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Vaillant ecoFit Pure 825 Combi Boiler – Review

In today’s review, we’ll focus on the Vaillant ecoFIT Pure 825 combination boiler, to give you all of the information you need to make an educated decision when looking for a new boiler.

With German engineering at the heart of the Vaillant boiler product line, this combi boiler is a popular choice for small to mid-sized properties due to its high-quality and long-lasting build. Founded in Germany in 1874, Vaillant is Europe’s second largest boiler manufacturer, competing against UK-based energy product manufacturer, Worcester Bosch.

Will the Vaillant ecoFIT Pure 825 be suitable for my home?

If you are looking for a boiler replacement, the Vaillant ecoFIT Pure 825 model is the ideal fit for homes with up to three bedrooms and one bathroom with either one non-electric shower or bath installed. What is really needed to understand whether a boiler is suitable for a property, though, is the number of radiators. In this case, the ecoFit Pure 825 will suit homes with up to ten radiators. It offers a central heating output of 19.1kW and a hot water output of 25.2kW. To ensure you have sufficient how water, this boiler offers a flow rate at 10.4 litres per minute (l/m). However, it’s essential to check that your mains pressure is powerful enough for a combination boiler to be installed.

An alternative combination boiler suitable for up to ten radiators is the Worcester Bosch Greenstar 25i, although it’s larger in size. If you isnist on a slimmer boiler, we recommend you opt for the WB Greenstar 25Si.

If your home has more than ten radiators installed, the ecoFit Pure 830 is a better fit due to its higher flow rate. In fact, the ecoFit 825 wouldn;t be powerful enough. Alternatively, the ecoFit Pure 835 is the largest the three in this model range and can heat up to 20 radiators.

Vaillant combi boiler controls

The ecoFIT Pure 825 offers a standard control panel with buttons to increase or decrease output for the boiler, as well as switching the boiler on or off. The control panel also has a small display installed, which will show error codes as well the boiler’s current running temperature. Error codes will allow you to diagnose internal issues with your boiler, and make it easier for an engineer to fix the problem quickly and often without even having to open up the boiler. Due to advances in the design of boilers, boiler issues are now more straightforward to diagnose, which has reduced call-out fees. The build of the 825 has been kept simple, which means that components can be replaced or repaired with ease.

As part of the building regulation that deals with the replacement of your old gas boiler, Boiler Plus came into effect in April 2018 and mandates temperature controls to ensure that every newly installed boiler reaches a 92% efficiency rating. Boiler Plus aims to improve the way homes use energy by improving the efficiency of heating systems.

Vaillant offers a wide selection of boiler controls from mechanical to smart thermostats. Mechanical thermostats provide the most basic boiler control. From the turn of a dial, you can dil your heating up or down as you please. However, please be aware that mechanical thermostats are no longer compliant due to the introduction of Boiler Plus. To ensure you’re compliant with Boiler Plus, you need to opt for a digital or smart thermostat, which is a more modern and technology-driven take on the traditional thermostat.

For combination boilers, there are four additional requirements. Only one of the four measures will need to be fulfilled by the homeowner. The requirements are as follows:

  • Weather compensation – A system that alters the water temperature from the boiler based on the outdoor temperature.
  • Load compensation – A system that alters the temperature of the hot water from the boiler based on the room temperature.
  • Smart control – A type of control that automates and optimises your central heating system
  • PFGHRD (Passive Flue Gas Heat Recovery Device)

In the case of digital thermostats (also known as programmable thermostats), you can set temperatures and heating schedules 24 hours a day, 7 days a week. The only issue with digital thermostats is the fact that setting different heating schedules is limited, with some models only allowing up to three programs per day.

If you’re looking to take a big step up in your thermostat game, smart thermostats come with an abundance of features including the ability to control your heating and schedules from your smartphone or tablet with an app. Within the smart thermostat app, you’ll be able to monitor your energy use, and switch your heating on or off remotely, whether you’re at home or away.


If you are looking for a boiler replacement, it is important to take the size of the boiler into consideration and whether it will fit in the allotted space in your property. The Vaillant ecoFIT Pure 825 comes in at 700 x 390 x 295mm, which makes it one of the most compact combi boilers on offer from Vaillant. If you’re looking to fit your boiler within a kitchen cupboard, then this boiler would be a great choice.

Vaillant ecoFIT warranty

Each Vaillant boiler within the ecoFIT range comes with a standard 5-year warranty for your peace of mind. With us, you’ll receive a 5-year warranty, free of charge, with your new boiler installation, which can be extended to 10 years for an extra charge. Boilers tend to last for up to 10 to 15 years, so you probably won’t need to think about purchasing a new boiler for some time.

Boiler cost

To get your quote for a Vaillant boiler, you can get your price through our website within 90 seconds. Just answer a few questions about your home, and we’ll recommend the ideal boilers for your home, heating and hot water usage within 90 seconds, and your new boiler can be installed within 7 days.

Energy Efficiency

The ecoFIT Pure 825 is a high-performance boiler with an impressive ErP (Energy-related Products) rating of 94%, which is an A-grade for efficiency. Although it depends on the energy efficiency of your current boiler, you’ll start to see a saving on your energy bills relatively quickly due to the 825’s high ERP rating and low energy consumption.

The ERP directive was introduced by the EU to test energy products (including boilers) before they’re available to engineers and homeowners. Each energy product has to pass specific criteria for performance and efficiency. If an energy product were to fail the tests, the directive would recommend a list of improvements to the product before it can then be released.

Verdict – Is this Vaillant boiler the one for you?

The ecoFit Pure is a keeper, especially for those of you that prefer slimline boilers, be it because space comes at a premium or simply for aesthetic reasons. Granted, if you’re after a more modern design, the ecoTec Plus 832 might be the better choice; however, you’d sacrifice the smaller size, and it won’t fit into a cupboard. In addition to the ecoFit Pure’s high energy efficiency and outstanding flow rate, it is also one of the quietest combi boilers on the market, for which it has won the Quiet Mark award for reduced noise design. All in all, this boiler model ticks all the boxes and is the perfect choice for smaller households that are looking to replace their old boiler.

 Vaillant ecoFit Pure 825
ErP rating (energy efficiency)A (94%)
Size (HxWxD in mm)700x390x295
Heating output (kW)19.1
How water output (kW)25.2
Flow rate (litres/min)10.4
Standard warranty (years)5 (extended warranties available)
Other available sizes (kW)30, 35

Which? boiler review

The consumer group Which? review each boiler on the market to find the most (and least) reliable boilers according to a survey completed by thousands of boiler owners. In each review, Which? supply a brand score percentage and star ratings for each category. Take a look at the Vaillant ecoFit Pure 825 ratings below:

Which? Score 
Efficiency rating★★★★★
Brand reliability★★★★☆
Brand customer score★★★★★
Ease of repair★★★★★
Ease of service★★★★★
Availability of parts and spares★★★★★
Build quality★★★★★
Engineer recommendation★★★★★
Brand score80%

Boiler manual

Vaillant ecoFit Pure 825 Combi boiler manual

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