According to the U.S. Energy Information Administration, “more than half of energy use in homes is for heating and air conditioning”. Add to this the fact that the average U.S. household uses almost 11,000 kWh of energy per year, and it becomes clear that we need to change our energy use in our homes to have the biggest impact on our energy consumption and environmental issues like climate change.
One of the methods of design that could have the best chance at changing those stats is Passivhaus. In this article, we will be telling you more about Passivhaus design and why it is so good at reducing energy consumption in homes.
What Is Passivhaus design?
Passivhaus is considered by many to be the gold standard in energy efficiency. Seen mostly in European countries like Germany and the U.K., Passivhaus is considered to be one of the most energy efficient home designs.
First developed in Germany, Passivhaus follows a set of building principles. The five principles of Passivhaus design are:
- Super insulated envelopes
- Airtight construction
- High-performance glazing
- Thermal-bridge-free detailing
- Heat recovery ventilation
How Is Energy Consumption Reduced?
Energy consumption is reduced through the five principles of Passivhaus. These principles work together to reduce energy consumption. Here is how each principles contributes.
Super Insulated Envelopes
In a Passivhaus, the outside insulation can be double or tiple the required insulation in standard homes. This greatly improves the thermal performance of the building. The reduction of heat transfer means less energy is required to keep the home at a comfortable temperature.
A second principles of Passivhaus design, airtight construction, ensures that there is no heat lost by air leaking through the envelope. Much like the super insultation, this reduces the heat transfer – lowering the energy needs to heat or cool the house.
The restrictions here to gain Passivhaus certification are pretty strict. When tested, the house cannot have more than 0.6 air changes per hour. In comparison, another energy efficient standard, the R2000 program, allows up to 1.5 air changes per hour.
High Performance Glazing
Tons of heat transfer happens through the windows. That is why, with Passivhaus, high-performance glazing system are required.
Passivhaus design also takes into consideration the location of windows. Passivhaus was given that name because the heating in a Passivhaus should largely be passive heating from the sun. Placing the windows optimally to allow for that in winter months goes a long way towards reducing the energy consumption of the home.
Thermal Bridge Free Detailing
The goal of this design principle is to reduce the thermal bridging in locations where architectural features meet, like where a window meets a wall, or where walls meet.
When not minimizing thermal bridging, you can have significant heat loss, even in houses with superinsulation.
Heat Recovery Ventilation
Proper ventilation is needed, especially with the airtight construction. In a non-Passivhaus design, the warm air in the house is exchanged for cold air outside. This cold air then needs to be heated once it enters the home.
Passivhaus design includes a heat recovery ventilator. This allows the home to heat the cold, incoming air using the heat in the air that is leaving the home. Using this ventilator, 75% of the heat in outgoing air is recovered.
Is Passivhaus the Best Method of Design to Reduce Energy Use?
It is hard to answer this with a definitive answer, as the industry is constantly changing and adapting new methods and technologies.
However, it seems that Passivhaus is certainly one of the best. Passivhaus designs have been found to consume 90% less energy for heating and cooling that your average home. Since most of the energy we use in our homes goes to heating and cooling, it seems like Passivhaus designs would have a massive impact on energy consumption.