Energy suppliers offering free electricity days in the UK
Learn which UK energy deals include “free electricity” events, how they work in practice, who they suit, and the pitfalls to check before switching.
- Clear explanation of “free electricity days” (and what’s usually not free)
- Eligibility checks: smart meters, payment method, tariff type, region
- Two realistic household examples with estimated numbers and assumptions
Important: “Free” events vary by supplier and tariff. You’ll still pay your standing charge and any usage outside the offer window. Always check terms and unit rates.
Fast answer: do “free electricity days” exist in the UK?
Yes — a small number of UK tariffs run occasional promotional “free electricity” events (for example, a free-hours window on a set day). These are usually limited to specific tariffs and often require a smart meter so the supplier can measure your usage in the free window.
Key reality check: the “free” part is typically the unit rate for electricity during the offer window. You normally still pay the daily standing charge, and you’ll pay your usual unit rate at all other times. If the tariff’s normal rates are higher, the offer can be poor value overall.
Who it can suit
- Homes that can shift usage (laundry, dishwasher, immersion, EV charging) into the free window
- Smart-meter households comfortable with time-based offers
- People who check total annual cost, not just “free” headlines
Who it may not suit
- Low electricity users (little to “move” into free hours)
- Households with high daytime essential usage outside the window
- Anyone who doesn’t want variable promotions or eligibility checks
What to check first
- Tariff name + exact free window (hours, day, frequency)
- Standing charge and standard unit rate
- Smart meter and payment method requirements
How “free electricity days” usually work (UK)
In the UK, “free electricity” promotions typically work as a time-limited unit-rate discount for electricity — often a handful of hours on a particular day. Your supplier records usage via your meter reads (commonly a smart meter), then applies credits or a zero unit rate for the eligible period.
Common structures you’ll see
- Free-hours window (most common)
- Electricity unit rate set to £0.00 for a defined window (e.g., 11:00–14:00). All other hours charged at the tariff rate.
- Credit-back promotion
- You’re billed normally, then receive a bill credit equivalent to the eligible electricity usage during the promo period.
- Bundled “perk” tariff
- The free electricity event is part of a wider bundle (apps, membership, smart features). You must judge the full tariff cost, not just the perk.
Not usually included: gas usage, standing charges, and electricity used outside the window. Some offers exclude prepayment meters or require Direct Debit.
Quick self-check: are you likely to benefit?
1) Do you have a smart meter?
Many free-hour deals rely on half-hourly readings. Without a smart meter, you may be ineligible or the offer may be harder to administer.
2) Can you shift at least 2–6 kWh into the window?
Typical shiftable loads: washing machine (0.7–1.2 kWh), tumble dryer (2–4 kWh), dishwasher (1–2 kWh), EV charging (7+ kWh/hour depending on charger).
3) Will the tariff’s normal rates cost you more?
Compare the annual cost against standard fixed/variable options. A higher day-to-day unit rate can cancel out a few free hours.
4) Are you OK with promotions changing?
Some offers are time-limited or subject to availability. Plan based on the tariff’s core pricing first.
Compare tariffs (including time-based offers) across the market
If you’re considering a free electricity day tariff, the safest approach is to compare the full annual cost and terms — then treat free hours as a bonus if you can realistically use them.
What we’ll help you check
- Standing charge + unit rates
- Tariff type (fixed/variable/time-of-use)
- Exit fees and contract length
- Smart meter and payment method eligibility
Good to have handy
- Postcode (rates vary by region)
- Whether you have a smart meter
- Approx. monthly spend or annual kWh
- Preferred payment method
Prefer to read first? Jump to the comparison table and common pitfalls.
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Comparison: what to look for in “free electricity” supplier offers
Suppliers change promotions and product names over time, so the most reliable way to compare is by offer mechanics and total cost. Use this table as a decision tool when you’re reviewing any tariff that mentions free days/hours.
| Offer style | Typical requirements | Best for | Watch-outs |
|---|---|---|---|
| Free-hours window (promo) | Often smart meter; sometimes app sign-up; usually direct debit | People who can run appliances or charge an EV in the window | Higher standard unit rates; limited dates; cap/exclusions may apply |
| Credit-back event | Smart meter helps; credit timing varies | Those who want a simple bill credit rather than time-rate changes | Credits may appear later; may not apply if you’re in debt/arrears |
| Time-of-use (cheap off-peak) | Smart meter; multiple day parts; sometimes EV-specific | EV owners; storage heaters; households that can shift load daily | Peak rates can be high; not the same as “free” |
| Bundled perk tariff | Membership/app; specific tariff; fixed term more common | People who value the bundle beyond energy pricing | You may pay more overall for perks; check exit fees and auto-renewal |
Decision checklist (printable logic)
Choose a free-day style tariff if…
- You can reliably shift meaningful usage into the free window (not just once)
- The tariff’s non-free unit rates and standing charge are competitive for your region
- You’ve checked contract length, exit fees, and how the promo is applied (zero-rate vs credit)
- You have (or can get) a smart meter and are happy with half-hourly readings where required
Avoid or be cautious if…
- Your electricity use is already low (there’s little to “make free”)
- Most of your usage is unavoidable outside the free hours (e.g., home working, medical equipment)
- The deal feels good only because of the free hours, but the standard rate is notably higher
- You may need to move again soon (tenants) and want to avoid fixed-term exit fees
Costs, exclusions and common pitfalls (UK-specific)
“Free electricity” promotions are easy to misunderstand. These are the checks we recommend making before you switch.
1) Standing charge still applies
Even if electricity unit rates drop to £0.00 for a window, the daily standing charge is normally unchanged. That can be a large part of the bill for low users.
