How much energy do you use to heat your home?
This guide is intended to provide general guidance only. It is not intended to give you advice on your personal financial circumstances. You should seek independent professional advice if you’re unsure about anything mentioned in this guide or what choices to make.
Do you know how much energy you use to heat your home?
Is it about 20,000 kWh a year, or more like 10,000 kWh? Do you know what you use per square metre?
Although many people have a rough idea of how much they spend on fuel bills, people don’t often know how much energy they use specifically for heating their home.
Which is surprising, because it’s the first question to ask yourself if you want to lower the price of your heating bills.
Measuring the energy used to heat your home
A ‘typical’ home in a mild climate uses between 5,000 kWh and 30,000 kWh of energy a year for its heating. So how much does your home use?
Whether you use natural gas, fuel oil, electricity or something else, you should be able to measure the energy used to heat your home. The two best places to start are energy meters and energy bills. If you use just one fuel for heating, and nothing else, then the annual usage of that fuel is the number you’re looking for, and should be quite easy to find.
If you use electricity or gas for your heating, then the chances are you also use it for other things like cooking, water heating, lighting and appliances. To account for this, you can take advantage of the fact that unlike most other energy needs, heating is seasonal.
Let’s say a home only uses electricity for its energy needs, and over a year uses 16,000 kWh for everything, including lighting, appliances, cooking, water heating and space heating. If we know that over six months when the house isn’t heated it uses 3,000 kWh for everything except heating, we can assume roughly the same is used over the winter months for these same things. So over a year, non-heating demands account for 6,000 kWh, and the remaining 10,000 kWh are used for heating.
Depending on where you live, and the type of fuel you use, you will work out your energy consumption in any number of different units. To keep things simple, we are only using kilowatt-hours (kWh) in this post. To convert other measures of energy consumption to kWh, you can use the following conversion factors. In each case you simply multiply by a constant to convert to kWh.
- Conversion factors
- Therms x 29.3 = kWh
- Tons of oil equivalent (toe) x 11,630 = kWh
- Gigajoule (GJ) x 278 = kWh
- Kilocalorie x 0.00116 = kWh
If you have isolated how much energy you use for heating, and converted it to kWh, you are in a position to compare your energy use with other houses and benchmarks. And how much energy you use for heating depends on a number of things, including the size of the home, the local climate, the comfort level maintained, the heating system and the construction of the home.
Comparing the energy used to heat your home
Let’s say you’ve worked out the energy used to heat your home, and it turns out to be 10,000 kWh. How does this compare?
The following chart shows the energy used to heat homes in a number of European countries in 2010. These numbers represent energy used for space heating, per dwelling, per year. Just like you can calculate for your own home.
European heating needs
Based on this data, if you use 10,000 kWh of energy to heat your home, you use just a little more than the average Italian home. If you lived in a country with cold winters like Denmark, then 10,000 kWh is quite a low figure; in a warm place like Spain, it is relatively high.
Even when you account for differences in climate, however, average energy use figures like this don’t allow for variation in the home size.
Accounting for differences in home size
To get around the issue of varying house size, it is standard that energy used for heating is compared per unit of floor area.
If our example home (that uses 10,000 kWh of energy) has a floor area of 100 m2, then it uses 100 kWh/(m2a), where the ‘a’ denotes per annum (year).
We can do the same thing with our average European example homes, based on the typical dwelling size for each country.
European heating needs per unit of floor area
Once we account for floor size we get a slightly different picture. Now, our energy used for heating – 100 kWh/(m2a) – is the same as Greece.
Estimating how much energy you use to heat your home per unit of floor area is really useful, because it lets you compare your usage to various benchmarks. Perhaps the most famous of these is the Passive House (Passivhaus) standard, which limits energy used for heating to just 15 kWh/(m2a).
If you’ve worked out your energy use in terms of floor area, you can really start to understand how much energy you use for heating. This is the starting point from which you can form strategies to reduce your heating bills, and your carbon footprint.
Adjusting for difference in climate
If you want to get really technical, you can also compare energy used to heat your home by accounting for your local climate. This is done using ‘degree days’, a specialist type of weather data which is calculated from readings of outside air temperature. Degree days are used in calculations relating to building energy consumption, and can tell us the amount of heating required to maintain a certain temperature in a given climate.
This process is a bit technical, so we aren’t going to deal with it properly here. We can, however, show our European homes example again – but this time with how much energy is used to heat each European home, scaled to their average climates using degree days.
It is worth stressing that these numbers are not actual usage numbers. They are instead a comparison of energy used for heating per square metre, with all usages scaled to their particular average climate.
European heating demands per home
Now that we have accounted for variations in average climate, the countries are ranked quite differently. Places like Denmark and Germany actually use less heating energy than most, once you have accounted for their colder climates and the differences in dwelling size.
Putting it together
The first step towards reducing your heating bills and carbon footprint is understanding how much energy you use to heat your home.
Using this number, you can calculate your current footprint based on heating, compare the potential of new heating systems, assess your use of heating controls, and analyse how to improve your home’s insulation.
*Source and notes for graphs and table
Energy used for space heating: kWh/dw
Note: Annual heating energy used represents primary energy demand for heating per dwelling. It is kilowatthours per dwelling (kWh/dw) for the year 2010. Figures are based on data by Odysee Indicators. Source: Odyssee
Heating energy per floor area: kWh/(m2a)
Note: Annual heat energy used represents primary energy demand for heating per unit floor area. It is expressed in kilowatthours per square metre per annum: kWh/(m2a). Figures are based on data by Odysee Indicators for 2010.
Heating energy per floor space, scaled to the average European cliamte kWh/(m2a)
Note: Annual heat energy used represents primary energy demand for heating per unit floor area, scaled to the European average climate using degree days. Units are kilowatthours per square metre per annum: kWh/(m2a). Figures are based on data by Odysee Indicators for 2010.