Glossary · Boilers and boiler types
What is a Vaillant boiler?
A Vaillant boiler is a gas boiler from Vaillant, a heating company founded in Remscheid, Germany, in 1874 and now sold in more than 60 countries. Its UK range includes the ecoTEC plus. Vaillant gives a 5-year guarantee as standard, and says it can reach 10 years when registered through an approved installer.
Key points
- Vaillant was founded in 1874 by Johann Vaillant in Remscheid, Germany. It opened its UK sales and production site in Belper in 2001, per its own timeline.
- The ecoTEC plus range has a 5-year guarantee out of the box. Vaillant says it can be extended to 10 years through its installer scheme.
- The 10-year route needs an installer registered with Vaillant's myREWARDS scheme and a boiler protection kit with a filter.
- Vaillant says the ecoTEC plus can drop to 16% of its maximum power when less heat is needed.
- BASI says it is an accredited Vaillant installer and offers up to a 10-year warranty on fitted boilers.
What a Vaillant boiler is
Vaillant is a heating manufacturer with German roots. Its heritage page says Johann Vaillant founded the company in Remscheid, Germany, in 1874, and that Vaillant is now represented in more than 60 countries.[1]Vaillant, Our heritage The same timeline says the Vaillant Group opened its UK sales and production site in Belper, Derbyshire, in 2001, and that a first condensing appliance followed earlier, in 1995.[1]Vaillant, Our heritage
The page lists later milestones too: a boiler called the ecoTEC exclusive with Green iQ technology in 2016, a remastered ecoTEC plus in 2023 with smart home ready capabilities, and a new range of hot water cylinders made at a Derby facility opened in 2025.[1]Vaillant, Our heritage Vaillant also makes heat pumps, which this page does not cover.
The ecoTEC plus range
The ecoTEC plus is one of Vaillant’s boiler ranges, and BASI fits it. Vaillant describes the open vent version as a high-performance, efficient boiler for existing buildings with an aluminium heat exchanger, and says it can drop to 16% of its maximum power when you do not need as much heat.[2]Vaillant, ecoTEC plus open vent boiler That ability to adjust output is called modulation, which you can read about under modulating boiler. The page we read covers the open vent version. Check Vaillant’s product page for the version you are considering, because terms can differ.
| Point | What Vaillant says |
|---|---|
| Standard guarantee | 5 years out of the box |
| Extended guarantee | Up to 10 years when fitted by a myREWARDS installer |
| Condition for 10 years | Registered with the Boiler Protection Kit or the Advanced Boiler Protection Kit (a filter) |
| Installer scheme | Open to Gas Safe registered or MCS certified installers, in Silver, Gold and Platinum tiers |
All of this comes from the ecoTEC plus product page.[2]Vaillant, ecoTEC plus open vent boiler The tiers carry different perks, so what is on offer depends on which installer you use. Ask for the guarantee length, in writing, for the exact model on your quote.
Servicing and the guarantee
Vaillant says an annual service from a Gas Safe registered engineer is needed to keep the guarantee valid after the first year, and recommends a magnetic filter to catch sludge before it reaches the boiler.[3]Vaillant, How long do boilers last? See the magnetic system filter page for how that works and how long do boilers last for the lifespan figures. The HSE says anyone employed to work on gas appliances in a home must be Gas Safe registered, so the Gas Safe Register is where to check an engineer.[5]Health and Safety Executive, Domestic gas: frequently asked questions
Buying one through BASI
BASI says it is an accredited installer for both Worcester Bosch and Vaillant, and that Vaillant boilers fitted by it carry up to a 10-year warranty.[4]BASI Heating, Worcester Bosch and Vaillant: side-by-side Its comparison page lists a Vaillant ecoTEC 28 combi as a fixed-price package with a magnetic system filter and cleanse and a 10-year parts and labour warranty.[4]BASI Heating, Worcester Bosch and Vaillant: side-by-side Prices and terms change, so check boiler installation and prices. The manufacturers page compares Vaillant and Worcester Bosch, and the Worcester Bosch boiler page covers the other brand.
Example
Fatima in Leeds gets quotes for a new combi. One quote is for an ecoTEC plus. The installer explains that the 5-year guarantee extends to 10 years only when they register it through Vaillant’s scheme and fit a boiler protection kit with a filter. Fatima asks for that to be written on the quote and for the annual service dates to be set out.
What people get wrong
The headline “10 year guarantee” reads like a property of the boiler. It is a property of the boiler plus the installer plus the filter plus the yearly service. Miss one and you may be back to the standard term.
The other mistake is assuming a page about one version covers all. One range can have several versions, and each version’s terms are set on its own product page.
The bottom line
A Vaillant boiler is a gas boiler from a company founded in 1874, with the ecoTEC plus among its UK ranges. It carries a 5-year guarantee that can reach 10 through an approved installer, a filter and annual servicing. Ask for the exact guarantee in writing and use a Gas Safe registered engineer.
Common questions
Where are Vaillant boilers made?
Vaillant is a German company, and its timeline says it opened a UK sales and production site in Belper, Derbyshire, in 2001. It also lists a manufacturing facility in Derby opened in 2025 for cylinders.
How long is a Vaillant guarantee?
Vaillant says the ecoTEC plus has a 5-year out-of-the-box guarantee, extendable to 10 years when fitted by a myREWARDS installer with a boiler protection kit. Terms vary by product and change over time.
What is the ecoTEC plus?
It is a Vaillant gas boiler range. Vaillant says it was remastered in 2023 with smart home ready capabilities, and its product page covers an open vent version.
Does a Vaillant boiler need a yearly service?
Yes to keep the guarantee valid. Vaillant says an annual service by a Gas Safe registered engineer is needed to keep its guarantee after the first year.
Sources
We cite the original source for every figure: government, regulators, standards bodies and manufacturers' own documents. Each one shows the date we last checked it.
- Vaillant. Our heritage. Checked 11 November 2026. ↩
- Vaillant. ecoTEC plus open vent boiler. Checked 11 November 2026. ↩
- Vaillant. How long do boilers last?. Checked 11 November 2026. ↩
- BASI Heating. Worcester Bosch and Vaillant: side-by-side. Checked 11 November 2026. ↩
- Health and Safety Executive. Domestic gas: frequently asked questions. Checked 11 November 2026. ↩