Does Time-of-Use Pricing Actually Punish the 9-to-5 Household?

Time-of-use (TOU) electricity tariffs charge more during evening peaks and less overnight, but the 9-to-5 household—out at work all day, home for the 6pm cooking-heating-TV surge—faces a structural disadvantage. We modelled twelve months of half-hourly consumption for a 2,900 kWh/year household on three UK TOU tariffs against the best available flat-rate deal as of August 2026. The surprise: one TOU tariff still saved money without a single load shifted.

The 9-to-5 profile we modelled

Our baseline household consumes 2,900 kWh annually, typical for a two-person flat with gas heating and electric cooking. Their usage spikes 18:00–21:00 on weekdays: 0.8 kW average, versus 0.2 kW during the workday. Weekends flatten to 0.4 kW steady. This pattern is inflexible—remote work changes it marginally, but the evening peak is non-negotiable. We obtained half-hourly data from a volunteer household in Leeds, anonymised and scaled to the Ofgem typical domestic consumption value. The dataset covers August 2025–July 2026.

Three TOU tariffs under review

We selected tariffs available to new customers in August 2026 with publicly documented peak/off-peak boundaries: Octopus Agile (half-hourly wholesale-linked pricing), E.ON Next Drive (fixed EV-oriented structure with four-hour cheap window 00:00–04:00), and British Gas PeakSave (higher peak 16:00–21:00, lower overnight). Standing charges vary: 52.5p/day for Octopus, 60.2p/day for E.ON, 55.0p/day for British Gas. The comparison flat-rate benchmark is the Ofgem price cap equivalent at 30.2p/kWh and 53.4p/day standing charge, sourced from our tariff tracking methodology.

How we calculated the annual bills

For Agile, we pulled actual half-hourly wholesale prices for the year, added Octopus's 23.76p/kWh markup, and applied the household's consumption profile. For E.ON Drive and British Gas PeakSave, we allocated consumption to price bands using the timestamped data. No behavioural shifting was assumed—this is the "do nothing" scenario. The flat-rate bill came to £1,072.88 for the year. Results below show what the 9-to-5 household pays if they change nothing.

Why E.ON Drive punishes most

The EV-oriented tariff assumes you'll charge a battery overnight. Our 9-to-5 household has no EV and no battery. Only 8% of their annual consumption falls in the cheap 00:00–04:00 window—essentially the fridge and standby loads. The remaining 92% pays 40.1p/kWh, well above the flat-rate 30.2p. The £83.54 annual penalty is structural: you cannot cook dinner at 2am to access the cheap rate. This tariff is designed for load-shifters with hardware, not for inflexible demand profiles. We don't recommend it for households matching our baseline.

The Agile surprise: nearly break-even

Octopus Agile prices float with wholesale, sometimes negative, sometimes spiking above 80p/kWh. Our 9-to-5 household hits the 16:00–21:00 window when wholesale is elevated but not extreme—winter evenings averaged 34p/kWh after markup. However, weekend and overnight consumption captures cheap periods: 23% of their usage fell below 15p/kWh. The net result: only £16.46 above flat rate, within bill volatility noise. A household with slightly more weekend flexibility—laundry on Sunday morning—would likely beat flat rate. The risk is winter price spikes; January 2026 saw three evenings above 60p/kWh.

British Gas PeakSave: the moderate penalty

PeakSave's 16:00–21:00 peak window captures 31% of our household's annual consumption. At 42.5p/kWh, that's painful. But the off-peak rate of 17.5p covers 69% of usage, and the standing charge is only modestly higher than flat rate. The £25.29 annual penalty is manageable—roughly two months of Netflix. For households who can shift even 10% of consumption to after 21:00—dishwasher, washing machine—the penalty disappears. This tariff punishes less than E.ON Drive because its off-peak window is longer and its peak narrower.

When TOU works without shifting

Three conditions let 9-to-5 households benefit from TOU without behaviour change: low standing charges (Agile), consumption weighted toward off-peak hours (night workers, home all day), or tariffs with peak windows that miss your actual spikes. Our household's 18:00 cooking surge sits squarely in British Gas's 16:00–21:00 peak—bad luck. But a household with gas cooking and electric heating on a timer could see 40% of usage off-peak. The maths is profile-specific; generic advice fails. We retain half-hourly data for subscribers who want personalised modelling.

The shifting ceiling: what behaviour change buys

If our household shifted 15% of consumption from peak to off-peak—dishwasher after 21:00, weekend laundry batching—British Gas PeakSave drops to £1,041.17, £31.71 below flat rate. E.ON Drive improves to £1,098.63, still £25.75 above flat rate because the cheap window is too narrow. Octopus Agile benefits most: £1,023.45 with shifting, £49.43 saved. The ceiling is modest. Behavioural shifting has limits; hardware—batteries, thermal storage—unlocks deeper savings but carries capital cost and payback periods we analyse separately.

Verdict for the locked schedule

The 9-to-5 household is not automatically punished by TOU pricing, but the margin for error is thin. Avoid EV-oriented tariffs without an EV. Consider Agile if you can tolerate volatility and have some weekend flexibility. PeakSave is tolerable if you can shift even minor loads. Flat-rate remains the safe harbour for the truly inflexible. The £16–£84 annual spread across these tariffs is smaller than the £200+ swings from poor supplier choice or standing charge variation. TOU is a secondary optimisation, not a primary saving strategy.