What Is A Passive House?
Why and How Can We Build One?
- Introduction to a Passive House
- The parties who need to be involved in the process?
- What incentives can a homeowner receive from municipalities?
- The Passive House design-build process.
- Passive House costs
- Passive House Certification
- Net Zero Homes
- Passive House renovations
1- Introduction To Passive House
The Passive House movement started in Germany and is currently spreading all around the world because it offers builders and homeowners a chance to reduce their carbon footprint while saving energy.
A Passive House is a building constructed to certain standards and details in order to minimize the building’s energy consumption and its dependency on outsourced energies like hydro or gas. The building can be an apartment building, an institutional building, a commercial building or a single-family house.
There are many programs that lay out standards to construct better and more energy efficient buildings. These include Leed, Built Green, r2000 and Net Zero. Many use rating systems or standards that rate the material source, construction practices and recycling methods. Some of the standards set by these programs are similar. Generally, a Passive House concentrates specifically on a building’s performance including: airtightness, indoor air quality, thermal bridges and insulation values within the building.
If a designer and a contractor follow the required standards, the building will ultimately need to show proof of performance during and after construction which will entail several stages of examination before the building can achieve a Passive House Certification.
In a nutshell, anyone interested in saving on their energy bill while they reduce their carbon footprint can choose to build a Passive House or do a passive home renovation. It might look more costly at the beginning but the investment pays of in no time.
2- Parties Who Need To Be Involved In The Process
When a developer or a homeowner decides to build a Passive House, first he or she needs to discuss the options with a home designer/architect who has some familiarity with Passive House.
In a normal building the designer/architect can take the lead on the design process and hand the final permit drawing which includes the structural drawings to the homeowner/developer to call for tender, but in Passive House there should be co-ordinations between the designer/architect, contractor and city staff and all other consultants from the beginning.
The following is the list of the parties who are involved:
1- Designer/Architect who is familiar with the process and knows how to deal with other parties
2- Energy Modeler (Sometimes the Designer can do this part, sometimes not. Some Designers prefer to leave this part to a third party)
3- Passive House Certifier. This person cannot be the same as Energy Modeler.
4- Building Envelope Consultant. In some cases a Building Envelope Consultant needed to approve the details of the exterior walls.
5- A Structural Engineer who has some knowledge on Passive House and modern framing. It is important to have this knowledge, as the structural elements are a key point in avoiding thermal bridges.
6- Energy Auditor (advisor) to determine the building performance.
Most of municipalities require this stage for new homes. For a Passive House this stage will be more comprehensive.
In addition, the following consultants are required for any constructions regardless of whether it is a Passive House or not. These include: a Survey engineer, a geotechnical engineer, and a landscape designer.
3- What Incentives Can A Homeowner Receive From Municipalities?
In the City of Vancouver a standard thirty-three foot size lot has a certain maximum floor area depends on where it is located and the zoning in that area. Many lots are narrow and by adding the side setbacks to the equation the remaining width might be too limited.
In a Passive House the thickness of the exterior walls and roof will be increased due to the amount of insulation required to meet a Passive House standard requirement. The City of Vancouver has established a specific department within the Development Department to deal with these issues and will allow some relaxations to the zoning. The
North Shore municipalities on the other hand have their own unique approach and projects needed to be discussed on a case-by-case basis, as there are many different requirements.
BC Hydro and Fortis BC have a rebate program for Energy Star appliances and all appliances in a Passive House should be energy star.
4- The Passive House Design-Build Process
There are two stages to consider:
- Pre-construction Stage.
- Construction Stage.
A- Pre-construction.
The idea to build a Passive House could be generated by a well-informed homeowner, developer or builder, or in many cases by a designer/architect.
Regardless of who starts the conversation be sure your designer has the required knowledge to be able to design a Passive House. There are set work frames and standards that must be designed into the Passive Home. Once the client has approved an initial concept, the design will need to move into the modeling stage to make sure it meets the necessary requirements of a Passive House. Co-ordinations between the designer and municipal staff need to take place, so the modeling design maybe tweaked to meet building requirements.
During the concept approval stage, the designer may start conversations with a builder who is familiar with Passive House construction and details. After the building details are discussed and approved the modeling of the project can be finalized.
At this point all construction details need to be discussed, reviewed and perhaps revised by a knowledgeable structural engineer in order to avoid any thermal bridging.
Finally, the designer and builder need to co-ordinate construction details making sure all materials will be available when the construction starts.
