What do customers say?
Hawken Energy Rating: ★★★★☆
Central Boiler Rating: ★★★☆☆
Hawken Energy Rating: ★★★★☆
Central Boiler Rating: ★★★☆☆
All trademarks mentioned belong to their owners, third party brands, product names, trade names, corporate names and company names mentioned may be trademarks of their respective owners or registered trademarks of other companies and are used for purposes of explanation and to the owner's benefit, without implying a violation of copyright law.
One of the most important things to consider when buying an outdoor wood-burning furnace is the warranty. Like buying a car, a warranty can be the difference between a working machine and a $10k pile of scrap metal. If properly maintained, a well-manufactured wood-burning furnace should last several decades.
Yes! We have been in this business a long time, and we have seen a lot of poorly made stoves. We have found that the warranty of a furnace usually reflects its quality, and a good warranty can protect you from catastrophic failures that leave you cold in the dead of winter.
Because warranties vary drastically from brand to brand, and warranties can be notoriously hard to research, we have done the work for you and put together some of the key points from all the major manufacturer warranties... You're welcome.
As you might guess, the most important thing with any warranty is coverage. All furnace warranties are "limited," but each manufacturer has different limits, conditions, and terms. For example, Central BoilerTM has a 25-year limited warranty, but the firebox is only warranted for 10 years. HeatmorTM has a lifetime warranty, but they cover only 15% of the replacement value after 10 years.
Hawken Energy has the best warranty coverage in the industry.
If you are like most customers, an outdoor furnace is an investment. You want a furnace that will save you money immediately on your heating bills, but also one that will last more than just a couple of years. One of the things that you should consider is the material used to manufacture your furnace.
There are three important things to consider when looking at the steel of an outdoor wood furnace.
Type of Steel - The type of steel used in a furnace determines the efficiency and durability of your furnace, and has a large impact on the price.
Thickness of Steel - The gauge, or thickness, of the steel also affects the price of a furnace, as well as its ability to transfer heat. Generally, a manufacturer will use thinner steel for parts that are less susceptible to abuse and/or corrosion. Hawken uses 1/4" steel for the firebox assembly and other key parts, which provides a good balance of heat transfer efficiency and durability.
Grade of Steel - Even for particular types of steel, there are different grades or quality levels. This is determined by the standards used in the production, selection, and melting of the raw steel.
In our research, we have found that there are three types of steel used in outdoor wood-burning furnaces:
A36 Structural Carbon Steel - Hawken Energy uses carbon steel that is CS (commercial steel) grade or better. This grade, also known as structural steel, is great for consistent, high-quality welding and has one of the highest yield strengths of any carbon steel. It has very high thermal conductivity, relatively low cost, and considerable durability. You should always use water treatment in a furnace made from carbon steel.
409 Stainless Steel - The least expensive type of stainless steel is also the least useful in an outdoor furnace. It is at least 15% more expensive than structural carbon steel, and because it doesn't transfer heat as well, it requires twice the amount of wood to extract the same amount of heat. Many companies mitigate these problems by using a much thinner gauge of steel, claiming that stainless steel is stronger. Unfortunately, that is not true of 409 stainless. It is actually weaker than A36 carbon steel. That is why after only a few years of operation, furnaces made from thinner gauge 409 stainless steel can often develop stress fractures and fail.
409 stainless steel is more resistant to corrosion than carbon steel. However, without water treatment, 409 steel will still corrode over time. Because water treatment is still required (or at least highly recommended), corrosion resistance should not be a primary factor when considering a furnace made from 409 stainless steel.
A furnace made with 1/8" 304 stainless steel requires 50% more wood to get the same amount of heat even though it has only 58% of the strength of a furnace made with 1/4" A36 structural carbon steel.
304 Stainless Steel - This type of stainless steel is often called "food grade" stainless because it is used in kitchen applications and cooking. Because of its strength and corrosion resistance, this higher grade of stainless steel is a great material for durability. It usually does not require water treatment, and it is stronger than carbon steel. A quick way to verify the type of stainless in a furnace is to remember that 409 is magnetic and the higher grade 304 is not.
Regrettably, this durability comes at a price. 304 stainless steel is at least 40% more expensive than structural carbon steel. It also takes 3x the amount of fuel to transfer the same amount of heat. Unlike 409 stainless, some of that cost and efficiency can be recaptured by using thinner gauge steel, but furnaces made with 304 stainless steel are typically much more expensive.
|A36 Structural Steel||409 Stainless Steel||304 Stainless Steel|
|Raw Material Cost||✓||15% more expensive||40% more expensive|
|Tensile Strength||Very strong||2% weaker||16% stronger ✓|
|Thermal Conductivity||✓||1/2 the heat transfer||1/3 the heat transfer|
For more information about the properties of various types of steel, please visit MakeItFrom.com
The kind of steel used to make your furnace will determine the efficiency (how well heat can be transferred from the fire to the water that heats your home), the durability (how susceptible it will be to rust and corrosion), and the price of your furnace. Be careful that you do not pay more for a type of steel that does nothing for you!
With an Afterburner furnace from Hawken Energy you can breath easy knowing you'll have a furnace that pays for itself over and over again, saves you thousands of dollars off your heating bills, and protects you with the best warranty coverage in the industry.
You can also enjoy a breath of fresh air with the best emission rating in America.
What will you do with all the money you save?Build Your Own