If you haven’t yet heard of the term “passive house” being spoken about at the office water cooler, it won’t be long. With energy companies going bust in the UK at every turn, and the price of primary energy sources like coal and gas rising to uncomfortable heights, homebuilders are having to construct new houses that have a higher rate of energy efficiency and thus produce less carbon emissions. Less energy usage means reduced energy bills -something that is now on the minds of countless people around the world.
The United Nations has produced a video on passive house technology where it is stated that, in the United States, “our buildings are responsible for over 40% of our carbon emissions.”
This huge number may come as a big surprise to many who are accustomed to thinking about transport – our cars, lorries, and planes – as the primary source of our individual carbon emissions. However, how much thought do we give each day to how much energy our buildings are producing? Homes, schools, hospitals, shopping malls, and entertainment complexes such as cinemas, hotels, and restaurants all use energy to operate.
Well, passive house building is a new technology that is being utilised by homebuilders to help reduce carbon emissions and will play a pivotal role in the future of home building and eco-friendly living. With many governments adopting tough targets of reducing emissions by 2020 -in compliance with the 2015 Paris Climate Agreement – followed by a further 50% in every subsequent decade thereafter, passive house building is a potent tool in the armoury in achieving all this.
What is Passive House Technology?
Passive house building technology is using scientific innovations to help combat climate change; it is climate activism in action. The concept revolves around the notion that it is possible to design and build a house that works for people, a house that embodies comfort and a certain methodology.
Passive houses are designed with a specific focus in mind: to be as energy efficient as possible and thereby hugely reduce the energy necessary to heat and cool the house. There is a defined criteria for a house to be recognised as a passive house. It must incorporate a specific set of best practises that effectively seal it from external temperatures while maintaining good air flow and constant temperatures inside. These best practises have been articulated by the Passive House Institute (PHI) based in Germany, which has been working on improving this building technology for 30 years. https://passivehouse.com/ Due to their research and dedication, this technology has been constantly refined and has now been adopted by many homebuilders around the globe. In other words, a passive house is defined as being built in compliance with the stringent standards for insulation and energy use, as laid out by the PHI.
How does passive house technology work?
A good analogy to the passive house concept is comparing a passive house to a thermos, a hermetically sealed unit that has good air flow and ventilation. A thermos and passive houses have things in common, such as being airtight and insulated, which basically constitute the rules for maintaining the temperature within a defined space. To be defined as such, passive houses require:
- Being airtight
- Permanent and continuous insulation
- Triple-paned windows
- A good system for a high level of air quality control
Another feature of this technology is its ability to remove the energy impediment known as “thermal bridging.” This is the process in which temperature passes from one material to another from being in physical contact. This concept of heat transference between physical objects can be visualised by thinking of the outside cold winter temperature passing through the brickwork and freezing the steel beams that support the floor, resulting in the room feeling cold.
With hermetically sealing off space inside the house, thermal bridging is eliminated to a high degree, resulting in a more stable air temperature by default, hence the name “passive housing.” Heat from everyday things like body heat, the sun, and electrical appliances will heat the inside and be much harder to escape. The result is a house that is up to 90% more energy efficient compared to traditionally built houses.
Why would buyers opt for a passive house?
With the price of energy increasingly becoming a hot potato, and with pressure to drastically reduce carbon emissions, the high energy efficiency of passive housing means that heating and cooling are dramatically reduced. Furthermore, the stable and consistent air temperature stops temperature swings which can result in people feeling unwell, like the outside fluctuating temperatures between the extremes of hot freezing. In other words, passive housing makes for a much more comfortable living environment compared to traditional hosing.
The air flow quality is much higher than the standard built house as any staleness or fumes are eradicated, which is achieved by the air being constantly circulated and filtered.
Although many more passive homes need to be and will be built, it is also possible to retrofit some existing houses to enable households to benefit from the passive house concept.
How are passive houses constructed?
The good thing about building passive houses is that they are built like any other house, largely constructed from the same materials, construction techniques and contractors as building a regular house.
The key to passive house technology is in the design stage of the project, whereby a holistic approach ensures that all the elements work together, taking full advantage of the passive house methodology. The crux of the issue is about solidifying the insulation and thermal isolation aspect of the design.
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