Logo primary
Logo secondary
The Transformation of Our Urban Home
The Transformation of Our Urban Home
Last updated:
227 Fonda Way SE, Calgary, Alberta, CA
Climate zone:
Cold Temperate

My Projects

(projects i'm involved in)

Verge Permaculture

Verge Permaculture

Calgary, CA

Alicia Cheatwood Andrea Olson Ann Orr Ann Samuels B. Santifer R. Beckins McLean Blank Kimono Briana Lyon Bron(wyn) Elliott Christian Douglas Crystal Young Dan West Denise Grant Eoghan O'Driscoll Collins Flordeliza Harris Frank  Wolf Gail Calloway Geoff Capper Geoff Lawton Gordon Williams Hillary Farm Howard Story Jana Macanb Jay Strauss Jevin Barton Joakim Pettersson Jorge Crespo Kathy Bowing Kathy Parsons Kelly June Hutcheson Kenton Zerbin Khulthum Russell LÁszlo Wein Laurie J Sykes Lee Robertson Leslie Waldner Liam Phelan Lu Zhao Lynn DeVlieg Maddie Hoffmann Mari Korhonen Maria Svennbeck María Luz Cardozo Marie Jones Megan Bridge Misty Coruscate murat  çölkesen Mustafa Fatih Bakir Nick Huggins Nick Sikorski Nicola Chatham Nora Bouhaddada Paul Ciaramitaro Pete Blake Rene Michalak Ricardo Alwares Selena Fraut Starr Brainard Stephanie Ladwig-Cooper Stephen Koen Sven Horner Velvet Ginnis Wen Rolland Yone Ward

Back to The Transformation of Our Urban Home

How We Designed Our Solar Greenhouse

Project: The Transformation of Our Urban Home

Posted by Rob Avis about 13 years ago

We live and garden on an urban lot in Calgary, Canada, located on the 51st parallel north and approximately 80 km east of the front ranges of the Canadian Rockies. In good ol’ permaculture fashion, we set out to enhance sectors and conditions that would i


We live and garden on an urban lot in Calgary, Canada, located on the 51st parallel north and approximately 80 km east of the front ranges of the Canadian Rockies. This northern climate presents many design challenges, including less than one hundred frost-free days, an annual mean temperature of 4.1 degrees Celcius and summer cyclonic weather patterns (i.e. high risk of hail). We are also considered to be a moderate temperate desert as our precipitation is around 500 mm including snow. However, one of the advantages of growing food up north is the long summer days. There is no better place to observe this than in Alaska which also has an average of 100 frost free days but is renown for growing the largest vegetables in the world. Also, despite being cold in the winter, it is rarely overcast and we enjoy mostly sunny days. These two factors combined results in Calgary having nearly the same solar potential as Florida.

Traditional European Greenhouse (above) and Passive Solar Greenhouse (below)

In good ol’ permaculture fashion, we set out to enhance sectors and conditions that would improve our growing season (sunlight, heat) while minimizing those that we considered detrimental (cold, hail, frost). We quickly determined that a passive solar greenhouse was just what we needed and we set out to design one for our backyard.

There are two major considerations when designing a greenhouse: heat and light. Interestingly, the traditional European-style greenhouses were developed in the low countries of northern Europe as a response to low level of predominantly diffuse light prevalent in the winter time (think cloudy, overcast winters). This design was brought to this continent with little consideration of the differences in climate and latitude encountered here.

A greenhouse that is better suited to our winter conditions is a passive solar greenhouse. These greenhouses are designed to accept and enhance the direct sunlight and heat from the south while preventing heat loss by insulating the north, east and west sides.

Just this past December our greenhouse went up. She's still empty - we still have to design out and build the interior, but here's some info of how she was built and our future plans. 

To see a nifty timelapse of the construction, go here:


The General Design

We chose to site the greenhouse on the concrete pad behind the house (originally designed as a parking pad - who needs all that parking space anyways?). The size of the greenhouse is 10’ x 20’ with a 10’ ceiling (3 m x 6 m x 3 m) which covers nearly half of the cement pad. Generally, this style of greenhouse works best if it is twice as long as wide. We also designed a shed style roof with an overhang to capture rain and reject some of the overhead summer sun.

