Currently, a home can be sustainable in various ways. In fact, sometimes it isn’t even necessary for it to have been built with energy efficiency in mind, because there are solutions to retrofit it and install heating, cooling, and energy-saving systems that deliver good results.
But, as we’ve said, in other cases we can enjoy a home that, right from the planning stage, has been designed to provide its residents with optimal energy efficiency in their daily lives. And this is precisely what defines the type of homes we want to tell you about today at CULMIA: passive houses.
What are passive houses?
When we talk about passive houses, we are referring to a specific type of building that emerged in Germany in the late 1980s and was further developed in the years that followed, particularly in the 1990s. The conceptual basis for this is the so-called Passivhaus standard, which was developed in 1988 by Professors Bo Adamson (of Lund University, Sweden) and Wolfgang Feist (of the German Institute for Building and the Environment).
Two years after this standard was created, in 1990, the first project was carried out in Darmstadt (Germany); it consisted of the construction of four townhouses. Then, in 1996, Dr. Feist himself founded the “Passivhaus Institut (PHI),” an organization that currently leads research, implementation, training, and certification for Passivhaus buildings worldwide .
All of these buildings are easily identifiable because they share a design and construction that follow basic principles intended to minimize the homes’ heating and cooling needs. This also ensures that they have low energy consumption, regardless of the season.
As a result, passive houses are extremely comfortable inside without the need for HVAC systems or other types of installations. This is achieved because they are designed to offer benefits such as a high degree of insulation, optimal ventilation, high-quality windows and doors, and rigorous control of thermal bridges.
What are the basic principles of a passive house?
The Passivhaus standard is based on seven fundamental principles for building sustainable homes.
Superinsulation
Optimal insulation is achieved through a well-designed thermal envelope. Therefore, it is important to consider the climate of the area where the house will be built in order to optimize the thickness of the insulation, as well as to evaluate the cost and the energy efficiency gains achieved.
Absence of thermal bridges
Energy loss in a home does not occur only through windows or doors. Due to the nature of the home’s construction, it is possible to identify areas where energy escapes—either because the insulation layer has deteriorated or because of the junctions between different structural planes or elements (such as corners, joints, etc.).
That is why it is important to take several factors into account, such as never interrupting the insulation layer, using materials with high thermal resistance, and, of course, paying special attention to areas most likely to become thermal bridges, such as the joints mentioned above.
Leak Control
With proper advance planning, the building can provide complete control over air infiltration. This is a very important consideration because, if done correctly, it ensures that the building is heated through mechanical ventilation with heat recovery.
Mechanical ventilation with heat recovery
Building on the previous point, it is easy to conclude that this technology is key to providing adequate climate control in a passive house. It relies on heat recovery units, which improve indoor air quality and allow air coming from outside to be heated by the warm indoor air itself.
This has a twofold advantage: on the one hand, it heats the house, and on the other, it also ventilates it by bringing in fresh air from outside. And all of this is done without consuming any energy, since the process is entirely mechanical.
High-Performance Windows and Doors
Since window and door frames are the weakest points in a home’s building envelope, the windows and doors in Passivhaus homes are very important. For these, it is recommended to use double weatherstripping and double- or triple-pane low-emissivity glass that offers excellent thermal transmittance coefficients.
Proper planning to optimize solar gains and internal heat
Activity inside the home itself generates energy that can be harnessed by the home. We’re referring to the heat generated by people, lighting, and appliances, so the design of passive houses must take this into account to “capture” as much energy as possible. And let’s not forget the benefits provided by sunlight, as well as the need for protection from this type of radiation during the hottest months, such as those in the summer.
Using Technology to Calculate Energy Gains and Losses
This building standard has its own software application to facilitate its implementation. It is called the “Passivhaus Planning Package” (PHPP) and is a simple, intuitive (Excel-based) tool for adjusting a home’s thermal calculations to align with the principles of the Passivhaus model.
What are the benefits of living in a passive house?
If the seven Passive House principles we just mentioned are met, the home will offer its occupants guarantees of indoor comfort, sustainability, and energy efficiency. Not surprisingly, the goal of this standard is to limit energy demand to 15kWh/m²-yearfor heating and 15kWh/m²-yearfor cooling, with the building’s total primary energy demand not exceeding 120kWh/m²-year.
Thus, opting for the Passivhaus standard when building a home is not only good for the environment, but also for the homeowner’s wallet. And this was recently demonstrated by a study conducted in Valladolid, which compared the performance of two buildings designed as single-family homes, each with a usable floor area of 287m².
In one of the cases, the home was built according to energy-efficiency criteria under the Passivhaus Classic standard ;the other was built using standard systems, based on compliance with the requirements established by the current Technical Building Code (CTE), and received a “B” energy rating.
After two families with similar profiles lived in them for just over five months, it was concluded that the passive house yielded a favorable difference of 260 euros in a single winter season, with a daily cost ranging from 0.59 euros for the Passivhaus to 2.31 euros for the CTE. The former provided consistently high levels of comfort, while the latter required up to 70% more energy to achieve similar levels.
Save money on everyday household expenses with CULMIA
What do you think of passive houses? As you can see, they’re a great eco-friendly solution for making your home more sustainable. But they’re not the only option—you can also make small changes in your daily life to make your home more energy-efficient and save money.
Find out how in our “Guide to Saving Money at Home.” It’s sure to be a big help!
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