Technical Information

Wide Area Network

The Wide Area Network or WAN is the name given to the communications network between the meters and the company responsible for collecting the data and passing it on to other businesses such as suppliers; this company will usually be the DCC (Data Communications Company) which the government has set up especially for this role. Depending on the Communications Service Provider, which varies by areas of the UK, the technology can change depending on what works best in a local area. Sometimes your meter will communicate directly with DCC and sometimes it will talk through the meters around you to reach a particular meter which has direct communications with DCC. This form of communications looks like a mesh when you draw out the possible links between meters and is therefore known as a Mesh network.

Home Area Network

The Home Area network or HAN is a bit like your home broadband wireless network and will be used to communicate between the meters, the In Home Display (previously known as Smart Meter Display or Home Energy Monitor) and other items as and when they become available. However where the meter is a long way from the location of the In Home Display the current technology (Zigbee at 2.4GHz) won't work. There are various ways around this (Zigbee 868MHz, repeaters and mains signalling); the BEIS (Department for Business, Energy & Industrial Strategy) team is looking at what developments are needed.

Meter Alerts

Smart Meters can send information about the meter's environment and status as well as meter readings. This information can be used to diagnose meter faults, detect theft and security issues. There are some 250 events which can be sent in this way, suppliers and distributors will monitor these alerts, and take action at the appropriate point. For example a memory alert may mean the meter is faulty, whereas a reverse low alert could mean that someone has reversed the meter in order steal energy.


Security has been considered very carefully for Smart Meters. The communications network is not part of the internet, it is a closed network only accessible to parties with the right security keys and physical connections. Additionally there is no central database containing customers' information, the information is only stored on the Smart Meters and sent through DCC onto Suppliers and other parties who have a right to that data and where the customer has given them permission. The customer information inside messages is encrypted and only the receiving party can look at the data, the DCC cannot view the data. The parties receiving the data undergo a rigorous security assessment at the beginning and then have regular security audits.

The National Cyber Security Centre has an excellent document explaining how the security works in relatively simple english.

End to End Security Model


The ability to purchase electricity and gas on a PAYG (Pay As You Go) basis is a big advantage of Smart Meters. Once you've paid, top up can be sent to your meter automatically without having to use chargeable key fobs. If communication to the meter is down you can still top up by entering the long reference number provided with your purchase into the meter, although this may not be an easy thing to do. For customers on PAYG who have difficulty with reliable communications and entering the long number, a separate number entry pad can be provided by your supplier. However it should be noted that many suppliers won't be offering the PAYG service until late 2017.

Distribution Network

As well as Suppliers getting information from smart meters the Distribution Network Operators (DNOs), who look after the cables in the ground, will also get information. They can use this information to detect power drops and power cuts and to help analyse the performance of the network.

Questions & Answers

Are smart meters safe?
Yes. DECC (Department of Energy and Climate Change) have stated that all smart meters are subject to the same safety regulations and testing of any in-home technological devices, including baby monitors and mobile phones.

Can my supply be turned off remotely?
Smart meters have the facility to remotely disconnect and reconnect both the electricity and gas supply. However most suppliers seem to have decided it is too dangerous to remotely disconnect or reconnect, as in the case of disconnection they cannot always be sure that the customer isn't relying on a supply for serious health reasons and in the case of reconnection the customer may have left a cooker on for example.

Will my meters have to be changed if I change supplier?
There are a number of meter standards out there currently, only the latest SMETS2 standard is fully interoperable, meaning only SMETS2 will be supported by all suppliers and allow customer to switch without losing any services or requiring any equipment changes. Unfortunately SMETS2 meters are just being tested and will only start to be installed from June 2017.
The SMETS1 meters currently being installed usually require replacing when you change supplier. However as the programme has been so slow in implementation, there is now an initiative to allow SMETS1 meters to be enrolled into the future systems and thus allow smooth switching for customers, but that is some years away.
So currently it is very likely that your smart meters will have to be replaced if you want to use their functionality. If you don't want the smart functionality, most suppliers will leave them on the wall and treat them as a traditional meter.