The Structure

The building is made from a structurally insulated panels (SIPs). These pre-fabricated panels consist of an insulating layer (styrofoam) sandwiched between two layers of structural board. Although the idea of building the greenhouse from natural materials (i.e. straw & cob) was very appealing to us - the truth is that I did some engineering consulting for the SIP panel manufacturer which resulted in getting a sweet deal on the building materials. There are also some great advantages to using SIPs - they are mold and rot proof which is very important in high humid environments. These panels are fire proof and do not off-gas. They are highly insulative with an average R -value of 25 (better than most homes) and because the panels are pre-fabricated, the main structure itself went up in less than one day.

In the end this greenhouse is going to supplant far more energy in its life than it consumed in its manufacture. Every calorie of food that is supplies to my family is 10 - 25 that do not have to be expended in the industrial system when you consider tractors, fertilization, pesticides, shipping, refrigeration and transport. With a life expectancy of at least several decades we are quite satisfied with the energy payback.


The entire building (with the exception of the glazing) is made from structurally insulated panels. 


The angle of the glazing from horizontal is an important design consideration. 


Low and high vent holes have been cut out to provide passive ventilation. 

Glazing on a greenhouse is the surface that lets the light in - usually glass or plastic sheets. Having the glazing at an angle allows us to maximize winter sun (increasing heat in the winter) and minimize the summer sun (reducing overheating in the summer). The angle of the glazing from horizontal is an important design consideration and the optimal angle depends on which part of the season you want to do most of your growing.

As a rule of thumb, to optimize the glazing angle for winter growing take your latitude and add 15 degrees. In our case the optimal angle would have been 51 + 15 or 66 degrees. However, as long as the glazing angle is within 45 and 75 degrees you will be within 5% of optimum - therefore it often makes more sense to design the building to height restriction and material constraints vs optimal glazing angle. In our case, the actual glazing angle is 55 degrees.

For glazing we chose to use triple glazed polycarbonate with an R-value of 2. This is dramatically less insulative than the walls (R-25) and so to keep the heat in we are going to use an insulated draw-down curtain which will be drawn at night and raised in the morning.

What’s Left To Do (there’s lots!)

With the structure and glazing up, our big project over the next few months is to complete the interior features. There are quite a few other considerations, here’s a brief description of our plans at this time:

Heat Retention & Rejection

Typically in passive solar building design the recommended percentage of glazing to prevent overheating is 7% - 12% of the total southern wall surface. For instance, if your southern wall was 100 m2, you should have only 7 to 12 m2 of windows. If you go above 12% you have to add additional mass in the building to absorb the incoming solar energy. If you go above 20% you are going to overheat your building.

Well, our greenhouse has 90% glazing coverage on the south surface. This amount of glazing is required to capture sufficient energy in the cold months to keep the space warm but is setting us up for potentially major overheating issues in the summer. There are a couple of strategies to deal with overheating which we intend on employing: (i) heat retention and (ii) heat rejection.

For heat retention, we plan to install six inch non-perforated weeping tiles below the raised garden beds. These “earth tubes” will receive hot air directed from the ceiling of the greenhouse using a small solar-powered fan. Effectively we will be storing surplus heat in the soil of the garden beds.

For thermal mass, we will use black containers of water along the back wall. We are also considering installing some cob features to soak up additional heat, however we are a little concerned about the cob being exposed to high humidity - I’d be interested to know if anyone has experience with this.

For heat rejection we have cut out multiple air vents, both high and low, which will be operated with powerless wax-driven arms (here’s a link to a similar product). A rule of thumb for sizing ventilation is to have the total venting area equal to 25 to 30 percent of the total area of glazing. We may also need to install a shade cloth under the front eave in the summer to further reduce the heating load. Time and experimentation will tell.



Auxiliary Heating System

When we get to the inevitable -30 degrees Celcius day with cloud cover the greenhouse is going to need some extra heat. Our plan is to build a rocket stove back-up heating system. While driving through the Calgary industrial park several weeks back I was amazed at the amount of good wooden pallets that were being disposed of. When I stopped to talk to one small business, the owner pleaded for me to take them away. And so, these pallets will serves as fuel for the rocket heating system and will also make great building material. Sawdust left from the processing will be used for our composting toilets and mulch.

