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All you need to know about Passive Houses

Jun 24, 2021

If you are in the construction business or are looking to build a new home, the chances are that you may have heard the term Passive House bandied about. Let’s look at the concept of Passive Houses that is gaining popularity across the world.

What Is A Passive House?

Passive Houses, also called Passivhaus buildings, are designed according to a set of building standards. They aim to create a structure or a comfortable and healthy house and has deficient levels of energy consumption.

However, A passive house is more than an efficient way of constructing a low-energy building. It is a concept that stands for the test of practice. If done right, it can potentially decrease a building’s ecological footprint.

Passive House was first established by the Passivhaus Institute in Darmstadt, Germany. Starting in 1996, it has now become a leading standard for building construction. 

The concept of Passive House is not limited to residential properties alone. Corporate buildings, schools, universities, supermarkets, businesses, etc., can also be built according to the same concept. 

Passive house design plans are not standalone; they are integrated into the architectural design. The concept of Passive House Design is used both for new buildings and refurbishments.

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Passive House

What Are the Benefits of a Passive House?

The Passive House concept is a tried and tested concept, conforming to the accepted global standards. Passive houses worldwide are tested for air quality, thermal comfort, energy consumption, and operating costs.

The results of these tests are available widely on the internet. They back the main benefits of Passive Houses as envisaged – low energy consumption paired with a significant comfort level. 

Passive Houses are sustainable and affordable. Basic building knowledge can be put to use along with the knowledge of building components as required by Passive House standards.

A Passive House has it all, from comfort, quality, sustainability, versatility to retrofits and affordability.

Types of Passive Houses 

There are currently 2 standards of Passive House- International Passivhaus Standard and Passive House Institute- US Standard

International Passivhaus Standard

It was developed by the Passive House Institute (PHI); this standard was developed after researching and reviewing alternate passive solar designs on an international level.

Launched in 1988, it is prevalent in buildings worldwide. Following the International Passivhaus Standard, buildings constructed under the passive house certification are usually found in European countries.

The PHI places special emphasis on testing, research, open-source sharing, and verification while ensuring continuous improvement.

Passive House Institute- US Standard

As the name goes, Passive House Institute-US Standard (PHIUS+) is the American version of PHI. First developed in 2003, PHIUS was formalized 12 years down the line, and in 2018, it was updated to PHIUS+.

Buildings built to this standard use 40-80% less energy than standard conventional buildings. Statistically, that’s a large positive impact on the environment and the quality of living coupled with economic value.

How to Build a Passive House

While building a Passive House, every element in the methodology needs to work together to prove beneficial. It is important to follow the standard set of principles to attain a quantifiable level of energy efficiency alongside specific comfort housing levels. 

Passive House Design works on the following five principles:

  • Airtight construction
  • Balanced ventilation
  • Continuous insulation
  • Thermal Bridge Free
  • Optimized windows

Let’s look at these Passive House principles:

Airtight Construction

Air sealing techniques are a sure-fire way to reduce individual energy bills and carbon footprints. Many city governments provide free air sealing kits to homeowners for the same. These sealing kits can prove to be a simple DIY home improvement project.

The Passive House standard has established a new level of airtightness, ensuring zero gaps or leaks around doors and windows, piping, electrical outlets, and lighting. Lightly put, it seals just about every hole or space that may threaten its effectiveness.

For houses in colder climates, plugging can effectively reduce the loss of heat and moisture accumulation. It improves indoor air quality by preventing cold spots, drafts, and condensation, making the house a comfortable and healthy space to live in.

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How to Build a Passive House

Balanced Ventilation

To some, airtight construction and complete insulation may seem like an open invitation to the poor air quality within the house, leading to difficulty breathing in an enclosed space.

However, this is far from the truth. Passive house insulation ensures a continuous flow of filtered, fresh air and efficient removal of stale air for a healthy balance. This is achieved through several efficient, silent, and cost-effective ventilators like Heat Recovery Ventilators (HRV) or Energy Recovery Ventilators (ERV). These ventilators work by transferring heat and moisture, contributing to healthier indoor air quality. 

Continuous Insulation

The Passive Home design starts with continuous super-insulation through the entirety of the house, from slabs to walls and roofs. In order to link with the strict performance metric, additional insulation is required in building Passive Houses compared to other conventional buildings.

Keeping in mind the environmental benefits of building Passive Homes, it’s important to look for eco-friendly and natural options like cellulose insulation and sheep’s wool. 

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Passive House Isolation

Thermal Bridge Free

An area of an object with comparatively less insulation than the surrounding area is called a thermal bridge. Because of it, the heat inside the house will steadily try to move towards the cooler area outside the house’s walls. It helps create a path that offers the least resistance to heat transfer.  

A thermal bridge can have adverse effects on the overall energy efficiency. The building team needs to be cautious and alert when insulating the house, paying attention to every small area to ensure the house is Thermal Bridge Free.

Optimized Windows

Passive House Windows can be a middle ground for heat gain and heat loss. Unlike the standard house, Passive House standard requires triple-pane windows, glass spacers, and insulated frames. The same goes for Passive House Doors.

Passive House isn’t just about optimizing the benefits; it’s also about knowing where something needs to be placed to avail maximum protection and benefit. 

Passive Houses are designed to make the most of the naturally available light and heat. Passive Solar Building Techniques are brought into effect here. Windows are strategically placed to maximize passive solar gain, ensuring a smooth transfer of heat in the house. This ensures that Passive House heating is efficiently managed throughout the different seasons, leading to low utility bills.

