Flatrock Passive House: A Passive House in Newfoundland

Who would have thought that putting a wood stove into a house could be so complicated!!!  I know I didn't.  It really started when we decided to put the wood stove more centralized in the home.  Running a chimney inside the building envelope is much more efficient than running it outside the thermal envelope from many perspectives.  The chimney will develop draft much more quickly if the chimney runs inside the envelope, and there is less thermal bridging to the outside. Have a look at the stove in question below, the Walltherm gasification boiler ( www.waltherm.ca ).  The picture below illustrates the back of the stove. It has a sealed combustion chamber with an air intake at the bottom that is ducted to the outside.  It is a closed combustion system.  This is a necessity in a passive house for several reasons 1.  Draft in the chimney requires air to be pulled into the stove.  In a super tight house, the draft necessary to keep the...

The National Building Code of Canada is a prescriptive standard.  A prescriptive standard is one where instructional information is provided to ensure that the components are built to ensure longevity, safety and health of the occupants.  The end game is not necessarily energy efficiency.  For example, 2x6 stud walls 16" o.c. with double headers over windows is purely prescriptive.  We need prescriptive standards but we also need a way to ensure that homes are also energy efficiency.  Here's where performance standards are important.  A performance standard is one where the performance of a building as a whole is important and can be measured and compared against a set of standard metrics eg. air leakage, thermal performance, energy usage.  Mixing the two ensures that a home is energy efficient, safe, healthy and comfortable. To ensure that structures are more efficient, Canada introduced the National Energy Code for Buildings.  This code is pre...

We have been working to further refine the elevations to meet our likes/dislikes.  Since the last drawing set, we have added windows to the garage, a sliding barn door on the garage,  taken a window out of the mechanical room, changed the window configuration on the west elevation and added a trellis shade structure to the south elevation.  At the bottom of the page you'll see a different window configuration for the west elevation.  Having those windows on the west side is really necessary since the floor plan has the staircase going up on that end.  If those windows weren't there the staircase would be dark and uninviting.  In the last image, the trellis shade structure has been moved upwards to account for an outswing door.  Here it is:

Heating a home which has such a small heat load can be a little more complicated then you think.  Ultimately I think it depends on many factors including questions of the energy source, sustainability,  purpose, etc. You may think "use a heat pump and have it over with!".  But what about other options? Can it be done more efficiently?  Can you plan for less dependency on the grid?  Can you minimize energy to the point where solar voltaic panels become your route to net zero energy? The nice thing about a Passive House is that you can't build a passive house unless its modelled.  Passive House is a performance standard not a prescriptive one.  A prescriptive standard, like the National Building Code of Canada, tells you how to build a structure to maintain safety, longevity and the health of the inhabitants but it doesn't tell you anything about the performance of the building.  It tells you about the performance of the whole package, upfront, be...

In the previous post, I presented some numbers from the modelling of my passive house.  Although, the loads showed, a maximum of 3.8 kW, that didn't include the thermal gains or the solar gains so infact, the total load will be significantly less.   The PHPP software can only provide static numbers for a whole house and doesn't do any type of room-by-room analysis for heat loads.  The PHPP software showed that the total load would be 2.8 kW once internal gains are taken into account.  However, in order to ensure heating is distributed uniformly, a more conventional engineering heat load calculation program is used.  The table below shows the heat loads required to maintain 20 C inside when its -18 C outside: Look closely...the numbers are tiny!  The upstairs hallway requires 22 W!, The main bath requires 83 W!  Even running a 100 W light bulb in that room will be sufficient!   However a light bulb is not considered a heat source so we n...

The numbers are in!  And there are lots of them! and they're all good!  The first round of energy modelling has been completed.  Based on the model and the orientation of the house on the lot, the energy usage looks great.  There are too many numbers to talk about so I'll focus on the important numbers.  The PHPP software used to model the home is quite complex.  The data entry is exhaustive and it contains information from the transparency of windows to the air change rate related to the wind blowing on the building (based on the weather data)! First lets look at the total energy balances: The BLUE columns show the energy lost by the building and the RED columns show energy gained by the building based on our climate.  Windows typically drain energy from a building in the winter.  However, if oriented properly the winter solar gains can offset the loss through the windows.  In our model, the south windows gain slightly more energy than...

Our designer, Mike Anderson, has been busy!    The current refinements have been finalized enough that we are ready to submit them to the town for our building permit....well, we already have a building permit but it didn't have an attached garage.  The town of Flatrock will only allow you to build a garage once the house has started.  To avoid this, we have attached the house so both the house and garage can be built at the same time. I mentioned in a previous post about the lot layout shown below.  In it's current orientation, the long axis of the house is less than 15 deg from geographical south.  This will ensure that our solar coverage will be greater than 95% during the winter months.  There will be some energy penalty in the summer since the setting sun will lead to solar gains later in the day.  Some trellis shading over the main level windows should take care of this problem but only the energy modelling will tell the tale. There...