Wednesday, 20 January 2021

How have we reduced our domestic energy use?

Domestic energy bills have reduced about 20% over the last decade - in terms of energy used. We have reduced consumption in lighting, refrigeration, TV and electronics. Unfortunately, prices have risen such that the overall bill has often increased – probably that is one of the reasons why we are using less, to save money. In this post I attempt to dig deeper into the mechanisms behind these changes and see what lessons can be learnt.

Comparing domestic electricity and gas bills in 2008 and 2019 (the last year of full data), both gas and electricity use is down 12.5% overall despite a 10% increase in the number of households [1] and 7.5% increase in population [2]. Energy use has been adjusted for the weather, to make the comparison fair.

This is illustrated in the chart below which shows trends in the number of households (X axis), and in energy use per household (Y axis). The area of each rectangle, also shown in figures, indicates the total energy used. The dotted line shows the ‘no change situation (100% for number of households and per household energy). For electricity the number of households (actually the number of domestic electricity meters) has increased by 10% to 110%, and the usage per household is down to 80%: on average, households have reduced consumption by 20%! The changes for gas use are similar.

Domestic energy use. Data from [1]


The next chart shows the total electricity use for common appliances – these make up about 55% of our electricity use in 2019. In almost all cases, the energy use has decreased, though there is an increase in cooking energy. These reductions account for more than the overall decrease in electricity bills - there are small increases elsewhere. 

Data from [3]

I should add that this data is not exact as we do not know precisely how much is used for different appliances. It is a fair estimate based on sales figures of different sorts of appliances and surveys on appliance usage.

This chart is like the first one, splitting out trends in number and energy use per appliance. The X axis shows the number of appliances per household – so this time the dotted line at 100% for ‘no change’ from 2008 actually represents an overall increase of 10% after allowing for the growth in the number of households. The area of each rectangle indicates the new energy use per household but the figures indicate the energy use at UK level, as in the previous chart. Below we look at the trends in each sector in detail.

Data from [3]

 Cooking – switching from gas to electricity has increased power use.

The number of appliances per household has increased, which more than compensates for the slight reduction in energy per appliance. The extra appliances are mainly ovens (up 14%) and hobs (up 19%). It looks like we are moving away from cooking with gas. This is a behaviour change in buying choices, probably influenced by new technology such as ceramic and induction hobs. This is good from the point of view of carbon emissions as electric appliances are more efficient and carbon emissions are reducing rapidly.

Laundry/dishwasher – more dishwashers but overall little change

When it comes to washing machines, tumble dryers and dishwashers, we now have more appliances per household than before: the extra appliances are mostly dishwashers.

This increase is offset by less energy use per appliance, partly due to improvements in energy efficiency, since regulations have improved standards for these appliances. The change is not so great as with fridges and freezer (below) and some of the energy savings are probably due to changing behaviour as we heed advice to run the washing machine less frequently and at lower temperatures. Overall, there is little change in energy consumption.

Fridges and freezers – abandonment of separate fridges and huge improvements in efficiency

There is a remarkable decrease in the number of appliances we own – down 18%. This is largely due to abandoning separate refrigerators and freezers as even in 2008 nearly two thirds of households of households had a fridge freezer. 

In addition there has been a staggering increase in efficiency of cold appliances – 29% less energy per appliance for fridge freezers, up to 42% saving for chest freezers. This is largely due to increasing stringent EU minimum efficiency regulations. Initially, appliances were rated A-G and there was no minimum standard but from 1999 new appliances had to be C or better and over time ratings up to A+++ were defined. As from 2010 only class A or better were allowed which is 40% more efficient than C, and as from 2012 only A+ or better [4]. However there is some leeway for manufacturers as they are allowed to sell old stock. Hence sales of A rated appliances tailed off gradually from 2012 and there are still very many of these and worse in our homes.

In a comparison of eight EU countries [4] the UK was the last country to reach the point where sales of A+ and better rated appliances overtook sales of A. I find this a little worrying. The switch happened first in Italy and Germany. Is the UK a dumping ground for old stock?

Lighting – from tungsten to halogen, LEDs now on the rise

For lighting, the chart shows the total lighting in each dwelling rather than per bulb, so the number per home is unchanged between 2008 and 2019. However we have a large reduction in energy consumption, due to a shift in the type of lighting we use, as shown in the chart below. In 2008 most lighting was old style tungsten filament bulbs with some halogens – which are more efficient than tungsten but not much. Compact Fluorescents (CFL) were just getting going and LEDs hardly off the starting blocks. The EU minimum efficiency regulations phased out tungsten bulbs gradually between 2009 and 2012 [5] while halogens were finally banned in December 2018 [6]. 

In 2019, there are hardly any tungsten left, about half our bulbs are halogen and the remainder are evenly split between LEDs and CFLs. However, the popularity of LEDs is on the rise. LEDs are slowly replacing halogens but the shift away from CFLs is slow because they last a long time.

