A Semi in Ottawa goes Passive House

Category: Passivhaus

Door #22 – Can we afford Passive House?

At a dinner party a while ago, one of the guests started asking me about what I do, my job and what project I am currently working on. So of course, the conversation turned towards energy efficient buildings and how much more could be done here in Canada. Well, my guest was not agreeing with me – that would be way to expensive to build such high quality buildings and there would be no way anyone could still afford to construct anything. And that whole climate change thing might not be happening anytime soon….

But then he went on to ask me how the building code addresses the fact that Ottawa is in a seismic zone and earth quakes could happen anytime. I was happy to tell him that in 2006 there was a big change in the Ontario Building Code to improve the seismic performance of our buildings in the event of an earthquake. This of course results often in more expansive foundation design, thicker columns and shear walls, more steel reinforcing and so on. And makes the construction more expensive!

The latest update of the Ontario Building Code in 2012 made big changes to address the accessibility of our buildings for everyone – that means for example wider doors, more clearances in barrier free washrooms, more elevators and the new Universal Washroom, that has to be provided in every new building over a certain size.  I think you can agree with me, that this adds cost to the construction.

Strangely this never came up in discussion on construction budgets with any of my clients. No one ever questioned those changes and the necessity of adjusting the design and construction of our buildings to make them safer or more accessible.

Which tells me that if we as a society decide to improve our build environment – we can do it. So if we accept that climate change is here and happening then the question is not can we afford passive house – the question really becomes can we afford NOT to do passive house.

Today a short video, where Wolfgang Feist himself gives you an overview on the passive house concept.

Door #15 – No heat

When we came home from work yesterday our boiler had stopped working. It was supposed to go down to -12 last night and the house was starting to get cold. We have radiant heat throughout and the floors felt freezing. The temperature in some of the corner rooms fell quickly down to 17-18 degrees. Thankfully we have a Danish wood burning stove, that kept us warm all night – and right now we have already someone here to fix the problem.

But what does this have to do with passive house? Well if we would have been living in one, it wouldn’t have been a big issue – the house would have held the temperature over night. And with a family of 4 living in it, cooking, having the lights on and a sunny day coming up we probably would have been fine for a few days.

Door #13 – Like a Tesla

I saw a great photo posted on twitter by Monte Paulsen of RDH Building Science  which I want to share with you today.


From his post: “Next time someone brags about their “passive design” building that’s “just like a Passive House” consider these two electric vehicles…”

I certainly plan to have my project certified.


Advent Calendar


advenrWell, I have been very quiet on this blog and it has been a long time since my last post – somehow I lost momentum and my excitement about my project was affected from the process of getting a demolition and building permit: I am still trying to get all the utilities disconnected, very lengthy process, I had to get a hazardous materials report done, I got word from the city that my parking spots were not compliant with the zoning, so I need to make some changes to the design – thankfully I am my own client – so I can only get mad at myself to have missed that.

But it is almost December and we had the first snow fall already here in Ottawa. Last Sunday was  the first advent with one candle lit on our “Adventskranz”, a German custom to mark the four Sundays before Christmas. In the past we also always had an advent calendar for my kids – often home made with little presents or candy. Now my kids are older – so they are out of luck this year. But I will have one for you – the first Passive House Advent Calendar, with 24 posts until Christmas. Everyday you will learn something about my project or passive house – I hope it will be interesting for everyone. And it will force me to overcome my writers blog…

A Logo and Comfort

My daughters ringette team is looking for sponsors for the upcoming season. So I decided to be a sponsor and get my logo on their shirts, that they will be wearing from now on until March. Hopefully that will get me some additional attention. But what logo?? I spend a day with Illustrator and came up with one.


I got some input from my friend who is coordinating the fundraising and is not an architect or designer. Which is probably a good thing. She was wondering if I could add an explanation of Passive House to the logo in 3-5 words. Because there are a lot of people that don’t know what that means. HA! Not that easy. I asked if I could get half the shirt to explain that a Passive House is a super-insulated building, very airtight, you can basically heat it with the equivalent of your toaster, it has triple glazed windows, it doesn’t need an air-conditioner, it is quiet, it provides comfortable living throughout the entire year, it has superior air quality, especially beneficial for people with allergies, it is affordable, it is the most rigorous green building standard in the world, it can be applied for renovations….well by now I might have covered the entire t-shirt… And even for the sake of saving the planet – every sponsor gets the same amount of space.

While trying to come up with a three word definition for Passive House, one quality of this building standard came up most: COMFORT. And this might get your attention even more than energy efficiency: A Passive House is really comfortable to live in.

I will quote British architect Elrond Burrell and his post Passivhaus; Comfort, Comfort, Comfort, Energy Efficiency  on his excellent blog to try to explain this.

“….energy efficiency is actually only part of passivhaus. People don’t often realize that the Passivhaus Standard is also a rigorous comfort standard that ensures a building is free from drafts, free from cold spots, free from excessive over heating and provided with a constant supply of fresh clean air. And it does so with the minimum amount of energy.”

The standard for airtightness (0.6 air changes per hour) makes the house completely draft-free. Since the windows are so good, designed to have interior surfaces that are within 3°C of interior temperature, there are no cold drafts off the glass like there are in most conventional houses. (That’s why typically in your house duct vents are placed under windows, to counteract this). It also means there are no cold spots.

“Windows that are much colder than the room temperature are also uncomfortable because we experience them as cold spots. The glass acts like a radiator in reverse, drawing warmth away from our body. And the reverse is true in summer; the glass acts like a radiator adding unwanted heat into the room. The effect of this is a band of discomfort around the perimeter of a room where convection currents and cold spots make the space too uncomfortable to enjoy and make use of.”

