How SwitchInsights reviewed So Energy: we looked at price versus the forecast Q4 cap, the Trustpilot and Citizens Advice record, smart meter support and exit-fee terms. We update it whenever Ofgem moves the cap or So Energy changes a tariff.
The short version
So Energy sits roughly in line with the forecast Q4 cap on price - not below it, not far above it - and clearly ahead of most large suppliers on customer service. Its loyalty rate for existing customers actually undercuts the cap; its cheapest new-customer fix, So Iguana 18m, lands within £18 of it. But cheaper peers exist. Fuse Energy's 18-month fix comes in around £150 a year lower, and E.ON Next's 24-month fix comes in around £100 lower, so anyone chasing the absolute cheapest sticker will find it elsewhere.
Where So Energy earns its place is a mix of service (4.6 Trustpilot from around 32,000 reviews, Sunday Times Best Places to Work three years running) and stability (traded continuously since 2015, backed by Ireland's state-owned ESB since 2021). For households who value that mix over price-hunting, So Energy is a defensible pick. For everyone else, at least run the loyalty and 18-month fix past the tariff tracker before switching away.
What is So Energy?
So Energy is a UK domestic energy supplier founded in 2015 by Simon Oscroft and Charlie Davies, both former Macquarie energy traders. It went to market as a challenger brand selling 100% renewable electricity to households frustrated with the Big Six, and grew steadily rather than aggressively - avoiding the loss-leading pricing that collapsed around thirty rival suppliers in the 2021-22 wholesale gas crisis.
Ownership changed materially in August 2021, when Ireland's state-owned electricity company ESB (95% owned by the Irish state) took a 75% majority stake and merged its own UK retail arm, ESB Energy, into So Energy. The two co-founders kept a combined 10% stake and stayed on the executive team; Charlie Davies is CEO today. So Energy now serves around 300,000 UK households from London, with roughly 440 employees. The 100% renewable electricity promise carried through the merger, though as with every UK supplier the underlying electricity mix depends on grid conditions rather than direct farm-to-plug supply.
From start-up to ESB majority-owned green supplier
2015Founded on 100% renewable electricity
Simon Oscroft and Charlie Davies launch So Energy in London, funded initially by their own savings and small angel cheques. The pitch is straightforward: renewable electricity at prices that undercut the Big Six's premium green tariffs.
2021ESB takes 75% majority stake
Ireland's state-owned ESB acquires a controlling 75% stake and merges its UK arm, ESB Energy, into So Energy. The founders retain a combined 10% and stay on the executive team. So Energy holds pricing through the 2021-22 wholesale gas crisis while around thirty rival suppliers collapse into administration.
2026~300,000 customers, Sunday Times Best Places to Work three years running
So Energy serves around 300,000 UK households from London with roughly 440 staff. Charlie Davies leads as CEO. Trustpilot rating 4.6 from ~32,000 reviews; Sunday Times Best Places to Work (Big Company) for the third year running.
So Energy tariffs and prices versus the forecast Q4 cap
Ofgem is due to confirm the Q4 2026 price cap on Tuesday 26 August, with new rates running from 1 October to 31 December. E.ON Next's most recent published forecast puts the Q4 cap at £1,729 a year for a typical dual-fuel Direct Debit household on Ofgem's current TDCV standard (2,500 kWh electricity, 9,500 kWh gas), a rise of about £66 from the Q3 figure of £1,663 on the same TDCV. Cornwall Insight and EDF publish separately on the older TDCV; the E.ON Next figure is the closest apples-to-apples benchmark for the tables below. The final confirmed number lands on Ofgem announcement day and we will update this page then.
