In this 7 minute review, we will be reviewing the Vaillant ecoTec Pro 24 Combi Boiler and discussing the positives and negatives. In addition, we will discuss the size of the boiler and what it costs to have one fully installed.
But first, a little bit about Vaillant. The Vaillant Group employs 13,000 people worldwide with an annual turnover of approximately 2.5 billion euros. This makes the Vaillant Group one of the largest companies in its sector in Europe.
They’ve been building boilers for over 100 years and are extremely trusted in the UK. So much so that they ranked extremely well in our Engineer Survey of 600 gas engineers. OK, so on to the review.
What’s covered
We will cover:
- Introduction
- Features – Output and flow rates, size and special features and guarantee
- Price
- Conclusion
Introduction

With so many boilers on the market (literally 100’s to choose from) you’re never going to be short of choice – which is a good thing right? Well not quite. It’s easy to get confused with the plethora of different names Vaillant has for its combi boiler range: ecoTec Pro, ecoFit, ecoTec Plus and the ecoTEC Exclusive Green iQ. So it’s safe for me to assume that the customer can, at times, be overwhelmed and confused somewhat.
Adding further confusion will be different gas engineers recommending different boilers – maybe because they are used to installing that particular boiler. It could be they find it easy to install or they worked on the model for a large contract, or maybe that they receive large discounts from manufacturers for being loyal customers.
In this review
In this review, I will hope to arm you with information that lets you make up your own mind whether the Vaillant ecoTec Pro 24 combi boiler is the one for you. We won’t be discussing boiler installation costs which are discussed in great detail here.
The Vaillant ecoTec Pro 24 combi boiler is probably the most popular Vaillant boiler fitted in UK homes. Being a small to mid-range boiler, it’s most suited to smaller homes and would be ideal for a 1 or 2 bedroom property with a smaller 3 bedroom property also being suitable. If you’ve got up to 3 bedrooms and just 1 bathroom, Vaillant recommends this boiler. This boiler is not suitable if you high hot water demands, e.g. two showers or one bath and one shower running at the same time. It simply isn’t able to produce hot water at the required rate (more on that later).
Features
Vaillant ecoTec Pro 24 combi boiler – Output and flow rate
The Vaillant ecoTec Pro 24 Combi Boiler has a heat output rate of 23.4kW which is consistent with smaller to medium range boilers which have entry-level boilers with heat inputs of 24kW. Heat input is a measure concerned with how many radiators the boiler is able to heat up at any given time. I’ve calculated BTU’s of radiators installed in a 3 bedroom new build property and worked out that a 24kW boiler is able to heat the average 14 radiator home. I doubt you have a 3 bedroom property with more than 14 radiators so we don’t have to worry about the heating and whether this boiler will cope with the demand. We’ll instead concentrate on the hot water flow – that is, how many litres of water this boiler is able to heat per minute.
Flow rate
The Vaillant ecoTec Pro 24 Combi Boiler has a hot water flow rate of 9.6 litres per minute.
For comparison sake, at more than twice the price, the Vaillant ecoTEC Plus 938 produces a hot water flow rate of 20 litres per minute. The average 4 bedroom property with two showers would be perfectly happy with a Vaillant ecoTEC Plus 835 (14.3 litres per minute).
So is 9.6 litres per minute good enough? Not really. This boiler is more suited to a 1 or 2 bedroom property that is well insulated. I’ve heard far too many complaints from people with old 24kW boilers who say their hot water isn’t as hot in the winter. A 24kW boiler with a corroded heat exchanger in winter conditions isn’t going to give you steaming hot showers, unfortunately.
If you can stretch your budget a further £150 the ecoTec Pro 30 becomes a viable option. With a heat input of 30kW and a hot water flow rate of 12.3 litres per minute, I think it makes sense.
Vaillant ecoTec Pro 24 Combi Boiler Size
Measurements: height 72cm, depth 34cm and width 44cm. Or in mm, it would be height 720mm, depth 340mm and width 440mm.
Important note: this boiler is unlikely to fit into a cupboard. You’ll need to take a look at Vaillant’s ecoFIT pure range with dimensions starting at height 700mm, depth 300mm and width 390mm.
Vaillant ecoTec Pro 24 Combi Boiler Guarantee
Out of the box, legally, all boiler manufacturers are obliged to offer a 2 year warranty as standard. Vaillant, because of their amazingly reliable build quality, offers a 5 year out of the box warranty – which is pretty good. What’s more amazing is that if you use a Vaillant accredited partner, like us, the warranty goes up to 7 years.
For a further £180 including VAT, if going through an accredited partner such as us, you are able to increase the warranty to 10 years – peace of mind for all breakdowns with all parts and labour covered for the duration of the guarantee.
Vaillant ecoTec Pro 24 Combi Boiler Price
The Vaillant ecoTec Pro 24 combi boiler costs £1,007 including the flue but not including installation, slightly cheaper when compared to its direct competitor, the Worcester Greenstar 25i.
Conclusion
The Vaillant ecoTec Pro 24 combi boiler is one of our preferred choices of model for a smaller 1 to 2 bedroom property. It is perfectly adequate for a smaller 3 bedroom house. The only decision you now need to make is whether paying an extra £150 for the upgraded Vaillant ecoTec Pro 30 makes sense to you. You get an extra 2.7 litres of hot water per minute. For me, it’s a no-brainer. These boilers are built to last 15 years, so that’s only an extra £10 per year for 28% better hot water flow.
What else to consider
Bear in mind that Vaillant is one of the most popular brands in the UK due to their award-winning reliability and quality so you won’t go far wrong with one of them. However, with so many boilers on the market, choosing a boiler has never been more difficult. As a result, we decided to conduct a survey that involved more than 600 registered gas engineers who voted for which boiler they think is the best and you can see how well Vaillant did here. The full results of the survey are here. It’s well worth a read. Vaillant is leading the way when it comes to innovation and efficiency in regards to meeting new standards set by the ERP directive. They are super-efficient and provide much better flow rates than the old models.
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