There are a few, here's a rundown:
Credit Meters
Credit Meters are the most common type of meter in the UK today. Electricity meters usually measure your electricity consumption in terms of kWh or kilowatt-hours (this is the number of units of energy you use in one hour). Your gas meter will usually measure your gas consumption in terms of Meters Cubed (M³). These meters usually present a reading in numbers.
To take a meter reading, take the first four or five figures displayed from left to right, excluding any red numbers if they appear.
Smart Meters
A Smart meter is a next-generation meter which displays a digital meter reading and can automatically send meter readings to your energy supplier directly for more accurate energy bills. Your smart meter will be provided with a handheld in home display from your provider which will show how much energy you are using in values.
Prepayment Meters
A prepayment meter is a type of meter which can be installed into domestic properties. This kind of meter includes a prepayment or 'pay as you go' tariff, meaning that you are required to pay for your energy before you use it. This is usually done by applying credit to a 'key' or smart card.
Before you buy credit on your new key, you’ll need to activate it. To do this, you will need to insert your top-up key or card into your meter for at least 30 seconds.