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Passive House Windows

How Much Does A Passive House Cost?

It’s incredible how people associate eco-friendly houses with more than standard expenditure. They think it’s costly, but that’s not true.

This myth was busted by a Passive House Architect, Richard Pedranti, who designed a house according to the Passive House Standard at just about $165 per square foot. Compared to standard homes in the same area that cost about $175 to $200 per square foot, a Passive House proved financially more affordable, had great personal comfort, and was more energy efficient.

Contrary to popular opinion-a Passive House is not overly expensive. Owing to the energy-efficient design, these houses can even reduce your monthly electricity bill, translating to long-term benefits compared to their traditional counterparts.

Of course, how you build your passive house is a great determiner of the cost. You could want added features or just a simple, modest house. The price per square meter will differ for each house, as every house owner has his own set of individual wants, needs, and expectations.

Depending on where you stay, you can expect a 5% to 10% additional cost for each level up in the building standard. You may look at it as a sort of investment. Before handing over the construction of your house to a passive house builder, here are some cost factors you should consider:

  • Reduced insurance and operating costs
  • Transparency in building supply cost 
  • Reduces construction costs if prefabricated passive building components are used
  • Investment assets with great returns over the years lead to a reduction in monthly utility bills and carbon footprint.

I would suggest checking out Plus Render. They can help you build a cost-effective 3D model of the house you envisage with extreme precision. What’s better than giving a shape/form to your ideas?

The designers and architects at Plus Render work according to your preference, providing both simple and fully detailed models. Much like the life-size PassiveHouses, their physical models are innovative and come with a high degree of realism. 

Passive Houses Around the Globe

Here are some Passive House Examples:

 

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Passive House in Germany
  • (The original) Passivehaus, Darmstadt, Germany

It was built almost 25 years ago by German physicist Wolfgang Feist. Along with Swedish scientist Dr. Bo Adamson, he was among the first to refine the principle and develop the design techniques and performance metrics for Passive houses. Feist put his theory into practice during the Autumn of 1990 and constructed the private-terraced housing complex, the first Passivhaus and Europe’s first inhabited multi-family house built according to the Passive House standards.

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Passive House in Ireland
  • Meat House, Ireland

This beautiful, sleek, structurally complex Passive House deviates from the stereotypical Passive House. The design and thermal performance walk hand in hand, all thanks to Architects Peter Legge Associates. They believed they could bring the ecological aspects of Passive Houses to work alongside good architecture.

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Passive House in China
  • The Halo Home, Genglou, China

The Halo Dome was constructed by Simon Law Anthill Constructions using sustainable Timber for British furniture designer Timothy Oulton. The Dome is built to act as a heat sink by using an insulated stone floor and paired with LED lighting to keep the electricity demand low.

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Passive House in Spain
  • FabLab House, Madrid, Spain

The construction of the FabLab house involves a solar panel-covered design. Standing on 3 legs, it offers natural ventilation from the space underneath, which doubles up as a shaded patio. It also features a garden and a rainwater collection system on its roof.

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Passive House in France
  • La Maison Bambou, Val d’Oise, France

This Passive House is constructed using bamboo, and its appearance is designed to change through the folding doors located on both levels of the south facade. The bamboo structure ensures light passes through even when the inhabitants isolate themselves by closing the large openwork.

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Passive House in Mexico
  • Taos Passive House, New Mexico

This house, consisting in 3 bedrooms and 2 bathrooms, was built for a couple in their 60’s. It’s a sustainably oriented, adult cohousing community that has an aging-in-place design that provides flexibility for any health changes that might occur. The interiors are designed with earth pigmented plaster walls, concrete floors, and bamboo casement work.

What Is A Certified Passive House?

Also called Fabric Approach, the main idea behind a Certified Passive House (CPH) is to get the skin of the building right. The CPH ensures a superior building structure while providing the best level of comfort. 

Standing for quality, comfort, and energy efficiency, Passive House is the World’s leading standard of energy-efficient construction. They require very little energy to provide a comfortable temperature all year round.

To be certified as a Passive House, a building has to meet these criteria:

  • Space heating demand – not exceeding 15kWh annually per square meter of useable space
  • Space cooling demand – should match the heat demand while allowing a significant allowance for dehumidification
  • Thermal comfort – not exceeding 10% of the hours in a given year over 25 degrees Celsius.
  • Primary Energy Demand – should not exceed 120kWh annually for domestic appliances per square meter.
  • Airtightness – maximum 0.6 air changes per hour at 50 pascals pressure.

How to Heat a Passive House?

One common misconception surrounding the passive house is that it is self-heated. It’s not. It is built in a way that ensures maximum retention of any generated heat. The heat won’t just materialize; it needs a medium.

Passive houses generally require 90% less energy to heat the building than standard houses, as they are built to optimize thermal gain and minimize thermal loss. Renewable energy sources like solar panels, heat pumps, and geothermal energy can be used instead of extreme heating sources like furnaces and boilers. 

To sum it up, Passive Houses have innumerable benefits, both for an individual and the environment at large. Due to the energy savings, they promise during their lifecycle; they’re considered “green buildings.”

The design and other Passive House details are flexible and customized according to the owner’s preferences. Because of its many benefits, it’s quickly becoming the preferred way of constructing buildings worldwide.