| Tariff | Term | Electricity | Gas | Typical annual cost |
|---|---|---|---|---|
| Q4 2026 cap forecast (E.ON Next) | Benchmark | ~27.05p/kWh, ~58.70p/day | ~7.55p/kWh, ~29.75p/day | ~£1,729/year |
| So Energy default tariff | Variable | Tracks the Q4 cap rate | Tracks the Q4 cap rate | ~£1,729/year |
| So Iguana 12m | Fixed | 26.90p/kWh, 56.00p/day | 8.30p/kWh, 29.49p/day | £1,773/year |
| So Iguana 18m | Fixed | 28.00p/kWh, 47.00p/day | 7.90p/kWh, 24.45p/day | £1,711/year |
| So Iguana 24m | Fixed | 27.20p/kWh, 58.00p/day | 7.85p/kWh, 30.21p/day | £1,748/year |
| So Iguana Loyal 24m | Existing customers | 26.20p/kWh, 58.00p/day | 7.50p/kWh, 30.21p/day | £1,689/year |
| So EV Fixed 12m | Electricity only | 7.50p/kWh, 57.00p/day | Not applicable | £396/year |
Against the forecast Q4 cap of around £1,729, the picture is close. So Iguana 18m lands £18 below the cap, So Iguana 24m sits £19 above, So Iguana 12m runs £44 above, and the loyalty-only 24-month rate for existing customers undercuts the cap by £40 a year. That is a much narrower spread than the "every fix beats the cap" story the tariff-tracker gives on the true cheapest options - which is why the comparison table in the next section matters more than the vs-cap column here. So EV Fixed 12m is an electricity-only rate for EV households running a separate gas deal or an all-electric home.
Exit fees: So Iguana 12m charges £75 per fuel to leave early, £150 total for a dual-fuel household. The 18, 24 and loyalty 24-month fixes charge £95 per fuel, waived in the final 49 days.
So Energy vs Octopus Energy, E.ON Next and Fuse: fixed deal comparison
The table below lines up So Energy's nearest-term fixes against the cheapest live fixed deals from three peer suppliers - Fuse Energy (the current cheapest), E.ON Next and Octopus Energy - priced on the same typical dual-fuel usage against the E.ON Next Q4 cap forecast. All annual costs are the midpoint across 14 GB regions.
| Supplier | Tariff | Term | Typical annual cost | Vs Q4 cap forecast | Exit fee |
|---|---|---|---|---|---|
| Q4 2026 cap forecast | Benchmark | N/A | ~£1,729/year | - | - |
| Fuse Energy | Fixed 18m v5 | 18 months | ~£1,563/year | -£166/year | £50/fuel |
| E.ON Next | Next Fixed 24m v63 | 24 months | ~£1,615/year | -£114/year | £100/fuel |
| Octopus Energy | Octopus 12M Fixed | 12 months | ~£1,694/year | -£35/year | £50/fuel |
| So Energy | So Iguana Loyal 24m (existing only) | 24 months | ~£1,689/year | -£40/year | £95/fuel |
| So Energy | So Iguana 18m | 18 months | ~£1,711/year | -£18/year | £95/fuel |
| So Energy | So Iguana 24m | 24 months | ~£1,748/year | +£19/year | £95/fuel |
| So Energy | So Iguana 12m | 12 months | ~£1,773/year | +£44/year | £75/fuel |
Fuse Energy's 18-month fix undercuts the Q4 cap forecast by £166 a year, and E.ON Next's 24-month fix by £114 - the two most aggressively priced deals on the tariff tracker for a typical dual-fuel household. So Energy's cheapest 18-month option lands £18 below the cap, and the loyalty rate for existing customers £40 below. So Energy is not the cheapest, but it is nowhere near "expensive" once the benchmark is set at a realistic Q4 cap number rather than a Q3 comparison. The main gap between So Energy and Fuse or E.ON Next is service model and product depth, not headline sticker price.
So Energy customer service and Trustpilot record
Trustpilot and Citizens Advice: So Energy's Trustpilot rating sits at 4.6 stars from around 32,000 entries, ahead of E.ON Next and most legacy suppliers, though behind Octopus Energy's 4.8 stars from over 700,000 reviews. On the Citizens Advice complaints scorecard, So Energy holds a mid-table spot.
So Energy billing and the app
So Energy runs phone and live chat support with UK-based agents, and most queries resolve within a day or two. The billing platform is straightforward, not innovative, lacking the granular usage dashboards Octopus Energy's Kraken platform provides.
Which So Energy tariffs work with a smart meter
So Energy smart meter support covers SMETS2 devices at no extra cost, feeding accurate monthly billing across every tariff. There is no time-of-use or half-hourly smart tariff, unlike Octopus Energy's Agile and Cosy range, so it improves billing accuracy without unlocking a cheaper off-peak rate.
