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.

Taking action on Climate Change

by Michelle Agha-Hossein, BSRIA Building Performance Lead

Most nations now recognise climate change as an established, perturbing fact that needs immediate attention. We can see the effects in the worsening and more frequent extremes of weather: flash floods, droughts, strong winds, heavy snow, heat waves, etc.

UK temperatures in 2019 were 1.1°C above the 1961-1990 long-term average and it was a particularly wet year across parts of central and northern England. Still fresh in the memory are storms Ciara and Dennis in February 2020 with strong winds and heavy rain that caused significant damage to homes and commercial buildings. There is growing evidence that periods of intensely strong winds and heavy rain are likely to increase in the future.

The UK is not the only country affected by climate change. Many other countries are (and will be) suffering disproportionately. The world’s leading climate scientists have warned that we might have just 12 years to keep global warming at a maximum of 1.5°C. After this point, the risk of extreme weather conditions will significantly increase. The increased frequency and intensity of extreme weather will affect all but is most likely to bring catastrophic consequences in many less economically developed countries, where food shortages and water scarcity can trigger deep social changes.

Immediate radical action is required to limit carbon emissions, and the built environment industry can play a crucial role by changing the prevailing culture.

Most building-related carbon emissions are generated from energy use in buildings. However, there are choices that building owners/operators can make and initiatives that they can undertake to lessen the related negative impact on the environment:

In brand new buildings, the most effective way for addressing emissions is reducing consumption through energy efficient design. In existing buildings, the issue can be addressed by efficient retrofitting and effective maintenance strategy. Adopting renewable energy technologies in both cases can significantly reduce building emissions.

Steps building owners and operators can take today.

There are several initiatives/activities that can help building owners/operators combat climate change:

  • Consider ‘net-zero carbon’ targets for your building: UKGBC launched its Advancing Net Zero programme in 2018 and published the ‘Net Zero Carbon Buildings: A Framework Definition’ in 2019. The framework provides the construction industry with clarity on the outcomes required for a net zero carbon building.
  • Ensure the required outcomes for a ‘net-zero carbon’ building are achieved: As advised by UKGBC in the framework definition, initiatives like BSRIA Soft Landings should be adopted in new build as well as in refurbishment projects to ensure a net zero carbon building will be achieved. The BSRIA Soft Landings framework provides a platform for project teams to understand the required outcomes for their project and ensure all decisions made during the project are based on meeting those outcomes.
  • Maintain your net zero carbon building effectively: Business-focused maintenance is a methodology developed by BSRIA that can be adopted to help building operators maintain critical assets effectively and efficiently to sustain a net zero carbon building within budget.
  • Investigate failure quickly: Is the energy bill for your building higher than it should be? Investigate the problem as soon as you can. The first and easiest step would be looking at the energy end use breakdown to see which areas are using more energy than expected. If the issue is related to the HVAC system, check the system’s setting points and monitor the indoor air temperature and relative humidity. Thermal imaging of the fabric of the building can also help to identify, thermal bridging, missing/damaged insulation and areas of excessive air leakage.
  • Promote a healthy diet among building occupants: This is a non-technical initiative that building owners/operators can adopt in their buildings. Eating less meat and gradually shifting to more plant-based foods is vital for keeping us and our planet healthy.  It is important to think about initiatives such as using signage or lunchtime talks, to educate building occupants about healthy diets and encourage them to eat more fruit and vegetables. Research has shown that adhering to health guidelines on meat consumption could cut global food-related emissions by nearly a third by 2050. Healthy diet is also supported by Fitwel and the WELL building standard.

Building owners and operators, to play their role in combating climate change, should ensure their decisions and the way they create and run their buildings contribute positively to the wellbeing of our planet and its citizens.

So, make a start today and choose the first thing you are going to assess/change in your building to help combat climate change.

To find out more about how BSRIA can help you improve building performance, visit us here.

The wellbeing and environmental effects of agile working

by David Bleicher, BSRIA Publications Manager

How many times in the last few months have you started a sentence with “When things get back to normal…”? For those of us whose work mostly involves tapping keys on a keyboard, “normal” implies commuting to an office building five days a week and staying there for eight or more hours a day.

When lockdown restrictions were imposed, things that were previously unthinkable, such as working from home every day, conducting all our meetings by video call, and not having easy access to a printer, became “the new normal”.

One thing the pandemic has taught us is that changes to our work habits are possible – we don’t have to do things the way we’ve always done them. Since lockdown, agile working has been high on companies’ agendas; but agile working has a broader scope than flexible working. It is defined as “bringing people, processes, connectivity and technology, time and place together to find the most appropriate and effective way of working to carry out a particular task.”

Working from home with a cat

The triple bottom line

Agile working is indeed about much more than changing people’s working hours and locations. It’s about how people work – becoming focused on the outcome rather than the process. It’s about making the best use of technology to achieve those outcomes and it’s also about reconfiguring workplaces to better suit the new ways of working. But, when considering these outcomes, we should be looking further than the financial bottom line. The term triple bottom line is a framework that also brings social and environmental aspects into consideration.

How, when and where people work has a major impact on their wellbeing. The past few months have served as an unintentional experiment in the wellbeing effects of mass home working. Some people are less stressed and more productive working from home, providing they have regular contact with their colleagues. Other people – particularly those who don’t have a dedicated home working space – returned to their offices as soon as it was safe to do so. It depends on the individual’s preferences, personal circumstances and the nature of the work they do.

On the face of it, it would seem that increased working from home or from local coworking spaces would be a win-win for the environment. Less commuting means fewer CO2 emissions and less urban air pollution. But a study by global consulting firm and BSRIA member, WSP, found that year-round home working could result in an overall increase in CO2 emissions.

In short, it reduces office air conditioning energy use in the summer, but greatly increases home heating energy use in the winter – more than offsetting carbon savings from reduced commuting. Perhaps what this highlights most is just how inefficient the UK’s housing stock is. If we all lived in low energy homes with good level insulation and electric heat pumps, the equation would be very different. Perhaps a flexible solution allowing home working in summer and promoting office working in winter would be best from an environmental perspective.

A possible long-term effect of increased home working is that some people may move further away from their offices. For example, someone might choose to swap a five-days-a-week 20 km commute for a one-day-a-week 100 km commute. If that is also a move to a more suburban or rural location with more scattered development, less public transport and fewer amenities within walking distance, then (for that individual at least) there’ll be an increased carbon footprint. Not very agile.

Impact of technology

There’s another aspect that may not yet come high up in public awareness. Remote working is dependent on technology – in particular, the video calls that so many of us have become adept at over the past few months. All this processing burns up energy. The effect on home and office electricity bills may be negligible because the processing is done in the cloud. This isn’t some imaginary, nebulous place. The cloud is really a network of data centres around the world, churning data at lightning speed and, despite ongoing efforts, still generating a whole lot of CO2 emissions in the process. Videoconferencing definitely makes sense from both an economic and environmental perspective when it reduces the need for business travel, but if those people would “normally” be working in the same building, isn’t it just adding to global CO2 emissions?

We don’t yet know what “the new normal” is going to look like. Undoubtedly, we’re going to see more remote working, but responsible employers should weigh up the pros and cons economically, environmentally and socially. Terminating the lease on an office building may seem like a sensible cost saving, but can a workforce really be productive when they never meet face-to-face? Does an activity that seemingly reduces CO2 emissions actually just increase emissions elsewhere? Any agile working solution must take all of these things into account, and not attempt a one-size-fits-all approach to productivity, environmental good practice and employee wellbeing.

For more information on how BSRIA can support your business with energy advice and related services, visit us here: BSRIA Energy Advice.

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