Is a ‘free electricity hours’ tariff worth it in the UK?
A practical, UK-focused guide to ‘free hours’ energy tariffs (including the hidden costs). See when they can work, who should avoid them, and how to compare properly.
- Best for households that can shift a chunk of usage into the free window (often overnight or a set time block)
- Not automatically cheaper: unit rates outside the free hours can be higher
- We show two realistic examples with numbers and a comparison table
Estimates only. Tariff availability and ‘free hour’ windows vary by supplier, region and meter type.
Fast answer: sometimes — but only if you can genuinely shift usage
A UK “free electricity hours” tariff can be worth it if you can move a meaningful share of your electricity use into the free window (for example, charging an EV overnight, running a heat pump or doing laundry/dishwasher cycles at set times). If most of your use stays outside the free hours, the higher standard unit rate (and sometimes higher standing charge) can wipe out the benefit.
Key takeaways
- Do the maths on your shiftable kWh, not just the headline “free” hours.
- Check the non-free unit rate (often materially higher than standard tariffs).
- Smart meter usually required to measure usage by time block.
- Peak-time costs still matter (evening cooking, showers, lighting, TV).
- It’s not the same as Economy 7 — windows and pricing structure can differ.
A quick “worth it” rule of thumb
A free-hours tariff is more likely to be competitive when:
- You can shift ~25–40%+ of your electricity into the free window (varies by tariff pricing).
- You can automate usage (EV schedule, timer plugs, smart appliances).
- You’re happy to change habits (laundry, dishwasher, immersion heater timing).
What is a ‘free electricity hours’ tariff?
A “free hours” tariff is a time-based electricity deal where the unit rate drops to £0.00/kWh for a specific window (for example, a fixed overnight block or occasional promotional hours). Outside that window, you pay a different unit rate (often higher than a typical single-rate tariff). The supplier uses your smart meter readings to bill usage by time period.
Common UK variations you’ll see
- Fixed daily free window
- E.g. a set overnight period. Best if you can schedule EV charging or appliances.
- Weekend or off-peak “free” blocks
- Sometimes aimed at laundry/dishwasher loads and flexible households.
- Dynamic / TOU (time-of-use) products
- Not always “free”, but can include ultra-cheap periods and expensive peak periods. Requires careful monitoring.
What to check before you switch
- Exact free window times (and whether they change seasonally).
- Unit rate outside the free hours (and whether there are multiple rates).
- Standing charge (still payable every day).
- Contract length and whether it’s fixed or variable.
- Exit fees and any switching restrictions.
- Payment method: Direct Debit vs prepayment vs receipt of bill.
- Meter set-up: smart meter required; some legacy meters may need upgrading.
Check ‘free hours’ tariffs available to you
Tell us a few details and we’ll show whole-of-market home energy options for your postcode, including time-of-use and “free hours” style deals where available.
Two realistic UK examples (with numbers)
These are illustrative estimates to show how “free hours” can help (or hurt). Actual prices vary by supplier, region, payment method and your meter. For simplicity, we keep standing charges the same in both options (in reality, they may differ).
Scenario A: EV driver who can charge overnight
Household: 2 adults, EV on driveway, smart charger scheduled in free window.
- Annual electricity use: 4,500 kWh
- Free window usage shifted: 1,800 kWh/year (EV charging mostly)
- Standard single-rate tariff: 26p/kWh
- Free-hours tariff: 0p/kWh in free window; 33p/kWh outside
Estimated annual electricity cost (unit rates only):
- Single-rate: 4,500 × £0.26 = £1,170
- Free-hours: (1,800 × £0.00) + (2,700 × £0.33) = £891
Estimated difference: ~£279/year cheaper (before any standing charge differences).
Scenario B: Typical flat with little shiftable usage
Household: 1–2 adults, no EV, most usage evenings/weekends.
- Annual electricity use: 2,400 kWh
- Free window usage shifted: 300 kWh/year (dishwasher + occasional laundry)
- Standard single-rate tariff: 26p/kWh
- Free-hours tariff: 0p/kWh in free window; 33p/kWh outside
Estimated annual electricity cost (unit rates only):
- Single-rate: 2,400 × £0.26 = £624
- Free-hours: (300 × £0.00) + (2,100 × £0.33) = £693
Estimated difference: ~£69/year more expensive (and could be worse if standing charge is higher).
Free-hours vs other UK tariff types (quick comparison)
Use this table to sense-check whether a “free hours” deal is the right tool for your household — or whether a standard single-rate or traditional off-peak tariff could suit you better.
| Tariff type | Best for | Typical watch-outs | Meter needs |
|---|---|---|---|
| Free electricity hours | EV charging, heat pumps, households that can schedule high loads into the window | Higher unit rate outside free hours; standing charge still applies; windows can be restrictive | Usually smart meter |
| Single-rate (standard) | Most households with normal day/evening usage patterns | Less opportunity to benefit from off-peak shifting | Any meter type |
| Economy 7 / off-peak | Storage heaters, immersion heaters, strong night-time usage | Day rate may be higher; exact off-peak hours vary by meter/region | E7 capable meter or smart meter |
| Time-of-use (multi-rate) | Very flexible households; EV/heat pump users willing to track peaks | Peak pricing can be expensive; needs active management | Smart meter |
Decision checklist: it likely suits you if…
- You have an EV, heat pump, immersion heater, or can batch appliance use.
