Why it is worth learning to read them
You cannot manage what you cannot see. Your bill and meter are the only direct record of how much energy your home uses, and reading them lets you test whether a change, such as a new heating schedule, has made any difference. They also help you spot errors, such as estimated readings that are too high or too low.
Terms and layouts differ between countries and suppliers, so use this as a general guide and check your own documents for details.
The units
Electricity is normally billed in kilowatt-hours (kWh). A kilowatt-hour is the energy used by a 1 kilowatt appliance running for one hour, or, equally, a 100 watt device running for ten hours. It is a measure of energy used over time, not of how fast power is drawn at a given moment. That difference is why a powerful appliance used briefly can use less than a small one left on all day.
Gas is often measured by volume (such as cubic metres or cubic feet) and then converted to kilowatt-hours on the bill using a conversion factor that depends on the gas. That is why gas bills can show a volume and a different kWh figure. Some places use other units for heating oil or other fuels, such as litres. If you use heating oil, LPG or wood, you will have delivery receipts instead of a meter.
Once everything is in kWh, you can compare different fuels and see which parts of your home use the most.
The parts of a bill
Most bills include some or all of these:
- Unit rate. The price per kWh. Some tariffs have a single rate. Others charge more during peak hours and less at off-peak times.
- Standing charge. A fixed daily amount that you pay regardless of how much you use, covering the cost of connecting your home to the network. Low use does not remove it.
- Meter readings. The start and end figures for the billing period, marked as actual, customer or estimated.
- Total usage. The difference between readings, in kWh.
- Taxes and other charges. Often added as a percentage or as separate lines.
- Account balance. Whether you are in credit or debt, which matters if you pay a fixed monthly amount.
Fixed monthly payments can hide changes in use, because the amount you pay does not move with your consumption. The payments are reviewed periodically, so you can end up in credit or debt. Looking at the kWh figure rather than the money is a more reliable way to see what you actually use.
Tariffs
A tariff is the pricing plan. Common types include:
- Fixed. The unit rate stays the same for a set period, which gives predictability. It may be higher or lower than the variable rate during that time, and exit fees can apply if you leave early.
- Variable. The rate can change, usually in line with market costs and rules in your region.
- Time-of-use. Different rates at different times of day. These can reward shifting use away from peak periods, but only help if your habits can change. They may suit people who charge an electric vehicle overnight, for example.
- Renewable or green. Marketed as supplying electricity from renewable sources. What this means in practice varies, which is why it is worth reading about green tariffs before assuming a particular environmental effect.
For your carbon footprint, the tariff matters less than the amount of energy you use, though it affects your costs. The electricity grid mixes all sources together, so what comes out of your socket does not change when you switch.
Reading your meter
Accurate energy meter readings are the foundation of everything above, so it is worth knowing how each type works.
Traditional dial or digital meters. Digital meters show a row of digits; read from left to right and ignore any digits in red or after a decimal point, if your supplier says so. Dial meters have several small dials, and you read each one in turn, taking the lower number when a pointer sits between two digits. Photograph the meter each time so you have a record.
Two-rate meters. Some meters show two sets of readings for day and night. Record both.
Smart meters. These send readings to your supplier automatically and typically have an in-home display showing use and cost. They can reduce estimated bills and make it easier to see which activities use the most. Their effect on energy use depends on whether you act on what they show. Check your supplier’s guidance for how they work in your area.
Estimated versus actual readings
If the supplier has no recent reading, they estimate. Estimates can be too high or too low, and the correction can come later as a large adjustment. Submitting your own readings regularly, or using a smart meter, avoids this. If the bill says the reading is estimated and the meter says otherwise, contact your supplier.
Tracking your own use
A simple method is to read the meter at the same time each week and write down the number. Subtract the previous reading to get your weekly use in kWh. After a few weeks you will see your normal pattern. Because heating changes with the weather, compare similar weeks or months. If you want to measure a single appliance, a plug-in energy monitor can show how much it uses.
Treat any pattern as a clue, not a verdict. A high baseline at night may point to appliances left on, an old fridge or other standby power. A rise in winter use is expected, but a jump larger than weather would explain might suggest a heating problem or a change in habits.
When something looks wrong
If your reading seems far off, check the meter number on your bill matches the one on your meter. Check you are looking at the right meter if you have more than one. If you suspect a fault, or an unexplained spike, contact your supplier or network operator. If you cannot resolve a dispute, many countries have an independent ombudsman or consumer body, which you can find through your supplier’s complaints procedure. Do not open a meter or tamper with it, as this can be dangerous and illegal.