Octopus Energy 100Green (July 2026)
Overview
Octopus Energy offers a lower-priced variable tariff and higher-rated apps, while 100Green ranks higher for customer service and has a slightly cheaper fixed deal.
Octopus Energy leads this comparison due to its lower-priced variable tariff and higher app ratings. However, 100Green may suit households prioritising traditional customer service, ranking first with Citizens Advice and offering a marginally cheaper fixed deal.
About Octopus Energy and 100Green
Who are Octopus Energy?
Octopus Energy started in 2015 and is backed by the Octopus Group and other investors. Through its own growth and by buying other suppliers like Bulb and Shell Energy, it has grown to become the UK's largest domestic energy supplier. It runs its customer accounts on its own software system, Kraken, and installs green technology like heat pumps and electric vehicle chargers.
Who are 100Green?
100Green started in 2001 as Green Energy UK and is an independent, privately owned business based in Hertfordshire. It is a smaller UK supplier that focuses entirely on green energy. Because it costs more to buy real green energy, 100Green has an exemption from the Ofgem price cap, meaning its standard prices can be higher than other suppliers.
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Tariffs and pricing
For those looking to lock in their rates, 100Green's cheapest overall tariff is the Exclusive Spring 100% Green 12M July 27, a fixed deal priced at £1,671 a year. Octopus Energy's lowest-priced equivalent is the Octopus 12M Fixed July 2026 v2 at £1,697 a year. While both are 12-month fixed contracts, Octopus applies a total exit fee of £100, whereas 100Green does not charge for leaving early.
Households preferring a flexible contract without a fixed term will find Octopus Energy's variable option costs less. The Flexible Octopus tariff is priced at £1,792 a year, which is £184 below 100Green's Sparkling SVT at £1,976 a year. It is worth noting that neither supplier currently participates in the Energy Switch Guarantee.
Tariff Options
Octopus Energy tariffs
Octopus Energy offers standard variable and fixed-term tariffs for everyday household use, alongside a wide choice of smart and specialist tariffs for homes with electric vehicles, heat pumps, solar panels, and battery storage.
100Green tariffs
100Green offers a focused range of domestic tariffs, including standard variable and fixed-term options, as well as premium green and time-of-use smart tariffs.
Customer reviews
On Trustpilot, Octopus Energy holds a 4.8 rating across a substantial volume of over 800,000 reviews, with 90% of respondents awarding five stars. 100Green scores 4.6 from a smaller sample of around 1,500 reviews, where 74% give five stars. Both suppliers actively engage on the platform; 100Green replies to 100% of its negative reviews, while Octopus responds to 96%.
Review text indicates that Octopus customers frequently mention helpful staff and quick response times, though some report occasional unanswered calls. 100Green customers similarly note the ease of speaking to a representative quickly, alongside a few reports of communication issues during account changes. Across both suppliers, common review themes centre on customer service, staff interactions, and response times.
The annual Which? survey awards Octopus Energy an overall score of 74, placing it slightly ahead of 100Green at 72. Both suppliers achieve 4 out of 5 for overall customer service. Octopus receives 10 out of 10 for helping those who need it, whereas 100Green scores 4 out of 10 in this category. Conversely, 100Green scores 12 out of 15 for complaints handling, compared to 8 out of 15 for Octopus. For the switching process, 100Green receives 1 out of 5, while Octopus scores 3 out of 5.
App quality and features
Octopus Energy provides digital account management through its apps, scoring 4.8 on the App Store and 4.4 on Google Play, alongside over a million Android installs. In contrast, 100Green does not currently have an iOS app rating available in the provided data, and its Android app scores 1.2 on Google Play based on a small number of reviews.
Both suppliers actively maintain their mobile platforms. The Octopus apps have received updates within the last few weeks. 100Green's Android app was also recently updated, introducing a redesigned interface intended to simplify navigation.
Service and support
In the latest Citizens Advice data, 100Green ranks first overall with a score of 4.33 out of 5. Octopus Energy places fourth, scoring 3.67.
100Green records an average call centre wait time of seven seconds, compared to 1 minute 17 seconds for Octopus Energy. For digital correspondence, 100Green responds to 90.9% of emails within two days, slightly ahead of Octopus at 86.1%. Additionally, 100Green averages a social media response time of 55 seconds; this specific metric is not available for Octopus.
