Passivhaus and energy efficiency...
- gillianjones48
- 2 minutes ago
- 3 min read
What is a Passivhaus? If you work in construction, architecture, or engineering and focus on energy efficiency and sustainability, you will have heard of this.
It refers to any building that has been created using energy-efficient standards as a guide, so that the house or office retains heat in winter and remains cool in summer. Their energy efficiency is so good that the owner will save on energy bills, but construction costs can be significantly higher.
There are five rules for a house to be considered energy-efficient and a “Passivhaus.” We'll look at this in more detail shortly.
The Passivhaus name comes from the Passivhaus Institute in Germany, which came up with some guiding principles to help those who are building energy-efficient homes. Following a research project looking into energy-saving buildings, it was discovered that many buildings in the past did not provide the energy savings they’d promised. With this in mind, the Passivhaus Institute was developed.
If you’re building sustainable homes, you can apply to the Passivhaus for certification, but to get it, you’d need to prove you’d created your buildings following the Passivhaus’s 5 guiding principles.
What are these 5 principles?
They are, in no particular order: Continuous Insulation, Airtight Construction, High Performance Windows and Doors, Thermal Free Bridge Free Design, and finally Mechanical Ventilation with Heat Recovery (MVHR).
1/ Continuous Insulation is what it says basically, the house needs to be surrounded by a thick thermal layer that is unbroken. This keeps the inside warm in winter and nice and cool in the summer.
2/ Airtight Construction is all about controlling the airflow and any drafts that come in. It helps to significantly reduce heat loss and prevent condensation inside the walls. This will help protect the structure for years to come.
3/ High Performance Windows and Doors. This is all about glazing, triple rather than double, insulating the frames and coating them in a layer of low emissivity.
4/ Thermal Bridge-Free Design. The devil is in the details, and making sure that any materials that cross a layer of insulation are not thermally broken and are minimised as much as possible. This might include structural steel or connections between balconies. By doing this, cold spots are erased before they can start, and heat loss is prevented.
5/ Mechanical Ventilation with Heat Recovery (MVHR). This is all about making sure the building is airtight with a ventilation system that removes stale air and replaces it with fresh air. A ventilation system will pass both the outgoing and ingoing air through what’s known as a ‘heat exchanger,’ and is able to recover up to 90% of heat, so there’s always a consistent temperature. This also helps to reduce energy waste.
And this is the impressive bit - Passivhaus doesn’t need a heating system.
But there will be some mechanisms attached to the property, such as a small element attached to the ventilation system.
It’s all very well, you might say, you can’t afford to buy a house designed in this way. However, many houses, older houses, can be altered to make them more energy efficient. And state housing is now catching up, too, because everyone deserves to live in an energy-efficient home.
As you can imagine, the cost-of-living crisis has raised the issue of fuel poverty, placing more importance on energy saving than ever before. Hard-to-heat homes cost money, money that low-income people don't have.
If social housing is built with energy efficiency in mind, it can address fuel poverty and provide a solution, reducing the carbon footprint at the same time.
Thankfully, there are Passivhaus buildings all over the UK, with many in the development phase. There are some in Plymouth, and some are in the process of being developed in Scotland. And while Passivhaus principles are expensive to put together, the savings in energy efficiency are worth working towards for both the house dweller and the environment at large.