Cheapest green gas tariff UK: compare & switch now
Find the lowest-cost green gas options available for your home, with clear caveats on what “green gas” means in the UK (biomethane vs carbon offset). Compare by price, payment method and exit fees, then switch in minutes.
- Whole-of-market comparison: prices and tariff terms can vary by region, meter type and payment method
- See whether a tariff uses biomethane, carbon offsets, or a mix (and why that matters)
- Switching usually takes days (not hours) and your gas supply won’t be interrupted
Estimates only. Availability, unit rates and standing charges vary by postcode, meter type and payment method. “Green gas” definitions differ by supplier and tariff.
Fast answer: what is the cheapest green gas tariff in the UK?
There isn’t one universal “cheapest green gas tariff” for every UK home. The lowest-cost option depends on your postcode/region, payment method (Direct Debit vs prepayment), meter type (smart/traditional), and whether you want biomethane-backed green gas or a lower-cost carbon offset tariff.
Important: In the UK, most “green gas” tariffs do not deliver different molecules to your home. Your gas comes from the same network; the difference is what the supplier funds or matches (for example, biomethane injected into the grid) and/or what it offsets. Always check the tariff’s evidence and wording.
Key takeaways
- Cheapest is usually the tariff with the lowest standing charge + unit rate for your postcode.
- Green gas types: biomethane-backed tends to cost more; offsets may cost less but vary in quality.
- Check exit fees, price guarantees, and whether rates are fixed or variable.
- Switching typically completes in around 5 working days in normal circumstances; no engineer visit is usually needed.
Quick checklist (before you compare)
- Your postcode and current supplier/tariff (from a recent bill).
- Your gas usage in kWh (or estimate if you’ve just moved).
- Whether you can pay by monthly Direct Debit (often cheapest).
- Whether you want 100% biomethane match or you’re comfortable with offsetting.
If you’re in a hurry
Start with a quote and filter for green/eco gas, then compare:
- Total estimated annual cost
- Standing charge
- Exit fee
- Green gas definition (biomethane vs offset)
Compare cheapest green gas tariffs (whole-of-market)
Use the form to get tailored quotes for your home. We’ll match tariffs available in your area and highlight the “green gas” basis (where provided by suppliers), plus key terms like exit fees and payment method.
Tip: If you don’t know your annual gas usage, you can still compare. We’ll use an estimate, but your best accuracy comes from your latest bill (kWh) or smart meter history.
What “green gas” means in the UK (in plain English)
Biomethane-backed / “green gas match”
Supplier buys biomethane (from anaerobic digestion) and matches your usage with an equivalent amount injected into the grid (via certificates/contracts). This is usually the stronger “green gas” claim, but often costs more.
Carbon offset gas
Tariff may offset emissions linked to your gas use via carbon credits. This can be cheaper but quality varies. Look for clear details on the scheme and independent standards.
Hybrid / partial green gas
Some tariffs use a blend (for example, a smaller biomethane match plus offsets). These can balance cost and impact—but read the wording carefully.
Reality check: Your home still receives gas from the national distribution network. “Green gas” is about what’s funded or matched on your behalf, not dedicated green molecules delivered to your boiler.
Two realistic cost scenarios (with assumptions)
Scenario A: small flat, low usage, London
- Assumptions
- Annual gas use 8,000 kWh; standing charge 32p/day; unit rate 6.8p/kWh; paying by monthly Direct Debit; no exit fees.
- Estimated annual gas cost
- ~£640/year (standing charge ~£117 + usage ~£544). Rounded; VAT and price changes can affect totals.
- What changes the “cheapest green” outcome
- If the biomethane premium adds ~0.4–1.2p/kWh, low-usage homes may see a smaller £ difference than high-usage homes, but standing charge still matters.
Scenario B: 3-bed house, higher usage, North West
- Assumptions
- Annual gas use 16,000 kWh; standing charge 29p/day; unit rate 6.2p/kWh; monthly Direct Debit; fixed tariff with £50 exit fee.
- Estimated annual gas cost
- ~£1,066/year (standing charge ~£106 + usage ~£992). Rounded; excludes any early-exit fee unless you leave early.
- What changes the “cheapest green” outcome
- On higher usage, a small unit-rate difference can outweigh standing charge. Exit fees can wipe out savings if you switch again soon.
Get green gas quotes
Tell us a few details and we’ll show tariffs available for your postcode, including green/eco options.
What you’ll need to switch
- Your address and postcode
- Bank details (if paying by Direct Debit)
- A recent meter reading (optional but helps avoid billing surprises)
- Details of any fixed-term contract or exit fee
Compare green gas tariffs: what to look at (beyond headline price)
When people search for the “cheapest green gas tariff”, they often focus on the annual estimate only. Use the table below to avoid common traps—especially if you might move home, switch again, or your usage changes.
| What you compare | Why it matters | Best for | Watch out for |
|---|---|---|---|
| Total annual estimate | Combines standing charge + unit rate for your usage and region. | Most households as a starting point. | If your usage estimate is off, the ranking can change. |
| Standing charge (p/day) | You pay it regardless of usage—big factor for low-use homes. | Small flats, second homes. | A “cheap unit rate” can be offset by a high standing charge. |
| Unit rate (p/kWh) | Main driver of cost for medium/high usage homes. | Families, larger homes. | Green premiums (biomethane) often show up here. |
| Green gas basis | Biomethane-backed vs offsets affects environmental claim and price. | Anyone prioritising impact, not just cost. | Vague wording like “eco” without evidence details. |
| Exit fees | Could outweigh savings if you switch or move before term ends. | Those staying put for the full fixed term. | Multiple fuels can mean multiple fees. |
| Payment method eligibility | Direct Debit tariffs are often priced lower than pay-on-receipt. | People who can pay monthly. | Prepayment and some meter types have fewer options. |
Decision checklist: who a “cheapest green gas” switch suits
- You can pay by monthly Direct Debit and want to minimise cost.
