A quarter of all Ireland's energy use is directly by all homes, known as the "residential" sector. With the exception of 2020, residential energy use is usually below transport, and above industry.

Residential sector has a large share of energy use

The residential sector accounts for about one quarter of the energy used in Ireland. It is also responsible for one quarter of the energy-related CO2 emissions. From 2006 to 2014, there were significant reductions in the energy use by homes and resulting CO2 emissions.

After 2014, this trend reversed into growth. Correcting for weather, energy use in homes was almost 19% higher in 2020 than in 2014. Despite the increase in energy use, CO2 emissions increased by merely 1% between 2014 and 2020. The small increase in CO2 was achieved by decreases in both electricity carbon intensity and home coal consumption that offset increasing oil consumption.

Residential Final Energy Demand

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Residential Final Energy (ktoe),Residential Final Energy Demand,Weather Corrected Residential Final Energy Demand
Source: SEAI

Adjusting for weather

Weather variations from year to year affect energy demand, particularly for space heating. It is useful to adjust for annual weather variations, which we can do using the degree-days method.

Return to growth

Weather corrected residential energy use decreased between 2007 and 2014, but has since increased yearly, with the exceptions of 2017 and 2019 (the year after Storm Emma). Between 2014 and 2020, weather corrected residential final energy consumption increased by almost 19%.

In 2018 we had storm Emma, which brought snow and cold temperatures to all parts of the country, but when averaged over the entire year, it was just a little colder than the previous year. Actual residential energy use increased by 7% in 2018. When we correct for weather, the increase was still 3%. Despite the 2018 storms, the weather corrected energy use fell by only 1.1% in the following year.

Reasons for changes

Potential reasons for the decrease in household energy use between 2007 and 2014 include:

  • Improved thermal efficiency due to retrofitting and building regulations
  • Reduced household incomes and expenditure, due to the economic downturn
  • High energy prices

Potential reasons for the increase between 2014 and 2020 include:

  • Increasing household incomes and expenditure
  • Reduced energy prices, particularly of oil

Final residential energy use by fuel type

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Residential Final Energy by fuel (ktoe),Coal,Peat,Oil,Natural Gas,Renewables,Electricity
Source: SEAI

Dominance of oil

Oil has remained the largest fuel source since 1995. It accounted for 42% of all final energy used in the residential sector in 2020. The next largest source was electricity at 24%.

Between 1990 and 2000 there was a clear switch away from solid fuels used in open fires towards oil- or gas-fired central heating. After 2000, fuel shares became more stable. We can see a gradual increase in electricity and gas shares, and gradual decrease in coal and peat shares. Only oil increased its share in 2020, from 40% to 42%.

Weather corrected oil and gas use

Changes in oil consumption caused most of the fluctuation in residential energy use between 2007 and 2020. Weather corrected oil consumption decreased by 38% between 2007 and 2014, but increased by 40% between 2014 and 2020. In comparison, weather corrected gas consumption decreased by 16% between 2007 and 2014 and increased by almost 10% between 2014 and 2020. In 2020, oil and gas increased by 17% and 1% respectively.

A likely reason for the higher fluctuation in oil consumption may be the volatility in oil prices. Additionally, the majority of oil-fired homes are located in rural areas and constructed as detached buildings (with more external wall area). Finally, rural areas may offer greater opportunity to fuel switch from oil to solid fuels.


Total electricity consumption had peaked in 2008, having more than doubled since 1990. It reduced between 2008 and 2014, but since grew yearly — reaching a new peak in 2020. There is evidence that the growth of large household appliances is levelling off. At the same time, there has been an increase in appliance efficiency. Additionally, there was an increase in electricity prices over the period.


From 2005 to 2020 renewable energy quadrupled, but from a low starting point. New building regulations require new homes to generate a portion of their energy from renewable energy, and this has seen a large increase in the use of solar thermal water heating, solar PV electricity, and heat pumps which provide renewable ambient energy.

Final energy by end-use

Electricity,Space heating,68.06
Electricity,Water heating,82.45
Electricity,Lighting and appliances,477.47
Electricity,Other end uses,25.96
Gas,Space heating,431.82
Gas,Water heating,157.85
Gas,Lighting and appliances,0
Gas,Other end uses,0
Solid Fuels,Space heating,323.24
Solid Fuels,Water heating,31.99
Solid Fuels,Cooking,0
Solid Fuels,Lighting and appliances,0
Solid Fuels,Other end uses,0
Oil,Space heating,819.68
Oil,Water heating,234.87
Oil,Lighting and appliances,0
Oil,Other end uses,0
Renewables,Space heating,43.24
Renewables,Water heating,25.14
Renewables,Lighting and appliances,0
Renewables,Other end uses,0
Source: SEAI

Challenge of gathering end-use data

It's important for us to understand how energy is consumed in homes. In particular, it is useful to know the portion of energy consumed for the main end-uses. These include space heating, water heating, cooking, lighting and electric appliances. For 2018 we estimate that 61% of all energy used in households was for space heating, 19% for water heating, 17% for lighting & appliances, and 2% for cooking.

