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Energy Review
Supplier comparison

100Green vs British Gas (September 2026)

Overview

Our verdict
Too close to call

There is no single best choice: compare price, service, app and green-energy evidence separately.

Trustpilot
100Green
4.6
1,559 reviews
British Gas
4.5
353,681 reviews
Citizens Advice rank
100Green
#1
British Gas
#13
Cheapest variable
100Green
£1,762
/year
British Gas
£1,551
/year
iOS app
100Green
1.1
21 ratings
British Gas
4.5
14,000 ratings
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Tariffs and pricing

100Green
VARIABLE
Sparkling SVT
£1,762/year
No fixed term · Variable rates can change
Best for: maximum flexibility
FIXED 12M
Exclusive Spring 100% Green 12M September 27
£1,717/year
12-month term
Best for: price certainty
British Gas
CHEAPEST
VARIABLE
Cap Tracker Plus Sep27 v1
£1,551/year
No fixed term · Variable rates can change · Exit fee £50
Best for: customers who accept a £50 exit fee to leave
FIXED 21M
Fix and Boiler Bonus v14
£1,649/year
21-month term · Exit fee £200
Best for: price certainty

Annual estimates use the stored consumption assumptions. Check current regional rates, terms and eligibility before switching.

Customer reviews

Trustpilot
100Green4.6 / 5
British Gas4.5 / 5
Citizens Advice
100Green#1
British Gas#13
Which?
100Green72 %
British Gas59 %

Each review service uses its own method and scale, so the measures below should be read separately.

App quality and features

App Store
100Green1.1 · 21 reviews
British Gas4.5 · 14,000 reviews
Google Play
100Green1.23 · 32 reviews
British Gas4.18 · 13,701 reviews

App-store scores are shown by platform. No winner is declared where either ratings sample is missing or too small.

Service and support

Citizens Advice rank
100Green
#1
British Gas
#13
Citizens Advice score
100Green
4.33
out of 5
British Gas
2.61
out of 5
Emails ≤2 days
100Green
91%
British Gas
98%
Avg call wait
100Green
7 sec
British Gas
51 sec
Channel100GreenBritish Gas
PhoneWeekdays 8am–8pm, open Saturday and Sunday 9am–1pmWeekdays 8am–6pm, open Saturday 9am–2pm, closed Sunday
Email24/724/7
Social mediaBusiness hrsBusiness hrs

Only like-for-like service measures with data for both suppliers are ranked.

Complaints and performance

Per 100k customers
100Green
144
Q1 2026
British Gas
944
Q2 2026
CA per 10k
100Green
14.4
Citizens Advice
British Gas
68.7
Citizens Advice
Resolved same/next day
100Green
N/A
British Gas
43%
Resolved ≤8 weeks
100Green
N/A
British Gas
86%

Complaint figures are shown with each supplier’s reporting period. No winner is declared when periods differ or one figure is missing.

100Green — complaint themes
No complaint-reason breakdown was available in the supplied data
British Gas — complaint themes
Billing
51%
We focus on delivering quality service to our customers, ensuring they are billed accurately and in a timely manner as well as making sure our teams are equipped with the right tools to be able to support and help customers through to a swift resolution when they contact.
Payments
20%
We're improving our refund processes to ensure customers receive their money back more quickly when they've been paying too much.
Credit Management
12%
Reported complaint category for Q2 2026.
Customer Service
8%
We continue to make significant investment into our customer service operation recruiting more front-line agents again this quarter to support our customers. We ask our customers for feedback after our interactions which helps us understand how customers are feeling and respond where necessary. We have achieved a strong Net Promoter score of +34 this quarter which means that 58% of our customers rate us as happy.
Metering
4%
We continue to invest in Smart meters, providing meters to those who want them as well as fixing issues with existing meters or the In-House Display units.

Green Energy Comparison

100Green
100%Renewable
January to March 2026
Renewable100%
British Gas
20%Renewable
January to March 2026
Renewable20%
Nuclear57%
Fossil fuel21%
Other2%

Published fuel-mix figures are shown only where both a source URL and reporting period are present in the stored data.

Our verdict

Which should you choose?
If you care most aboutChoose
The lowest annual cost on our assumptionsBritish Gas
Overall customer service100Green
A greener fuel mix100Green
Our verdict
Too close to call

There is no single best choice: compare price, service, app and green-energy evidence separately.

Use the decision table to match the available evidence to the factors that matter most to your household.

100Green
Pros
  • Cheapest variable tariff at £1,762 / year
  • 4.6 Trustpilot from 1,559 reviews
  • Top-1 Citizens Advice ranking
  • 91% of emails answered within 2 days
×Cons
  • 94% of Google Play ratings are negative
British Gas
Pros
  • Cheapest variable tariff at £1,551 / year
  • 4.5 Trustpilot from 353,681 reviews
  • iOS app rated 4.5 out of 5
  • 98% of emails answered within 2 days
×Cons
  • Cheapest overall tariff carries a £50 exit fee
  • 20% of Trustpilot reviews are 1-star
  • 16% of Google Play ratings are negative

Frequently asked questions

Which is cheaper, 100Green or British Gas?

On the stored annual-cost assumptions, 100Green is £1,717 and British Gas is £1,551. British Gas is lower by about £167 a year.

Can 100Green and British Gas complaint rates be compared directly?

No direct complaint-rate winner is declared because 100Green and British Gas do not both have figures for the same stated reporting period.

Which supplier leads on customer service?

On the comparable customer-service measure used in the decision table, 100Green leads.

Which supplier has the better app evidence?

The supplied data does not support a like-for-like app winner.

Do tariff eligibility rules matter?

Yes. Specialist, time-of-use, EV, heat-pump and export tariffs can have equipment, meter or account requirements. Check the current supplier terms before applying.

Which supplier has the greener evidence?

On the comparable green-energy measure used in the decision table, 100Green leads. This row is based on published fuel-mix percentages.

Which is better overall, 100Green or British Gas?

There is no single overall winner in this repaired draft. Price, service, app and green-energy evidence are kept as separate choices in the decision table.

When was this comparison updated?

The structured source payload is for September 2026.

What changed this month

This month, British Gas's fixed tariffs available rose from 1 to 3, British Gas's iOS sampled negative reviews rose from 0 to 3, and British Gas's play store days since last update rose from 10 to 18. There were 34 other data changes this month — see the full changelog below for details.

Data changes this month (44)

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Rob Gibbs

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.

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