- Your current deal is ending or you’re on a variable tariff and want to review options.
- You’re happy to choose between biomethane match and offset-based claims based on evidence and price.
- You’ve checked for exit fees and the likely length of stay in the property.
Who it may not suit (or needs extra care)
- You’re on a prepayment meter (choice can be more limited; check eligibility first).
- You might move soon and the tariff has a high exit fee.
- You want the strongest environmental claim—you may prefer a biomethane-backed tariff even if it isn’t the cheapest.
- You’re in the middle of a billing dispute—consider resolving it before switching (not essential, but can reduce admin issues).
EnergyPlus perspective: The “best” green gas tariff is the one that fits your budget and has clear, verifiable claims. If two tariffs are similar in price, we’d usually prioritise clearer biomethane matching and transparent reporting.
Costs, exclusions and common pitfalls (UK-specific)
These are the most common reasons a “cheap” green gas quote ends up being less suitable once you read the tariff terms.
1) Standing charges dominate low usage
If you use little gas (well-insulated flat, heat pump, or you’re out a lot), a slightly cheaper unit rate may not help if the standing charge is higher.
2) Exit fees and fixed terms
A fixed tariff can be good for budgeting, but if you may switch again soon (or move), exit fees can remove the benefit.
3) “Green” wording can be vague
Eco/green branding doesn’t always mean biomethane matching. Check for details: percentages, certificates/contracts, and reporting.
Regional pricing (why your friend gets a different deal)
UK gas network charges vary by region, so the same tariff name can have different standing charges/unit rates in different postcodes.
Payment method and meter constraints
Some tariffs are only available for Direct Debit. Prepayment options can be more limited. Smart meters usually help, but aren’t always required.
Switch timing and bills
You won’t lose supply when you switch. Take a meter reading around the switch date to help ensure your closing/opening bills are accurate.
Moving home? If you’re about to move, you can still compare for your new address. In many cases you’ll start on a deemed/default tariff at the new property, then switch once you’re responsible for the supply.
FAQs: cheapest green gas tariffs in the UK
Is green gas actually greener in the UK?
It can be, depending on the tariff. Biomethane-backed tariffs generally have a clearer link to renewable gas entering the grid. Offset-based tariffs may reduce net emissions on paper, but quality depends on the offset project and standards used.
Will I need a new boiler or a smart meter to get green gas?
Usually no. Green gas tariffs typically use the same gas network supply. A smart meter can improve billing accuracy, but it isn’t always required to switch tariffs.
Can I get green gas on a prepayment meter?
Sometimes, but options can be more limited than Direct Debit tariffs. If you’re on prepay and want more choice, it may be possible to switch to credit mode (subject to supplier checks and eligibility).
What’s the difference between fixed and variable green gas tariffs?
Fixed tariffs keep unit rates/standing charges set for a term (unless the contract allows changes), which can help budgeting but may include exit fees. Variable tariffs can change with supplier pricing and market conditions and are often easier to leave.
Does switching green gas affect my gas supply or pressure?
No. Your physical supply comes from the same network and won’t be interrupted by switching supplier. You’re changing who bills you and the tariff terms.
Why do I see different prices for gas-only vs dual fuel?
Some suppliers price dual fuel differently (and may offer incentives). Always compare the total cost and terms for each fuel. A dual-fuel deal isn’t automatically cheaper.
How can I check whether a supplier’s green claims are credible?
Look for clear explanations of how biomethane is matched (and how it’s evidenced), transparent reporting, and details of any offset standards. If a tariff only uses broad marketing terms, ask for the written tariff details.
Is there a cooling-off period when I switch gas in the UK?
Consumer protections apply and you’ll usually have a cooling-off period for distance sales. Exact rights can depend on how you sign up and the supplier terms—always read the tariff information before confirming.
Trust, methodology and sources
Page ownership
- Written by
- EnergyPlus Editorial Team
- Reviewed by
- Energy Specialist
- Last updated
- April 2026
How we assess “cheapest green gas”
- Price: we focus on estimated annual cost using unit rate + standing charge for your postcode and usage where available.
- Eligibility: we consider payment method, meter type, and availability by region.
- Tariff terms: fixed vs variable, exit fees, contract length, and key conditions.
- Green basis: we surface whether a tariff states biomethane matching, offsets, or a blend (as described by the supplier).
Limitations (what we can’t promise)
- Prices change; quotes are time-sensitive and can differ by postcode.
- Supplier “green gas” descriptions are not fully standardised across the market.
- Your final cost depends on your actual usage, billing dates, and any tariff conditions.
- We do not guarantee that the cheapest option is the best environmental choice for every household.
Sources (UK): We reference regulator and consumer guidance for switching and consumer rights. See: Ofgem, Citizens Advice energy guidance, and GOV.UK.
Ready to find the cheapest green gas tariff for your postcode?
Get tailored quotes, compare tariff terms, and switch with confidence—without losing supply.
Estimates only. Always check the supplier’s tariff information and whether an exit fee applies before you switch.
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