B- Construction Stage
After the building permit is issued and the utilities lines are located and the builder is ready to set their work, an initial site meeting between the consultants, contractors and the client is necessary to make sure everyone is on the same page and everyone understands each other’s role and responsibilities.
In this meeting the builder can present his or her expected schedule so that each consultant and sub-contractor know their timelines and expected inspections.
It is a good idea to schedule another meeting after the excavation is done and make a mockup of the wall and roof assembly so each and every trade knows the exact requirements, timeline and details of the project. Assuming everyone knows this can cause many problems down the road.
After the framing is done, the designer or Energy Advisor will inspect the framing to minimize thermal bridging in the framing. If there is an issue now will be the time to explore alternative solutions.
After the insulation and vapour barrier is installed the energy advisor will have to do a door blow test to determine the airtightness of the building. If the building is large or has multi stories tests can be done in multiple stages.
Any deficiencies have to be taken care of at this stage to make sure the building has the desire airtightness. If desired, the designer can request more testing prior to the drywall installation.
After the drywall installation, all cabinets, mirrors and other finishings a second air blow test should be performed.
At this stage the Passive House Certifier would need the reports and documentation to start the certification process. The designer or the modeler can help facilitate this step.
The rest of building inspections related to final occupancy will be the same as any other buildings.
5- Passive House Costs
Even though many people might think building a high performance house will be very costly the reality is it is not. Of course any higher quality product requires more upfront investment. But if you think about the house as a long term investment the Passive House will ultimately require less maintenance and less energy to operate and will therefore require less money in the long run.
Here are some rough approximations of costs you can expect.
- Starting from pre-construction the cost of the designer and structural engineer will be fifteen percent over a regular house.
- The modeling, inspections, door blow tests, and certification will cost minimum of fifteen thousand (check with your designer).
- During construction the extra material won’t be a huge cost but the trained labor to be able to build it will be more than regular construction.
- There are savings on heating and cooling system. The Hrv unit used in a Passive House is more costly than in a regular house but the heating system is way less costly.
- The windows and exterior doors will be fifteen to twenty per cent more.
Overall, the upfront cost of building a Passive House can be as little as fifteen percent above average construction prices. Think of it like buying an electric car, you pay more up front, but you save on monthly gasoline and maintenance charges.
If someone has a limited budget and wishes to build a Passive House, they can reduce the cost of their home’s finishing budget in order to recoup the cost of building a high performance Passive House.
6- Passive House Certification. Why Certify?
The global certifying body for Passive Houses is located in Germany. But there are several identities in Canada who can do the certification of your house.
The designer/architect should take the lead and gather all the reports and documents to pass to the certifier so they have everything they need to issue the certification.
Once a building is certified, the owner will receive a plaque to proudly hang on the wall.
The honour of hanging this plaque is almost like showcasing your Olympic gold medal to your friends, family or the public. It’s an honour to show the achievement the developer and all the team has accomplished.
By doing so, the building will be register on the world wide directory of Passive Houses.
Anyone who is thoughtful about:
- Their investment
- The environment
- And the well being of the building’s occupants
will want to consider the advantages of building a Passive House as its high quality design delivers on all fronts.
7- Net Zero House
A Passive House has three different classes:
- Standard or Classic,
- Plus and
- Premium.
The class a Passive House gets is determined by the dependency of the building on a power grid. A Premium Passive House will have no dependency on a power grid and will be self sufficient for all its energy consumption.
The Premium Passive House is often referred to within the construction industry as a Net Zero building. Not all Net Zero buildings are Passive Houses as a less efficient building can be Net Zero as well.
The difference is the energy production in a non-Passive House building needs to be higher to recover the energy loss of the building. Remember what makes a Passive House unique is that the overall energy loss in a Passive House is minimized so the occupants need less energy to keep the building running. If someone wants to have a Net Zero Passive House the cost of the energy production will be less as well.
8-Passive House Renovations
It is possible to turn an existing building into a Passive House. A program called EnterPHit exists for retrofit projects and refurbishing components of an existing building.
These renovation projects have to go through the same steps as a new construction except it is often much more difficult because the existing foundation and wall insulation all has to be upgraded to meet the Passive House standards. In addition, to eliminate the thermal bridging, windows and exterior doors have to be replaced and the building modeling should make sure the building will perform after final inspection.
If you have questions please forward them to: Home Designer:
Aryo Falakrou at the following email: info@myhomedesigner.com
For more information on Passive Houses visit: passivehousecanada.com
For a free consult on building a Passive House or a Passive commercial building please give me a call: Aryo Falakrou at:
604-929-6696.
