How can we move to a sustainable future if we keep using energy-intensive heating and cooling?

In this piece, Cohort 3 BGFer Demi examines how we can make our homes more energy-efficient, and more sustainable. You can also read this, and other similar pieces, on Demi's personal blog about her passion for science, technology, engineering and maths - MySTEMCloud.



According to UK Power, a ‘typical’ home uses between 8,000 kWh and 17,000 kWh of energy a year for its heating and according to World Watch Institute data, buildings are responsible for the annual consumption of 40% of the world’s energy.


The design of many buildings for living and working make them inefficient in terms of their ability to produce, use, conserve and recycle the energy that is generated. Businesses are paying around £60 million in superfluous energy bills annually because of energy being wasted by office buildings in cities across the UK. This is the same amount of energy that could be used to power 65,000 homes, clearly showing that change is needed if we want to reduce our reliance on energy-intensive heating and cooling and in order to move towards an energy sustainable future.


The basis of any energy efficient and sustainable design is beginning with Smart Design, which includes the installation of insulation in walls and throughout homes to reduce heat loss. Highly insulated windows and doors can also be an efficient form of heat conservation with up to 30% of heating lost from buildings escaping through the crevices in windows and doors. Another important factor is the heat that is lost through uninsulated roofs or attics as heat rises due to convection currents. This accounts for around 25% for all the heat loss in homes and to be able to reduce the need for energy-intensive heating and cooling systems, there must be a significant decrease in the percentages of heat loss mentioned above. This will not only reduce the need for burning fossil fuels but will have more large positive impacts on the environment.


Houses and buildings could be designed to harness the solar energy that enters the home though the windows in summer months to generate energy to heat water or be stored to supply energy in the winter. In more recent times, homes are being designed with larger windows which will allow for the sun’s rays to be absorbed. So, if you are a fan of ‘getting that lighting’, this would be a good move. This will not only increase the amount of light coming in and reducing the need for energy consuming light bulbs, but will increase the amount of natural heating, therefore, diminishing the need for energy-intensive heating.

There is also a need to move from double to triple glazed windows to radically reduce the heat lost through the insufficient insulation of windows. The lack of insulation in windows allows heat to leak though the gaps around the windows, be lost by radiation through the window glazing, and also through conduction, thus making the window frames which can typically, in total, account for 20% of heat loss in a home. Triple glazed windows can be up to 50% more insulating than double glazed windows, meaning the switch to triple glazing could save between £20 and £40 a year on heating bills depending on the size of a house. By increasing the sizes of windows to allow light to enter a house and investing in triple -glazed windows, we could see a substantial decrease on the reliance of energy-intensive heating systems in the winter months and a decrease in the energy needed for lighting in the summer.


Around 10% of heat generated by heating systems is lost through uninsulated flooring. Insulating under floorboards on the ground floor could save up to £60 a year in the UK and can seal the gaps between floors and skirting boards to reduce draughts. According to the Energy Saving Trust, a semi-detached house can save 160kg of CO₂ per year which is equivalent to £40 of savings per year by insulating the house floors. Designing flooring that disallows heat to escape through the floor or is allowed to escape but is captured and stored to heat, or generate electricity to heat, the home would significantly reduce the need to burn excess fossil fuels and would drastically reduce energy bills.


Water vapour and air condensation is a major threat to the structure of buildings due to its ability to weaken the structure. In cold climates, the difference in air pressure can cause the warm, moist air to be forced into the exterior walls, where the most insulation of the building would be placed. The air condenses as it cools, and the liquid weakens the barrier between the interior and the external climates. In warmer climates, the more humid air enters the walls and meets the cooler wall cavities. This causes the air to condense, again weakening the insulation. To resolve this issue, buildings will have to be designed with a vapour retarder, a material or structural element that can be used to hinder the movement of water vapour. An air retarder, a material that can reduce air flow in a house for a building’s envelope, can also be used. These would both be installed so that the quality of insulation remains of a high standard, in turn reducing heat loss both in the short and long term and reducing the need of energy intensive heating.


In much warmer countries where air conditioning is considered as an essential household item, the aim is to reduce the amount of heat being allowed into the building but also taking into account that temperatures can plummet in the evening, when it gets dark. Creating an efficient form of air circulation in a building will reduce the need for air conditioning which consumes a lot of electricity. To strike a balance between these two conditions, buildings will have to be designed to allow the cooling to be efficient enough to allow for a lower temperature but not cold to the point where heating systems will be having to be used in order to strike a balance. Currently, to allow for cooling homes and offices in countries such as African and South American countries, external horizontal overhangs are used to create shade or by using electric fans.


The cause of burning excess fossil fuels to power energy-intensive heating and cooling houses, is down to a building’s inability to preserve the heat that is produced. To reduce the need for intensive heating, we need to find the most efficient way to trap the heat that is produced in areas of colder climate and give buildings in hotter climates the capability to cool with natural ventilators and reducing the reliance on air-conditioning. Buildings designed in the future, should have high quality insulation in walls, roofs and floors and the capability to minimise an air leakage. The higher starting cost of insulation will be both cheaper in the long term compared to the need to buy more energy, further decreasing the amount of energy that is wasted to burn fossil fuels or renewables. Building smart homes is not only about the installation of innovative technology but about the building’s ability to retain and recycle the energy produced.

Centre for Sustainable Energy

St James Court, St James Parade, Bristol BS1 3LH
0117 934 1400 | www.cse.org.uk | Charity 298740 

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Bright Green Future is managed by the Centre for Sustainable Energy and is part of a National Lottery Community Fund project called Our Bright Future, aimed at empowering young people to lead progressive change in their communities and local environment.