2) “Free” can be limited or capped
Some tariffs restrict the number of events, require opt-in, or apply a maximum eligible consumption. Check the tariff’s T&Cs and your supplier’s event rules.
3) Smart meter + readings settings
Time-based offers often need half-hourly data. If you don’t have a smart meter, or your settings don’t allow the required readings, you may not qualify.
Tariff pricing can outweigh the perk
If the standard unit rate is higher than alternatives, you can pay more overall even with occasional free hours.
Rule of thumb: estimate your “free-window kWh” per event and multiply by your unit rate to see the maximum possible benefit. Then compare that to any difference in day-to-day rates.
Exit fees and fixed terms
Some promotional tariffs are fixed-term. Always check for exit fees, what happens at the end of the fix, and whether the “free day” element can be withdrawn or changed.
Two realistic scenarios (with estimated numbers)
Scenario A: flat with no EV (limited shiftable usage)
Household: 2 adults, electric cooking, gas boiler. Smart meter installed. Can run dishwasher + washing machine during the window.
- Assumed shiftable usage per event: 3.0 kWh (dishwasher 1.2 + washing machine 0.8 + extra cooking/charging 1.0)
- Assumed electricity unit rate: 24p/kWh (illustrative)
- Estimated value per event: 3.0 kWh × £0.24 = £0.72
- If 8 events/year: ~£5.76/year benefit (maximum, if you fully use the window)
What this shows: if you don’t have big shiftable loads, the free hours may not move the needle. A slightly cheaper unit rate on a normal tariff could beat this.
Scenario B: house with an EV (high shiftable usage)
Household: 3–4 people, EV with home charger, smart meter. Can schedule EV charging in the window.
- Assumed EV charge power: 7 kW (typical home charger)
- Assumed free window: 3 hours
- Estimated eligible energy: 7 kW × 3 h = 21 kWh (if the car needs it)
- Assumed electricity unit rate: 24p/kWh (illustrative)
- Estimated value per event: 21 kWh × £0.24 = £5.04
- If 12 events/year: ~£60.48/year benefit (maximum, if you can use it)
What to check: if the tariff’s standard rates are higher by, say, 2–4p/kWh across the rest of the year, that uplift could reduce or cancel the benefit unless you regularly shift large kWh into the free window.
Assumptions & limitations: These scenarios use illustrative unit rates and typical appliance loads. Actual costs depend on your region, tariff, standing charge, household patterns, and whether events run (and you opt in) when you can use them.
FAQs
Is electricity ever truly free on these tariffs?
Usually it’s the electricity unit rate during a defined window that’s discounted to £0.00 or credited back. You will typically still pay the standing charge and any usage outside the window. Gas is generally not included unless explicitly stated.
Do I need a smart meter to get free electricity days?
Often, yes. Many suppliers rely on smart meter data (sometimes half-hourly) to identify consumption during the free window. Some deals may be available without one, but it’s less common and may come with tighter conditions.
Can prepayment meter customers get these offers?
It depends on the supplier and tariff. Some promotions exclude traditional prepayment, and some require Direct Debit. If you have a smart prepayment meter, availability may differ — always check the tariff’s eligibility rules before switching.
Are free electricity days the same as Economy 7 or other time-of-use tariffs?
Not exactly. Economy 7 and other time-of-use tariffs have regular off-peak rates (cheaper at set times). Free electricity promotions are typically occasional events or special windows and may be separate from standard off-peak pricing.
Will I be told in advance when the free window is?
Most suppliers that run events provide notice (for example via app, email, or account messages), but timing and notice period vary. If you can’t reliably plan around the window, the offer may have limited value.
Could a “free day” tariff still cost more overall?
Yes. If the tariff’s standard unit rate and/or standing charge are higher than alternatives, occasional free windows may not compensate. Always compare the estimated annual cost for your usage and region and check for exit fees if it’s fixed-term.
Does moving home or being a tenant affect eligibility?
You can usually switch supplier as a tenant if you pay the bills, but fixed-term tariffs may include exit fees if you leave early. Also consider whether you can install or keep a smart meter and whether you’ll be in the property long enough to benefit.
Is there a cooling-off period when switching?
In many cases you’ll have a cooling-off period for distance sales, but your exact rights depend on how the contract is agreed and the supplier’s process. If you’re unsure, check your contract documentation and consumer guidance.
Trust, methodology and sources
Page accountability
- Written by: EnergyPlus Editorial Team
- Reviewed by: Energy Specialist
- Last updated: March 2026
How we assess “free electricity day” claims
We focus on whether an offer is likely to reduce a household’s overall costs — not whether the marketing sounds attractive. Our assessment is based on:
- Total cost first: standing charge + unit rates for your region (electricity and gas where relevant)
- Eligibility: smart meter needs, payment method requirements, tariff type and contract term
- Practical usability: whether a typical household can shift enough kWh into the promo window
- Consumer protections: clear T&Cs, transparent billing/crediting, and fair exit terms
Limitations: Suppliers can change or withdraw promotions, and availability can vary by tariff, region and meter type. Always check the supplier’s current tariff information and your personalised quote before switching.
Helpful UK sources
- Ofgem — UK energy regulator information on consumer rights and the retail energy market
- Citizens Advice: Energy — practical guidance on bills, switching and complaints
- GOV.UK — official government guidance, including support schemes where applicable
Ready to check whether a free-day tariff is actually worth it?
Compare whole-of-market home energy deals by postcode and see the full cost breakdown. Treat free electricity hours as a bonus — not the decision.
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