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Wolfe Island Passive: Windows, Doors, and Utilities

Windows and doors are coming from Europe, while potable water will come from the sky

The Waterloo Flat Bed Biofilter septic system was one of two options recommended by an engineer. The Waterloo required less excavation than the alternative.
Image Credit: Image #1: Waterloo Biofilter
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The Waterloo Flat Bed Biofilter septic system was one of two options recommended by an engineer. The Waterloo required less excavation than the alternative.
Image Credit: Image #1: Waterloo Biofilter
The data sheet for Optiwin's Resista windows. The windows have aluminum-clad wood frames. Note: The U-factors noted on these spec sheets are metric values. To get the imperial equivalents, divide the number by 5.678.
Image Credit: Images #2, #3, #4, and #5: Optiwin Windows
An isothermal image of the Optiwin Resista window. Optiwin's sliding door is rated as an "advanced component" by Germany's Passivhaus Institut. The Motura sliding door uses the same glazing as the Resista windows.

Editor’s note: David and Kayo Murakami Wood are building what they hope will be Ontario’s first certified Passive House on Wolfe Island, the largest of the Thousand Islands on the St. Lawrence River. They are documenting their work at their blog, Wolfe Island Passive House. For a list of earlier posts in this series, see the sidebar below.

While almost all Passive Houses have advanced, triple-glazed windows, many of these windows, especially those made in North America, fall down in certain respects, particularly in the frames. The frames often seem like an afterthought, with thermal bridges allowing heat to escape and gaps where there should be insulation.

For some reason, manufacturers here just don’t seem to bother going all the way. This is certainly not true of windows made in Germany and Austria, whose manufacturers seem to think of everything. The downside? First, price. Such technically advanced windows can be very expensive. Second, weight. These highly engineered windows are often heavy and with the large spans of glass on our south wall, we will need a crane to install them.

However, if you cut corners on the windows and doors, you undermine many of the insulation gains you make elsewhere. We also wanted wooden frames, not fiberglass, aluminum, or the most common (but environmentally the worst solution of all) PVC.

Going with Optiwin doors and windows

We have been lucky enough to find a solution. Again, through Malcolm Isaacs of the Canadian Passive House Institute, we were introduced to Optiwin, a cooperative of small window manufacturers in Germany, Austria, and other central European countries, which produces some of the best windows and doors in the world.

However, they don’t have much of a presence in Ontario, or Canada more generally — at least not yet. So we’re going to be one of the first customers for them, and as a result they are providing us with windows at a great introductory price, and will be sending over one of their installers to train our builder to install them.

We’re using three of their products:

(1) The new Resista windows with aluminium-clad solid wood frames and triple glazing with inert gas fill.

(2) The new Motura lifting/sliding door, which has the same window construction as the Resista windows. Because of the aircraft door-type closing mechanism, it suffers from none of the poor insulation properties of standard French doors.

(3) The Premium Frostkorken front door.

These are all certified at the highest performance level (A) by the German Passivhaus Institut. In fact, the front door may be the world’s only Passive House certified door! (Spec sheets for the windows and sliding door appear below.)

Home battery system

Our project is not fundamentally a high-tech one. Most of what we plan to do is, by choice, relatively low-tech and affordable. But a reliable and efficient off-grid electricity generation system is the one exception.

A breakthrough in battery technology is a necessity for a society based on renewable energy. Does the recently announced home battery system from electric car manufacturer Tesla fall into that category? As we’re in the process of building an entirely solar-powered house, which will be finished when this new battery is supposedly going to be available, we are naturally curious about this.

The standard battery technology for renewable energy at the moment isn’t fundamentally much different from lots of linked-up old-fashioned lead-acid car batteries, and these need ventilation because of the dangerous off-gassing. These batteries preferably should not be inside a Passive House envelope at all.

But Tesla’s electric motor doesn’t work that way at all. It uses a very dense array of lithium-ion batteries, familiar to many of us as the rechargeable batteries used in consumer electronics. Presumably, the new home battery system will be based on similar technology. Lithium-ion batteries are smaller, less bulky, and contain less toxic material than either lead, cadmium, or mercury-based batteries. There are some suggestions they can be less safe and are vulnerable to overheating. Consumer varieties have a life in constant cycling use of no more than three years, although supposedly 30-year lifespans are not impossible in theory.

If these batteries do become available when Tesla is saying they will, at a price that makes sense, I’ve no doubt we’ll be among the first to install them. However, even if not, there are other less publicized lithium-ion battery systems available or under development from Bosch and others. That means we are almost certainly going to have solar panels installed. If we have to, we’ll wait until we can get a lithium-ion battery rather than buying lead-acid batteries.

