Many UK business owners are surprised to discover that a significant portion of their energy bill is generated when nobody is on the premises. Overnight electricity consumption, weekend heating, and equipment left running through bank holidays can quietly inflate costs month after month. Identifying and addressing out-of-hours energy waste is one of the most straightforward ways to reduce overheads without disrupting daily operations.
How to Read Your Smart Meter Data for Clues
Your smart meter or half-hourly data is the starting point. Log in to your energy supplier's online portal and look at consumption broken down by hour or half-hour. Compare a busy trading day against an overnight period or a Sunday when the premises are closed.
Compare overnight consumption with the loads your business genuinely needs. A high overnight figure is a prompt to investigate, not proof of waste. Common culprits include air handling units, server rooms, vending machines, display lighting, and heating systems running to schedules set years ago and never updated.
If detailed data is not visible, ask your existing supplier about access first. A missing portal chart is not, by itself, a reason to switch. Our smart-meter data guide explains how to begin.
Heating and Cooling Schedules That No Longer Match Reality
Heating, ventilation, and air conditioning (HVAC) systems are frequently the largest source of out-of-hours energy waste. Many businesses set their schedules during installation and never revisit them, meaning the boiler fires up at 5 am for an office that now opens at 9 am, or the cooling runs through the weekend.
Walk through your controls and confirm:
- Start times reflect your actual earliest arrival, not a legacy setting.
- Stop times account for the last person leaving, not an optimistic estimate.
- Weekend and bank holiday overrides are set correctly and are not defaulting to weekday programmes.
- Frost protection setpoints are sensible for the season rather than holding the building at an unnecessarily warm overnight temperature.
Ask a qualified heating engineer to review controls where needed. Confirm the scope and cost; savings and payback depend on the building and its use.
Never switch off refrigeration needed for food safety, security systems, essential IT, required ventilation or frost protection merely to lower the overnight reading. Follow equipment instructions and obtain qualified advice where needed.
Lighting Controls and Always-On Equipment
Lighting is a visible and fixable problem. Motion sensors or occupancy-linked controls in corridors, toilets, and storage areas prevent lights running through the night. Keep required emergency, security and safety lighting operational. Review non-essential lighting against the premises' actual safety requirements.
Beyond lighting, take a close look at:
- Refrigeration — commercial fridges and freezers must run continuously, but check door seals, condenser coils, and temperature settings. An overworked refrigeration unit uses considerably more power than one that is well maintained.
- IT and AV equipment — desktop computers, monitors, printers, and projectors left in standby still consume power. Managed power strips and a policy of full shutdown at close of day make a measurable difference.
- Catering equipment — combination ovens, hot-holding units, and commercial dishwashers are often left in standby mode overnight when a full power-off would be safe and appropriate.
Reducing unnecessary kWh can reduce consumption charges even on a single-rate tariff. Shifting use only changes the unit price where the tariff has different time bands; compare the full cost before changing products.
Building Staff Routines Into Your Closing Process
Technology helps, but human behaviour is still a factor. A simple one-page closing checklist posted near the exit reduces reliance on individual memory.
Step-by-Step: Create a Closing Energy Checklist
- Step 1 — Assign a closer: Designate one person per shift responsible for the energy walkthrough before locking up.
- Step 2 — List every zone: Write down each area of the building and the equipment or systems within it that should be off.
- Step 3 — Check and sign off: The closer physically walks each zone, confirms the state of equipment, and signs the checklist.
- Step 4 — Review monthly: Compare your overnight smart meter readings month-on-month. If consumption creeps up, recheck the checklist.
- Step 5 — Reward compliance: Make energy-saving part of team culture, not just a management directive.
Action Checklist
- Pull half-hourly or hourly smart meter data and identify your closed-hours baseline consumption.
- Review HVAC start and stop times and update them to match current operating hours.
- Fit occupancy sensors to non-essential lighting zones if they are not already installed.
- Inspect refrigeration door seals and schedule a maintenance service if units are working harder than expected.
- Audit IT and catering equipment for standby power draw and create a shutdown policy.
- Introduce a signed closing checklist and assign responsibility clearly to one staff member per shift.
- Compare your current tariff to check whether a time-of-use or smart business contract would better reflect your consumption profile.
Related business energy FAQs
For concise answers on this topic and links to official guidance, see our business energy FAQs.
Reviewed on 30 September 2026.