Data from [3]


TVs – switch to LCD displays has improved efficiency 

The total number of TVs out there is hardly changed but we have slightly fewer per household in 2019 than in 2018. The vast majority now have LCD displays which explains most of the reduction in energy use. We watch less broadcast TV but more from streaming services [7] - some of this is on computers rather than TV screens. Doubtless screen time has increased in 2020 because the pandemic requires more people to stay at home.

Computers – laptops replacing desktops saves energy.

Computer appliances covers desktop and laptop computers, separate monitors, printers and ‘multi-function devices’. In 2008, laptops were less common than desktop computers but now there are seven times as many, as you can see in the chart. The number of desktops is down by two thirds. There are more than twice as many laptops now as there ever were of desktops.

Data from [3]


Laptops each use only a third the energy of desktops (though the difference was greater in 2008) and the switch away from desktops is the main reason why overall energy use has decreased. There have been no mandatory efficiency improvements on these devices in the time period. However, there is always pressure on efficiency of laptops in order to maximise battery life. 

Other electronics – savings mainly from standby power regulations

This sector includes special purpose devices such as DVD/VCRs, games consoles and set top boxes though in terms of numbers it is mainly power supply units (PSU) – which we use to charge our phones and tablets and many other devices. Four fifths in this category are PSUs – about 10 per household - and they are responsible for a third of the total energy use in this category. 

Most of these devices are plugged in but on standby a lot of the time and the maximum standby power requirements have reduced the energy use considerably. This is the main source of energy savings in this sector. For example, in the Household Energy Study, using 2010 data a typical set top box standby power was 14W. The regulations now require no more than 1W (for devices with active displays). This alone would save 113 kWh/year [8]. Most devices are now required to use less than 0.5W on standby and if left on 24x7 for a year this would add up to 4.4 kWh, which is 0.1% of a typical bill.

Tablets and smart phones are not explicitly listed in this category. A typical tablet battery holds about 15-30 Wh. If you charge this from 50% up to 100% every day for a year, with 60% efficiency this would consume 9-18 kWh over the year. Even the top estimate is 0.6% of a typical bill. 

Savings on gas from insulation and boiler upgrades

Household gas bills have reduced by 19% over the decade, similar to electricity bills. Some of this is likely to be due to installing energy efficiency measures. Back in 2008, only 19% of gas boilers in England were condensing compared to 78% in 2018[9]. This change alone typically saves 8-10% on your bill [10] – including rebound effects where you keep your house warmer afterwards. In addition, the proportion of homes with insulated cavity walls went up from 48% to 67%, with likely similar savings, and there were increases in double glazing [9]. Many if not most of these efficiency measures were funded by the Energy Companies Obligation which we pay for through our bills, and earlier schemes such as the Carbon Emissions Reduction Obligation – government statistics seem to assume that the number of insulation projects installed without funding support is insignificant.

In any case, these measures do not seem sufficient to account for the whole reduction in energy use so it is likely that there are also savings from less costly measures such as fixing draughts, adjusting our heating controls and using less hot water.

Behaviour change or regulation?

It seems from the above that almost all the savings on electricity bills that have been achieved are the result of energy efficiency regulations mandating higher efficiency (e.g. lighting, fridges and freezers) and reductions in standby power. Behaviour change is evident in the switch away from standalone fridges and freezers to fridge-freezers and from desktop computers to laptops. However most of the savings have come from having our choices limited rather than selecting efficient appliances. This is despite the increase in electricity prices which you would expect would drive energy savings. No doubt this has happened in many households but not all, or even the majority. For gas use it seems that around half the decrease has been from improved energy efficiency, often with government subsidy, and half has been due to voluntary low cost measures.

The advantage of regulation for energy efficiency is that it requires no effort on the part of the consumer. In the case of electrical appliances, studies show overall savings for the consumer in most cases, even if upfront costs are sometimes higher. This is not necessarily true for other sectors, but where it is, or where the difference is small, this is a very good way to drive energy savings or carbon savings. A pure market driven approach, based on price signals alone, requires consumers to think and make the ‘right’ choices, which can be complex with conflicting priorities.


[1] Annual Domestic energy bills (www.gov.uk)

[2] United Kingdom Population estimates (ONS)

[3] Energy consumption in the UK (www.gov.uk)

[4] How effective are EU minimum energy performance standards and energy labels for cold appliances?, Schleich, Joachim; Durand, Antoine; Brugger, Heike (Econstor) 2020

[5] Light goes out for incandescent bulbs (Guardian) Aug 2012

[6] Europe to ban halogen lightbulbs (Guardian) Aug 2018

[7] Media Nations: 2019 (OFCOM) August 2019

[8] Household Electricity Survey (BEIS) 2014

[9] English Housing Survey data on energy performance (HCLG) July 2020

[10] National Energy Efficiency Data-Framework Summary of analysis (BEIS) July 2017



No comments:

Post a comment

Comments on this blog are moderated. Your comment will not appear until it has been reviewed.