Water and septic systems

Wolfe Island has neither a municipal water nor sewer system. This means that householders have to deal with whatever water supply and septic systems came with the property. Inevitably, there is a lot wrong with both and neither will conform to the contemporary standards set by the local public health authority.

So, when renovations or a new build is planned, the first thing you have to do is have the property and the current water and septic systems inspected with the equally inevitable outcome that one or the other or both will have to be replaced entirely.

First, water. Most people on the island who are close enough to the shore take water directly from the lake. The big problem is that if the water levels drop enough, you can find the end of your supply pipe above the water line and you’ll be sucking in air.

For those farther from the lake, the best option is a drilled well, which takes water up from deep in the bedrock. That’s fine if your bedrock doesn’t contain anything too nasty. However, the island’s water seems to have very large amounts of iron and sulfur.

There’s one other conventional option, and one of the oldest: a dug well. This is what we have right now and it is just about the worst of both worlds: prone to running dry if you aren’t very careful, and full of excess sulfur and iron as will as all the run-off from farms and old neighboring septic systems. We stopped drinking water from our dug well after we first had it tested (without the UV filtering) and saw just how much E. coli bacteria and fecal coliform (i.e. poo) it contained.

We still use the filtered water for washing and bathing. But we’d really not have to use this at all.

The rainwater option

There is, of course, another possibility: rainwater. Some people, including our neighbors on the street who built their own place a few years back, have cisterns that collect rainwater from their roofs, and this is what we are going to do.

The only problem is where to put the cistern. Around the house, there is only about 12 inches of soil before you hit limestone. And digging very large holes in limestone is hard work. Luckily, the verdict of the public health authority on our current septic system – that is must be replaced – helps us out here.

We have a very large two-chamber concrete septic tank, mostly under the deck to the northwest of the old house. If we didn’t have any other reason, we’d just leave it, but the space will be perfect for a big rainwater cistern. We’ll be getting someone in to break up the old tank and take the pieces away.

We’re also lucky in that we will have two buildings adjacent to the new cistern and two roofs to collect from.

A low-profile septic system

As for the septic system, we decided, as with most things, to get it right from the beginning and had an excellent local sewage engineer, Martin Burger of Groundwork Engineering in Kingston, take a look at the site and design us a system to suit our needs and the legal requirements.

He identified two systems that would work best for us: Premier Tech’s Ecoflo biofilter and the relatively new Waterloo Flat Bed biofilter. Both are good systems and both have similar annual inspection requirements from the makers. But the Waterloo system needs less excavation and is less prominent in the landscape than the Ecoflo, so that’s what we’ve selected.


  1. Expert Member

    Water Supply

    Some of my neighbours here on the west coast of Vancouver Island use roof top rain collection systems. Can you flesh out yours a bit? What is the projected annual amount your roof will product, and how big is your tank?

  2. charlie_sullivan | | #2

    Aquion batteries
    Take a look at Aquion batteries.

    Tesla and other lithium ion batteries were developed with a primary objective of having high energy density, so you can have long range in a EV. But Aquion developed a battery with low toxicity, long life, and low cost being the primary objectives. I think that's a better choice to put inside a home.

  3. David Murakami Wood | | #3

    Rainwater Collection
    Hi Malcolm,

    We took the advice of both a friend of ours who used to work as a water conservation specialist and the government of Canada documents on domestic rainwater collection. The full PDF is available from this page: . The water use suggestions in this document reflect conventional North American assumptions and are ludicrously high for anyone who practices water conservation or installs low flow toilets, showers and taps at home, as we have in this house. So we adjusted the figures, but still erred on the high side to make sure that we didn't underestimate our water use.

    We have installed a 5000L poly tank, in the location this blog post suggested that we would - so it's fully underground. The tank is fed by eavestroughs and downspouts from the main roof and the porch roof of the house, which is a total of around 1900 sq ft. The eavestroughs are (or will be) covered with gutter guards to prevent leaf accumulation etc., and there will be a first flush system that diverts the first few liters of any rainfall away from the tank - because that basically washes off whatever dirt etc. is on the roof. The system that takes the water from the tank to the house has a heat line that can be used to ensure that the pipe will not freeze.

  4. Expert Member

    Thanks for the reply. You wrote:
    "The water use suggestions in this document reflect conventional North American assumptions and are ludicrously high"

    That's what my neighbours have found too. They are easily able to make their stored supply last several times as long as the guidelines suggest.