Both suppliers maintain formal vulnerability commitments registered with Citizens Advice. Octopus Energy's phone lines operate Monday to Thursday from 9am to 5pm, and Friday from 9am to 4pm, remaining closed on weekends. 100Green provides longer contact hours, operating weekdays from 8am to 8pm, and weekends from 9am to 1pm.
Complaints and Performance
In the last three months of 2025, 100Green received 150 complaints for every 100,000 customers. Octopus Energy received 495 complaints per 100,000 customers in the same time.
Green Energy Comparison
Octopus Energy
Based on Citizens Advice data from January to March 2026, Octopus Energy supplies a mostly renewable mix, with some nuclear. The company invests in green power and owns renewable energy sites, such as wind and solar farms, across the UK and in other countries. It also helps customers move away from fossil fuels by installing heat pumps and offering electric vehicle leasing.[1]
100Green
Based on Citizens Advice data from January to March 2026, 100Green supplies a 100% renewable electricity mix. The supplier buys its electricity directly from small UK renewable generators, such as wind, solar, hydro, and biomass sites, rather than just buying green certificates. It is also the only UK supplier to give customers 100% green gas made from organic waste.[2]
Our verdict
| If you care most about | Choose |
|---|---|
| The lowest annual cost on our assumptions | 100Green |
| Overall customer service | 100Green |
| A well-rated mobile app | Octopus Energy |
| A greener fuel mix | 100Green |
Octopus Energy offers a much cheaper variable tariff and higher-rated apps, though 100Green ranks higher for customer service and has a slightly cheaper fixed deal.
Octopus Energy provides a lower-priced variable tariff and higher-rated mobile apps, which may suit households preferring digital account management. Alternatively, 100Green may appeal to those prioritising fast phone support, leading the Citizens Advice rankings and offering a slightly cheaper fixed tariff with no exit fees.
There is no clear all-round winner: Octopus Energy may suit households prioritising a lower-priced variable tariff and established apps, while 100Green may suit those prioritising phone support, the lowest annual cost on our assumptions and a fixed deal without exit fees.
- Lower-priced standard variable tariff
- Higher app ratings on iOS and Android
- High volume of five-star Trustpilot reviews
- Scores 10/10 in Which? for helping those who need it
- £100 total exit fee on its cheapest fixed deal
- Longer average call centre wait times than 100Green
- Ranks first overall in Citizens Advice data
- Average call wait time of seven seconds
- Marginally cheaper fixed deal with no exit fees
- 100% green gas and electricity
- Standard variable tariff costs more than Octopus
- Low app rating on Google Play
- No iOS app rating available in provided data
- Lower Which? scores for switching and helping those who need it
Frequently asked questions
Which supplier is better overall, Octopus Energy or 100Green?
Octopus Energy offers a lower-priced variable tariff and highly rated mobile apps. However, 100Green is a strong alternative if you prioritise customer service, as it ranks first with Citizens Advice and has a slightly cheaper fixed deal.
Does Octopus Energy or 100Green have cheaper tariffs?
100Green currently offers the cheapest fixed deal at £1,671 a year, compared to £1,697 for Octopus Energy. However, if you want a variable tariff, Octopus is much cheaper at £1,792 a year, compared to £1,976 for 100Green.
What do customers say about Octopus Energy and 100Green on Trustpilot?
Both suppliers review well, but Octopus Energy has a higher rating of 4.8 from over 800,000 reviews, with customers praising its helpful staff and quick responses. 100Green scores 4.6 from around 1,500 reviews, with reviewers also highlighting helpful service and the ease of speaking to a real person.
Are the Octopus Energy and 100Green apps any good?
Octopus Energy has highly rated apps on both Apple and Android devices. In contrast, 100Green's Android app has a very low rating on the Google Play Store, and it does not currently have an iOS app rating available in the data we reviewed.
Which supplier is easier to contact, Octopus Energy or 100Green?
100Green is faster to contact by phone, with an average call centre wait time of just seven seconds, compared to 1 minute 17 seconds for Octopus Energy. 100Green also responds to emails slightly faster.
