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Some more details on this list of things that @CityofVancouver has done to incentivize passive house projects.
cc @DianaUrge
cc @DianaUrge
Thick wall exclusions:
In Vancouver the floor area of a project is measured to the OUTSIDE of the wall.
The total amount of floor area that you can build on a given lot is capped in the zoning, so most people want to build to the max size allowed.
In Vancouver the floor area of a project is measured to the OUTSIDE of the wall.
The total amount of floor area that you can build on a given lot is capped in the zoning, so most people want to build to the max size allowed.
When the floor area caps were written into the zoning the thickness of a typical wall was only 6".
In the ensuing years the walls have gotten much thicker.
Our typical passive house wall for a single family house is 17" in total.
In the ensuing years the walls have gotten much thicker.
Our typical passive house wall for a single family house is 17" in total.
This can mean that several hundred square feet of area is tied up just in the thick wall.
If the city doesn't grant a 'thick wall exclusion' then PH clients are paying a huge penalty for going green.
Hence: step 1 is to adopt a thick wall exclusion so there's no penalty!
If the city doesn't grant a 'thick wall exclusion' then PH clients are paying a huge penalty for going green.
Hence: step 1 is to adopt a thick wall exclusion so there's no penalty!
Setbacks and Height:
Because the walls and roof of a PH project are thicker, those extra square feet need somewhere to go (especially on tight city sites).
We now get relaxations to make PH projects a bit taller, and a bit longer so that we can fit those thicker walls in.
Because the walls and roof of a PH project are thicker, those extra square feet need somewhere to go (especially on tight city sites).
We now get relaxations to make PH projects a bit taller, and a bit longer so that we can fit those thicker walls in.
Floor Area Incentives:
Thick wall exclusions are needed to remove the biggest barrier, but they only put PH projects on par with code-minimum buildings.
If a city wants PH projects to scale up, then we need to do more than remove barriers, we need incentives (extra floor area)
Thick wall exclusions are needed to remove the biggest barrier, but they only put PH projects on par with code-minimum buildings.
If a city wants PH projects to scale up, then we need to do more than remove barriers, we need incentives (extra floor area)
Massing and Design Guidelines:
Passive houses work best (and are cheapest) when they have 'compact massing' i.e. not too many bump outs, jogs, wings, and other complicated forms that increase the area of the exterior walls.
Passive houses work best (and are cheapest) when they have 'compact massing' i.e. not too many bump outs, jogs, wings, and other complicated forms that increase the area of the exterior walls.
Unfortunately a lot of city design guidelines incentivize 'articulation' where the envelope of the building is pushed in and out all over the place.
The rules often push 'wedding cake' shapes where the upper floor are stepped in.
All of these make PH harder.
The rules often push 'wedding cake' shapes where the upper floor are stepped in.
All of these make PH harder.
Passive house projects can be articulated, but it tends to be with items like balconies and awnings that aren't part of the energy saving 'thermal envelope'.
Design guidelines and zoning need to support this new approach.
Design guidelines and zoning need to support this new approach.
Planning Staff and Building Inspector Training:
After your team has learned how to do PH projects, and you have a client onboard, then you still have to navigate through a complicated permitting and approvals process.
Plan checkers and building inspectors need to know PH basics
After your team has learned how to do PH projects, and you have a client onboard, then you still have to navigate through a complicated permitting and approvals process.
Plan checkers and building inspectors need to know PH basics
For instance, the way that a PH approaches air tightness and vapour control might be very different from a typical Vancouver house.
The new wall assembly has to get through permit review as well as pass all of the inspections in a timely manner.
The new wall assembly has to get through permit review as well as pass all of the inspections in a timely manner.
Vancouver has done a good job of training staff on the basics of Passive House design and the process is getting smoother with every new project.
Financial Incentives:
A passive house building makes a lot of sense because the investment in better windows and more insulation starts paying dividends on day 1.
The extra design and certification costs, however, can be a barrier to having clients take on PH projects.
A passive house building makes a lot of sense because the investment in better windows and more insulation starts paying dividends on day 1.
The extra design and certification costs, however, can be a barrier to having clients take on PH projects.
It's helpful for early adopters if there is financial support to offset the increased costs for design, energy modelling and certification.
On a single family house these costs might be ~$10k.
On a single family house these costs might be ~$10k.
The newly formed Zero Emissions Building Exchange @ZEBxchange is an organization that plays a variety of support roles, but (most importantly to designers/builders like us) it administers incentive funds that can help cover the cost of design and certification.
So, in summary:
Support your early adopters!
Make it easier and cheaper to do PH vs code minimum!
If you do these things you'll see the same rapid uptake that we've had in Vancouver.
thanks!
Support your early adopters!
Make it easier and cheaper to do PH vs code minimum!
If you do these things you'll see the same rapid uptake that we've had in Vancouver.
thanks!
