Vaillant ecoTEC boilers review

A review of the most popular gas condensing boilers from Vaillant, ecoTEC boilers, designed for space and domestic hot water heating, as the combination, system and open vent type. Use the review below to see the differences and choose the best model.

Vaillant ecoTEC boilers have a stylish and compact design that fits in almost any part of the house and are offering many great benefits for the new owners: condensing technology and advanced features that provide the ultra-high efficiency and performance, quality, reliable and durable operation. The article about the ecoTEC boilers, reviews different models, its features, benefits, pros, and cons.

Model reviews

Vaillant produces three types of gas-powered condensing boilers; combinations, open vent and system boilers, all coming from the same ecoTEC series, the most selling group and a series that has the best possible rating for low carbon emission and the award for the ultra-quiet gas combustion.

Combination boilers

Combination boilers are high-efficient and versatile boilers that are very popular in Europe due to its space-saving design and advanced features.

Vaillant combination boilers do not require hot water cylinders, as the domestic hot water is supplied directly from the boiler. These are recommended for homes with up to four bedrooms and two baths. Vaillant produces three types of the combination boilers: ecoTEC plus, ecoTEC pro and ecoTEC exclusive.

ecoTEC plus

Vaillant ecoTEC plus boiler

The ecoTEC plus combination boilers are available in three sizes: 24 kW (model 824), 31 kW (model 831) and 37 kW (model 837 and 937).

A model ecoTEC plus 937 with the dimensions of 720x440x601mm and weight of approximately 41 kg is the largest model, that also provides easy handling and wall installation. The second largest 837 model has the same weight but smaller dimensions of 720x440x403mm so all can fit even in the homes that lack in space.

The ecoTEC plus 937 is the only model that utilizes a small 15-liter actoSTOR hot water storage tank that allows a boiler to transfer hot water fast and reheat water in a matter of minutes. This model is recommended for larger homes and families with the high hot water demand. It is compatible with the Vaillant heat pump hybrid system.

With the energy saving and modulating gas valve, boilers 837 and 937 are able to produce up to 37 kW of the power, while the minimum is 6.4 kW, good for small jobs when working in the domestic hot water heating mode. While the models are factory built to use natural gas, some models are made for LPG gas too.

ecoTEC Pro

The ecoTEC Pro combination boiler is found in two, the most popular sizes; 24 kW (model 824) and 28 kW (model 828). These models are also wall-hanging units thanks to its small size of 720x440x335 mm. The hot water flow rate is in the range from 7.8 to 9.6 l/min and the maximum temperature is 85 C.

The ecoTEC exclusive

The ecoTEC exclusive comes with the higher heating output of 32 kW (model 832) and 38 kW (model 838), which makes it great for larger homes.

This group of water heaters comes in sizes up to 800x480x450 mm and maximum weight up to 46 kg, still recommended for smaller houses. Thanks to the advanced modulating gas valve, the power goes from the low 10.2 kW to the maximum value of 37.2 kW, heating the water up to the temperature of 85 C. Domestic hot water flow rate varies from model to model, but is in the range from 10.6 to 13.5 l/min.

System boilers

The ecoTEC system boilers (612, 615, 618, 624 and 630 models) are high-efficient and low NOx gas-powered units that when combined with the indirect hot water cylinders provide domestic hot water and central heating. These are equipped with the advanced modulating system, efficient circulation pump, and other great features… all working to provide high efficiency of over 89%. The system boilers from ecoTEC are found in the range from 12 kW to 37 kW and can be part of the solar thermal systems.

Open vent boilers

The ecoTEC open vent boilers are high-efficient and low NOx gas-powered units that are used for central heating and hot water production by using the hot water cylinder, cold water storage tank and expansion tank. The open vent boilers do not provide an instant hot water as the combination and system boilers.

These can be found in several sizes; 15 kW (model 415), 18 kW (model 418), 28 kW (model 428) and 38 kW (model 438) which ensures enough heat for up to 4 bedrooms and three baths homes. The open vent models differ in the power output and water flow rate, while the features, connections and the size are the same. For example, the size is approximately 600x375x334 mm, and the weight is little different, it is in the range from 3.1 to 3.3 kg. The energy efficiency is in the range from 90.4 to 90.8 % which is found on the ecoTEC plus 438, which also has the highest power output and flow rate. This model is also LPG compatible. The open vent boilers have a standard warranty of 5 years while the maximum is 7 years. It is not intended for use in mobile homes or commercial applications.

All the ecoTEC models are equipped with the advanced electronics that allow the accurate settings, programming, two-stage frost protection, provide useful information on the operating status and diagnostics.

Automatic gas modulation system allows better performance and comfort, the efficient circulation pump delivers hot water fast, while all working with the reduced energy waste.

The model is compatible with the Vaillant’s aquaCOMFORT warm start feature for the added comfort as the water at the temperature of 55C is available as soon as the tap is open.


Vaillant provides two types of warranties, depending on the model; 5-year warranty for the ecoTEC pro models and 7-year warranty for the ecoTEC plus and exclusive models.


Vaillant ecoTEC boilers come in 18 different models with the output power ranging from 18 kW to 38 kW and the energy efficiency up to 90%. Such a versatility, including its open, combination and system setup, makes this group of boilers the preferable choice. Great savings, small and compact size, easy wall installation and the advanced engineering, makes these boilers the top selling gas boilers in the UK and other parts of Europe. The ecoTEC carries many awards for its quality and great performance.

With so many models available, the ecoTEC can be used equally in new and old houses, from one bedroom and bath to homes with four bedrooms and two baths.

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