Energy Consciousness Raising

Friends, energy is invisible. I think this is why many people have a hard time understanding the way it ‘flows’ into and out of their homes.

But fortunately we have ‘meters’ that record the flow of energy into our homes: and all the energy which flows into our homes eventually flows out.

If you want to raise your consciousness of these energy flows, the very best way is to read your electricity and gas meters regularly. I recommend once a week.

This article is about how to read electricity and gas meters, how to record the results in a spreadsheet and how to visualise your week-by-week energy consumption.

And if you are thinking vaguely about ‘doing something’ about insulation or heat pumps, then this habit will allow you to assess the benefits of any steps you are considering.

I have made a short video which will hopefully convey the power of this simple habit.

The best time to start recording your energy usage is about one year ago. But fortunately the second best time is right now!

If you are too excited and want to get started straightaway, then feel free to ignore the one thousand helpful words I have written below, and just skip straight to the end of the article for the download links for the spreadsheets.

Reading the Meters

First of all, I am afraid I don’t have the energy to describe how to read the hundreds of different types of meter out there. But fortunately, if you have difficulty with that, there is help available:

But there is one difference between reading the meter for an energy company and reading it for yourself. When reading for the meter for the energy company they tell you to miss off the last digits. This is because they want to minimise the chance of mis-reading and transcription errors. And they know that what you don’t pay for this month you will pay for next month!

But there is information in these digits which can be useful, especially if your usage is low.

Units

Electricity meters read in units of kilowatt hours (kWh). This is a unit of energy, and so one just writes down the number.

Gas meters record the volume of gas that flows through them, and so one needs to make a note of the units on the meter.

Click image for a larger version. Two different designs of gas meters, one reading in cubic metres and one in cubic feet.

Gas meters record your gas usage by measuring the volume of gas passing through them in cubic metres or cubic feet. To estimate the energy contained in that gas you need to multiply by a factor which tells you the energy content per unit volume (energy density) of the gas. Irritatingly, gas meters report the volume of gas that has passed through them in different units: cubic metres, cubic feet, and 100’s of cubic feet.

Click image for a larger version. Spreadsheet excerpt showing how to subtract two readings to obtain the volume of gas used in one day, and multiply them by the energy density to find the energy contained in the gas that flowed through the meter.

An example of conversion from volume units to energy units is shown in the graphic above. The spreadsheet described at the end of the article will do the conversions for you as long as you know the units.

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Meter-Reading Tip

Gas and electricity meters are often placed in places that make them quite inconvenient to read. Try using a mobile phone to photograph the meter and then write down the results from the photograph rather than directly from your view of the meter.
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Writing things down: A simple spreadsheet.

Having read the meters, the next thing is record the numbers in a spreadsheet. An extract from a basic spreadsheet is shown below.

Click image for a larger version. Screenshot of a simple spreadsheet recording meter readings versus date, and showing charts of gas and electricity consumption. The data is from my own home.

The graphic above shows how the meter readings in my home changed over the years since November 2018. The graphs tell an interesting story: you should be able to spot the installation of:

  • Solar PV/battery: the electricity graph flattens in the summer
  • External Wall Insulation: the gas graph shows a smaller winter ‘step’.
  • A heat pump: the gas graph goes completely flat and the the electricity graph gets steep in winter.

But the presentation is frustrating for three reasons.

  • Plotting Dates in Excel – or most other spreadsheets is horrible. We would like it to understand that we want dividing lines at yearly or monthly intervals, but Excel can’t do that!
  • The graphs are in the same units as we read the meters: we need to convert the gas volume units (cubic metres) to energy units (kilowatt hours).
  • We are actually more interested in the rate at which we use energy. This corresponds to the slope of the graphs.

Writing things down: A more complicated spreadsheet.

To overcome the problem with units, we need to convert the gas meter readings to kWh.

To overcome the problem with dates, we need to convert Excel’s date format into either a number of days, or fractions of a year.

To plot the rate at which we use energy we need to:

  • Subtract the previous meter reading from the current meter reading.
  • Divide this difference by the number of days between the readings

A spreadsheet which does all this is illustrated below and can be downloaded here.

On the graphs I have also added a smoothed line through the data that makes trends easier to see

The spreadsheet also includes additional columns for plotting the meter readings from a solar PV system.

There are two versions of the spreadsheet that you can download. The first is the spreadsheet containing my own data that you can look at to see how it works. The second is the same spreadsheet but with no data in and dates adjusted to start in 2022 instead of 2018.

Spreadsheets.

Jean Paul Satre once said that “Hell is other people“. I believe if he had lived he would have changed his mind and instead said “Hell is other people’s spreadsheets“.

Personally, I love using spreadsheets to check out ideas and to record and plot data. But preparing spreadsheets for other people to use is a nightmare, so these spreadsheets come with a health warning: they may not work quite how I intended.

If you are not familiar at all with spreadsheets, then this may not be for you. But if you are looking to get on top of your energy use, this could be a great opportunity to learn about spreadsheets.

The Excel spreadsheets are downloadable at the links below:

 

 

  • Empty Spreadsheet for reading from the hand-held readout units that accompany most smart meters such those illustrated below.

Good luck!

6 Responses to “Energy Consciousness Raising”

  1. Tim Says:

    These are really useful, thank you for making them available

  2. Sue Says:

    I’ll add my thanks too – your spreadsheets are much more comprehensive than mine. I have 10 years of daily PV readings and I never thought to record electricity & gas consumption!

  3. Ross Mason Says:

    Once a metrologist. Always a metrologist.

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