    What they did find was that in our wet climate, it was the storage capacity that proved to be the limiting factor in the system. Their roof provides 70,000 (imp) gallons annually, but even with their large 15,000 gal cistern, they have had to bring in additional water at the end of our very dry summers. It will be interesting to see if you feel the need to increase your storage capacity above the 5000L over time, or if your climate provides a more even supply.

  5. David Murakami Wood | | #5

    Rainwater Collection
    We shall see! We still have the back-up of the dug well, should we need it. Clearly we will be treating the water even from the rainwater system via UV and conentional filters anyway, so while we still don't like drinking the well-water, as it is testably 'clean' after filtration, it is at least usable for washing etc.

  6. David Murakami Wood | | #6

    Aquion batteries
    Wow! Looks like a great idea. From what I can see, the downsides seem to be a relatively short life (3000 cycles, which could be as little as 7 years) and they seem to be quite large. Plus, the website doesn't give any indication of their cost... However, this might well be an option, especially as we have had no communication from Tesla for almost a year after they finally acknowledged our interest... I think they are concentrating on American customers first, and also are simply unable to meet the demand.

  7. user-917907 | | #7

    Winter Water
    Do you expect to have trouble collecting water in the dead of winter? Will snow not melt on the roofs; will water freeze in the gutters and downspots?

  8. vensonata | | #8

    I live in an off grid community in B.C. We use solar PV and batteries and a back up Kubota low cycle diesel generator. The generator runs about 80 hours per year. We use a 12 kw pv array and have used various lead acid batteries for 16 years. Our present batteries are AGM sealed lead acid which do not vent. They are OK, but all lead acid is going the way of the Dodo. Aquion have some advantages, but I would not invest in them. They are still about the same price per kwh (17 cents) as lead acid. They are also heavier than lead acid and do not accept charge or discharge well. They are better than lead acid in that they do not require full recharge each time (lead acid is damaged by not fully recharging). So I have been paying close attention to lithium over the last 5 years. Nothing has been really suitable, including the Tesla powerwall 1... up until this week. The Powerwall 2.0 is a dream come true. And it is available in Canada and nothing competes with the price...not even close. It comes with a built in off grid inverter which is also made by Tesla and is considerably less expensive per watt than any off grid inverter you can buy. I think it is game, set, match for Tesla Powerwall 2.0. I am planning on purchasing 3 in 2017.

  9. Jon_R | | #9

    > The Powerwall 2.0 is a
    > The Powerwall 2.0 is a dream come true. And it is available in Canada

    I believe that it isn't yet available anywhere and important details haven't been released.

  10. Expert Member
    Dana Dorsett | | #10

    They'll start taking orders in December
    Volume production of the Powerwall-II hasn't yet started, and they won't even begin to take orders for another month or so. If it all goes on schedule without a hitch deliveries might start some time in Q1 2017.

  11. David Murakami Wood | | #11

    Powerwall 2.0
    If the 'order' process is anything like that for the first version, they just won't bother replying to most of the people who place orders, especially in Canada. And I have no faith in their 'timetables' for delivery either. Essentially Tesla seem to use 'orders' to generate investment capital for production, but they don't treat them as actual 'orders' in the old-fashioned sense of the term. Of course, I'll still order one, and I'll be very happy for them to prove me wrong, because technologically, they are ahead of the game...

  12. Expert Member
    Dana Dorsett | | #12

    The pent-up demand is different this time around.
    On the first Powerwall they had no idea that pent up demand in Germany & Australia would instantly vacuum up the first year's scheduled production. There is now more competition in the market, and it's unlikely that experience of the initial Powerwall release will be repeated, since by all accounts the huge demand was unexpected, whereas now the demand is more predictable, if still somewhat volatile. (cood b rong, offen am)

    The residential battery market is more savvy now too- more people know how to read the (as yet unreleased) full specifications, and do the financial math. In Oz the first effect won't be to buy up all the manufacturing capacity of Tesla, but rather, to drive competitive pricing downward more rapidly:

  13. vensonata | | #13

    Tesla Powerwall 2.0 (Canadian dollars)
    One 14 kWh Powerwall battery $7,800
    Installation and supporting hardware starts at $1,350
    Total estimate $9,150
    Requires $650 deposit for each Powerwall
    Total cost excludes sales tax, permitting and fees.
    Installations begin January 2017.
    That is pasted from the Tesla Canada site. Sounds like they are serious this time

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