How Much of an Energy Hog is Our Existing House?

Our goal is to create housing for 2.5 families that uses less energy than the existing single family house. So how much of an energy hog is our existing house?

Here’s what our daily energy consumption looks like for the first 6 months we’ve lived here, starting in July 2015:

So…is this a lot?

Let’s do some very rough comparisons. I’ve doubled our first 6-month consumption to estimate annual consumption; converted to a per square meter metric and then compared against some other references:

• Canadian average consumption for a household our size, kWh/square meter/year
• Our existing house consumption, estimated, kWh/square meter/year
• A typical German house, kWh/square meter/year
• The first local certified Passive House (Bernhardt Passive House), kWh/square meter/year*

*We’re just talking ballparks here. It’s pretty difficult to find comparative numbers that all use the same assumptions – my intent is to show a reasonable range in potential consumption.

Hey! We’re actually doing really well by our abysmal Canadian standards, and pretty average by German standards. Of course, we would expect our consumption to be lower than the Canadian average because we have the mildest winter in Canada, although it’s unlikely to result in this much of a difference on its own.

But wait – this is only part of the story.

The other part of the story is that, boy, were we cold over the winter!

Our house came with an oil furnace and an empty tank. We didn’t want to buy a full tank of oil to heat the house for a winter when we’re getting rid of this system with our renovation, nor did we particularly want to use the existing duct work. The previous owner was a smoker and lord knows what might come puffing out of those ducts. Better to let sleeping dogs lie.

Matt cobbled together storm windows for some of our original single pane wood windows, and we put plastic film on the inside of others. And we shivered through the (albeit mild) Victoria winter, with two wall-mounted electric baseboard heaters and 2 plug-in electric heaters. We moved the heaters around depending on what room we were in and closed doors of rooms we weren’t in.

In conclusion, then, our existing house isn’t an energy hog based on the way we’re currently running it, but it surely would be one if we heated to a modern-day standard of comfort.

This comparison shows very clearly the range of what is possible. I think we can hit our target compared to what a typical house in our climate consumes. And I for one am looking forward to experiencing the comfort promised by a well insulated, airtight, and properly ventilated house!