- You can automate the timing (charger schedule, timers, smart plugs).
- You’re home/comfortable running appliances at off-peak times (noise permitting).
- You’ve checked the non-free unit rate and it still works for your usage.
- You’ve confirmed any exit fees and the contract terms.
It’s usually not worth it if…
- Most of your electricity is used during evenings (cooking, heating, showers).
- You can’t (or don’t want to) shift routine usage into a strict time window.
- You’re in a flat where overnight appliance use is impractical.
- You’re comparing against a good-value single-rate tariff and the “free-hours” day rate is high.
- You’re on prepayment and choices are limited (you may have fewer suitable options).
Costs, exclusions and common pitfalls (UK-specific)
“Free hours” deals can be genuinely useful — but most disappointment comes from a few predictable gotchas. Use the cards below as your pre-switch checklist.
1) Higher unit rate outside free hours
This is the big one. If your “day” or “peak” rate is higher than a standard tariff, you need enough free-window usage to offset it.
2) Standing charges still apply
Even with 0p/kWh at certain times, you’ll still pay a daily standing charge (and it can vary by region and tariff).
3) Smart meter & data dependency
Time-based billing usually needs a working smart meter. If your smart meter isn’t communicating reliably, billing can be more complex.
4) Window restrictions (and lifestyle fit)
If the free window is short or at inconvenient hours, you might not capture enough free kWh in real life.
5) Exit fees & fixed-term lock-in
Some tariffs have exit fees. If wholesale prices fall or your usage changes, leaving early could cost you.
6) Gas isn’t affected (usually)
Most “free hours” offers are electricity-focused. If most of your spend is gas, the impact on total bills may be smaller.
FAQs
Do I need a smart meter for a free-hours tariff?
In most cases, yes. The supplier needs half-hourly (or time-sliced) readings to identify what you used during the free window versus other times. If you don’t have a smart meter, you may need to get one installed before you can join.
Are the free hours always overnight?
Not always. Some are overnight, some are fixed daytime blocks, and some are weekend-focused. Always check the exact times in the tariff terms — and whether the hours can change (for example, seasonally or with product updates).
Is this the same as Economy 7?
No. Economy 7 usually has a cheaper night rate and a more expensive day rate, not “free” electricity. The off-peak window length and timing can differ, and Economy 7 is often linked to specific meter setups. A free-hours tariff is typically a separate time-of-use product with its own conditions.
Will I definitely save money if I have an EV?
Not definitely. EVs make it easier to benefit, but savings depend on the non-free unit rate, your total household usage, standing charge, and how consistently you can charge in the free window. Also check whether the tariff requires specific charger settings or minimum usage patterns.
Can I get a free-hours tariff on a prepayment meter?
Sometimes, but availability can be limited. Many time-of-use products are aimed at smart credit meters (often paid by Direct Debit). If you’re on prepayment, it’s still worth checking what’s available in your area and whether you can move to a smart prepay setup.
Do the free hours apply to my whole home, or only to EV charging?
It depends on the tariff. Some apply to all electricity used during the window, while others may be linked to certain conditions. Always read the tariff details carefully and confirm what counts as “free” consumption.
Could switching to a free-hours tariff affect my smart meter readings or billing?
Your meter still records usage normally, but billing becomes time-segmented. If your smart meter communications are unreliable, ask the supplier how they handle missing reads and whether they’ll estimate usage across time bands.
What if my circumstances change (e.g. I sell my EV or move home)?
If your shiftable usage drops, a free-hours tariff can become poor value. Check your contract length and any exit fees. If you move, your new property may have different eligibility (meter type, region, network area), and tariffs may not carry over.
Trust, methodology and sources
Editorial details
- Written by: EnergyPlus Editorial Team
- Reviewed by: Energy Specialist
- Last updated: March 2026
How we assess whether it’s “worth it”
We focus on the decision the tariff actually changes: what you pay for electricity outside the free window versus how many kWh you can realistically shift into the free hours.
- Inputs: annual kWh; estimated shiftable kWh; free-window unit rate; non-free unit rate; standing charge; contract terms.
- Approach: compare annual unit-cost under a standard single-rate tariff vs a free-hours tariff, then flag where standing charges, fees and eligibility can change the outcome.
- Limitations: examples assume stable rates and do not model half-hourly wholesale volatility, VAT rounding, seasonal consumption swings, or supplier-specific conditions.
Sources (UK)
- Ofgem (Great Britain energy regulator) — consumer protections, market rules and guidance.
- Citizens Advice: energy — switching advice and billing support.
- GOV.UK: Smart meters — how smart meters work and what to expect.
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