[Greenbuilding] Can a house in cold Edmonton produce as much power as it consumes?

[Gordon Howell -- Howell Mayhew Engineering]

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Saving Green Building Green

Can a house in cold Edmonton produce as much power as it consumes?
Environmentalists are trying

Published February 17, 2011
by Maurice Tougas
SEE Magazine
News & Views
http://www.seemagazine.com/article/news/news-main/netzero/


It’s a cold February morning, with the 
temperature barely nudging -25C. Inside a Mill 
Creek home shared by Conrad Nobert, his wife 
Rechel Amores and their two young children, it’s 
cool but comfortable. Very comfortable, in fact, 
if you take into consideration their home doesn’t have a furnace.

The Nobert-Amores home looks like any other from 
the front, but if you go around the back — where 
you’ll find a garden and the three different 
fruit trees in the summer months —  you’ll see 
more than 30 solar-electric modules, some on the 
roof, others on movable awnings. It’s all part of 
the Nobert-Amores family’s efforts to make as 
small an imprint on the planet as humanely 
possible, and as a hedge against the future.

It’s what is called a net zero home, one of only 
two in the city, with more in the construction and planning state.
A net zero building is one that produces all of 
its own energy for heating, lighting , 
appliances, and hot water on site over the course 
of a year. To do this, the house might draw on 
the power grid during the cold winter months, but 
sell back to the grid during the summer or warmer 
winter days. The net result, if all goes well, is zero.

Whether the Nobert-Amores home — or the first 
Edmonton net zero home in Riverdale — has 
achieved actual net zero is not entirely clear. 
Nobert has been scrupulously gauging his energy 
production and use this year, and so far it looks 
promising. Nobert expects they might be able to 
achieve net zero from the period of October 2010 to October 2011.

Saving your pocket book
----------------------------
But even if it doesn’t achieve the net zero 
effect, you have to be envious of his power bill, 
which is about $25 a month, all of which is 
service charges. And, thanks to the absence of a 
furnace, there is no natural gas being used, 
resulting in a remarkable level of savings. To 
gauge how much, just look at your gas bill for a 
month like January, and imagine that entire bill, 
with its laundry list of incomprehensible riders and usage fees, all gone.

Raised by parents who taught him the value of 
conservation, Nobert is a dedicated 
environmentalist (he doesn’t even own a car). He 
and Rechel did everything you can do with their 
previous house, just a few doors down from their 
current house, like replacing windows and improving insulation.

Still, that wasn’t enough.

“I realized that it was still consuming a huge 
amount of energy,” says Nobert. “We don’t really 
have a good idea, because it just comes in from a 
pipe in the basement. But the amount of energy used was massive.”

Worried about climate change, and the potential 
for energy scarcity — one day, he warns, there 
will be no natural gas left — he and his wife 
decided to go big and go home, and the easiest 
way to do that was to start from scratch. Net 
zero, or even coming close to it, isn’t just a 
matter of improving insulation and using 
energy-efficient appliances. The net zero effort 
begins, literally, from the ground up.

In 2008, he “deconstructed” a house that stood on 
the site of his current net zero home, saving the 
fir and maple flooring, the brickwork and the 
interior doors for use in the new house.

Now with just a hole in the ground, they planned 
a house that would “push the envelope” of energy 
conservation, aiming for a net zero house.

Expert Help
----------------------------
This is not the kind of project that one 
undertakes without expert help. And this is where Peter Amerongen comes in.

Amerongen has been designing energy efficient 
houses since the early 1980s. His company, 
Habitat Studio & Workshop, has designed, built or 
renovated about 400 housing projects across 
Western Canada, and is responsible for designing 
Edmonton’s two attempts at net zero homes, first 
in Riverbend and now in Mill Creek.

He acknowledges that the net zero homes in 
Edmonton have yet to reach that elusive goal of 
being a fully net zero, but then, nobody has 
tried to build a net zero house this far north.

“We were overly complex with the first one, but 
we’ve been able to simplify quite a bit as we’ve 
gone through it. In all of them, aggressive 
conservation has been the starting point.”

So what’s the difference between a new home, no 
matter how energy efficient, and the net zero 
home? There are three key design decisions made 
for the net zero home, which could apply to any 
new home being built, if the owner wants it.

First, the walls are 16 inches thick, filled with 
blown-in cellulose fibre insulation that is made 
with recycled newspapers. A critically important 
insulation decision involved pouring the concrete 
slab over a five-inch layer of insulating foam.

“It’s like a big, foot-and-a-half inch sweater around the house,” says Nobert.

Second, the house is sealed tight as a drum.

“It’s like living in a plastic bag,” Nobert says. 
(Naturally, a house sealed that tight needs 
improved air circulation, which comes courtesy of 
a heat recovery ventilator, or HRV. Both the 
exhaust and outdoor air streams pass through HRV, 
and the heat from the exhaust air is used to 
pre-heat the outdoor air stream. An HRV is able 
to recover 70 to 80 per cent of the heat from the 
exhaust air and transfer it to the incoming air.)

