Overheating

Can new builds rise to the challenge of Climate Change?

The recent record-breaking heatwaves across the UK, following the previous heatwaves of 2018, have brought the risks of overheating into the public eye, even though it has been declared as a public issue by England’s Health Protection Agency since 2011.

The negative impacts of exposure to heat can be seen when daily temperatures surpass just 16-20⁰C (Committee on Climate Change: CCC). The social and economic impacts can range from, poor thermal comfort, reduced productivity and wellbeing, to fatalities. In 2017 the average number of heat related deaths per year was recorded at around 2,000 (CCC). At present an estimated 20% of the UK housing stock overheats in standard summer conditions, therefore as climate change takes hold and extreme weather conditions become the norm, more fatalities will inevitably occur, unless significant action is taken to reduce indoor overheating. The Environmental Audit Committee expect the average number of annual heat related mortalities to reach 7,000 by 2050. It is concerning that the number of heat related deaths is likely to triple in 31 years, and should be mitigated against as far as possible. Furthermore, it is estimated that circa 90% of UK hospital wards are prone to overheating (CCC). This puts already vulnerable groups at greater risk. This is a clear indicator of how the impacts of overheating will be felt more severely as the effects of climate change become more apparent.

Building Regulations, which must be met by all new build properties, require a certain level of fabric energy efficiency (i.e. the efficacy of building materials in retaining heat) to be achieved as well as low carbon emissions rates. These standards dictate well-insulated, air tight structures to maximise thermal performance. A well-insulated property will both prevent initial heat gain, and trap existing heat. It is therefore crucial to find a balance whereby heat gains from sunlight are utilised in the winter, and minimised in the summer. Accounting for the effect of thermal mass at design stage is also important.  Homes with high thermal mass can be very effective at combating overheating, however, when the materials do not have sufficient time to cool down during extended periods of hot weather, the heat builds up and it is difficult to achieve cooler temperatures at night. This highlights the difficulty in achieving the balance required to maintain comfortable indoor temperatures year-round, especially where overheating is not considered early on.

Low & High Thermal Mass

However, where overheating is considered early in the design process, there are many strategies and features that can be implemented in new buildings to combat overheating. Overheating can be reduced by:

  • Limiting glazing area on southern facades
  • Installing external shutters, this can enable the homeowner direct control of the amount of sunlight entering the property
  • Incorporation of cross ventilation. This allows air to flow through the building and alleviate high temperatures.
  • Utilising louvres which encourage ventilation whilst also blocking sunlight
  • Extending roofs to provide shade over windows
  • Green roofs and walls which work through insulation, shade, evapotranspirative cooling and the albedo effect
  • Wider landscape design to provide local shading
  • Window design to allow secure ventilation on the ground floor

While some of the features detailed in the list above can be retrofitted, most must be considered at design stage if they are to be cost effective. Air conditioning is a popular retrofit cooling solution and, while effective, it is problematic as it:

  • Is expensive to install and to run
  • Is energy intensive
  • Can worsen overheating for surrounding buildings by moving the warm indoor air outside
  • Can intensify the urban heat island effect
  • Uses Hydrofluorocarbons as the primary refrigerant, a greenhouse gas more potent than CO2

Air Conditioning Cycle

Air conditioning is therefore contributing to the problem that it is being installed to help solve. This is a vicious and counterproductive cycle, as shown in the diagram above, that could be stopped with more effective early design solutions to overheating.

It is estimated that 80% of the current UK housing stock will still be in use in 2050, and therefore retrofitting will be necessary for existing houses. This need not be the case for new builds. Installing measures to combat overheating is crucial to avoid health issues and additional cost to homeowners. By highlighting overheating risks through updated Building Regulations, the government could facilitate changes to the new build market. Many of the passive measures to reduce overheating discussed in this article can be tested in dynamic simulation software, and some local authorities have even made it part of their planning process to consider future weather data. It goes to show that the technology is available now to combat current and future overheating, and placing this risk at the forefront of design could provide future proofed homes for generations to come.

Overheating is an issue that is not going away, it will continue to grow over the coming decades. Think about how uncomfortable you felt in your home on the 25th July 2019, these temperatures will soon become the norm. Without change now, both us and the generations to come will have little respite from the overwhelming heat. New build developments must be designed now to cope with the climate of the future and not the climate of the past.

 AES Sustainability Consultants can assist designers with analysing the risks of overheating now and in the future. If this is something you would like to discuss further please contact Silvio Junges on silvio.junges@aessc.co.uk.

Written by Ella Cowen, Graduate Consultant 

Consultants inside Energy Centre

Energy Centre Visit

Consultants visit Cranbrook’s Energy Centre

E.ON invited our consultants to visit the Cranbrook Energy Centre, located on the £120 million Skypark business development, supplying heat and hot water to both the community of Cranbrook and the Skypark business development.

