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Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review

Vaillant ecotec exclusive green


Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler Quotes

Welcome to Compare Boiler Quotes, the UK’s best source for boiler quotes, information, news, tips, and advice on everything boiler related. 

Our articles on the best and worst boiler systems are always being written and posted so chances are we have covered the boiler you’re looking for. Today’s review is on one of the most advanced and high end boilers for the modern British home. 

Most of us are familiar with the German manufacturer Vaillant and their range. If you’re not, they are certainly in the top 5 when it comes to quality and performance. 

We’re going to be looking at one of their premier systems, the efficiency, warranty, pricing, and overall conclusion on the system.

Let’s first take a short look at the company in case you haven’t heard of Vaillant.



The Company


Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler QuotesVaillant, is a part of the Vaillant Group and has been building boilers for over 100 years. They are one of the most respected boiler brands from the German boiler manufacturers. 

Vaillant has produced some of the most advanced and best performing boilers in the world and the EcoTEC Exclusive Green IQ 843 is certainly proof of this.


Core Features:


Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler QuotesThe key feature here is Vaillant’s green IQ technology, which offers a unique range of smart technologies and features, all merging to create a highly efficient boiler

These advances in green technology intelligently manage consumption and output while keeping its components running at peak performance for longer. It also offers a low maintenance solution that you are able to rely on year in and year out.

In addition to this the green IQ range includes extra condensing technology which includes an integrated diverter valve.  It also comes with a wide modulation range of up to 1:10 helping it to adapt to all types of systems. This results in far lower fuel bills especially since it optimises running cycles for lower gas consumption, using Vaillant’s smart heating control to give you even more control and reliability.

You will be hard pressed to find a more capable system for a family home , especially in the combi boiler variety so the green IQ range is really a great system from Vaillant.




Features at a Glance:Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler Quotes


  • Band Rating: A Rated
  • ERP Rating: A Heat A Water
  • Efficiency Rating: 94%
  • Standard Warranty: 5 Years
  • Output: 36 kW
  • Flow Rate: 17.8 l/min
  • LPG Compatible: Yes
  • Mounting: Wall Mounted
  • Typical Price: (inc VAT) £1,500
  • Typical installation Cost: (inc VAT)* £500 – £1,000
  • Total Cost: £2,000 – £2,500



Is the ecoTEC exclusive green IQ 843 Right for my Home?


Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler QuotesThe ecoTec exclusive 843 is designed to heat larger family homes with 15-20 radiators efficiently. If you have a larger detached family home with at least 4 bedrooms and 2 bathrooms then this is the boiler for you. Generally combi boilers don’t have the output or capacity to heat your home and hot water when it comes to 4+ bedrooms however the green IQ 843 is different.

The Vaillant ecoTec 843 has a highly powerful central heating output of 43kW and an almost unbelievable water flow rate of 17.8 l/min. 

So if you have a large, busy household with multiple showers and taps being used simultaneously then you need a boiler such as this with a high output and water flow rate.

You may also want to consider systems which have an integrated cylinder inside the combi system if you have an even bigger home with more bathrooms.



What About The ecoTEC exclusive green IQ 843 Efficiency?


The Green IQ range has been designed by Vaillant with green credentials and absolute efficiency. This fantastic boiler has an efficiency rating of 94% and is also ErP A-rated for heating and hot water. This means that even though this is a large output boiler it will still save you money on your heating and lower costs overall.



What if I have a System or Regular Boiler?


Chances are if you have a larger home you will have a system or regular boiler installed with a separate tank or cylinder. You can switch from a system or regular boiler to dramatically increase space and reduce heating costs in your home. What’s the difference? Well, Combi boilers provide heating and hot water on demand so there’s no need for any external tanks or cylinders. 


What about the Warranty?

Vaillant EcoTEC Exclusive Green IQ 843 Combi Gas Boiler Review Compare Boiler Quotes

Vaillant offers a respectable 5 year warranty as standard on all their Green IQ boilers however this can be extended to 7-10 years when installed by a Vaillant Advance installer. We do always prefer having a standard 10 year warranty although this boiler is so high output and high flow rate that it makes up for this as it stands out amongst most other competitors.






An extremely efficient and reliable green boiler system with some advanced and high output features that compete with even the best boilers on the market. We would rate this system a respectable 8/10.

In terms of alternative boilers, we would also recommend the Viessmann Vitodens 200-W which is a similar price however it is slightly more efficient and has a better heat exchanger, one of the highest fault parts in any boiler. 

If you are looking for a boiler quote“>new boiler quote, then why not look at our partner company Boiler Central?

Once you’re there, just answer a few questions about your home and it will provide you with a quote calculator, and the best boiler for your home specifically. 

After you have a quote and choose your boiler, you can pay online with flexible financing, book a convenient installation date, and wait for the installation of your next new boiler.

Boiler Central also offers boiler cover which can cover your boiler, central heating, and even provides an annual boiler service with selected plans!

Thankyou for reading our Vaillant boiler review, if there are other boiler systems you are interested in, we may have just reviewed those too so take a look through the site and hopefully we can help you in your search for your next new boiler system. 


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