Of course in such an airtight building you need to provide fresh air.

“The Passivhaus standard requires that the ventilation system provide 30m3 of fresh air, every hour, for every person in the building. This can be provided all year round by a mechanical ventilation system with heat recovery so there are no uncomfortable cold draughts from the ventilation. Alternatively it can be provided by ’natural ventilation’ in summer and mechanical ventilation with heat recovery for the rest of the year.”

This is one of the reasons I really like Passive House. Everyone can design a net-zero building by adding enough solar panels on the roof or adding an expensive geo-thermal system. But the house might still be drafty, have cold spots in the winter and overheat in the summer due to too many south facing windows.

Or imagine you renovate your house and add a nice new extension for a family room in the back. I came to the house of a friend of mine for the first time, they live in a very nice neighbourhood in Ottawa, they renovated their house, upgraded the kitchen and did an addition in the back. I really liked it, I walked around, looked at every thing (like architects do) and commented on the great new family room with a window seat overlooking the backyard. She said: “Yes, it is great, but we can’t really use it in the winter, it is too cold next to the window.” Well that is terrible! And really shouldn’t happen. If people ask me how expensive it is to build a Passive House, I like to bring up this example, because that really is expensive to build a space that is not comfortable to  live in year round.

And if you happen to see a ringette team with my logo at an arena around Ontario, why don’t you ask the girls if they know what a Passive House is? And if you are willing to sponsor the team let me know, there is still room on the shirts as I didn’t add any explanation to my logo.




What is this?
Cross Laminated Timber or short CLT has been developed in Europe in the 90s.  They are solid wood panels for walls, floors and roofs, massive plywood if you like.  Each panel consists of several layers of lumber boards stacked in alternating directions, glued and pressed to form a solid, straight, rectangular panel. They are delivered on the construction site including door and window openings and I have been told, that my building can be assembled in a few days. But there is a lot of concern out there, that it is expensive…
So are there advantages to traditional stick build walls?

One of the challenges in Passive House construction is the required airtight construction. To achieve this with built walls built from wood studs, a lot of things have to happen to get it airtight and the wall consist of many layers, which can get complicated at the junctions of wall-roof or wall-floor.


Compare this to a CLT wall assembly: the wood does a lot of things: it is the airtight layer, the vapor retarder, the interior finishes and the installation layer and reduces the number of layers that have to be put together.


Add the simpler wall assembly to the speed of construction – I really believe that there should not be any additional cost to the project due to the CLT construction.




So is this only for single family homes and smaller projects? Definitely not, there are built examples using CLT, mostly on the West Coast. If you are interested there are two of my favorite projects described by a former Carleton professor in this article.

The Design

Designing is sometimes easy and fun and sometimes very hard. In university we spend long days in studio working on our projects, usually we didn’t sleep at all the night before the deadline. In the morning we had to hang our drawings / plans / sketches / models for the dreaded critique by our teachers. Then you had to present your design  and it felt like turning your inside out in front of everyone, all that in a very tired and exhausted state of mind. Some of the professors were nice and understanding, tried to get something positive out of any project.
My favorite prof was a chainsmoker, his burning cigarette in his fingers, he was pointing out things over the model with the ash becoming longer and longer – until someone in the last minutes protected the precious work, often made out of white cardboard,  holding a small plate under the falling ash. We were too terrified to point it out to him.
One of the less supportive professors asked one of my friends after her presentation:”Can you cook?” – she wasn’t sure what to say, as it was in no way related to her work, so she hesitantly said:”Yes, a bit.” – His answer:”Why don’t you go home and cook!”

I have been working on the design for some time now, and want to share it here with my readers – hoping for some feedback….

Each side of the semi will be a three bedroom house with a nice kitchen / dining / living area on the ground floor. I have to stay within the setbacks of the zoning and provide one parking spot per unit. Those take up a lot of space in the front. I am lucky as my backyard is South facing, ideal for solar heat gain during the winter.






Can you see yourself moving in? Sorry for only showing the floor plans – elevations and 3D views to follow later. Comments are welcome – already got some regarding my angled walls….might think about that – and by the way: I can cook!!

What is a Passive House?


Trying to explain Passivhaus in a few sentences is probably not that easy, but I will start with this post today, to highlight some of the fundamental ideas behind this building standard. It is similar to the insulated thermos shown in the picture which helps to keep the coffee warm passively. Contrary to the coffee machine that requires constant active energy input.

There is a lot of talk about passive solar design, which really isn’t a new idea. Already the Greeks 2500 years ago had a building code requiring southern orientation! And a greek philospher wrote in 400 BC : “only primitives and barbarians lack knowledge of house turned to face the winter sun”. And who wants to be called a barbarian….


One of the first passive house was built here in Canada in the 70s in Regina: The Saskatchewan Conservation House by architect Harold Orr. It even won the 2015 Pioneer Award by the Passive House Institute. Very cool fact.

Passive Houses combine superior comfort with very low energy consumption. And how is that achieved?

  1. super high level of insulation for walls, roof and basement slab
  2. triple glazed windows with insulated frames
  3. thermal bridge free design
  4. an airtight building envelope
  5. ventilation with high efficient heat or energy recovery

That reads like an easy enough recipe?  If you follow through with this, you ensure minimal energy demand: A Passivhaus with 100 square meters could be kept warm with a 1000W toaster, even on one of our cold Canadian winter days. And as it feels like 32° C outside with the humidex today- what about staying cool in the summer? Insulation does not only keep the warm air in the house, it also keeps the heat out, and good shading elements will help to keep the house at a comfortable cool temperature.


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