we have also tended to heat our buildings to higher temperatures. This means that energy demand for heating has risen over recent decades, although it may be starting to decline. Energy demand for hot water however, has declined over recent decades, thanks to more efficient hot water systems. Together, heating and hot water accounted for 32% of total UK energy demand in 2017. (See Page 41 of 2019 ZCB report at https://issuu.com/billyaikencat/docs/zcb_2019/14). Well insulated homes make low carbon heat sources more viable because less heat is required overall, so the greater heating intensity of a gas boiler compared to a ground-source or air-source heat pump becomes less of an issue.


Public investment is required to move the system from one primarily focussed on combustion heating, to one primarily focussed on efficient ambient heating supplied by electrical heat pumps. The move to electricity-based heat pumps means decarbonisation of the electricity supply also decarbonises heating. Biomass and direct electrical heating can also be used for particular applications.


For useful international comparator examples see






For useful devolved administration examples see






  1. What key policies, priorities and timelines should be included in the Government’s forthcoming ‘Buildings and Heat Strategy’ to ensure that the UK is on track to deliver Net Zero? What are the most urgent decisions and actions that need to be taken over the course of this Parliament (by 2024)?

The successful scaling up of other technology shifts, such as solar PV and wind through public subsidies have resulted in feedbacks which have resulted in significant reductions in cost, making them better investments, which increases demand, which then leads to further cost falls. The Buildings and Heat Strategy needs concerted policies which can increase the scale needed to optimise the investments required in building retrofit for improved insulation, draught exclusion, heat recovery, smart heating control, solar heating for hot water and heat pump installation.


The completion of adequate retrofit within the timescales will require an additional workforce in excess of 2,000,000 individuals from apprentices to chartered professionals. Training of such a workforce needs to start immediately and continue for some time (dividing the number required by the UK training capacity gives the time it will take) or do we import overseas skills? It is also important to assess the increase in materials demands for insulation materials and the accompanying CO2  emissions spike etc. Policies will also be required for increasing electricity supply, combined with mini-grids and storage to manage such an increase (the grid/DNO companies can offer no more than an overall 30% increase in delivered energy).


Local authority planning and conservation area policies will need a substantial rethink; e.g. the number of old houses that would require a bat survey prior to any retrofit work.

  1. Which technologies are the most viable to deliver the decarbonisation of heating, and what would be the most appropriate mix of technologies across the UK?

First and foremost, we must reduce the energy demand for heating and so must improve our building stock. By reducing the heat our buildings lose we will reduce the energy needed to keep them warm. Heat loss from buildings can be reduced by:

• Improving insulation.

• Reducing draughtiness.

• Recovering heat from air leaving the building through ventilation.


New buildings can have very low heat loss if they are constructed with excellent insulation and air-tightness, and are fitted with heat recovery ventilation. Passivhaus standard buildings, for example, have very low heating demand – around 10% of an average existing building today, but higher energy and materials demand in construction.


Heat loss from existing buildings must also be reduced, since the vast majority of today’s buildings will still be in use in 2030, and beyond. Retrofitting existing buildings can include: cavity wall or solid wall insulation; floor and loft insulation; improved glazing (all of which reduce the ‘fabric heat loss’ of a building); and draughtproofing (which reduces the ‘ventilation heat loss’ of a building). A programme to retrofit all dwellings with the above measures, as required, could reduce the average heat loss of the UK’s housing stock by 50%. This must be done in a coordinated manner, with due consideration of moisture pathways in order to minimise risk of subsequent deterioration.


Improved heating controls could also reduce energy demand by only heating rooms to the temperature required and when they are in use. Also, a more widespread culture of putting on a jumper rather than turning up the thermostat would have an impact on heating demand and on our energy bills. With better heating controls and behavioural changes it could be possible to reduce average internal temperatures from the current average of 17.5°C to 16.7°C. This would further reduce energy demand for heating. (Of course, reducing average internal temperatures will not stop us heating individual rooms to a higher temperature, such as 18-21°C, when we need to.) In combination, the above measures can reduce space heating demand by around 50-60% per building on average.


Improved insulation can also help reduce the overheating of buildings in summer by keeping heat out rather than in. Adequate shading and ventilation are also needed though to prevent heat accumulating inside, and to allow the fabric of buildings to cool at night.


Even with these changes we will still need to heat our buildings, and a bigger population will also lead to a similar level of hot water demand to today (for washing, cleaning, etc.). This heating and hot water energy demand must be met without GHG emissions.


Solar heated hot water and geothermal heat can meet some of this demand, but most will be met by heat pumps. Heat pumps take ambient heat in air, water or the ground and ‘concentrate’ it, usually in water, to the required temperature. To do this they must use energy, but for each unit of electricity consumed, heat pumps can typically deliver two to four units of heat – a very efficient way to generate heat from electricity. Although more expensive to install, ground-source heat pumps have a significantly better capacity to deliver heat in the winter when most is required. In areas of high housing density this may be most usefully supplied through district heating networks. A mixture of biomass (only within 30 miles of source, beyond that it is less polluting to use gas) and direct electric heating systems can meet the remaining demand in situations where heat pumps are not practical, such as in buildings with large variations in energy demand, or which are not used regularly. 