Learn More: www.eonenergy.com/cranbrook

“Our visit to the E.ON Energy Centre provided a valuable insight into the functioning of a district heat network. Mark provided a comprehensive overview of how the system is developed, and how the system and its sources of energy will evolve over time towards zero carbon”. Aaron – Graduate Sustainability Consultant

 

“We learnt about the engineering challenges involved with constructing and maintaining a district heating network. In addition, we learned the differences between district heat networks and traditional centralised heating networks in terms of economics and customer experience. The presentation highlighted to us the importance of local planning policy in promoting the implementation of district heating networks e.g. East Devon council planning requirements. We learned about potential future projects in which waste heat form the FAB link could be used, along with heat pumps, to implement a more efficient, low temperature District Heating Network”. Kieran – Graduate Sustainability Consultant

Thank you for showing us around!

Plastic Free July Logo

Plastic Free July: My Honest Account

Plastic Free July: My Honest Account

Written by Charlotte Dutton

Last month, inspired by the BBC One programme: War on Plastic with Hugh and Anita, who over the series highlighted the shocking truths of our plastic consumption. I decided it was time to jump on the bandwagon and really reflect on what I could do to reduce my own impact. I have written my honest experience; it is safe to say it isn’t a fairy-tale ending with a plastic-free happily ever after account of things, but it has opened my eyes to where I and others can reduce waste.

At the start of the July 2019, much in the same way Hugh did in Bristol, I decided to look at all the single use plastic in my life, a bit like opening Pandora’s box! I discovered that committing to a plastic free life when out/ travelling is difficult without proper preparation, and the kitchen was somewhat of a disaster but I had a relative amount of success in the bathroom, with some plastic products lined up to change in the future once they are finished.

As a Graduate Consultant, on a Graduate salary, money is an obstacle. One I became painfully aware of whilst trying to reduce my plastic consumption during the weekly food shop. When trying to shop ‘plastic packaging free’, it meant I wasn’t able to buy 80% of my usual items, but the alternative options were out of budget.

Out and About

I re-used empty jam/honey jars as storage containers, invested in Tupperware of all shapes and sizes and bought an extra water bottle for my car. I drive a lot – usually to the beach for surfing, to the gym or visiting friends and I like to keep hydrated. I found, an extra bottle in the boot of the car stops me heading somewhere, realising I need some water and resorting to plastic. I don’t notice it’s there half the time, but since I did it at the start of July, I haven’t bought a single plastic bottle of water! (Mini Victory Dance) 

The Weekly Shop

Aldi had a limited choice of plastic free fruit and veg; broccoli, tomatoes, lettuce, bananas… all wrapped in plastic. When I looked at other supermarkets, I found it was often the case that the plastic free option was again, the more expensive option. Of course there are local grocery stores and farm shops, which have the added benefit of reduced air miles and supporting local business, but I found they still have an increased price tag, and aren’t easily accessible for everyone and usually closed after 5pm.

Veg not in plastic

I would gladly pay more for my food, shop locally and choose the plastic free options, but on top of rent, bills and fuel, I’d have very little money to put into savings or to enjoy life outside of work. My immediate thought is, it shouldn’t be this hard! It’s easy to see how we have such a reliance on single use plastic when the decision for many is as easy as ‘cheap and convenient’. The financial aspect of making a plastic free or more eco friendly choice is something that I struggled with in pretty much every decision I made, and I found it really frustrating.

Home Cleaning Products

Switching out dish brushes/ sponges for a natural coconut option, using a cloth and spray rather than one use surface wipes and using Ocean Saver refillable cleaning products. My housemate and I are also experimenting with less chemical based cleaners – citric acid, white vinegar, bicarb of soda – things your Nan definitely knows about, but they work! I could also purchase glass spray bottles, and refillable bottles for detergent, but this is a work in progress.

Eco-Coconut Scourer

The Bathroom

I invested in a solid shampoo and conditioner bar, ditched the shower gel products for solid soap/body wash bar options, purchased a traditional razor and made my own body scrub. You can find loads of ‘recipes’ for body scrub online, and you don’t need to spend much at all. The one I made is a mix of coconut oil, sugar, lemon and honey – which also doubles as an in-shower moisturiser!

Coconut Oil, purchased in a glass jar, has a myriad of uses; hair conditioner, make-up remover and shaving gel!

I’m still searching for alternative products for my skin care routine, unfortunately cost is the problem again! The products I currently buy, set me back no more than £10 every couple of months. The same products, in a plastic free variant (or in Lush’s non-virgin plastic, which I’m counting as re-usable) would cost me over £40 – A commitment I would love to make, especially as a huge fan of Lush’s products, but I can’t financially make that commitment at the moment.

Shampoo Bar

In Summary

The financial implications of making plastic free swaps can’t be overlooked, I think a lot of people my age are in the same situation and feel the same way. We want to reduce our impact, we understand that most packaging is now used just once and thrown away, which is damaging our environment, but why do customers have to foot the bill for this change???

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