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Wednesday, March 16, 2016

Q&A about Hybrid Stoves

As a factory direct company, we get calls everyday with customers asking questions about our hybrid technology. If you are curious about hybrid technology but have not called, please read our Q&A addressing some of the most commonly asked questions, and be sure to comment below if you have a question that we have not addressed here.

Q . What is the biggest difference between the new hybrid stoves and the more traditional wood stoves made at the Woodstock Soapstone Company (the Fireview, Keystone and Palladian)?

Durafoil Steel Catalyst
A. The biggest difference is that hybrid technology allows us to achieve ultra-low emissions.  We developed hybrid stoves as part of a quest to achieve lower wood stove emissions. The traditional stoves (Fireview, Keystone and Palladian), are similar to a reliable, fuel-efficient, family sedan (think Honda Civic). The smaller fireboxes and stainless steel Durafoil catalysts allow our catalytic soapstone stoves to burn cleanly and have great low emissions performance.  The hybrids have bigger fireboxes and spectacular emissions performance at all outputs.

Nine years ago (in 2007) we started to research ways to make our stoves burn cleaner.  We knew that new EPA regulations were coming.  Our 2007 wood stoves (Fireview, Keystone, and Palladian) already met what are now the 2020 emissions standards, but we made them even better.  We improved the longevity and performance of the catalysts in these stoves by making them out of Durafoil.

But until we introduced the Progress Hybrid Stove in 2011, all wood stoves used either a catalytic combustor or a secondary combustion system to meet EPA emission standards.  By combining the two (catalytic combustor and secondary system) we were able to achieve efficient, low-emission burns throughout the entire burn range (low-medium-high) that were dramatic, consistent and predictable.

Q . What is the difference between catalytic combustion and secondary combustion? Is one better than the other, or better together?

A.The difference really comes down to the temperature needed for each system (catalytic system and secondary air system) to begin to clean up emissions.  A stainless steel catalytic combustor heats up very quickly and depending on conditions (wood, draft, operator) it can be engaged within minutes of loading the stove, or as soon as the internal temperature is around 400°. Catalytic stoves burn best at low to moderate burn rates, which tends to be the most common way to operate a wood stove for overnight and daytime burns while at work. Catalytic only stoves test with lower emissions and greater efficiency than their secondary air system counterparts, and do require periodic cleaning of the catalyst to work most effectively.

The secondary air system requires higher temperatures (between 1000-1100° internally) to start burning the combustible gases in the wood smoke. Most secondary air only stoves burn best at moderate to moderately high burn rates, when the internal temperature is at its peak. Due to the high temperature requirement, secondary air only stoves have a higher tested emissions level and a lower efficiency than catalytic style stoves.

If you combine these two separate means of lowering emissions and increasing efficiency, you have what we would consider the “Gold Standard”, a hybrid stove that will burn cleanly throughout all the variations in burn rates and customer operation.  Hybrid technology is uniquely effective at high burn rates where either system may struggle alone.  The hybrid design is also very effective with large firebox stoves, which can produce a large volume of combustible gas and particulates.

Cutaway view of the Progress Hybrid
Q . Are there differences, other than emissions, between the hybrid woodstoves and your traditional woodstoves?

One example of custom art for the Ideal Steel Hybrid
A.  Yes.  As part of the hybrid development process, we have developed ways to make our new hybrid stoves more efficient, more affordable, and customizable.  These are all “extra” benefits from doing extended R&D over the last nine years.

Focusing on combustion design to reduce emissions also helped us to make our stoves more efficient.  We discovered that we could make high performance stoves that were completely affordable if they were fabricated from steel rather than cast iron.  Then we realized that we could customize stoves made of steel, which would have been prohibitively expensive with cast iron. Plus, making stoves out of steel has the added benefit of being fully fabricated in our NH factory, which ties back into greater affordability and the ability to customize.

Q . Why are you promoting only the Hybrids during this sale?

A. Partly it’s to focus attention on the Absolute Steel Hybrid, which we are introducing during this promotion.  We’ve made a big commitment of time, energy, and resources to cleaning up wood burning technology, so of course we want to talk about it and of course, we want to keep improving our combustion designs.


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