Information about a Passivhaus
A Passivhaus is a construction solution that provides the occupants of the building with excellent thermal performance, mechanical ventilation and exceptional airtightness. What may seem like a company name or an architectural style, Passivhaus is something everyone can achieve with the right planning and technology. If you are planning to build a new home, a Passivhaus is definitely a solution worth taking into consideration. But what is a Passivhaus anyway? What are the components needed to build a Passivhaus? How can you benefit from investing in a Passivhaus? In this article, you will find all the answers and a lot of other useful information about a Passivhaus.
What Is a Passivhaus?
It is important to note that a Passivhaus, as mentioned above, is not an architectural style, nor a brand name; but simply a construction standard. A Passivhaus is a building standard that originated in Germany more than 20 years ago. A Passivhaus construction can be applied to any type of house, although it might be a simpler task to build a new Passivhaus, rather than renovate your current building and transform it into a Passivhaus. The Passivhaus standard can be applied to residential buildings, as well as to commercial, industrial and public constructions.
The construction of a Passivhaus follows the simple principle of building a house that is highly insulated, air-tight, and with windows facing the South for solar energy gain, in order to virtually become a self-sufficient home. This is the idea behind a Passivhaus. A Passivhaus is meant to gain the energy from its occupants, lighting, appliances and sunlight, in order to keep the house heated for most of the year. Although a Passivhaus generally requires solar power in order to function optimally, a Passivhaus standard can be applied in virtually any climate, from warm to moderate. It is important to note that a Passivhaus is internationally recognised as passive house.
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What Characterises a Passivhaus?
Constructing a Passivhaus is different from constructing a more conventional home. Due to the fact that a Passivhaus relies on thermal gain and holding the generated heat inside the house, it is important to note that a Passivhaus requires many solutions to keep the thermal loss at a minimum. These are the most important characteristics of a Passivhaus:
- Insulation—a Passivhaus standard construction uses the generated heat to keep the building warm. Therefore, it is of the utmost importance to have a very high level of insulation. A Passivhaus requires a well-insulated building shell with the advantage of keeping the construction warm in the winter and cool during the summer. Hence, for your Passivhaus to reach the necessary thermal standard, it needs a depth of 300 mm of insulation or more on the roof and external walls.
- Thermal bridge free construction—a ‘thermal bridge’ or a ‘cold bridge’ causes a loss of heat in a Passivhaus. This occurs when the heat is transferred through a poorly insulated part of a wall, floor or roof. As mentioned above, a Passivhaus cumulates heat from the environment, thus it is important to have no thermal bridges in your Passivhaus or keep them to a minimum. This can be achieved through a careful design of the Passivhaus as well as informing the builder that thermal bridges cannot occur.
- Simple building form—a Passivhaus standard is easy to achieve if the form of the building is kept simple. In that case, a traditional rectangular floor plan of a Passivhaus will be more efficient than an 'L' shaped one. This is due to the fact, that a simple building will have a less exposed surface area, where the heat could be lost to the outside. However, as better and better solutions appear, there is a possibility of building a more complex Passivhaus, but this might prove to be a bit more challenging.
- Glazing—every solution in your Passivhaus works so that we can benefit from the smallest heat loss possible, therefore a Passivhaus requires triple glazed windows and doors. Glazing must be facing south in order to maximise solar energy gain, but at the same time shading might be required from preventing the system to overheat in the summer.
- Airtight construction—your Passivhaus must be built so that the heat loss through the building fabric is minimised. This is one of the mandatory requirements to be met for a house to be called a Passivhaus. This can be achieved by concealing the continuous membrane behind the plasterboard, carefully taped to the door's frames and windows. To make sure that your Passivhaus is air-tight, a number of pressurisation tests during the construction process needs to be carried out.
- Heat recovery ventilation system—due to the fact that a Passivhaus is so air-tight, it is essential to have a proper ventilation system to provide the building with clean and fresh air. This is particularly important during the winter months when windows are kept shut. A Passivhaus should, therefore, have a mechanical ventilation unit installed, which is also known as MVHR. These units do not require much energy to run and have up to 93% heat recovery efficiency. The cost of such a unit is similar to the cost of a conventional boiler or radiator.
These are the most important elements that need to be taken into consideration when constructing a Passivhaus. However, there is a number of requirements that a building must meet in order to be called a Passivhaus. You can read more about this on the page devoted to passive houses.
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A Passivhaus represents a building standard that not only improves the quality of living but also brings green solutions to construction planning. A Passivhaus provides homeowners with clean and fresh air due to its ventilation system, reduces utility costs, it's comfortable and durable, it reduces the dependence on outside power.Your Passivhaus does that by providing us with the energy harnessed from the renewable energy sources.