Do I have to be at home for the installation?
You must be at home for the installation even if your meter box is outside. The government rules under SMICOP (Smart Installation Code of Practice) say that the suppliers must explain to you how the Smart Meter and In Home Display work. Additionally it is considered dangerous to disconnect and reconnect the supply without checking with the householder that it is safe to do so.

What will energy companies do with the information they collect about my energy consumption?
Under Ofgem codes published July 2013, you can dictate how much data your energy supplier can retrieve from your smart meter and whether your supplier can share that info with third parties. You can also decide whether or not your supplier can use that information for marketing purposes.

How does a smart meter work?
A smart meter works by communicating directly with your energy supplier, so the company will always have an accurate meter reading and there's no need for you to take a meter reading yourself. Smart meters can work in a variety of different ways, including using wireless mobile phone type technology to send data.

Should I wait for a SMETS2 meter?
There are three types of smart meters, two in use currently (ADM & SMETS1), and one (SMETS2) will be available from April 2017. Only the SMETS2 meter, in conjunction with the new systems provided by DCC, will allow all customers to switch and allow more options for communications. Unless you want to try out the new technology early, we suggest you wait for a SMETS2 meter; eventually all meters will be replaced by these.

How do I top-up my smart meter PAYG if the mobile network is down?
Normally your PAYG top-up will be sent automatically to the smart meter, however if the communications link through the mobile network is not available then this cannot happen. However you can enter the long authorisation number that you received when you paid for the credit into the meter to apply your credit.
However this is not easy to do, so if you have difficulty with the entry of this number then your supplier can provide a special keypad to allow you to enter the authorisation number more easily and, probably, in a more convenient location.

How do Smart Meters send data?
A Smart Meter sends data through the Wide Area Network (WAN) to the company responsible for collecting the data and passing it on to other businesses such as suppliers; this company will usually be the DCC (Data Communications Company) which the government has set up especially for this role. Depending on the Communications Service Provider, which varies by areas of the UK, the technology can change depending on what works best in a local area. Sometimes your meter will communicate directly with DCC and sometimes it will talk through meters around you to step to a meter which has direct communications with DCC. This form of communications looks like a mesh when you draw out the links between meters and is known as a Mesh.

Can I look at my energy usage on the internet?
You will be able to view your energy usage on the internet at some stage. Suppliers are all working on new systems to make this possible.

How long will it take to install a Smart Meter?
A typical installation will take one and a half to two hours. However this will vary according to your property and where your meters are located.

How much data is stored on a Smart Meter?
The specification for these Smart Meters requires 13 months worth of consumption data to be stored at the highest level of detail, which is at half hourly measurement intervals.

Can I lay a cable to help join the devices togther?
The meters and IHD can only be joined through a radio link. This applies to all three standards of meters pre-SMETS, SMETS1 and SMETS2. However one or two suppliers may be able to offer a zigbee booster, this is similar to the wireless booster you can buy for your home broadband and just plug into a power socket.
Our recommendation would be to let your supplier sort it out, as more powerful communications hub (868MHz) will be available to suppliers to install with SMETS2 meters where needed next year.

Can smart meters be upgraded?
Smart meters can have a firmware upgrade just like you computer or mobile phone. The upgrade will be used to fix faults and add new functionality.

Why is two way communications important?
Smart meters send meter reading and event information to suppliers. Supplier can send product and payment details to the meter when you want to change your product or payment terms. Additionally this two way communications will support Pay As You Go in the future.

Are there special considerations for the location of a Smart Meter?
When a meter fitter first arrives at your premise he will usually check the signal available with a special tool and decide if the installation can go ahead; in some cases an additional aerial or alternate communications system can be used if the signal is poor. The Smart Meter must be fitted in place of or near your old meter as it is too expensive to move the incoming power cable and not good to have long cables from the main fuse (cutout) to the meter.

How do I know the meters are accurate?
Just as with traditional meters, smart meters must be certified by the Regulatory Delivery section of the Department for Business, Energy & Industrial Strategy.

What is a smart meter?
A Smart Meter is a new kind of meter to measure your energy, they are available for electricity and gas. Smart meters allow communications to and from your energy supplier and distribution network operator, and they can therefore can send meter readings automatically. An In Home Display will be provided with your meter to allow you to see how much power you are using and what it is costing.

