Interactive lesson

Saving energy, step by step

Interactive lesson: find where your house and homestead lose electricity and heat — measuring, appliances, the cylinder, cooking, the loft and draughts, tariffs and the sun.

Free sample Chapters 1 and 2 (8 steps) are free. The full lesson comes with the Saving energy module. Already bought? Unlock

This lesson is general guidance, not professional training. Local regulations and expert advice always take precedence. Read our disclaimer.

The whole lesson as text

1. Measure first

Before any measure, see what really uses electricity and where the house loses heat.

Plug-in meter — Plug it in between the plug and the socket: fridge, freezer, TV, washing machine. Leave it on each appliance for 24 hours.
Main meter — Read the meter for one day with the water heater on and one day without. The difference is the electricity for hot water.
A thermometer in every room — Living room and kitchen 20 °C (68 °F), bedrooms 16–18 °C (61–64 °F). Every degree lower saves roughly 6 % of heating fuel.
Draughts show up in smoke — On a windy day, with the stove out, move a candle or an incense stick along windows, doors and pipes. Where the smoke bends, cold air is coming in.

Why: Saving "by feel" often switches off 8 W bulbs and leaves the cylinder at 75 °C. A plug-in meter and the main meter show where the electricity goes. The biggest users are usually water heating, an old freezer and electric heating.

Write the findings in the room-by-room house survey and mark draughts on the sketch.
For a renovation or an insulation grant, the assessment is done by an accredited assessor: an EPC or retrofit assessor in the UK, a BER assessor in Ireland, a home energy auditor in the US, a registered energy advisor (EnerGuide) in Canada. Check grant conditions with gov.uk, SEAI, your utility, or your state or provincial energy office.

2. Lighting and standby

Small loads run 8,760 hours a year, and that is why they add up.

LED bulbs — An 8 W LED gives as much light as an old 60 W bulb. An old 60 W bulb lit 3 hours a day uses 66 kWh a year; the LED 9 kWh.
Standby — TV, set-top box, speakers, the router at night, a microwave with a clock. An appliance using 5 W on standby uses 44 kWh a year.
Switched extension lead — An extension lead with a switch behind the TV and computer turns everything off in one go. If a charger is warm when it isn't charging anything, it's using power.
Outdoor lights — Put outdoor lights on a motion sensor or dusk switch instead of leaving them on all night.

Why: An appliance on standby uses 1–15 W on its own, but it runs all year. That way the whole house uses 200–500 kWh a year without anyone watching anything.

An LED bulb pays off wherever a light is on for more than an hour a day.
Old set-top boxes, chargers and transformers for halogen lamps use power even when "off".