We tested our Net Zero home from October 18, 2010 to October 18, 2011. The initial post is here, and these are the questions that we wanted to answer.

The bottom line is that our house did not produce as much energy as it used throughout the course of the year. It was not a net zero energy house during the period indicated. Here are the numbers:

Net energy use: 2518 kWh

We used 2518 kWh more than we produced over the year for all of our energy needs (that's all electricity, as we are not connected to natural gas and we didn't use our wood stove at all). 

Total solar production: 7212 kWh

Our solar modules produced at a decent clip, although at slightly lower-than-average levels for Edmonton.

Total energy consumption:  9730 kWh

So what happened? Well, as I said at the outset, we didn't define Net Zero before we started out. Net Zero every year? On a ten year average? What we do know is that this  year, we didn't hit our goal.

Here's a bit of post mortem analysis.

• This house is clearly not going to be net zero every year. We missed by a relative long shot. Why?
  • It was almost 14% colder than average in the fourth quarter of 2010 (source).
  • It was overcast for virtually the entire month of March (as evidenced by my whining in this post). In March of 2010, we didn't heat at all, whereas in March 2011 we heated the house every day.
  • Given the year that we had, the HOT 2000 simulation only predicted about half of our heating energy use.
• Given the two points above, I'm confident that our house will be net zero some years. Whether that's 20% of the time or 50%, it's impossible to say right now.
• The average house (built between 1990 - 2003) in Edmonton uses 41,665 kWh for space heating and hot water (or 150 GJ -  pdf source) , and another 7800 kWh in general electricity use (pdf source). That's 49,465 kWh in total.
• So, our house used 19.8% of the energy that a newer Edmonton home uses, and it then turned around and produced 75% of that energy as solar electricity.

It was interesting to watch how the house performed this past year. We're still sworn off of the wood stove, so I'll check in again on December 14  and we'll see how close we'll have got to net zero when measuring Dec 14, 2010 - Dec 14, 2011 (after all, if you're not happy with the data, just change the parameters!).

Edit: below are the heating degree numbers for the last 12 months. As you can see, there was a lot more heating required in Edmonton during the last 12 months than during the period of Nov 2009 - Nov 2010. Especially in March!

 read more... »

Times were good this summer, as our 6 Kilowatt PV system churned out the juice like crazy.

During the months of May, June, July and August we only imported power, on a net basis, on eight different days. Not bad, not bad at all.

Here is what the data looked like:

May 2011: 600 kWh exported.

June 2011: 500 kWh exported.  read more... »

We decided to add a patch of grass to the Mill Creek NetZero Home’s yard. Although xeriscaping has become popular among Edmonton homeowners who don’t want to do any yard work (shouldn’t they really just buy condos?), there’s a problem with it: it can be ugly and uninviting. Too often, it involves yards full of itchy scratchy rocks:

Anyone feel like sitting down and having a picnic?

Grass has its place, and it can have a minimal impact while at the same time providing an inviting space to sit and/or play soccer.

(Not) Watering

I have never watered an established piece of grass turf. Not watering is the key to grass being a benign, easy-to-care-for piece of a yard. When it’s dry in Edmonton, I just let the grass go brown. Of course, this is easier in my neighbourhood than in most. You see, we’re dirty hippies in Mill Creek. We elect communist politicians, and we care more about how much food you grow in your yard than how immaculate your monoculture front lawn is. That said, I would take the same stand anywhere. Grass is not a good enough reason to use up drinking water.

I have also never fertilized grass. If you really want a yard to be a lot of work, fertilize and water your grass often.

Planting Grass (Just Say No To Sod)

The two major ways in which we "greened" our little patch of grass was to plant it from seed, and to choose a drought-resistant variety.

Sod production uses a lot of chemicals and a lot of diesel fuel. It then uses more diesel to transport the pieces of sod to your yard.

Instead of phoning the sod guy, I picked up a bag of Scotts Pure Premium Heat & Drought Grass Seed Mix from Home Depot for $17. Containing "varieties of Chewing Fescue, Creeping Red Fescue, Kentucky Bluegrass and turf-type Perennial Ryegrass", it will look and feel better than regular grass on the rain-only diet that I intend to feed it.

I seeded the grass in early spring following the instructions from one of the many grass seeding videos on Youtube. I did ignore the boilerplate advice to fertilize the soil before seeding. Grass will grow just fine without ever being fertilized. The city has great advice on grass' ongoing maintainenance.

We're happy with how our grass turned out. The kids will finally have a place to play soccer, and the cheapskate in me is enthused that we only spent a few bucks to get it.