What is a passive house?
Highly energy efficient residential buildings that are built to reduce the adverse effects of human activities on the environment are known as passive houses. These houses are built following the stringent norms laid down by the Passive House Institute (PHI). The first instances of such eco homes as these appeared in Darmstadt, Germany in 1990. Since then more than 25,000 passive houses were constructed in Europe and more than 3000 in North America.
Are passive houses common in Canada?
With increasing awareness, the rate of passive construction is also gaining momentum. In 2016 alone, the number of passive structures in Canada grew from 500 to over 2000. The major credit for this rapid change goes to the Passive House Canada, an affiliate of the International Passive House Association.
The first passive house in Canada named Lost Lake PassivHaus was built in 2010. However, some people believe the green building constructed in Saskatchewan in 1977 is the example of the first passive structure in Canada.
In the recent years, a large number of passive buildings have been constructed in Vancouver. The city is also the home to the largest passive house in the world, The Heights. It is a six stories high building and house 95 apartments.
What are the differences of passive house designs between countries?
The basics of the green building norms have clearly been noted down by PHI. But it has also allowed sufficient room to accommodate the country specific guidelines. So the regulations dictating the passive construction in one country are not exactly the same as another country.
The local climate conditions and energy norms are taken into account while making these guidelines. For example, Switzerland has its own standards known as Minergie P which is slightly different than the passive house guidelines followed in Canada and elsewhere in the world. Minergie P houses can use up to 42 kWh per sq metre for space heating. But passive houses are permitted to use no more than 15 kWh per sq meter.
Standards to follow while building a passive house in Canada
The following criteria must be met for a house to be considered as passive:
* The energy required for heating or cooling the interior atmosphere must not exceed 15 kWh per sq metre of living area annually.
* Use dehumidifiers to keep the moisture content in the interior air to a comfortable level. The relative humidity level of 30% to 50% is considered to be healthy for the interiors.
* The rate of air leakage must not exceed 0.6 times the total volume of the structure at 50 Pascal pressure.
* A green building that follows passive design must not consume more than 120 kWh energy per sq metre of living space annually for all domestic purposes. This includes energy requirements for cooking up food, heating up water and refrigeration.
* The interior temperature should not exceed 25 degree Celsius.
How passive houses maintain heating and ventilation standards?
Passive houses use alternative sources of energy to heat up or cool down the interior air. In case of a solar house, sunlight remains as the primary source of energy. Instead of centralised heating, it is built with small heat pumps. Passive structures make use of internal sources of energy such as heat emitted from the electrical fixtures, home appliances and electronic goods to maintain the air temperature.
The advanced ventilation system helps to maintain the energy efficiency of the entire structure. The process is powered by natural ventilation and heat recovery ventilation systems typical to this type of houses. The building is fitted with earth warming tubes which are installed in the ground. They heat up or cool down the air before it enters the ventilation system.
Design of eco homes in Canada
The shape and size of eco homes depend on your needs. The passive structure showcases contemporary design practices. Since most buildings are designed in clusters, they may give you a row house like feel. They are generally built with a central open plan living and kitchen cum dining parlour.
For maximum exposure to sunlight, place the master bedroom on the southeast corner of your home. The other bedrooms are positioned in southwest. For increased heating efficiency, the bathroom door is designed below the ductless heat pumps. Passive solar house plans take into account the availability of sunlight all year long. The solar photovoltaic cells are mounted on the terrace or on the ground where space constraint does not exist.
Lighting and insulation of passive houses
LED lighting which consumes very low level of energy is fitted in the interior and exterior of the house. To maximise daylight in the interiors, skylights are installed in suitable areas of the building. Solar powered lighting is used to brighten up the surroundings after the sunset.
Proper insulation is of paramount importance for these houses. Without this in place maintaining a comfortable interior atmosphere is nearly impossible. High resistance thermal insulation materials, collectively known as superinsulation, are used to minimise air leakage and maintain proper interior temperature and moisture levels.
Legal issues that may arise when building a passive house
In Canada, the standardisation, building and certification procedure of passive house plans are governed by Passive House Canada. Certified passive structures are approved with a PHI logo. To avoid the hassles of building a passive dwelling ground up, you may opt for a prefabricated passive building. Passive house principles can be applied for residential structures as well as commercial buildings and educational institutions.
Pros and cons building a passive house
Passive houses are comfortable to live in, sustainable and highly energy efficient. They are easy to maintain. As they have such a positive impact on reducing the ecological footprint, you do a great service to the humankind by opting to live in a passive home.
The initial charge for setting up a home like this is high. If you are living in or planning to live in remote areas of the country you may yet not have access to experienced passive house designers and materials needed to build the house. With increased popularity of this type of houses, these challenges will soon be a thing of the past.
Construction and maintenance costs of passive houses
The cost of building passive house ranges from CAD 250,000 to 520,000. Prefabricated structures can be bought at CAD 150 per sq metre. Certified houses are considered to be 90% more energy efficient than ordinary buildings. This has a significant impact on your utility bills. The cost of maintaining the structure will be around CAD 1000 per year for a newly built house. This would include minor repairing work of the ventilation, heating and insulation systems.
Which professionals are able to help you build a passive house or buy one?
To design a passive structure, consider speaking with a certified architect or passive house consultant. You will find experienced architects on homify’s platform. Passive House Canada also maintains a database of certified professionals. To decorate the interiors according to the contemporary style, seek help from professional interior designers.