Keep a Home Fire Burning?
Cold winter nights are a tempting reason to light a fire for heat and comfort. But whether you throw a log in the fireplace or use a modern US EPA-approved stove, it pays to know the pros and cons of wood-burning. Sierra magazine’s Mr. Green has the particulars on particulates in fireplaces, which usually aren’t efficient heating sources anyway.

Wood stoves, however, are another matter. Under the right circumstances, a modern one can be a cheap, relatively low-carbon home-heating source. Sierra Club Green Home’s guide to wood and pellet stoves has everything you need to know about the modern home fire.

Also on Sierra Club Green Homes web site is a good article about ground source heat pumps (geothermal) for heating and cooling.

Sixty people signing up for the discussion mailing list in 45 days certainly validates my hunch.

Until recently, the number one position Google search for “passive house canada” was a blog post of mine from a year ago titled “Canada lacking in Passive House movement“. Even that generated several email inquires, including some from the press. I’m happy to report that article has fallen to the fourth spot on the Google search results page.

My goal here is organization-building in whatever form it takes to bring Passive House to Canada, to do it well, and with expedience. I don’t see myself as profiting from this, as my particular business interest lies in energy reductions of existing larger buildings, facilities and plants. I just want to see Passive House happen here.

The work on organization-building continues. Please join us on the mailing list if you’re interested in seeing PassivHaus come to Canada.

There was a bit of a stir lately within the building science online communities when a well-known and respected building scientist published a review of the Passive House standard.

John Straube published a review of the Passive House standard on BuildingScience.com compared to standards and practices applicable in the U.S. and Canada, available at http://www.buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard. In it Straube takes a close look at Passive House from a North American context, comparing it to other low-energy building systems for cold climates.

Katrin Klingenberg of Passive House Institute U.S. posted a lengthy response to John Straube’s article at http://www.passivehouse.us/bulletinBoard/viewtopic.php?f=5&t=208, correcting a few misunderstandings.

On GreenBuildingAdvisor.com, there is an initial discussion and reaction to Straube’s article at http://www.greenbuildingadvisor.com/community/forum/passive-house/14647/very-recent-passivhaus-article. Later, Marc Rosenbaum and David White wrote a point-by-point clarification of why the Passive House Standard sets a worthy goal for North America at http://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/defense-passive-house-standard

Also on GreenBuildingAdvisor.com, Martin Holladay and John Straube discuss the lowest cost approach, which differs from Passive House. The lowest cost approach improves the building envelope until the incremental cost of further improvements would be more expensive than photovoltaic technology. Passive House on the other hand looks at absolute energy consumption of the building envelope, so in a sense it is more “future-proof” than a house with more technology, and is likely the best choice for a future with constrained energy supply. Plus, it is much less expensive to add PV later than to retrofit additional underslab insulation. See http://www.greenbuildingadvisor.com/blogs/dept/musings/can-foam-insulation-be-too-thick

And finally, John Straube clarified his position in the whole discussion at http://www.buildingscience.com/documents/insights/bsi-026-passivhaus-becomes-active-further-commentary-on-passivhaus.

If you are interested in helping bring Passive House to Canada, visit http://www.passivebuilding.ca and join the email discussion list.

Two houses of equal area but different shape

Architects designing custom homes often seem to go overboard on the complexity of the shape, seemingly unaware of the impacts on construction cost and operational cost. Let’s look at the walls of two custom homes of equal floor area but different shape.

Both homes are 5400 square feet on one level, nice sprawling ranch homes for a well-to-do business person. The first thought is that the house is too big, and it is, but this not an unusual size in the area of custom homes. It’s still well within Part 9 of the Ontario Building Code, which deals with houses and other small buildings.

House A was designed with a highly irregular shape to add “architectural interest”. It follows the room layout and offers more views of the local scenery. From the plans we count 56 corners.  This is not unusual for this size of house. If you walked around the perimeter of house A with a tape measure it would be 600 feet.

House B was designed by a home designer-builder who doesn’t know a lick about heat loss either, but didn’t want to do all the design work of a complicated home, especially the roof, and wanted a simple L-shape so that it would be faster to construct. House B has a perimeter of 370 feet and just 6 corners.

Assume the walls are 9 feet high. Let’s also assume an insulation R-value of R-20 for the walls and R-2.00 for windows. In reality the effective R-value for house A will be lower because of the extra wood framing material used to create the more complicated shape, but let’s hold as many things constant as we can for this exercise. Also assume that the windows are 40% of the wall area. Each of the two homes will be built in Toronto, which has 6426 heating degree days (in degrees Fahrenheit).

