And what is the difference between passive house, net zero, and building codes?
What is a passive house all about? is a question we hear often.
In this article, we explain the programs and standards (like Passive House, LEED, Net Zero, Energy Star, etc.) that are out there for high-performance building and construction.
All these are independent standards set by organizations to achieve lower energy use in building design. Each system has its own set of criteria, targets, points, and focus to achieve the goal of less energy use in buildings. Each system also has a process to verify that you are meeting the requirements in order to receive your certification, stamp, seal, or official status. In order to receive your certificates, you usually need a certified designer on the design team and significant paperwork and testing.
Uncertified Passive House built into the hill to take advantage of the cool earth temperatures! The large overhangs protect the interior spaces from overheating through the big south windows. It uses a combination of ICF and prefab panels. And boasts an R100 roof with a green roof planned to further blend into the landscape.
Passive House
Also known as Passivehuas, this energy standard orginated in Germany for buildings. It is a voluntary standard that focuses on a higher performance building envelope, one that uses higher R-values for walls and roofs, triple glazed window asssemblies, and super air tight construction.
It pairs this with passive strategies such as natural daylighting, passive solar heating, and natural ventilation. It also has the added benefits of quiet spaces, better air quality, and lots of daylight.
“Passive House is the building standard of tomorrow. It shows you how intentional design adapted to the site and simple improvements over our minimalist building standards can chop 85% of utilities.”(credits: Passive House Canada)
Net Zero
Net-zero is a way to say I am producing as much energy as I am using. It is a worldwide standand that is focused on buildings being carbon neutral and reducing greenhouse gasses due to energy production.
It can also be misused as I am going to use as much energy in my building and as long as I put up a solar panel to compensate, I meet net zero requirements. I may be biased, but be wary of “net zero ready homes”. It simply means the roof is designed to hold solar panels in the future.
There is some extra conduit in the walls for future electrical wires, and the heating, colling and ventilations systems (sometimes) are designed to be all electric. (credits: Canada.ca)
LEED
LEED is a well known building standard. It was developed by the non-profit U.S. Green Building Council (USGBC). It stands for "Leadership in Energy and Environmental Design." The certification orginally focused on larger commercial buildings, but since it's debut the council has created specific certiifcations for existing building, homes, and neighborhoods.
Unfortunately, it started a greenwashing skepticism as its buildings in the early days since it's buildings did not result in any energy savings. There are some pros and cons to the building standard and it has it's critics. Despite that, LEED does provide a framework for green building and operations. Outside of the U.S, Canada is one of the top territories in the world for LEED certification. Canada Green Building Council now oversees all certifications of projects in our country. (credits: CAGBC)
This pretty good house uses 4" of exterior insulation with a 2x8 stud wall filled with batt insulation.
Energy Star
Energy star ratings are a common measuring and testing program for windows, appliances, lighting, etc. Energy Star is based on individual components of buildings but does not take into consideration the whole building combined.
I don’t have all the details about the certification but it is derived on meeting the building code requirements. (credits and to learn more visit: Energy star)
But you may say, "The building code sets out an energy standard. Isn't that good enough?"
Well, the code is the bare minimum required by law. So if that's what you want to do, you can. But is the bare minimum what you want to live in, or what do you want to build something better for the next generation?
It should also be noted here that although there is a code minimum, much of the energy performance of a house is based on its air tightness, which is based on how well something is constructed. There is no testing required by the Ontario Building Code to verify the air-tightness of a home or building, so you would never know if you meet that target.
There is a cost premium to upgrading, and sometimes, the return on investment is hard to justify while our energy costs in Canada are still relatively low.
Blower door test to determine air tightness of the building envelope before closing in the finishes.
That's why, in our office, we often work with home and building owners who want "near passive" or "a high-performance building." We recognize that there are limitations to going all the way, costs, buildability, etc.
We've also found a sweet spot and call it High Performance. It's also closely related to "Pretty Good House," which is another program out there.
Pretty Good House
This program takes a common sense, cost-effective approach to high-performance building designs. It provides a framework to create better home. (credits: https://www.prettygoodhouse.org/
Here is a chart with some basic comparisons:
| Certification | R-values of walls | U-values of windows (3) | Air Tightness (ACH) (1) | Energy per m2 of floor area per year (2) | Cost premium to code minimum | Verification |
| Ontario Building Code | R24 | 0.28 | 2.5 | 150kwh/m2y | 0 | No |
| Energy Star | NA | Different scale | undefined | NA | 0 | Yes |
| Net Zero | R40 | 0.25 | undefined | 0 | Varies wildly | Yes, for certification |
| High Performance Or Pretty Good House | R40 | 0.15 | 1 | 120KWh/m2y | 5% | No, voluntary |
| Passive House | R60+ | 0.12 | .06 | 10% | Yes, required for certification |
(1) What is air tightness?
This is the rate at which your house leaks and has holes in the wall assemblies. And you can imagine if your house leaks air it is also leaking heat (IE energy). ACH is air changes per hour. This is the measurement of air tightness and refers to the number of times in an hour your house air leaks out the creaks! Older house ranges anywhere from 6-12 ACH.'
(2) Energy reduction sources
Green Building Advisor - See their blog about "Does a Passive House Use 90 Percent Less Energy?"
The Conscious Builder - See their blog about "SUSTAINABLE BUILDING STANDARDS: WHAT DO THEY MEAN AND HOW DO THEY COMPARE?"
125% more energy used in code minimum'
(3) Note for U values: the smaller the number, the better the performance.
This uncertified Passive House is under construction using prefab panels. It has an R60 wall and an R80 roof!
In Summary
Most of the building programs require fees and paperwork in order to earn your certification. We understand that not every homeowner or building owner wants a certification, stamp, seal, or official status.
Cultivating Green is one of our core values at Veld architect. We are committed to making responsible decisions to improve building design and reduce energy use in our buildings. We help clients find the right balance between costs and efficiencies.
We do not have any certified passive house designers in-house, but many of our staff have built their own passive houses and have completed the training. Also, note that we didn't talk about "off-grid" design. That's a whole different level! And we'll define carbon-neutral materials for those hardcore fans in a separate blog here!
So now you know more about Passive House, where do you fit into this spectrum for your house or building?
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