--- title: "Avoid smart meter overcharging: clock change guide" description: "Avoid smart meter overcharging fears during clock changes by learning why kitchen displays lag up to two days behind network records without inflating bills." url: "https://www.fuseenergy.com/blog/avoid-smart-meter-overcharging-clock-change" updated: "2026-10-27" --- Smart meters are designed to automatically adjust for Daylight Saving Time (DST) changes, but issues can arise, particularly for those on time-of-use tariffs like Economy 7. Concerns about smart meters misreading usage during clock changes, leading to inflated energy bills, are common. This guide provides clear, actionable steps to verify your smart meter's accuracy and prevent overcharging. # Avoid smart meter overcharging: clock change guide ## How clock changes affect smart meters Smart meters are generally designed to automatically update for DST changes, switching between Greenwich Mean Time (GMT) and British Summer Time (BST). This built-in functionality helps maintain accurate billing records without manual intervention. However, some smart meters may not update their internal clocks perfectly, potentially remaining on Coordinated Universal Time (UTC) or GMT when other devices switch to BST. ### Daylight saving time and your meter's internal clock Your smart meter contains an internal clock that dictates when different tariff rates apply and when readings are taken for billing purposes. This internal clock is synchronised with the energy network and is designed to adjust automatically with daylight saving changes. This ensures your energy supplier receives accurate consumption data. An In-Home Display (IHD) is a separate device from the smart meter itself; an incorrect time on your IHD does not necessarily mean your smart meter is faulty or that you are being overcharged. ### Potential impacts on your energy billing If your smart meter's internal clock does not adjust correctly, or if there's a discrepancy between your meter's time and your supplier's billing system, it can lead to incorrect charges. This is especially critical for time-of-use tariffs, where different rates apply at different times of the day. For single-rate tariffs, the unit rate of energy remains the same regardless of when you use it, so clock changes have no impact. ## Verifying your smart meter's accuracy Proactively checking your smart meter's accuracy after a clock change can help you avoid unexpected bills. ### Checking the time display on your smart meter You can usually check the time directly on your smart meter's display by pressing a button to cycle through the information screens. Compare the time shown on your meter with the actual time. If there's a discrepancy, particularly after a clock change, make a note of it. If your In-Home Display shows a different time, remember it's a separate device, and its display might be incorrect even if the meter's internal clock is accurate. ### Monitoring your energy readings for discrepancies Smart meters automatically send readings to your energy supplier, which helps eliminate estimated bills. However, it's still wise to monitor your energy readings for any unusual patterns or discrepancies after a clock change. Most smart meters allow you to view current and historical readings directly on the device. If you notice a sudden, unexplained increase in usage during what you believe should be off-peak hours, it could indicate a problem. ## Economy 7 and time-of-use tariffs Economy 7 tariffs offer cheaper off-peak electricity at certain times, usually overnight, with a higher rate during peak hours. These tariffs are particularly sensitive to clock changes. ### Understanding peak and off-peak hours after a clock change Economy 7 off-peak hours typically take place according to Coordinated Universal Time (UTC). This means when the clocks change in spring to BST, the off-peak hours will shift forward by an hour (e.g., from 12:30am-7:30am UTC to 1:30am-8:30am BST). When the clocks fall back in autumn, the off-peak hours revert to their original UTC timing. If your meter clock doesn't change while supplier-set off-peak hours do, you could be charged peak rates unexpectedly. ### What to check for if you're on Economy 7 If you're on an Economy 7 tariff, it's crucial to verify that your appliances set to run during off-peak times are still doing so correctly after a clock change. Check your energy bill to confirm your specific off-peak hours. If you have appliances on timers, such as your hot water tank or washing machine, you may need to adjust them manually if your smart meter hasn't recognised the clock change. Some smart meters may not automatically adjust for DST changes, which can lead to off-peak appliances running during peak times. ## What to do if you suspect overcharging If you believe your smart meter is not functioning correctly or you've been overcharged, taking prompt action is essential. ### Gathering evidence: readings, photos, and records Before contacting your supplier, gather as much evidence as possible. This should include: * **Meter readings:** Note down the readings from your smart meter, including the date and time. * **Photos:** Take timestamped photos of your meter's display showing the time and readings, especially if you suspect a discrepancy. * **Correspondence:** Keep records of any previous communications with your energy supplier regarding your meter or billing. * **Billing history:** Review past bills for patterns or sudden changes in usage that don't align with your consumption habits. ### Contacting your energy supplier for support If you suspect an issue, contact your energy supplier immediately. Explain the problem clearly and provide all the evidence you've gathered. Your supplier may be able to fix the problem remotely or send a technician to investigate. If your supplier fails to resolve the issue to your satisfaction within eight weeks, or if they send a 'deadlock letter' sooner, you can escalate your complaint to the Energy Ombudsman. The Energy Ombudsman is an independent body that reviews unresolved disputes between customers and suppliers. ## Preventing future smart meter issues Proactive monitoring and understanding your rights can help prevent future billing issues. ### Regular checks and proactive monitoring Make a habit of regularly checking your smart meter's display, especially after clock changes. While smart meters are designed for accuracy, occasional checks can catch issues early. You can also monitor your energy usage through your supplier's app or online account, which often provides detailed consumption data. > **How much electricity does the average UK home use?** > > The average UK home uses around 2,500 kilowatt-hours (kWh) of electricity per year, based on Ofgem's medium Typical Domestic Consumption Value (TDCV) effective from 1 July 2026. This translates to roughly 208 kWh per month or about 6.8 kWh per day. ### Leveraging your supplier's customer support Energy suppliers are responsible for ensuring smart meters are correctly configured and accurately reflect customer usage. If you encounter persistent problems, don't hesitate to contact their customer support. Ofgem, the UK's energy regulator, sets clear rules for energy suppliers regarding billing accuracy, meter functionality, and complaint handling. New rules from February 2026 also provide for compensation if suppliers fail to meet certain expectations regarding smart meter installations or repairs. --- Rates, availability, and regional off-peak windows change. Check the source page for current terms. **Disclaimer** For the avoidance of doubt, this article is provided for informational purposes only and is not intended to constitute legal or financial advice. The author and/or Fuse Energy shall not be responsible for any losses arising out of any reliance on the information contained herein.