
What is a Passive House?
The Passive House concept originates in Germany and is the leading approach for high-quality, healthy and sustain... 07.03.2021 architects doors ecowindows energyefficiency knowledge passivehouse sustainability windows
Passive House design is the ultimate solution for energy-efficient building as it requires none to very little active heating. But how does a Passive House work, and what components are needed to build it?
What is a Passive House?
The Passive House concept originates in Germany and is the leading approach for high-quality, healthy and sustainable building. The energy-saving capabilities of a Passive House exceed common building standards by far - not only here in New Zealand but worldwide.
To be called a Passive House, a residential or commercial building must generate most of its heat passively, without active heating. Instead, it uses natural energy sources, predominantly the sun and the heat that human occupants and household appliances create.
The goal is to create an ultra-low energy building that provides a high comfort level and healthy living environment while using very little heating and cooling energy.
A certified Passive House has exceptionally high building standards. The house uses a combination of high-quality building components and techniques, such as high insulation, an airtight building envelope, ventilation with heat recovery, thermal bridge-free construction and high-performance windows to create a controlled internal environment.
This construction method helps generate stable internal temperatures of cosy 19-22°C all year round, day and night, while the outside temperature varies and can drop well below 5°C in winter.
The key - Excellent insulation
Maximum thermal insulation is the key factor for an efficient Passive House. Therefore, Passive Houses are packed in very thickly.
The insulation protects the house against the weather's effects and reduces the risk of overheating on hot summer days, while the inside stays dry and warm all year round. Simultaneously, the rooms are protected against moisture damage from condensation or mould due to constant and controlled air movement.
The importance of high-quality glazing
Typically, windows are the weakest part of a house because they can generate high heat loss rates. It is crucial for a well-functioning, energy-efficient building that the windows and doors are equipped with equally high insulation as the exterior walls.
This is why Passive Houses are built with high-performance double- or triple-glazed windows and energy-efficient doors that help to keep the precious heat inside and moisture outside by avoiding any air gaps.
ECOWINDOWS high-quality, double-glazed windows have two thermally insulated window panes with Low-E (low-emissivity) glass and a hermetically sealed space between them. This space reduces the heat loss significantly because it is filled with Argon, rather than air, a noble gas with low heat-conducting properties. Our triple-glazed windows are made of three glass layers, each covered with a Low-E coating and an Argon filling in between them, reducing heat loss even further.
Using the power of the sun
Overall, the construction has to be thoroughly planned to allow optimal usage of solar power. The trick is to allow plenty of sunshine to enter the house when desired (winter) and easily keep it out when needed (summer).
Therefore, installing as many north-facing windows as possible to catch a maximum of sun rays in the colder months is recommended. Further, the building requires a reliable shading system made of blinds or other fixed shading structures, such as roof overhangs, or similar, to protect against overheating on hot summer days.
Eliminating thermal bridges
A Passive House must be free of thermal bridges, also widely known as cold bridges. These bridges are locally limited areas in the thermal envelope where heat exchange occurs. They exist because heat is always looking for an escape and takes the path of least resistance. In addition to heat loss, thermal bridges can also generate condensation and mould.
Thermal bridges often occur where components meet and materials form a solid connection from exterior to interior surfaces. This is why it is essential to carefully plan all corners, edges and junctions before building the house.
Airtightness - Creating controlled conditions
It is crucial to regulate and control the airflow in the house. To do so, the building envelope of a Passive House must be airtight. Being airtight does not mean that the building must be completely sealed and locked without any fresh air: airtightness only works in combination with a controlled ventilation system (read more about ventilation below).
You can create airtightness by applying one continuous and impermeable envelope that seals the whole building. It is crucial to meticulously plan the airtightness of the construction first because only what is thoroughly planned by the designer can later be made airtight by the builder.
The so-called blower door test can measure and prove the airtightness of the building envelope. The test device consists of a covered metal frame, a fan and a pressure gauge. The device is then clamped onto a window or door to test whether more air is escaping through the joints than is permitted. A Passive House must achieve no more than 0.6 ACH (air changes per hour).
Ventilation
Passive Houses do not rely solely on traditional heating systems such as oil, gas or wood. A sophisticated Heat Recovery Ventilation system regulates and controls the house's airflow, provides constant fresh air and retains heat. This method helps to create a healthy internal environment. The air exchange works very slowly and quietly and is therefore not noticeable, yet very effective.
Even though the Passive House system does not require additional ventilation next to the HRV, it is still possible to manually open windows and doors to ventilate the rooms. However, this will allow the external environment to enter the house. As a result, the internal temperature could change, and moisture, noise and pollutants, such as pollen and fine particles, can enter the building.
Conclusion - Healthy and comfortable living
A Passive House's goal is to create the lowest possible energy usage while providing a high comfort level and a healthy living environment.