So Energy pros and cons
What works
- 4.6-star Trustpilot rating from around 32,000 reviews, ahead of most large suppliers
- Loyalty-only 24-month fix for existing customers undercuts the Q4 cap forecast by around £40 a year
- ESB-backed since 2021 and traded continuously through the 2021-22 crisis - Ireland's state utility carries the balance sheet risk
- Sunday Times Best Places to Work (Big Company) three years running - service culture reflected in the Trustpilot score
- UK-based phone and live chat support, SMETS2 smart meters fitted free
Worth knowing
- Cheapest fixes on the market undercut So Energy by roughly £100-£150 a year (Fuse 18m, E.ON Next 24m)
- No time-of-use, EV smart, or solar export tariff, unlike Octopus Energy or E.ON Next
- Billing platform is straightforward but lacks the granular usage dashboards Kraken-based rivals offer
Verdict by household type
The right call depends on usage pattern and whether a household already holds a So Energy account.
Typical dual-fuel household
Fix elsewhere for the sticker-price saving. Fuse Energy's 18-month fix at around £1,563 undercuts the forecast cap by £166 and every So Energy fix by roughly £150. E.ON Next's 24-month fix at around £1,615 saves close to £100 versus So Iguana 18m. Existing So Energy customers eligible for the loyalty 24m rate (~£1,689) can reasonably stay put - it undercuts the cap and only trails Fuse and E.ON Next by moderate amounts.
Low-use flat
Favour the default tariff over any fix. Standing charges make up a larger share of a low-use bill, and the So Energy standing charge sits close to or above the cap on most fixes, so the usual fixing saving barely materialises.
High-gas home
Prioritise the lowest gas unit rate on the market over the So Energy unit rate specifically. E.ON Next's gas rate undercuts So Iguana 12m's by a margin that compounds on high winter usage.
Frequently asked questions
Is So Energy any good in 2026?
Solid on service, average on sticker price. So Energy scores 4.6 on Trustpilot from around 32,000 reviews, ahead of most large suppliers, and is Sunday Times Best Places to Work three years running. On price, its cheapest new-customer fix (So Iguana 18m) sits £18 below the forecast Q4 cap and the existing-customer loyalty 24m undercuts the cap by £40. Cheaper peers exist - Fuse and E.ON Next both run around £100-£150 lower - so So Energy is a fair mid-market pick, not the cheapest.
Is So Energy cheap right now?
Not the cheapest, but not expensive either. So Iguana 18m undercuts the forecast Q4 cap by around £18 a year, and the loyalty-only 24-month rate undercuts it by around £40. Fuse Energy's 18-month fix at around £1,563 and E.ON Next's 24-month fix at around £1,615 are still £100-£150 a year cheaper than any So Energy new-customer fix.
So Energy vs E.ON Next: which is cheaper?
E.ON Next's Next Fixed 24m at around £1,615 a year is meaningfully cheaper than So Iguana 18m at around £1,711 or 24m at around £1,748 - a £96 to £133 gap for a typical dual-fuel household. So Energy's edge is in customer service ratings, not price.
So Energy vs Octopus Energy: which is cheaper?
Octopus Energy's 12-month fixed tariff undercuts So Energy's equivalent term, and Octopus also offers time-of-use and EV tariffs that So Energy does not have.
Does So Energy support smart meters?
Yes, So Energy fits SMETS2 smart meters at no extra cost. There is no time-of-use or EV smart tariff, so a smart meter improves billing accuracy without unlocking a cheaper off-peak rate.
What is So Energy's Trustpilot score?
So Energy's Trustpilot rating sits at 4.6 out of 5 from around 32,000 reviews, ahead of E.ON Next but behind Octopus Energy's 4.8 from over 700,000 reviews.
How to switch to So Energy
Switching typically completes within three weeks, with no interruption to supply. Compare So Energy's current rate against the wider market on the SwitchPilot tariff tracker first, since other suppliers are sometimes cheaper.
So Energy exit fee: what does it cost to leave?
So Iguana 12m charges £75 per fuel to leave early, £150 total for a dual-fuel household. The 18 and 24-month fixes charge £95 per fuel, £190 total, waived in the final 49 days.
How financially stable is So Energy?
So Energy has traded continuously since 2015 and held its pricing through the 2026 wholesale gas swings. It remains a mid-sized independent supplier, worth weighing alongside price when choosing a fixed term.