What is dithering?
When a Smart Meter loses power and powers up it sends an alert message to suppliers and network operators to let them know. If a large area had lost power and thus a large number of meters were to send these messages at once it would put a heavy load on the communications network. To prevent this the meters "dither", that is to say they all wait a short random period before sending those first messages thus avoiding the simultaneous peak. For the first two years (to September 2018) the dithering period will be up to 2 minutes. After that a decision will be made on whether to set it to the default 5 minutes.

How often will my IHD (In Home Display) be updated with data from my meters?
Your IHD will be updated by your electricity meter about every 10 seconds and by your gas meter about every 30 minutes. The gas meter updates less often in order to preserve its battery life which in normal use is expected to be at least 10 years.

How do I read a smart meter?
It is possible to read information from your smart meter, unfortunately there are many different makes out there with different controls, so please contact your supplier for additional information.

My supplier says my signal is too weak?
Smart meters communicate through mobile communications and so the signal strength is an important factor to consider for installation.
For SMETS1 meters the installer will usually test on site and make a decision there and then whether to install. If there is not a sufficient signal they will usually walk away.
For SMETS2 there are more options. The communications are provided by the Data Communications Company (DCC) and suppliers can check that a premise has communications before visiting a site. Once on site they can check with a signal checking device if the signal is strong enough in the meter location. If it isn’t they can fit a number of different aerials to try to boost the signal. If that doesn’t work an external aerial or an alternative mesh communications method is available in some areas. Even then they can leave the meter de-commissioned and ask the DCC to get the communications working.

What is a traditional meter?
A traditional, dumb or legacy meter are all names for the kinds of mechanical or electronic meters that have been used for many years. These older meters do not have two way communications. The preferred term for them is a traditional meter.

How do I read an In Home Display?
The In Home Display (previously known as Smart Meter Display or Home Energy Monitor) has been designed to provide information to customers in their homes, and so should be easy to understand. For both electricity and gas it will display your energy consumption in either pounds and pence or kilowatt hours, helping you understand how you are using energy in your home at any given point in time. Unfortunately there are many different makes out there with different controls, so please contact your supplier for additional information.

Are the meters battery powered?
The electricity meter is mains powered but the gas meter is battery powered. The gas meter battery can be replaced by a Smart Meter Installer and is excepted to last the life of the meter, however its life can be greatly reduced heavy communications such as repeated firmware updates.

Could my IHD (In Home Display) link to my neighbour's meters?
Your IHD is paired to your own meters by the installer. It won't pick up information from your neighbours and can't be used in another house. If you need a repalcement IHD this will have to be paired with your meters.

Do I require a broadband connection or wi-fi in my home to be able to use a smart meter?
Smart meters don't need a broadband connection or wi-fi in your home as they use either the GSM mobile networks just like your mobile phone, or use a local mesh communications network to hop from meter to meter until a link to the GSM mobile network is found.

What is a SMETS1 meter?
Over 3 million meters built to the Smart Metering Equipment Technical Specification (SMETS) 1 have now been installed. These meters are better than ADM meters (Advanced Domestic Meters) but not as good as SMETS2 meters. Each supplier uses them through a different support and communications network; this means they have different functionality and effectively limits the customer from moving from one supplier to another with the same smart meter. For this reason, as SMETS1 meters are commonly in use, suppliers often have to change the meter to provide a continuing smart service. Meters to the SMETS2 standard will not have this restriction.

What is a SMETS2 meter?
No meters have been installed yet to the Smart Metering Equipment Technical Specification (SMETS) 2 standard. These are the most advanced meters available and will communicate through the new Data Communications Company (DCC). Suppliers are obliged by government rules to stop installing SMETS1 meters in early 2018 and only install these new SMETS2 meters. SMETS2 meters will start arriving in Q2 2017 but are likely to be only installed in low volumes during 2017.

Do smart meters work with home generated renewable energy?
Traditional meters are only capable of recording consumption and consequently don't take into account any energy generated by a household. If you have or are planning to install solar panels or any other renewable energy generating system in your home, a smart meter will enable you to measure how much energy you produce. The smart meter will also calculate whether or not there is a surplus which you could sell back to the grid.