The most efficient log burners available?

In a previous post on the various ways log burners supply oxygen to the fire Fireplace Product’s Reece Toscani described the Hwam autopilot air control system as ‘the future’ of wood burning stoves. The autopilot air system can save you as much as 40% on fuel by automatically regulating the amount of oxygen supplied to the firebox, but with Hwam’s new Intelligent Heat System (IHS) pushing savings north of 50%, we decided it was time to settle the issue of who produces the most efficient log burners in the world?

While the stated efficiency rating of the Hwam stoves are not as high as alternatives such as Burley Stoves, who boast efficinecy ratings as high as 89.9%, we had a hunch that the fuel savings you will enjoy from a Hwam stove might make them genuinely the most efficient log burners available. So to find out if this is true or not we sent our very own Reece Toscani over to the Hwam factory in Denmark to get to the bottom of this and find out if Hwam are making the most efficient log burners, and more importantly how they can save you money!

Hwam efficient log burners compared to similar stoves
Hwam 3120, Drooff Aprica 2, AGA Westbury, and Rais Epoca (left to right)

From the outside you would be forgiven for thinking Hwam stoves were like all the others. Offering a sleek contemporary styling, with an impressive build quality and crisp flame picture, whilst ticking all of the boxes when it comes to output, efficiency and approvals. However, what sets Hwam stoves apart from the rest lies deep in the heart of their stoves and is why we think makes them the most efficient log burners available.

How does it work?

The secret behind the success of Hwam is their Autopilot air system. As with all great inventions the idea is very simple, a metal coil is concealed within the firebox behind the firebricks that expands and contracts with the heat from the firebox opening and closing air supplies when required. At first when the stove is cold and ready to light the primary air will be fully open providing as much oxygen in low to the fire bed as possible to ensure an optimum lighting. Once ignited the temperature starts to rise, the coil starts to expand operating a lever that begins to close down the primary air and open up the tertiary air switching from ignition to main burn operation. From here the stove will continually adjust the amount of primary, secondary and tertiary air required based on the temperature inside the firebox. There are no sensors, no electronics, no batteries or mains power required, with Autopilot the stove is self-regulating and autonomous, meaning no user input is required. All of this operation is neatly hidden on the back of the stove and covered with a heat shield for maximum discretion.

Standard Stove without Autopilot performance graph

Automatic air regulation

Hwam back in the 1970’s were interested in manufacturing wood burning stoves that performed as well in peoples homes as they did in the labs. Hwam have pursued the idea that: if we can achieve it under test conditions, consumers should be able to achieve it in their homes. It was from this idea the Autopilot system was first conceived: Hwam soon realised that by minimising user input in the air supply, they could achieve a more complete combustion and give their customers similar real world efficiency ratings compared against their tests as well as significant fuel savings. On average the standard Hwam autopilot system can save you as much as 40% on your fuel bills compared against a stove that relies on you manually adjusting the air supply.

Hwam Stove with Autopilot performance graph

While the Autopilot system from Hwam is the most efficient way of delivering combustion air into a stove (more so than anything anyone else is currently offering), Hwam saw a way to make this system even more efficient with unbridled sensitivity and responsiveness. They realised the limitations with the Autopilot system and started to develop a system never seen before on a wood burning stove, integrating electronic air controls, temperature sensors and remote controls, the Intelligent Heat System was born.

IHS – Intelligent Heat System

Picking up on the improvements the mechanical autopilot system delivered, IHS took the principal of delivering exactly the right amount of air just when the stove requires it. Unlike traditional stoves that require a user to manually adjust the air controls as and when they remember/think they need to, and picking up from the drawbacks in response time from the mechanical autopilot system, IHS.

How much money can i really save?

Kiln Dried Wood Crate
Save an entire crate of logs a year with a Hwam Stove

Lets look at it another way, if you added two logs to your stove every charge, in a 10 hour period a manual input stove (without Autopilot) you would need 16 logs. With a Hwam stove and the Autopilot system you would only need 10 logs to achieve the same nominal heat output. So based on this if you used your stove in this way for 60 days. you would save approximately 360 logs, which is the same amount as you get in an entire cubic meter crate of firewood!

The ability to get the same amount of heat from less logs compared against a traditionally manually controlled stove is a welcome addition to any household. So while there are stoves available that boost a higher efficiency rating than Hwam stoves, how many stoves could save you this much fuel in a year? This is why we believe that Hwam are the most efficient log burners available to buy right now.

Fireplace Products are proud to be an authorised Hwam partner here in the UK. We aim to have all Hwam stoves including both autopilot and IHS models on our website shortly. In the mean time we leave you with a video Reece shot while at their showroom in Denmark. Hwam also make Wiking Stoves which feature their own version of the Autopilot system, read more about Wiking Stoves here.

If you have any questions relating to Hwam Stoves, please get in touch with us in the comments below or call us on – 01268 200139

4 comments

    1. Hi Joe,

      Autopilot has the bimetallic spring that mechanically opens and closes the air supply.

      IHS has sensors and probes that electronically opens and closes the air supply.

      Hope that helps, Reece

    1. Hi Denyse,

      Thanks for the questions. So Hwam do not offer a version with this Automatic air control system on a boiler stove, however there is German stove company called Cera Design who offer their own version called the IQ Airmatic system which auto regulates the primary and secondary air supplies and has a LED light fitted to the stove which changes colour to let you know the optimum time for adding wood. Cera make two boiler versions of their Divino range which are IQ compatible. You can see both of the Cera Divino Boiler stoves here – http://bit.ly/2HEgdWi as well as our other contemporary boiler stoves that are available.

      If you want to discuss this further, drop me an email reece.toscani@fireplaceproducts.co.uk and i will get some more information over to you.

      Thanks for the question

      Reece

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