Octopus Energy Sainsbury’s Energy (August 2026)
Overview
Octopus Energy wins this comparison comfortably, leading on price, customer reviews, and digital tools, though we lack complete service data for Sainsbury's Energy.
Octopus Energy leads on customer reviews and app ratings, and it offers a marginally cheaper standard variable tariff than Sainsbury's Energy.
About Octopus Energy and Sainsbury's Energy
Who are Octopus Energy?
Founded in 2015, Octopus Energy is backed by the Octopus Group and several large investment funds. Through its own growth and by buying other suppliers, it has become the UK's largest domestic energy supplier. It runs on its own technology platform, Kraken, which it also licenses to other energy companies. What sets it apart is its wide range of smart tariffs and its rewards programme, Octoplus.
Who are Sainsbury's Energy?
Sainsbury's Energy is the energy brand of the UK supermarket chain. It operates as a partnership and is powered by E.ON Next, which handles the energy supply and customer service, making it one of the UK's largest domestic suppliers. The main feature of the brand is its link with the Nectar rewards scheme, allowing customers to earn bonus points on their shopping.
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Tariffs and pricing
Octopus Energy provides the cheapest tariff overall in this comparison. Its Flexible Octopus standard variable tariff is priced at £1,792 a year and carries no fixed term or exit fees. The lowest-priced option from Sainsbury's Energy is its standard variable tariff, which costs £1,805 a year and also has no exit fees.
For households seeking fixed rates, both suppliers offer deals that cost £1,841 a year based on our usage assumptions. Octopus Energy's cheapest fixed tariff requires a 12-month term and includes a £100 exit fee. Sainsbury's Energy's equivalent fixed option costs the same annually but requires a 24-month commitment and carries a £200 exit fee.
Tariff Options
Octopus Energy
Octopus Energy offers mainstream standard variable and fixed-term tariffs, alongside a wide selection of specialist smart tariffs for homes with electric vehicles, heat pumps, or solar panels.
Sainsbury's Energy
Sainsbury's Energy offers standard variable and fixed-term tariffs. It does not currently offer specialist electric vehicle, export, or smart tariffs.
Customer reviews
Octopus Energy scores higher in customer feedback metrics. It holds a 4.8 out of 5 Trustpilot rating across more than 837,000 reviews, with 90% of respondents awarding it five stars. Sainsbury's Energy maintains a 4.3 out of 5 rating from 3,127 reviews; 80% of these are five stars, while 10% give a one-star rating. Octopus replies to 96% of negative reviews, usually within a week, whereas Sainsbury's Energy responds to 35%.
Reviewers frequently describe Octopus Energy staff as helpful and knowledgeable, though a portion note occasional delays in email responses. Sainsbury's Energy customers highlight polite agents and the availability of WhatsApp support, while recurring complaints point to billing mistakes and rigid service processes.
In the annual Which? survey, Octopus Energy achieves 74 out of 100, compared to 71 out of 100 for Sainsbury's Energy. Both suppliers receive 10 out of 10 for helping customers who need it. Sainsbury's Energy outperforms Octopus on smart meters, scoring 8 out of 10 against Octopus's 5 out of 10.
App quality and features
Octopus Energy provides mobile apps for account management, whereas app data for Sainsbury's Energy is unavailable in this comparison. The Octopus iOS app holds a score of 4.8 out of 5 from 249,000 ratings and receives frequent updates. A small sample of recent iOS reviews shows mixed feedback, with some users reporting technical bugs.
On the Google Play Store, the Octopus Android app scores 4.4 out of 5 across more than 47,000 ratings, recording over a million installs.
Customer service and support
Octopus Energy places 4th in the Citizens Advice ratings, achieving a score of 3.67 out of 5. Call centre wait times average 1 minute 17 seconds, and the supplier answers 86.1% of emails within two days. Additionally, Octopus maintains formal vulnerability commitments registered with Citizens Advice.
Because Sainsbury's Energy lacks Citizens Advice data in this comparison, a direct evaluation of its performance on these specific service metrics is not possible.
See the contact-hours table above for Octopus Energy's phone availability.
Complaints and performance
In Q4 2025, Octopus Energy received 495 complaints for every 100,000 customers. Sainsbury's Energy received 989 complaints per 100,000 customers during Q3 2025.
Green Energy Comparison
Octopus Energy
According to Citizens Advice data for early 2026, Octopus Energy's electricity fuel mix is mostly renewable, with some nuclear power. The supplier describes its electricity as 100% zero-carbon. Through its generation arm, it invests heavily in renewable energy projects such as wind and solar farms across Europe. It also helps customers move away from fossil fuels by installing low-carbon technology like heat pumps and solar panels.[1]
Sainsbury's Energy
Sainsbury's Energy offers 100% zero-carbon electricity across its tariffs. It achieves this by matching the electricity its customers use with Renewable Energy Guarantee of Origin (REGO) certificates. The supplier also focuses on helping customers improve their home energy efficiency by offering discounts on low-carbon technology, such as solar panels and electric vehicle chargers.[2]
Our verdict
| If you care most about | Choose |
|---|---|
| The lowest annual cost on our assumptions | Octopus Energy |
| Overall customer service | Octopus Energy |
Octopus Energy wins this comparison comfortably, leading on price, customer reviews, and digital tools, though we lack complete service data for Sainsbury's Energy.
