Wednesday, December 30, 2009

5 Years in a GreenHome

Below is 5-years of energy use data from our GreenHome.

What is show is the actual energy delivered to the house, so I've taken out the effect of the different efficiencies of electric, versus wood versus oil heat. I've also "normalized" the data - that means I've converted all the data to a common average year, thereby taking the effects of cold years and warm years. (interestingly, the all five of the last years have been about 10% warmer than average...hmmm, climate change?)

As you can see, our energy use has been rising until this year. I think this is largely due to having a baby in the house starting in 2006 and Georgi started staying home then, making the house occupied full time. Our energy use dropped dramatically this year - although we did a number of small energy efficiency upgrades, I think it is largely due to the end of diaper laundry (hahoo!).

And here are the total energy costs to us as we've actually experienced them:

Tuesday, December 15, 2009

The Roots of Sustainable Buildings

I put the following diagram together to show the interaction of the various elements that comprise the design of a sustainable building. I did this diagram to illustrate the concepts I described in a previous post on Elements of Sustainable Building.

Feel free to use this with appropriate credit. Special thanks to my brother Lake for the tree-roots illustration behind.

Wednesday, December 9, 2009

Kicking the Fossil Fuel Habit

Our house uses a "combo" heating system - an oil-fired hotwater tank that provides both space heating and domestic hot water. Two years ago when oil prices were higher, I installed a small electric hot water tank to pre-heat the water with electricity before the oil-fired hot water tank. I described this conversion in a previous post here. That conversion was saving us about $50 a month in energy and reduced our greenhouse gas emissions by 70% to 1.6 tonnes of CO2 / yr (Yukon average is about 12.6 tonnes / person / year)

A couple of months ago the insurance company decided to do an inspection of our home (we built it 5 years ago and they've never actually seen what they are insuring). Well, the inspector happened to notice that our above ground fuel oil tank does not have a "sticker" on it, and gave us 4 months to get it replaced. Now, this fuel tank is perfectly fine, but I had salvaged from the house we tore down previously. Given the fuel tank's age, it doesn't have a CSA sticker. We got a quote to replace the fuel tank, and due to the new code requirements for seismic tie-down, concrete pad, etc, it was going to cost us $2500 to get a new tank installed.

I've wanted to get off the oil for a while now, so I thought if my little pre-heat tank is providing 90% of my water heating already, why not go all the way with electric? In Whitehorse, our electricity is pretty green: in 2008 99.94% of our electricity came from renewable (hydro and a bit of wind) . The advantages of getting off oil include:
  • reduction in GHG emissions associated with our house
  • reduced risk of backdrafting (indoor air quality)
  • reduced heat leakage up the chimney (my chimney always had a lot of air rising in it, constantly sucking heat off of my hot water tank)
  • no annual maintenance on the oil burner (a savings of ~$200 /yr)
  • no worries about running out of fuel/fillups, etc.
  • no worries about oil leaks
  • reclaimed 15 sq. ft. of yard where the fuel tank used to be (living in downtown, I value every square foot of yard I have!)

I looked into an electric boiler first, but we only have a 100A service, so that looked like it was out of the question (replacing a electrical service can be big $$). As an alternative, I got a the largest electric hot water tank from Canadian Tire - it is 60 gallons and has a big heating element at 5.5 kW. So, combined with the little hot water tank, I have a total of 8.5 kW of heating. My house has a peak heating load of around 34,000 Btu, which is 10 kW--this means the heating system is a bit undersized, however I mostly heat with wood, so this is fine, it is adequate to keep the house from freezing up if were away!

Total cost to me?
  • Hot water tank: $560
  • Wire, new 35A breaker and electrical permit: $105
  • Plumber: $260
  • Stevie bucks (renovation tax credit): $-79
  • Total: $846
And that's not counting the $200 I saved on not doing burner maintenance this year! Now our house GHG emissions are just 0.19 tonnes / year from our propane cook stove.

So, anyone want to by a perfectly good 5-yr old oil-fired hot water tank? For sale, cheap!