WarmZilla vs British Gas: Stop Overpaying for the Same Boiler
By David Evans | Senior Heating Analyst | Updated: January 2026
At a Glance
Verified Analysis
If you are looking for the absolute premium experience of having a salesperson visit your home, British Gas is the traditional choice. However, our data shows you will pay a significant premium for this—often exceeding £1,000 for the exact same hardware.
The Head-to-Head Data
We compared a standard installation for a Worcester Bosch Greenstar 4000 (the UK’s most popular mid-range boiler) to see exactly where your money goes.
|
Feature |
WarmZilla |
British Gas |
|---|---|---|
|
Typical Price (Installed) |
£2,050 – £2,150 |
£2,850 – £3,200 |
|
Finance APR |
0% (2 Years) |
0% (3 Years) |
|
Warranty Terms |
10 Years (Included) |
5 Years (Subscription req.) |
|
Lead Time |
24 – 48 Hours |
1 – 3 Weeks (Avg) |
|
Survey Method |
Digital (Photo Upload) |
Physical (Sales Visit) |
Fact Check: The Hardware
Are the boilers actually identical?
Yes. A Worcester Bosch 4000 installed by WarmZilla comes from the exact same manufacturing line as one installed by British Gas. Both use standard copper pipework and magnetic filters. The £800+ price difference is purely operational overhead (sales commissions, fleet costs), not product quality.
1. The Price Gap: It’s Bigger Than It Looks
On the surface, British Gas quotes are approximately £800 higher than the independent market average. British Gas marketing highlights the inclusion of a Hive Mini thermostat (RRP £50) to justify this.
However, the total cost of ownership diverges significantly when analyzing warranty terms.
The “Warranty Catch” Calculator
British Gas typically offers a 5-year warranty. However, maintaining validity often requires an annual service, heavily incentivized via a HomeCare subscription.
British Gas: £2,850 Upfront + (£18/mo HomeCare x 60 months) = £3,930 Total
WarmZilla: £2,100 Upfront + (Standard Annual Service ~£80/yr) = £2,500 Total
Total 5-Year Saving with WarmZilla: £1,430
2. The Finance Reality
British Gas correctly advertises 0% APR for 3 years, which is a strong offer. It allows homeowners to spread the cost without penalty.
However, WarmZilla matches this with 0% finance (typically over 2 years). Because the WarmZilla baseline price is lower, the monthly impact is comparable, but the debt is cleared 12 months sooner.
- British Gas (36 Months): £79.16 per month.
- WarmZilla (24 Months): £87.50 per month.
3. Service & Speed Analysis
British Gas possesses the largest engineering fleet in the UK. In 2025 data, they reported an 80% same-day fix rate for morning breakdown calls. For customers prioritising long-term maintenance infrastructure over upfront cost, this is a valid selling point.
WarmZilla’s model prioritises installation speed. By removing the physical sales visit (replaced by AI-assisted photo surveys), they can deploy engineers within 24 hours. For distress purchases (broken boilers in winter), this speed metric often outweighs the “brand name” factor.
Final Verdict
If you value a physical sales consultation and an integrated “Hive” ecosystem, British Gas remains a reliable, albeit premium-priced, option.
However, from a purely financial perspective, WarmZilla is the logical choice. You receive identical Worcester Bosch hardware, a superior 10-year warranty (without subscription lock-in), and a total cost of ownership saving exceeding £1,000.