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Which? boiler brand reviews tell you which are the most and least reliable boilers according to our survey of thousands of boiler owners. We also tell you what expert heating engineers make of each brand. For a quick decision on which brands you can trust, and which you can't, head straight to our round-up of the best boiler brands.

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Viessmann boiler reviews

What is 'Brand score'?

The brand score is made up of brand reliability (assessed by customer survey), brand customer satisfaction (assessed by customer survey) and ratings from heating engineers (based on Which? Trusted Traders heating engineer survey). These surveys were carried out in May 2019. To learn more read how we assess boilers.
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