The Ravina Project is tracking several household parameters including power inputs. Our house has three energy inputs available to it. We use NG
natural gas for several appliances including our stove, dryer
and boiler. We use electrical power from both the grid and the
On the House Data
pages we will use graphs to present a picture of our household
thermodynamics. The Electric Usage page tracks our use of
electrical power. The Gas Usage page tracks out use of
What is the total daily
energy usage for our house from all sources? It seems like a
simple question until one realizes that the inputs, NG and
electricity are expressed in incompatible units. Luckily, we
found a conversion between them. We use a conversion factor of
10.35 kWh per cubic meter of natural gas. Our graphs present the
total usage of the house in kWh. See the House Thermo1
page for a look at the heat flow in our house broken out by
energy source for each day of the year.
How efficient is our house?
Can we see the results of changes we make to our house by seeing
a change in house heating efficiency? You can make the same
calculations for your house too! See the HDD Calculate
page for more information.
See our papers on Household
Thermodynamics, on the Project
Papers page for more background and detail on what we
have done for winter time heating and efficiencies.
Here are a few newer charts
using our years of data.
Natural Gas used
The chart directly below is
busy so I want to unpack it for you.
Over ten heating seasons we have kept all our
Natural Gas Utility invoices. We also have taken the data from
the local environment Canada weather station (our Tax Dollars at
work). From the weather data, we used the daily 24-hour average
temperature as a base and calculated for each day the
number of Heating Degree Days that can be assigned to that day.
See our HDD Calculate page for more info.
We subtract from each
wintertime monthly gas total the summertime gas usage. This
subtracts the non-heating usage of NG from each winter month and
gives us the Net NG monthly usage for heating.
The chart below compares the usage of net
natural gas with the number of heating degree days. The more
heating degree days in a season means the season was colder.
Now that you have an idea of
how the chart works, let's look closely at it. If we look at the
blue line, its daily value is positive only if the daily average
temperature is below 18 degrees centigrade. So that means as
this seasonal value increases the colder it is. We see the
linear trend is basically flat (very slightly positive). So on
average over the 10 years we have experienced about the same amount
The pink line traces the
amount of NG used to heat the house. The green line is the
linear trend of the NG we have used. It is strongly negative. Even as the average
winter time temperature over 10 years stays the same, the amount
of natural gas we use to heat the house falls dramatically.
The only difference from
season to season is
insulation, new windows, better heat flow inside the house using
curtains, a digital thermostat and the mindfulness of leveraging
all heat and humidity production into making the wintertime house