The way to calculate heat loss for a year is with the equation heat = 1/R * area * heating degree days * 24 hours per day.

When this is all multiplied out, the energy lost during the heating season is 192 million BTU’s for house A and 118 million BTU’s for house B.

Let’s put some dollars to that. Converting to kilowatt-hours the amount of heat is 56140 kWh for house A and 34620 kWh for house B.  For simplicity’s sake let’s say you’re paying $0.10 per kilowatt-hour after taking into account the distribution fee, debt retirement charge, taxes, and so on, and you decide to use electric baseboard heat that consumes 10% more energy than actually required, because of delays in responding to the thermostat’s call for heat. The annual heating cost of just the walls and windows is $6,175 for house A and $3,808 for house B.

That’s an added cost of of $2,367 per year, every year, for having a complicated shape instead of a simpler one. The same floor area, same wall insulation, and same window quality. If you prefer the environmental route, that’s 4.6 more metric tonnes of CO2 per year, about the emissions of an average passenger vehicle.

What about equipment costs? If it was heated with a furnace or hot water boiler the capacity of the equipment would need to be correspondingly larger and thus more expensive. That wouldn’t be too much—but move to a geothermal system and look out! It could be $12,000 more in ground loop installation costs and larger equipment.

I’ve only looked at conductive heat loss. The most diligent builder is going to have a great deal of difficulty providing a continuous air barrier with a more complicated housing plan. If the builder managed to pay very close attention to detail, even if the normalized leakage area (expressed in square inches of hole per square foot of wall) were the same between the two houses, the equivalent leakage area would be proportionally larger. Given that infiltration commonly accounts for 30% of heat loss, the impact is significant.

Then there’s the foundation required to support the wall. Ben Polley of Evolve Builders Group in Guelph, Ontario, tells me that in his estimation, every corner of a foundation wall adds the equivalent of 5 linear feet to the cost due to formwork and labour. Assuming 10 inch thick walls, 7 feet high and $80 per cubic yard of poured foundation wall, it would cost $15,210 for the house A wall foundation and $6,913 for the house B wall foundation, a capital cost increase of $8,297.

Don’t even get me started on the complicated roof design that goes on these complicated houses. Ask your local roof framer.

The take away from this evaluation is that “corners cost energy” and “corners cost money”. Lots of money.

Organizations such as Net-Zero Energy Home Coalition in Canada should take advantage of Passive House and run with it. The standards, methodology and technology have already been worked out, and Germany is several years ahead of us at that.

Of course the EQulibrium(TM) Housing initiative from CMHC is useful. It is out of demonstration programs like EQulibrium and its predecessors that we get innovation. But it’s a long process. Results are slow to trickle down. The only hard technical information on existing EQulibrium houses comes from the few projects that have established web sites and are willing to share the information.

It’s time to stop building a dozen demonstration houses every decade and adopt a proven system to actually build and certify these homes. There’s already over 12,000 in Europe.

UPDATE Nov 6 2009: I have started www.passivebuilding.ca as a meeting place for everyone interested in bringing Passive House to Canada.

Sustainable building construction worker

An elegant new green home is nearing the final stages of construction in Burlington, Ontario. Barry Imber and Leslie Aske’s are aiming to have their home certified as part of the LEED Canada for Homes Case Study, and Barry has been blogging the experience at ImberAkseHouse.ca.

In Why sustainable building is upside down and may cost more, Barry highlights some problems with green construction that few designers are aware of. Namely, that building green requires a complex interplay of the trades that disrupts the way Things Have Always Been Done, including financing by the banks.

While green designers know about the up-front integrated design process, and may involve some of the trades early on, when it comes down to working with the crews the timing is off, multiple visits are required, and so costs rise.

This also brings to mind the importance once again of bringing builders into the room. And I mean physically. We need much greater representation of the men and women doing the work and managing the site to come out and be a part of the Canada Green Building Council, especially at the local chapter level.

Actually, to the credit of site professionals who do come out, many are often turned off by the design-centric focus where everyone in the room appears to be an architect, engineer, or interior designer, all without a speck of dirt under the nails.

Perhaps there’s something to be said for over 3000 LEED Accredited Professionals in Canada yet only 126 buildings have been certified as of November 24 2008.

Featured there are lessons learned from the US-Department of Energy Building America program, delivered by some of the most well-known and respected building science professionals. The site incorporates content from the Affordable Comfort conferences, “Home Energy” Magazine articles, and the DOE Building America partner technology reports.

We have had the capability to build better homes and buildings for decades. The wealth of freely available information out there is truly astonishing. There is no excuse for why we can’t be building much better than we do.