The additional technical efforts are likely to result in slightly higher initial design and construction costs for a Passive House than those of a regular building. However, considering that energy prices are on a constant rise and that the finished building will create a much healthier living environment, this higher investment will pay off in the long term.
The Passive House building approach is also in line with New Zealand's target to reduce greenhouse gas emissions. This way, Kiwis can make a smooth transition to a low-emissions future of building sustainably to protect our natural resources for future generations.
Visit our showroom
ECOWINDOWS offers a wide variety of European windows, doors, shading solutions, and ventilation systems, all suitable for Passive House building's high standards and requirements.
Our showroom in Hamilton exhibits a comprehensive collection of our broad product range. We offer you the opportunity to discuss your building project's requirements with our friendly staff and, most importantly, to see, feel, and experience the advantages of our sustainable building solutions for yourself.
If you would like to learn more about our components for Passive House building or discuss your building project, please do not hesitate to contact us today. We look forward to hearing from you!
About ECOWINDOWS - Expertise for Passive House components
ECOWINDOWS is a pioneer in the field of Passive Houses. In 2011, we manufactured New Zealand's first certified Passive House windows. And in 2012, the first-ever Passive House in New Zealand was built with our high-performance windows and a controlled ventilation system that helps keep the house dry, warm and comfortable all year round.
As a member of the “Passive House Institute New Zealand” (PHINZ) and the “New Zealand Green Building Council” (NZGBC), ECOWINDOWS contributes to the mission of creating healthy and highly energy-efficient homes for all New Zealanders.
If you would like to learn more about Passive Houses, eHaus, a recognised expert in New Zealand Passive House design and construction, has some great additional resources on its website which answer more questions about Passive House design.
Setting a new standard for New Zealand
We believe that it is about time to shake up the building industry, change expectations, and set a whole new standard for housing in New Zealand. To make a positive change in the building sector, it is essential to utilise only building solutions that deliver outstanding performances.
High-quality and carefully manufactured European windows and doors achieve the best energetic results for your home. These products are made with decades of experience in energy-efficient building in Europe where for a long time, high-quality windows are most commonly used.
Germany’s and New Zealand’s building regulations – a comparison
As a world leader in manufacturing high-performance windows, Germany has a long history of stringent and rigorous government regulations, the so-called EnEV law. This law outlines the requirements for newly built and existing homes' energy efficiency. The principles focus on the high quality of insulation and low heat loss rates to ensure houses are kept warm and cosy, without generating sky-high power bills.
On the other side, the New Zealand Building Code sets the performance standards that all building work must meet. [1] The Code describes performance criteria and sets the standards for moisture control, energy efficiency features, and others for all sorts of buildings, from residential to commercial and industrial constructions [2]. However, the Building Code is mainly performance-oriented. It defines how a building must perform in its general use rather than describing how it must be designed and constructed. [3]
At first glance, the German approach seems to be very similar to the one in New Zealand. But, looking at the numbers, it becomes evident that the German law requirements are much stricter than those of the New Zealand building standard.
Looking at the numbers
The effectiveness of windows is usually calculated internationally as U-value. However, in New Zealand, the R-value is still widely used. In contrast to the desired high R-value, a lower U-value indicates better performance and insulation. The R-value is the reciprocal of the U value and vice versa (R = 1/U and U = 1/R).
The German EnEV law regulates the required U-value rates for each area of a house, including the windows, which play a crucial role in energy-efficient building. Hence, it is only allowed to install double-glazed windows with a low U-value of 1.30 in German houses. This rate is a minimum requirement. Triple-glazing can enhance performance even further.
In comparison to that, the BRANZ House Insulation Guide specifies the R-value for a high-performance window in wood or PVC with R 0.48. [4] To compare this value with the German requirements, we have to convert the R-value of 0.48 into the U-value, using the appropriate formula U = 1/0.48. The result is a U-value of 2.08.
This means that the minimum requirement for a German window (U 1.30) exceeds the value for a high-performance window in New Zealand (U 2.08) by far. Remember: a low U-value indicates better performance and is therefore desired.
Building houses with comparably low requirements means that a lot of the house's heat is still lost through the windows despite the reasonable efforts and building regulations.
Building better
We believe that it is vital to utilise windows that match the German market's high standards and strict requirements. This approach allows us to build dry, warm and healthy homes for everyone here in New Zealand. However, double- and triple-glazing of windows is only one part of a comprehensive heat-management system. Other measures include the installation of modern ventilation and shading systems.
No matter your requirements, ECOWINDOWS offers wholly customised solutions for new builds and renovations alike. If you want to find out more about our work and product range, please do not hesitate to contact us today. We look forward to hearing from you!
As the year is coming to an end and the holiday period approaches, we wanted to take the opportunity and say A BIG THANK YOU to all of you, our valued clients, partners and supporters. We are immensely grateful for your ongoing support and trust throughout this year.
And, what a year it has been
2020 was particularly challenging for all of us. The ongoing Coronavirus pandemic continues to create significant uncertainty all around the world, for individuals and businesses alike. Our thoughts are especially with our friends and partners in Germany whilst they are going into another complete lockdown over the festive season.