Should I choose Octopus Energy or 100Green?
If you want a cheap variable tariff and a great app experience, Octopus Energy is the better choice. If you prefer traditional phone support and want a fixed deal with no exit fees, 100Green is a strong option.
Do Octopus Energy or 100Green charge exit fees?
Octopus Energy charges a £100 total exit fee on its cheapest 12-month fixed tariff. 100Green does not charge any exit fees on its cheapest fixed deal. Neither supplier charges exit fees on their standard variable tariffs.
What are the opening hours for Octopus Energy and 100Green?
100Green is open on weekdays from 8am to 8pm, and on weekends from 9am to 1pm. Octopus Energy is open Monday to Thursday from 9am to 5pm, and Friday from 9am to 4pm, but is closed on weekends.
Do Octopus Energy and 100Green offer green energy?
Yes, 100Green offers 100% green electricity and is the only UK supplier to provide 100% green gas made from organic waste. Octopus Energy supplies a mostly renewable electricity mix and offers several green tariffs.
What changed this month
This month, Octopus Energy's cheapest tariff term changed from a variable tariff to a 12-month fixed deal, 100Green's cheapest tariff term changed from a variable tariff to a 12-month fixed deal, and 100Green's cheapest fixed tariff term rose from 1 month to 12 months. There were 35 other data changes this month — see the full changelog below for details.
Data changes this month (45)
Octopus Energy
- Trustpilot reviews807,247 → 821,111
- iOS app ratings count244,000 → 245,000
- iOS app days since last update25 → 9
- Play Store rating4.4444447 → 4.4341745
- Play Store ratings count46,777 → 46,873
- Play Store days since last update25 → 11
- Play Store positive ratings %87 → 86.7
- Play Store negative ratings %9.8 → 10
- Play Store neutral ratings %3.2 → 3.3
- Play Store net-positive %77.2 → 76.7
- Citizens Advice rank3 → 4
- Citizens Advice score3.78 → 3.67
- Complaints per 10,000 customers21.8 → 21.3
- Avg call centre wait time72 → 77
- Emails responded within 2 days %90.4 → 86.1
- Cheapest variable tariff£1,566.25 → £1,792.32
- Cheapest fixed tariff£1,691.36 → £1,697.05
- Cheapest tariff£1,566.25 → £1,697.05
- Cheapest tariff exit fee£0 → £100
- Cheapest tariff termvariable → 12 months
100Green
- Trustpilot reviews1,496 → 1,511
- iOS app rating1.1 → no longer available
- iOS app ratings count20 → no longer available
- iOS sampled reviews avg stars1 → no longer available
- iOS sampled negative reviews8 → 0
- Play Store rating1.2692307 → 1.2413793
- Play Store ratings count27 → 30
- Play Store days since last update121 → 15
- Play Store positive ratings %3.8 → 3.4
- Play Store negative ratings %92.3 → 93.1
- Play Store neutral ratings %3.8 → 3.4
- Play Store net-positive %-88.5 → -89.7
- Citizens Advice rank6 → 1
- Citizens Advice score3.62 → 4.33
- Complaints per 10,000 customers17.9 → 14.4
- Avg call centre wait time10 → 7
- Avg social media response timenow available (55)
- Emails responded within 2 days %96.9 → 90.9
- Cheapest variable tariff£1,914.44 → £1,975.79
- Cheapest fixed tariff£1,921.16 → £1,671.16
- Cheapest tariff£1,914.44 → £1,671.16
- Cheapest tariff termvariable → 12 months
- Cheapest fixed tariff term1 month → 12 months
- Shortest fixed term1 month → 12 months
- Longest fixed term1 month → 12 months
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Written by
Rob Gibbs
Hi, I'm Rob, and I run Energy-Review.co.uk. I initially started this project in 2018 when I was looking to switch energy suppliers and found there wasn't a website that provided simple, data-backed reviews on all the suppliers available. Since then, I have spent a lot of time (too much, some may say!) looking at all publicly available data about each supplier and writing reviews using this information. These reviews are updated as regularly as possible, and any data is backed up by a source where necessary. I have also started writing guides on various energy-related topics, which hopefully you will find useful. If you find any issues, please use our contact form to let us know.