Heat Pumps and Heat Waves: How overheating complicates ending gas in the UK

by Dr Aaron Gillich | Associate Professor and Director of the BSRIA LSBU Net Zero Building Centre

We have entered what many are calling the decisive decade on climate action. Among the most critical decisions that the UK faces this decade is how it will eliminate carbon emissions from heat. Heat accounts for over a third of our emissions, and over 80% of our buildings are linked to the gas grid. There is no pathway to Net Zero that doesn’t include ending the use of gas as we know it in the UK.

Given the size of the UK gas grid, no single technology or energy vector can replace it. We will need a combination of clean electricity and carbon‐free gas such hydrogen or biogas, delivered by a range of enabling technologies such as heat pumps and heat networks. And of course an extremely ambitious retrofit agenda that reduces the demand for heat in the first place.

The UK is investing widely in low carbon heating innovation. That innovation is essential, but is also unlikely to include any blue‐sky breakthroughs that aren’t currently on the table. In other words, the menu of low carbon heating technology options is set, and this decisive decade will be about deciding what goes best where, and how to ensure a just and equitable heat transition.

Low-carbon heating options

Of all the low‐carbon heating options available, low carbon heat pumps are the most efficient and scalable option that is market ready and can respond to the urgency of climate change this decade. The UK has set a laudable target of installing 600,000 heat pumps per year by 2028. Many have criticized this figure as unrealistic, but I believe that the target is highly achievable, and represents a pace that is in line with past transitions such as ‘the Big Switch’ that put us on the gas grid in the first place.

This race to replace gas in the UK has been widely discussed. As have the many barriers that face heat pump deployment in the UK. What I’ve heard discussed far less are the links between heating in the winter and overheating in the summer. Over the next decade, the end of gas will present both a threat and an opportunity to improve both the winter and summer performance of our building stock.

The threat of climate change is clear. The end of gas increases this threat because gas has allowed the UK to obscure poor building performance, and poor building knowledge for so long. Cheap gas has enabled a ‘set it and forget it’ approach to many building systems, and allowed us to maintain reasonable standards of comfort in most buildings despite very poor fabric performance. The irony is that this poor winter performance actually helps reduce the risk of overheating in the summer, as the leaky and poorly insulated buildings can more easily shed excess heat. It has been widely reported that many newer, better insulated buildings actually face an increased risk of summer overheating.

Replacing gas with heat pumps, or any other low carbon heat source, should be accompanied by ambitious retrofit to improve energy efficiency and reduce heat loss. There are many that argue heat pumps in fact require extensive fabric retrofit in order to function in most UK buildings. This is highly debatable and will be explored in detail in follow-up writings. Regardless, demand reduction and a fabric first approach is a good idea for its own sake.

Replacing gas with heat pumps, or any other low carbon heat source, should be accompanied by ambitious retrofit to improve energy efficiency and reduce heat loss.

But reducing the heat loss in winter will likely trap heat in the summer, presenting a conflict. The UK currently experiences over 20,000 excess winter cold deaths and around 2,000 heat related deaths in summer. It was previously thought that the increased temperatures from climate change would decrease winter cold deaths, but more recent work has shown that due to the increases in extreme weather events at both ends of the spectrum, it is far more likely that winter cold deaths will remain at similar levels, and summer heat deaths will increase dramatically under climate change.

We must use the transition from gas to low carbon heating as an opportunity to better understand our buildings. Many of 600,000 heat pumps we install by 2028 will be in new build, but up to half will need to be from existing homes.

Retrofitting a heat pump is also the time to think about not only how to improve energy efficiency for the winter but how to reduce summer overheating as well. Despite much effort towards a whole‐house approach to retrofit, most work remains quite siloed. Energy efficiency and heating installations are largely in separate supply chains, and the building physics knowledge to carry out an overheating risk assessment is even less likely to sit with the same project team. Overheating is also very poorly captured by the building regulations and planning process.

A holistic approach

The last few years has seen a growing awareness of overheating risk and an emergence of increasingly easy to use assessment tools. A very small fraction of UK homes have comfort cooling. Retrofitting a comfort cooling solution typically requires costly and complex changes to distribution systems. However, there are a range of low cost options, including using local extract fans to create interzonal air movement, or using night purges and thermal mass. Blinds are also incredibly useful, but often misused in summer, and can also help reduce heat loss in winter. There are also ways to use local microclimate features such as shaded areas or the North side of the building to bring in slightly cooler air from outside and reduce peak temperatures.

Improving the air tightness and fabric performance of our buildings to address heating in the winter will change how we implement these solutions for the summer. They require not only careful thought at the design stage, but also strong communication to help end users operate them properly. Simply opening a window is unlikely to help if the outside air is warmer than inside.

A significant problem is that there are insufficient drivers to force this type of holistic approach to design, performance, and communication. It is so often said that we need stronger policies in the area of heat and retrofit, and this is no doubt true. But while we await these policies it is incumbent upon each of us in this sector to share and collaborate as widely as possible, and use whatever influence we have over a given project to encourage a fair and forward looking solution.

In summary, the availability of cheap gas has allowed us to escape having to understand our buildings in much detail. Climate change is the catalyst for an untold level of change in our lives that we are going to start to truly experience in the coming decade. Heating and overheating are coupled issues that must be solved together. We must use the end of gas as an opportunity to understand our buildings better, and implement solutions to climate change that work across seasons, or we risk trading one problem for another.

In summary, the availability of cheap gas has allowed us to escape having to understand our buildings in much detail.

UK heat pump market has weathered Covid-19 challenges. Coherent policy support is now needed to unlock its full potential.

by Krystyna Dawson, BSRIA Commercial Director

BSRIA has released its latest global heat pump market reports, including the eagerly awaited report on the status of the UK heat pump market.

