Air Time: What does that mean?

By Rod Tinnemore, Wood Stove Coordinator, Air Quality Program

Have you ever tried to buy something only to find that the sales person seems to speak a foreign language? If you don’t know the meaning of these words, it can be confusing and frustrating.

The world of wood heating can have this problem, too. Today let’s talk about a few wood-burning devices: wood stoves, fireplaces, masonry heaters and pellet stoves. There are other wood-burning devices and terms that we’ll discuss in later blogs.

Wood stoves began as mere metal boxes designed to burn wood and radiate heat. Some are “free standing” while others are “inserts”, made to be inserted into an existing masonry fireplace. These early wood stoves were improvements over open-hearth fireplaces but are still highly polluting. Today’s wood stoves are designed to put far less smoke into the air IF fueled and operated properly. If you use wet wood or provide too little air to the flame, they may pollute as badly as those early stoves.

Wood stoves tested by EPA and shown in the lab to be less polluting become EPA certified. Wood stoves that meet the air standard in Washington State are Washington approved. All stoves sold in Washington must be both EPA certified and WA approved.

You may also see items called fireplaces or zero clearance fireplaces. Because the naming of fireplaces is not tied to regulation, many items called “fireplaces” may actually operate the same as a wood stove. These metal devices look much like a wood stove insert but are designed to be built into a wall. An open hearth or masonry fireplace differs from a factory-built fireplace since it is built of brick, stone or other masonry. New to the market are modular masonry fireplaces, which are also factory-built but made of masonry and assembled in pieces. See, it’s confusing already. While there is no EPA certification program for fireplaces, all factory-built fireplaces must meet an air quality standard and become Washington approved before they can be sold in this state.

A completely different device is called a masonry heater. These burn wood but direct the smoke through a network of channels within the masonry and then out a chimney. The heat they produce is transferred to the masonry and radiated into the room. These are also regulated in Washington like factory-built fireplaces.

Pellet stoves are cleaner burning devices fueled by pellets made of wood chips or sawdust that have been compressed. Most require electricity but some new stoves can operate fully without electricity while others have advanced batteries that power the stove for days in case of a power failure.

All these devices require a permit before installation. Insurance companies may deny claims related to unpermitted wood burning devices. When in doubt, check the Ecology web site for a complete and current list of approved wood burning devices and contact your local building permitting office about installation code requirements.

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