CrappieKeith
Addicted to ArboristSite
As a consumer I know that marketing of products can be twisted and very confusing. Just the terms we use in burning wood can be confusing..for example I hear the term wood stove which could mean anything burning wood.
In truth a wood stove is an appliance that does burn wood. It does not hook to ducting and are typically a smallish appliance made to heat a room or two. In some cases depending on how open the home is and how warm the climate is a stove could heat a home. It will have the main room awfully hot with the adjoining rooms coolish,but it will or can heat a home. They are marketed sometimes as zone heaters.
To have a more even heat and better control a wood furnace is the better option for most...not all.
A wood furnace typically hooks to ducting where you have a warm air supply and a cold air return.
Wood furnaces also have much more thermal mass ..well at least the better ones do and way more heat exchange surface area. For example a stove may have 8-10 square feet vs. a furnace that has 50-80 square feet like the Yukons.
Better wood furnaces and stoves have a way to burn off the smoke from the top of a fire. This process will make an extra 30%-40%of the available btu's in that lb of wood. Of coarse moisture contents will vary the solid mass...wood's ability to turn itself into a gas which is what actually is burning. The less water in the wood allows the gases to be made more easily.
The 3 processes are catalytic,up flow and down flow gasification.
Ok....without naming names...there's this smallish furnace being marketed as an EPA certified furnace. Talking to Mr. John Dupree of the EPA..he said this small furnace was tested to the stove test and that it was approved as a stove...not a furnace. As John admitted there is no test in the US for furnaces as of yet.
Talking to a few different engineers in the wood heating industry the topic of particulates which is what the
EPA tests for vs efficiency came up.All admitted that you can burn wood cleanly with a way to burn smoke and that if more air up to a point is added the emmisions really are cleaner...but that efficiencies suffer. They also admitted that if there is not enough heat exchange surface area even more heat is wasted with higher flue gas/stack temperatures being evident.
Another wood burning industry pro said to me that it is really misleading the public to get certification on one unit but adding their other product line to the same marketing ie...websites...signatures and printed materials.
My suggestion is that the buyer beware...it is vital to become educated when investing.
I've suggested many times that to look at the btu output and weight when comparing appliances.
Look at the heat exchange surface area.
A small furnace tested to stove standards may not actually do well heating a larger home in a colder climate. Sure it may be rated as a maximum to make 100,000 btu's ,but you have to ask yourself...what kind of burn times could I expect. Common sense should tell you that to max out anything the life of it will be shorter and the burn times will be less.
To end ...just because it may be low in particulates does not mean it is efficient nor does it mean it will heat your entire home. We all have different heating needs. Those that live in warmer climates may do well with this type of smaller furnace. Those that live in colder climates or those that have not so well insulated home may suffer short burn times.
In truth a wood stove is an appliance that does burn wood. It does not hook to ducting and are typically a smallish appliance made to heat a room or two. In some cases depending on how open the home is and how warm the climate is a stove could heat a home. It will have the main room awfully hot with the adjoining rooms coolish,but it will or can heat a home. They are marketed sometimes as zone heaters.
To have a more even heat and better control a wood furnace is the better option for most...not all.
A wood furnace typically hooks to ducting where you have a warm air supply and a cold air return.
Wood furnaces also have much more thermal mass ..well at least the better ones do and way more heat exchange surface area. For example a stove may have 8-10 square feet vs. a furnace that has 50-80 square feet like the Yukons.
Better wood furnaces and stoves have a way to burn off the smoke from the top of a fire. This process will make an extra 30%-40%of the available btu's in that lb of wood. Of coarse moisture contents will vary the solid mass...wood's ability to turn itself into a gas which is what actually is burning. The less water in the wood allows the gases to be made more easily.
The 3 processes are catalytic,up flow and down flow gasification.
Ok....without naming names...there's this smallish furnace being marketed as an EPA certified furnace. Talking to Mr. John Dupree of the EPA..he said this small furnace was tested to the stove test and that it was approved as a stove...not a furnace. As John admitted there is no test in the US for furnaces as of yet.
Talking to a few different engineers in the wood heating industry the topic of particulates which is what the
EPA tests for vs efficiency came up.All admitted that you can burn wood cleanly with a way to burn smoke and that if more air up to a point is added the emmisions really are cleaner...but that efficiencies suffer. They also admitted that if there is not enough heat exchange surface area even more heat is wasted with higher flue gas/stack temperatures being evident.
Another wood burning industry pro said to me that it is really misleading the public to get certification on one unit but adding their other product line to the same marketing ie...websites...signatures and printed materials.
My suggestion is that the buyer beware...it is vital to become educated when investing.
I've suggested many times that to look at the btu output and weight when comparing appliances.
Look at the heat exchange surface area.
A small furnace tested to stove standards may not actually do well heating a larger home in a colder climate. Sure it may be rated as a maximum to make 100,000 btu's ,but you have to ask yourself...what kind of burn times could I expect. Common sense should tell you that to max out anything the life of it will be shorter and the burn times will be less.
To end ...just because it may be low in particulates does not mean it is efficient nor does it mean it will heat your entire home. We all have different heating needs. Those that live in warmer climates may do well with this type of smaller furnace. Those that live in colder climates or those that have not so well insulated home may suffer short burn times.