Run appliance at capacity (e.g. washing machine, dryer, dish washer). - Wiki Thing

Carbon Saved by Running Fully Loaded Appliances

As you might expect, running a half-filled load on a normal programme setting in your dish washer or washing machine will use the same amount of energy and water as a full load. ¹ And yet, many of us routinely under-fill our appliances. According to a Which? survey, a typical load of laundry will only weigh around 2kg, even though most washing machines can take 6kg. ²

What you might not expect however is that even the half-load programme settings on household appliances actually use a great deal more than half the energy of a full load. ³ Running fully loaded appliances saves money, energy and CO2 emissions.

In order to compare the carbon saved by running a full load as opposed to a half load, let's first find out how much energy fully loaded appliances consume.

Energy used by the following appliances for a full load per cycle:

Tumble Dryers - on average about 3.5 kWh per cycle ⁴

Washing Machines - on average about 1.2 kWh per cycle ⁵

Dishwashers - on average about 1 kWh per cycle ⁶

Using our grid electricity conversion factor of 0.527 kg CO2 per kWh ⁷, this translates to CO2 outputs per cycle of:

Tumble Dryers - 1.84 kg CO2

Washing Machines - 0.63 kg CO2

Dishwashers - 0.53 kg CO2

This works out to an average of 1 kg CO2 per full load.

As we found earlier, a half-filled load running on an economy / half-load setting will still use much more than half the energy and water of a full load. A reasonable estimate to quantify this is that a half load programme uses about 70% of the energy of a full one. As an average full load emits 1 kg CO2, this would mean on average an output of 0.7kg of CO2 for a half load.

So running two half loads would emit 1.4 kg CO2 - an extra 0.4kg CO2 compared with a single full load.

So the carbon saved by running a full load rather than two half loads is 0.4 kg CO2.

Footnotes

Reference Notes

1 http://www.energy-info.co.uk/energy-saving-advice.php

2 Environment Agency article: http://www.environment-agency.gov.uk/subjects/waterres/286587/286911/548861/549443/?version=1?=_e

3 From 'Use water-efficient appliances':http://www.direct.gov.uk/en/Environmentandgreenerliving/Energyandwatersaving/DG_064370

4 From http://www.lowcarbonlife.net/default.asp?page=65

5 From http://www.sust-it.net/results.php?id=1,a comprehensive site with listings of various appliances and CO2 emissions by model.

6 From http://www.sust-it.net/results.php?id=19

7 According toAMME The World's Energy Meter http://wiki.co2.dgen.net/index.php/ActOnCO2_Methodology#Grid_Electricity