The Numbers Are In! 7300 kWh per year!
First lets look at the total energy balances:
Now lets look at loads:
What does all of this mean? Well lets decipher the balances and try to put this in perspective. First I want to talk about Demand or total yearly energy usage for heating. I'll use kWh to represent this rather then the BTU convention used in the diagrams. Look below at the plot. Summing up the red bars (in BTU and converting to kW) in the plot gives a total energy usage of 17kWh/sq. m. for heating during the whole year.
How about the load on the coldest day of the year? In the load bar plot above, the total heat used by the building is about 13000 BTU/hr or 3.8 kW!!! This is amazingly small for a house that's 2176 sq. ft. In fact, the heating load per square meter was determined to be about 13 W/sq.m.!! Most code built homes are about 5-10 times this number!
If electricity were used for everything in the building, the total yearly electricity usage would be about 12400 kWh including heating, appliances, hot water, etc. At todays rates, the cost averaged bill will be about $100/month. Using a heat pump and a heat pump hot water heater, this drops to 10300 kWh or $83 per month. A typical code built house of the same size would use almost 24000 or about $195 per month!!! At our current rate, the savings would be about (24000 kWh-10300 kWh)*$.0972/kWh = $1330 per year and the total monthly electricity bill would be $1001 per year...not too shabby! HST hasn't been included here.
One of the principles of passive house is adding renewable energy to further decrease the total energy usage. Do you think that you could be on the grid and minimize energy usage below this while still living comfortably? You betcha!!! Using a unique approach, we have further minimized our electrical consumption by another 3000 kWh! Our total estimated electrical energy usage will be around 7300 kWh. If all goes as planned...and it will, our estimated monthly electricity bill will be $86.30! This includes the HST tax and the monthly service fee. Compared to a code built home, the bill would be $245.67. That's a savings of 65%. I'm pleased.
With a total energy savings of about 65% and the heating requirement that's 75% less than a code built home of the same size, The Flatrock Passive House is on the road to be the most energy efficient detached home in Newfoundland!