Because of its particular location in relation to the Atlantic ocean, the UK has a much greater wind resource per unit land area than almost any other nation. Most of this generation will occur during the winter months, resulting in the ability to provide massive amounts of electricity to power heat pumps. If these heat pump systems have thermal mass, enabling the storage of heat, surplus wind power electricity can then be used when available to offer heat in the form of a modern, flexible zero carbon Economy 7 offering. This helps deal with the generation peaks and well as offering affordable power to key households.



  1. What are the barriers to scaling up low carbon heating technologies? What is needed to overcome these barriers?

One key barrier to upscaling on heat pumps is that fact that they are so much less efficient at providing warmth in poorly insulated and draughty homes. Investment in a high level of insulation and draughtproofing on all UK homes therefore needs to be prioritised.


A further barrier is the increased demand for electricity that the use of these will entail. This requires upgrading the Grid, as well as enabling a major increase in generating power, and storage.


In terms of upscaling the low carbon heating technologies themselves, we can learn from the policy measures which resulted in the successful scaling up of other technology shifts, such as solar PV and wind have resulted in feedbacks which have resulted in significant reductions in cost, making them better investments, which increases demand, which then leads to further cost falls. Heat provision needs concerted policies which can increase the scale needed to optimise the investments required. The technologies exist. The bottleneck will be mass production and quality control, not the technologies themselves.


Basically, a kick-start subsidy, backed by a mass-training scheme to get to zero carbon heating system deployment to a scale where the required investment reduces. This could focus on whole area transformations rather than a one here, one there, approach. However, it is worth noting that the existing building industry is already busy and traditionally wary of anything new.

  1. How can the costs of decarbonising heat be distributed fairly across consumers, taxpayers, business and government, taking account of the fuel poor and communities affected by the transition? What is the impact of the existing distribution of environmental levies across electricity, gas and fuel bills on drivers for switching to low carbon heating, and should this distribution be reviewed?

It is worth investing in an analysis to see what investment capital is available across the 4 sectors mentioned in the question. There are some issues to consider within such analysis:


  1. Energy companies are making significant profits and may see these as threatened by reduced demand.


  1. As the world grapples with the impact of the COVID-19 pandemic, the climate and ecological crises continue unabated. There is a massive need, in the UK and the wider world to re-skill at speed and scale. Government and devolved administrations are already looking to deliver post-lockdown build back re-training schemes.


  1. Energy bills to consumers will fall post retrofit, see Energiesprong funding model


  1. Optimisation of co-benefits will see the beneficial impact on the economy of better insulated homes leading to improved health, and reduction in medical demand, sick leave, missed schooling, etc.


  1. Investment in training and jobs will reduce unemployment.
  1. What incentives and regulatory measures should be employed to encourage and ensure households take up low carbon heat, and how will these need to vary for different household types?

For info on this topic see








  1. What action is required to ensure that households are engaged, informed, supported and protected during the transition to low carbon heat, including measures to minimise disruption in homes and to maintain consumer choice?

It is of crucial importance that people are put at the heart of the transition to low carbon lifestyles throughout the entirety of the process. Without the engagement of people, the uptake of transition is likely to be significantly reduced and may even be negatively impacted. The importance incorporating the public’s values, principles and practical abilities is well recognised (such as Hargreaves et al., 2013; Whitmarsh et al., 2011; Nye et al., 2010). Therefore, recognition of the people’s impact on the process of transition from their personal experiences must be a consideration of the whole transition. Engagement also integrates the promotion of choice to be included at the centre of the process. Furthermore, due consideration should be made not only of the people involved in the transition but also of the individuals and communities that they are connected to. The social aspects of transitions can easily be overlooked but it is of utmost importance to the promotion and sustainment of a project.

Furthermore, a clear and thoughtful education program is key to empowering people to feel responsible for the transition and take ownership of the process. Knowledge should be shared in a considerate way that enables people to understand the requirements for the transition – for it to be effective. An educational programme must be incorporated in all parts of the transition – inclusive of a follow up of the outcomes. This people-centred approach would support the public to engage in the transition by providing ongoing feedback about the process. This adaptive environment moves away from the linear process of transitions towards an iterative, interactive and engaging facilitation process. By giving people this sense of autonomy, sustained uptake is more likely. Finally, a just transition that recognises vulnerable communities will ensure that no-one is left behind. This requires inequality and diversity being at the core of the process’s values to give priority where it is needed most.

Complex processes make uptake more unlikely, so methods must be straightforward and easy to navigate at all parts of the transition. With clear procedures in place and expectations clearly defined, people can feel encouraged to make changes to their lifestyles with minimum disruption to their daily routines. With the provision of choice, peoples individual perspectives are respected and their autonomous decision-making processes can become an interactive part of the transition.

For good examples, see https://energiesprong.org

  1. Where should responsibility lie for the governance, coordination and delivery of low carbon heating? What will these organisations need in order to deliver such responsibilities?

Government is best placed to lead on the policies and scale-up incentives for this transition, as the UK has signed up to net zero by 2050. The Govt. should select, train and resource a ‘Zero Carbon Homes: Team UK’


November 2020