Speaking for ourselves, the great New Zealand lockdown in March 2020 put many of our projects unexpectedly on hold. And, in the following months, we had to deal with further disruptions caused by the pandemic. Most prominently we faced widespread delays in international deliveries, due to worldwide border restrictions and logistics being literally out of control.
However, our team stayed positive, and we went through all of this together, with confidence. Despite all the challenges, we finalised many exciting projects in Coromandel, Taupo, Auckland, Central Otago and the Waikato, to name a few. We are also tremendously grateful for the generous support from the New Zealand government in these hard times.
We have opened “The Barn”
The Barn is our newly-built, comprehensive showroom in Hamilton and one of our most notable achievements this year. It features a wide selection of high-quality double- and triple-glazed tilt and turn windows, modern entry doors, smart shading solutions and more. A visit of our showroom is an excellent opportunity for you to get a first-hand experience of our exclusive product range. Please get in touch with us if you would like to visit us. We would be happy to show you around.
ECOWINDOWS is growing
This year we welcomed two new employees in our team. They are operating in the areas of Operational Management and Marketing. This steady growth allows us to provide an even better service for our clients and partners. And ECOWINDOWS continues to grow. If you are interested in joining our hard-working and dedicated team, we would love to hear from you.
What’s waiting for us in 2021?
To keep it short: A lot!
ECOWINDOWS is exceptionally busy, with a high number of exciting projects already in the pipeline for the coming year. We are also looking forward to strengthening existing, and building new partnerships in 2021 in order to provide New Zealanders with more sustainable, healthy and comfortable homes.
Christmas Holidays
Our office will be closed from Monday, 21st December 2020 and we will re-open on Monday 4th of January 2021.
Should you have any questions in the meantime, please do not hesitate to contact us. We are happy to assist you.
Give us a call: (07) 825 8172
Or send us an Email: [email protected]
We wish you a Merry Christmas and happy holidays and look forward to seeing you again in 2021.
Thomas, Bjorn & the ECOWINDOWS Team
Due to the wide spread of COVID-19 globally, New Zealand is still experiencing major international delivery delays. This situation is aggravated by insufficient freight capacity and various international government restrictions. Judging by the current situation, with many countries around the world suffering a second wave of the outbreak, with high numbers of cases and several weeklong lockdowns worldwide, we regrettably expect this to continue for some time.
In addition to that, RNZ reported this week that Ports of Auckland is currently experiencing a major backlog of imports and is struggling to get slots available on its wharf for arriving vessels. Ports of Auckland General Manager of Communications, Matt Ball said container ships could be waiting between 10-12 days to get into the port. Although they are working hard to ease the situation, this problem will unlikely be solved before the end of this year.
Please consider this situation carefully when organising your building project and plan ahead. As international freights and containers are experiencing high volumes and the delivery timeframes are much longer than normal, we encourage you to not leave your order to the last minute. Be prepared and know exactly when you want your order to be delivered with plenty of time ahead. This will allow you to avoid delivery delays and disappointment.
If you have any more questions, please don’t hesitate to get in touch with us today!
Have you ever wondered how our windows are made?
This impressive behind the scenes video shows how our wooden double- and triple-glazed windows are manufactured with precision, years of experience and the highest skills in craftsmanship. Döpfner Fenster, with its headquarter in Germany, Gerolzhofen is our long-term partner and main supplier for our exclusive ECO WOOD and ECO WOODALU windows.
The wood from our timber windows is harvested exclusively from certified, sustainable forestry in Bavaria, Germany. Our wooden windows are made of pristine and robust spruce, larch and oak timbers, with multilayer laminated profiles that provide the best quality and outstanding durability.
One of our feature projects in Queenstown. What an amazing house and what a stunning architecture. Thanks to Team Green Architects for giving us the chance to contribute to this amazing piece of architecture!
The Passive House Institute of New Zealand has put together some great stories from satisfied owners of passive houses. Some of them are of course satisfied owners of our windows too. We would like to present some of these projects here...
#newstandardnz #phinz #betterthancode
The Passive House Institute of New Zealand has put together some great stories from satisfied owners of passive houses. Some of them are of course satisfied owners of our windows too. We would like to present some of these projects here...
#newstandardnz #phinz #betterthancode
The Passive House Institute of New Zealand has put together some great stories from satisfied owners of passive houses. Some of them are of course satisfied owners of our windows too. We would like to present some of these projects here...
#newstandardnz #phinz #betterthancode
Since we are currently not allowed to welcome you personally we'd like to invite you to take a short stroll through our new window barn. This barn style showroom is unique in New Zealand and has all of our different window series as well as other state-of-the-art building products on display. Once we're all back to (almost) normal we invite all our customers, friends and partners to enjoy this great place of sustainable building solutions. Until then we wish you all the best & stay safe!