Last spring, deep uncertainty set in across the markets as lockdowns in many countries disrupted trading. There was fear within the heat pump industry of a significant slowdown in what had previously shown dynamic market growth.

Indeed, the global heat pump market posted a decrease of 1.5% in 2020. However, performance varied across regions: with 12% market growth year-on-year, Europe has been at the forefront; the UK also saw positive development with heat pump sales increasing by 9.2% in 2020.  

Green Homes Grant

UK heat pump market sales were helped by the RHI and the Green Homes Grant scheme in 2020. The latter has proven to be important for the market, which has seen sustained growth in the refurbishment segment despite the number of installations in new buildings stalling due to the lower level of new home completions.

However, heat pump installation still represents a major challenge in existing homes. The ongoing review of Part L and Part F of building regulations offer hope that refurbishments in homes and buildings will be conceived with low carbon heating in mind, but the review’s outcomes are yet to become a legal requirement.

Moreover, even though there is market potential for a higher number of heat pump installations in existing homes, the government has, so far, been unable to unlock it. The Saturday 27th March announcement of the closing of the Green Home Grant scheme to new applicants by 31st March 2021 has been yet another example of the disappointing approach to deployment of energy efficiency measures and heat pumps.

UK heat pump market: Achieving a net zero carbon economy

Heat pumps are among the technologies the government has identified as key to achieving a net zero carbon economy by 2050. The Prime Minister’s 10 Point Plan for the UK Green Industrial Revolution includes the target to deploy 600,000 heat pumps a year by 2028.

The UK saw around 37,000 heat pumps sold in 2020. The extra £300 million in funding, moved from the soon-to-be defunct Green Homes Grant to local authorities to enable energy efficiency upgrades for lower income households, may bring additional installations. But even if all 30,000 applicable homes were fitted with heat pumps, the numbers are insufficient to sustain hope of reaching the PM’s ambitious target.. There is potential for more heat pump installations in existing homes, and the interest in heat pumps is growing among home and building owners. The heat pump industry is also working at full speed to deliver innovative products that respond to end-user expectations and environmental challenges.

HVAC industry skills gap

However, unless demand from existing homes and buildings is unlocked at full scale, and until real attention is paid to the sufficient availability of a skilled workforce, the heat pump market will struggle to see the acceleration needed to reach the government target and make a difference in the level of carbon emissions from UK homes and buildings.

Coherent policy and financial support are needed to match the readiness to act on both industry and consumer sides. Integration of heat pumps in a home or a commercial building requires a holistic approach where design and affordability should be considered to deliver carbon savings, cost savings and a healthy and comfortable environment.

2019 China Heating Market Dynamics

China has by far the largest heating market in the world in terms of units manufactured and sold. In 2019, a little over 40,000,000 units, including, boilers, water heaters and heat pumps, were sold in China. The country also has the world’s largest network of pipes supplying gas for heating systems. China has been developing its gas network very actively over the last years and consequently the country’s total building area covered by gas pipework has more than doubled in the past 15 years. Growing accessibility of gas across the country, coupled with government’s efforts to tackle air pollution and green house gas emissions underlines the potential for continuous growth of heating in the country. To give it some perspective, the sales of gas domestic boilers have grown 10-fold in the last 11 years.

 

boilers6

Source:  BSRIA

 

Today, the heating market is shaped by three areas of sales impact, each having its own dynamic:

  1. Government policy represented mainly by “Coal to gas” and “Coal to electricity” projects

Coupled with expansion of the gas network, stronger governance, better product quality and more competitive gas prices this policy is continuing to strongly impact sales of gas fuelled products, in line with the Chinese government’s 5-year plan (2016-2020 – 3th 5-year plan.

The policy has also a strong impact on the progression of the heat pump market, mainly for water heating, although growth of heat pumps for both, heating and hot water provision has also grown in the recent years.

Compared with the vigorous “coal-to-gas” and “coal-to-electricity” projects in the domestic market, commercial boilers have higher requirements for large-scale, stable and constant fuel supply and corresponding infrastructure construction, which makes the transition from coal to cleaner energy more difficult. Nevertheless, a moderate growth was also seen in the commercial gas boiler and commercial heat pump markets.

  1. Regular project market (new build)

New build is currently driving sales of heating products thanks to the existing pre-decoration policy, which is currently supported by local government to deliver fully fitted buildings, with operational heating systems installed.

The importance of the new build market is significant in China as it delivered sales of some 1.5 million gas boilers and over 900 thousand heat pumps to the new residential dwellings.

  1. Retail market (replacement and high-end new build)

Retail distribution chain has a strong impact on sales of all heating products as it is the most common place of provision of products for clients. Those replacing old, inefficient appliances or willing to install the appliances of their own choice in the newly acquired dwellings source them in retail shops. This market is very sensitive to economic situation and changes quickly depending on the consumer confidence level. It represents a large opportunity as there are millions of heating systems in China, which are older than 10 years – the time after which replacement is normally considered. Similarly, in many new houses owners opt to have better quality heat systems than those installed by the contractor as part of the pre-decoration policy.

With regards to district heating, the market has accelerated in recent years as policies to deal with air quality have been promoted and investments have been made. There are currently more than 400 projects underway and nearly 100 enterprises engaged. The industry generally believes that the development of smart district heating projects opens attractive strategic opportunities.

However, China is in a period of low economic growth and dealing with the aftermath of COVID-19 implications. Both will have an impact on the performance of the country’s heating product sales this year.

BSRIA is preparing the updated view on 2020 market performance and short term forecast for boilers and heat pump markets that will be available in September 2020.


By Socrates Christidis, Research Manager Heating & Renewables,

BSRIA, World Wide Market Intelligence


Notes to editors:
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