We cannot collect data on energy by end-use in the same way as by fuel type. For example, it's not possible to know from an electricity meter reading how much electricity is used for for water heating versus appliances. To estimate the split, SEAI developed a model of household energy use based on information from the BER database.

Energy-related CO₂ emissions

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Residential Carbon Emissions (ktCO2),Coal,Peat,Oil,Natural Gas,Electricity
Source: SEAI

Second highest source of CO2

The residential sector accounted for 24% of energy-related CO2 emissions in 2019, but increased to 29% in 2020. These include upstream electricity emissions. The 2020 increase in residential's emission share was mainly caused by a contraction in transport's share from 41% to 34%. In both 2019 and 2020, the residential sector was the second largest source of CO2 emissions after transport, and was ahead of industry.

Traditionally, the trend for residential energy-related CO2 emissions followed the sector's trend in energy use. In recent years however, the two trends are moving apart. Correcting for weather, energy use in homes was almost 19% higher in 2020 than in 2014. Despite the increase in energy use, CO2 emissions increased by merely 1% between 2014 and 2020. The small increase in CO2 was achieved by decreases in both electricity carbon intensity and home coal consumption that offset increasing oil consumption.


CO2 emissions by fuel source

The chart shows residential energy-related CO2 emissions split by fuel source. Oil, gas, coal and peat are burnt directly within the home. We also factor in CO2 emissions from electricity generating stations producing electricity for homes.

Electricity use was the largest source of CO2 emissions from households from 1990 up to 2017. From 2018 onwards, emissions from electricity were overtaken by those from oil consumption. By 2020, oil and electricity accounted for 42% and 27% of residential CO2 emissions respectively. If we exclude electricity, oil accounted for 57% of residential CO2 emissions from fuels burnt directly within the home.

Final energy per home

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Energy intensity per dwelling,Non-electric energy,Non-electric (Weather corrected),Electricity
Source: SEAI

In 2020 the average home used 20,955 kWh of energy — split into 76% from direct fuel (non-electric) and 24% from electricity. This 76:24 split of energy sources was steady since 2011, the year when fuel use dropped significantly. Moving to the above chart's first year, the 2005 energy split of 80:20 was even more dominated by direct fuel.

Weather-corrected final energy use per home fell by 33% during 2005–2014, but rose 15% during 2014–2020. The increase in 2020 home energy use, the first year of pandemic restrictions, accounted for over half the 2014–2020 rise.

Energy-related CO₂ emissions per home

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CO2 emissions per home,Total CO2,Non-electrical CO2,Electricity CO2
Source: SEAI

Overall energy related CO₂ emissions

In 2020 the average home emitted 5.5 tonnes of energy-related CO2. Of this total, 73% were from direct-fuel use, and 27% indirectly from electricity use.

Emissions of energy-related CO2 per home fell by 42.3% between 2005 and 2019. This compares to a reduction in energy per home of 29.5%. The first year of the pandemic, 2020, saw a small 1.3% increase in energy-related CO2 per home, despite a larger 9.1% increase in weather-corrected energy use. After decreases in the CO2 intensity of grid electricity, increases in home CO2 emissions have diverged from increases in home energy use.

Fuel use

Home CO2 emissions for fuel use (non-electric) fell by 38% between 2005 and 2014, but then rose by 14% from 2014 to 2020. The fall and rise in fuel emissions simply reflect the fall and rise in the burning of fossil fuels, particularly oil.

Electricity use

Home CO2 emissions from electricity reduced by 56% during the entire 2005-2020 period. This long-term decline reflects the reductions in usage and carbon intensity of grid electricity.

SEAI National BER research tool

The BER Research Tool gives researchers access to statistical data from the Building Energy Rating (BER) scheme which is administered by SEAI. The BER certificate indicates the annual primary energy usage and carbon dioxide emissions associated with the provision of space heating, water heating, ventilation and lighting to the home. This tool provides access to information on all aspects of construction that affect the energy performance of homes. Results can be viewed on screen or downloaded in the form of a Microsoft Excel spreadsheet.

Go to National BER research tool

Energy in the Residential Sector report

Our Energy in the Residential Sector 2018 report provides detailed data and analysis. It also offers a comparison of Irish homes to those of other EU countries.

Go to latest Energy in the Residential Sector report