Aquaponics System

I am very interested in experimenting with combined fish and hydroponics systems - and the greenhouse will provide just the space I need. The added beauty of combining an aquaponics with the solar greenhouse is that the aquaponics system will increase the thermal mass while providing a bounty of fish and veggies. However an important consideration will be the increased humidity. While condensation & rot is not a concern with our mold-proof structure, most plants do grow best at a relative humidity between 45 and 60 percent. Leaf rot and flower, fruit and stem diseases increase in very high humidity environments.

In Summary

The solar greenhouse is certainly going to make a big re-appearance here in our climate (and similar climates) as people start to re-connect with their food and desire more local and sustainable ways of nourishing themselves.

We are very excited about working on the interior design and construction over the remainder of the winter and have already been perusing specialty seed catalogues looking for appropriate banana and fig tree varieties. There is a steep learning curve ahead as we expand our gardening knowledge with new plant varieties, techniques, time and space stacking and generally about greenhouse operation. But we are keen and eager and look forward to sharing our successes... and failures too!

Stay tuned for updates...

Comments (1)

You must be logged in to comment.

Wen Rolland
Wen Rolland : Great project! The information about the angle of the glazing is exactly what I was looking for! Can't wait for your updates.
Posted about 13 years ago

Report Wen Rolland on How We Designed Our Solar Greenhouse


or cancel

Courses Taught Here!
Project Badges
Urban Residential
Rob Avis - Admin
Team Members

Report The Transformation of Our Urban Home


or cancel

Hide The Transformation of Our Urban Home


or cancel

Hide How We Designed Our Solar Greenhouse


or cancel

Legend of Badges

Note: The various badges displayed in people profiles are largely honesty-based self-proclamations by the individuals themselves. There are reporting functions users can use if they know of blatant misrepresentation (for both people and projects). Legitimacy, competency and reputation for all people and projects can be evidenced and/or developed through their providing regular updates on permaculture work they’re involved in, before/after photographs, etc. A spirit of objective nurturing of both people and projects through knowledge/encouragement/inspiration/resource sharing is the aim of the Worldwide Permaculture Network.



A member is a permaculturist who has never taken a PDC course. These cannot become PDC teachers. Members may be novice or highly experienced permaculturists or anywhere in between. Watch their updates for evaluation.

Male memberFemale member

Permaculture Matchmaker

One of these badges will show if you select your gender and the "I'm single, looking for a permaculture partner" option in your profile.



People who claim to have taken a Permaculture Design Certificate (PDC) course somewhere in the world.


PDC Verified

People who have entered an email address for the teacher of their PDC course, and have had their PDC status verified by that teacher. Watch their updates for evaluation.



People who’ve taken a Permaculture Research Institute PDC somewhere in the world.


PDC Teacher

People who claim to teach some version of PDC somewhere in the world.


PRI Teacher

With the exception of the ‘Member’ who has never taken a PDC, all of the above can apply to become a PRI PDC Teacher. PRI PDC Teachers are those who the PRI recognise, through a vetting board, as determined and competent to teach the full 72-hour course as developed by Permaculture founder Bill Mollison – covering all the topics of The Designers’ Manual as well as possible (i.e. not cherry picking only aspects the teacher feels most interested or competent in). Such teachers also commit to focussing on the design science, and not including subjective spiritual/metaphysical elements. The reason these items are not included in the PDC curriculum is because they are “belief” based. Permaculture Design education concerns itself with teaching good design based on strategies and techniques which are scientifically provable.

PRI PDC Teachers may be given teaching and/or consultancy offerings as they become available as the network grows.


Aid Worker

The individual with this badge is indicating they are, have, or would like to be involved in permaculture aid work. As such, the individual may or may not have permaculture aid worker experience. Watch their updates for evaluation.



The individual with this badge is indicating they are, have, or would like to do paid permaculture design consultancy work. As such, the individual may or may not have permaculture consultancy experience. Watch their updates for evaluation.


Community Project

Community projects are projects that help develop sustainable community interaction and increase localised resiliency.

Report How We Designed Our Solar Greenhouse


or cancel