Passive house is an energy efficient building standard that provides affordable, high quality buildings with low energy running costs, while at the same time having a very low ecological footprint.
The additional costs to build a new house or upgrade an existing one, in order to meet the Passive house criteria, are not very high. The heating energy consumption is almost zero and, the most important for low operating costs, it requires very little building technology. The low additional costs you can save through the European subsidy (for example “Εξοικονόμηση κατ’ οίκον” in Greece) and over the years additional energy cost savings easily again.
How Passive House can benefit your life?
- High quality energy-efficient buildings with low ecological footprint
- Maximum level of comfort both during cold and warm months
- Affordable, low operating energy costs
- Healthy living conditions. Excellent quality of indoor air and temperature
How can you keep your home warm during winter without consuming too much energy?
The idea of Passive house rests on designing a building which will maintain a comfortable and healthy interior environment (living conditions) across all seasons of the year, without excess energy consumption. The excellent quality of indoor air, free from pollen and dust particles; the maintenance of desirable levels of humidity and the mild and comfortable indoor temperature across all seasons, are criteria of Passive house.
The criteria for a passive house are attained by means of careful and smart design and the implementation of the five principles for passive houses: insulation, energy efficient frames and glass panels, air conditioning with heat recovery, the airtightness of the construction and the lack of heat bridges.
All exterior walls must be very well insulated. Thickness and quality of the insulation help significantly save money as well as greatly improve the thermal comfort of your home and protects the environment by reducing the heating energy requirements.
In combination with, a continuous, strong, stiff, and durable air impermeable barrier will stop uncontrolled air flow which may carry water vapor, and become trapped, condense, and create microbial growth issues. A properly insulated and air-tight dwelling envelope will keep heat inside the building in winter, while blocking it in the summer.
Lack of heat bridges
Another important aspect is absence of thermal bridges. Air needs an opening or hole to flow through and a driving force to move it. Uncontrolled and unintended air-exchange often cause several building performance problems. They are simply fragments of the building envelope where thermal performance is much reduced in comparison to the neighboring construction parts. The weakened thermal insulation can be linear (i.e. the gaps at the joints of insulation boards) or pointed (penetrations of the insulation layer). The thermal bridges not only cause the heat to escape. The structure can get colder and the vapour can condensate in it, making the structure or insulation wet and even leading to the growth of fungi or mould. The best method to verify the insulation quality is thermal imaging.
Other essential components include energy efficient frames and glazing panels and a heat recovery ventilation system.
Energy efficient frames and glass panels
The frames’ profiles must be well insulated and fitted with low-emissivity coatings, multi-pane glass panels, argon or other gas-filled to make windows more energy-efficient and decrease heat transfer/flow through them. There are no special requirements for the size of the window surfaces. A south orientation of the main window areas is beneficial/ profitable, but not mandatory. In the north, the window area should be kept rather small. The windows can be opened at any time in the winter, but due to the ventilation system this rarely makes sense.
Ventilation with heat recovery
In new buildings, the window ventilation causes about half of the total building heat losses. These high heat losses can be reduced at least 75% by installing a mechanical ventilation system with heat recovery. The ventilation systems are in passive houses under no circumstances necessary because the building could “breathe” less due to the good insulation and airtightness. At the same time, heat recovery ventilation with provides a highly comfortable and completely draft-free form of fresh air supply, control humidity and offer maximum energy efficiency due to heat recovery. So, you can easily dry the laundry in the apartment, leave the bathroom door after showering and set up any number of plants. Another advantage: If you suffer from a pollen allergy, you can also equip the ventilation system with a pollen filter.
Ventilation with heat recovery is a very simple technique. It is the only passive house component that has to care for once a year. It is necessary to clean the device, replace the supply air filter and wash out the remaining air filters. The operating effort is limited to adjust the desired amount of fresh air on an operating unit.
Is passive house standard reliable?
It started out as a construction concept for residential buildings in Central Europe. Since the construction of the first passive house in 1991, thousands of residential buildings and numerous schools, kindergartens and companies have been built in the passive house standard. The passive house is a further development of the low-energy house, which has been tested for decades. Today, the Passive House Standard can be implemented in all types of building almost everywhere in the world. The European Union aims to build passive-house buildings from 2021 onwards.