Third, the windows are the best you can buy. They 
have three panes of glass and are coated for 
maximum energy efficiency. As Nobert explains, 
these windows are as energy efficient as a wall 
in some houses. Indeed, they are quite warm to the touch.

These three design decisions cost them less than 
$25,000, and got them 80 per cent of the way towards their net zero goal.

The next big step, and the most complex and costly, is solar power.

The house has 32 solar modules — 20 on movable 
awnings, and 12 on the roof — that generate 
electricity when the sun is out. When they are 
snow covered, solar modules are useless (just 
like at night). But any amount of sun melts the 
snow, and the solar array is at such an extreme 
angle that most the snow falls off.

The solar arrays are in the back of the 
Nobert-Amores house, with an unobstructed south 
view allowing for maximum sunlight. You can do 
the same in a regular house, but that much 
sunlight coming in will heat up a house to 
sauna-like temperatures during the day. The 
solution to that, Nobert says, is the use 
of  thermal mass  —  in this case, 2 1/2” of 
concrete floors, using 10 tonnes of concrete. In 
October, when the sun is low and streaming into 
the house, the concrete acts as a heat battery, 
absorbing the heat during the day and releasing 
it at night. The house has a wood burning stove, 
the heat from which would be absorbed by the concrete floor.

A solar hot water heater, which is not “super 
effective” in the winter, supplies the house on a 
summer day with almost 100 per cent solar heated water.

Of course, even the best built house needs some 
artificial heat during an brutal Edmonton winter. 
And while they have no furnace, the house does 
have electric baseboard heaters in all the rooms, 
each with its own control so there is no heating 
up an empty room. (During my visit, he turned off 
the baseboard heating because the day’s sun will heat the house.)

Even energy efficient windows, super insulation 
and the solar systems aren’t enough, house designer Amerongen points out.

“The only way that it is remotely possible is to 
drastically reduce the amount of energy you’re 
using. There just isn’t enough space on the 
average urban lot for enough collectors to even 
begin to get all of the energy used by a typical house.”

There is no escaping the use of electricity, but 
there are ways to reduce its usage. For example, 
the Nobert-Amores don’t have an electric dryer; 
they’ve been hang-drying their laundry for a decade.

While most of us wait till we get our monthly 
power bill and gasp in horror at how much we owe, 
Nobert uses a web program that measures how much 
electricity is house is using — or redistributing to the grid — in real time.
“Yesterday at work I was watching this, and 
thinking, cool, it’s -30 out, and we’re feeding to the grid.”

The house is “smart enough” that it knows when to 
convert electrons from the sun for use in the 
house, so only surplus power is redistributed to 
the grid. All of this, of course, adds to the 
cost of the house. Producing your own energy on 
site is quite expensive — the solar system cost 
about $50,000 — so they only pay off about two per cent.
“But compared to an SUV, the payoff is amazing,” he’s quick to add.

Aside from the long-term cost savings, Nobert is 
comforted by the fact he has “energy security.
“In 40 years, these (solar systems) are going to 
be a financial asset still. They will be 
generating most of what they generate now. I 
don’t think you can get that safe of an investment anywhere.”

The Edmonton Market
----------------------------
So why aren’t there more net zero or near net zero houses?

“The conventional building industry doesn’t have 
the time, and consumers aren’t demanding it 
because they don’t know to. A lot of houses look 
nice, but they don’t know they’re buying an energy pig.”

Amerongen wishes consumers were more 
knowledgeable about their choices when 
building  new home.  For anyone thinking of 
building a house today, the key is a higher level 
of insulation and air tightness throughout the 
building, and that includes the best windows you can afford.

“I think there is really a need for more consumer 
education. On a cost basis, going to net zero is 
not something you can justify on today’s energy 
prices. But building a cost on today’s energy costs is short sighted.”

His clients are not just looking at cost savings, 
but are willing to spend the money because it’s 
the right thing to do. Super insulating a home 
under construction can add about $15,000 to the 
cost, but if you can achieve EnerGuide level of 
86 (the max is 100), you’ll get a $10,000 grant 
from the government. That makes the payback on energy costs very short.

(The federal government has produced an EnerGuide 
listing for houses, similar to that seen on 
appliances. New House build to building code 
standards  should have an EnerGuide of 65-72; a 
new house with some energy-efficiency 
improvements should reach 73-79;  and 
energy-efficient new house 80-90; and a house 
requiring little or no purchased energy, like a net zero house,  rates 91-100.)

There is tremendous interest in net zero housing 
in Edmonton, Amerongen says. His firm has another 
net zero house under construction and two more under construction.

“I’ve also been involved very peripherally in an 
apartment building that has the potential to 
achieve net zero. Our company also has another 10 
ultra energy efficient houses finished or under construction.”

He also knows of four other net zero houses under construction.

“From discussions with people from across the 
country I’d say that there is more net zero and 
near net zero activity in Edmonton than anywhere 
in the country. We should be proud as heck.”

Amerongen says he’s building energy efficient 
homes not just for the present, but for the future.

“I’m worried about looking my kid in the eye in 
30 years when things are all going to hell. I 
want to be able to tell him I did what I could.”

You can follow Nobert’s posting about his attempt 
at a net zero lifestyle at www.greenedmonton.ca
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