Based on the available evidence, Octopus Energy may suit a wider range of households. It provides a slightly cheaper standard variable tariff and scores higher on customer reviews and digital tools. A complete evaluation of Sainsbury's Energy is limited by the absence of Citizens Advice and app data in this comparison.
Households prioritising the slightly lower standard-variable price, stronger Trustpilot results or app availability may prefer Octopus Energy. Sainsbury's Energy cannot be fully assessed on Citizens Advice and app measures because data is unavailable.
- Cheaper standard variable tariff
- 4.8 out of 5 Trustpilot rating
- High ratings for mobile apps
- Average call centre wait time of 1 minute 17 seconds
- £100 exit fee on its cheapest fixed deal
- Lower Which? score for smart meters
- 8 out of 10 Which? score for smart meters
- 4.3 out of 5 Trustpilot rating
- Missing app and Citizens Advice data
- £200 exit fee and 24-month term on its cheapest fixed tariff
- Slower to reply to negative reviews
Frequently asked questions
Which supplier is better overall?
Octopus Energy performs better in this comparison. It offers a slightly cheaper standard variable tariff, significantly higher Trustpilot scores, and highly rated mobile apps, whereas Sainsbury's Energy is missing key app and service data.
Who offers the cheapest fixed tariff?
Both suppliers offer fixed deals that cost effectively identical amounts under our assumptions, priced at £1,841 a year. However, Octopus Energy's cheapest fixed deal ties you in for 12 months with a £100 exit fee, while Sainsbury's Energy's deal requires a 24-month commitment with a £200 exit fee.
Do customers prefer Octopus Energy or Sainsbury's Energy?
Customers rate Octopus Energy higher. It holds a 4.8 out of 5 rating on Trustpilot from over 837,000 reviews, compared to Sainsbury's Energy's 4.3 out of 5 rating from just over 3,000 reviews.
Which supplier has the better mobile app?
Octopus Energy has highly rated apps on both iOS and Android, scoring 4.8 and 4.4 out of 5 respectively. We do not currently have app data available for Sainsbury's Energy in this comparison.
How quickly does Octopus Energy answer the phone?
According to Citizens Advice data, Octopus Energy customers wait an average of 1 minute 17 seconds to speak to a call centre agent.
Should I switch to Octopus Energy or Sainsbury's Energy?
Octopus Energy is the recommended choice based on the available data. It leads on price, customer reviews, and digital tools. Sainsbury's Energy is missing some service data, making it harder to fully evaluate.
What are the exit fees for these suppliers?
Both suppliers offer standard variable tariffs with no exit fees. For their cheapest fixed deals, Octopus Energy charges a £100 exit fee, while Sainsbury's Energy charges £200.
How good is Sainsbury's Energy's customer service?
Sainsbury's Energy holds a generally positive 4.3 out of 5 rating on Trustpilot and scores 71 out of 100 in the annual Which? survey. However, it is missing Citizens Advice data in this comparison.
Do these suppliers offer variable tariffs without exit fees?
Yes, both Octopus Energy and Sainsbury's Energy offer standard variable tariffs that you can leave at any time without paying an exit fee.
What changed this month
This month, Sainsbury’s Energy's Trustpilot 2-star % rose from 1 to 2, Octopus Energy's iOS sampled positive reviews rose from 0 to 1, and Octopus Energy's iOS sampled negative reviews rose from 0 to 2. There were 26 other data changes this month — see the full changelog below for details.
Data changes this month (33)
Octopus Energy
- Trustpilot reviews821,111 → 837,814
- iOS app ratings count245,000 → 249,000
- iOS app days since last update9 → 6
- iOS sampled reviews avg starsnow available (2)
- iOS sampled positive reviews0 → 1
- iOS sampled negative reviews0 → 2
- Play Store rating4.4341745 → 4.3956046
- Play Store ratings count46,873 → 47,091
- Play Store days since last update11 → 2
- Play Store positive ratings %86.7 → 85.5
- Play Store negative ratings %10 → 11
- Play Store neutral ratings %3.3 → 3.5
- Play Store net-positive %76.7 → 74.5
- Cheapest fixed tariff£1,697.05 → £1,841.19
- Cheapest tariff£1,697.05 → £1,792.32
- Cheapest tariff exit fee£100 → £0
- Cheapest tariff term12 months → 0 months
- Tariff count2 → 3
- Fixed tariffs available1 → 2
Sainsbury’s Energy
- Trustpilot rating4.5 → 4.3
- Trustpilot reviews3,115 → 3,127
- Trustpilot 4-star %8 → 7
- Trustpilot 2-star %1 → 2
- Trustpilot negative reviews replied %36 → 35
- Trustpilot positive reviews %88 → 87
- Trustpilot negative reviews %11 → 12
- Trustpilot net-positive %77 → 75
- Cheapest fixed tariff£1,743.58 → £1,840.79
- Cheapest tariff£1,743.58 → £1,804.81
- Cheapest tariff exit fee£200 → £0
- Cheapest tariff term24 months → 0 months
- Cheapest fixed tariff exit fee£100 → £200
- Cheapest fixed tariff term12 months → 24 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.