New Wood Burning Stove EPA Standards for 2020
Starting in 2020, the new NSPS standards require wood stoves to operate with emission levels no higher than 2.0 when tested with crib wood (pieces of wood cut 2”x4”or 4”x4”) and 2.5 grams per hour when burning cord wood ( typical firewood). EPA Standards
These new standards have resulted in a requirement that all manufacturers of wood stoves retest their products and prove that they can operate within these limits. Under these new standards, no stoves can be sold after 2020 that do not meet these standards. Some manufacturers have met these requirements by testing their products at lower BTUs and by using crib wood. These conditions are not typical of how the product will be used in the home. We urge the consumer to compare the rate of burn, or the BTU output at the moment of compliance, in order to choose the safest product.
Here is an example of the kind of testing that has been done. The following study was performed in 1980 on wood stoves that were much less efficient than the stoves we use today.
Follow the links at the end of the post to see how wood stoves have changed to meet the rigorous standards set by the EPA.
According to Hall and DeAngelis, wood burning stove emissions have been under investigation since 1972. In 1988 the The New Source Performance Standards required that certified wood burning stoves be tested in an accredited laboratory and prove emission levels no higher than 4.5 grams per hour.
Robert E. Hall & Daryl G. DeAngelis To cite this article: Robert E. Hall & Daryl G. DeAngelis (1980) epa’s research program for controlling residential wood combustion emissions, Journal of the Air Pollution Control Association, 30:8, 862-867, DOI: 10.1080/00022470.1980.10465120 To link to this article: https://doi.org/10.1080/00022470.1980.10465120
So What’s So Dangerous About Burning Wood?
The combustion branch of the EPA’s industrial environmental research lab has been investigating the problem of reducing air pollution emissions from residential heating combustion equipment for the past 15 years.
As an example, Robert E.Hall, from the US Environmental Protection Agency and Daryl G. De Angelis from the Monsanto Research Corporation completed a study that made the following conclusions in 1980.
“A recently completed study has shown that emissions of participate, carbon monoxide, and organics (including polycyclic organic matter) are relatively high from residential wood burning stoves and fireplaces when compared to emissions from residential gas- and oil fired furnaces. Since these emissions include a number of potentially hazardous compounds; the trend toward greater residential wood usage can have a negative impact on local ambient air quality. EPA is currently studying ways to operate existing stoves and design new stoves to minimize air pollutant emissions.”
Results from the Hall and DeAngelis study found that CO2 and particulate emissions are significantly higher in wood burning combustion equipment than in oil or gas fueled equipment. See the chart in their study here.
The testing procedures compared fireplaces and baffled and nonbaffled stoves using seasoned and green, oak and pine.
“The airtight stoves had significantly higher emissions of CO and POM, while NO2 emissions were greater from the fireplace. Other than higher organic emissions from green pine, wood type was not a major variable. It should be noted that the results of this study only represent one set of combustion conditions and there are many significant variables in the residential wood combustion process (e.g., air damper setting, wood burning rate, log size, physical arrangement of the fuel, and flame intensity). However, the conditions tested do represent a significant portion of the source population. The units were operated with air dampers fully opened.”
There was no significant variation between emissions from the fireplace and wood stoves.Filterable particulate emissions were found to be mostly organic(50% to 80% carbon).
Condensable (gases) emissions were greater in number than filterable (solid that is less than or equal to 30 microns in diameter) emissions and sulfur oxide emissions were very low due to the low levels of sulfur in wood.(.01)
Not surprisingly, flue gas temperatures affected emissions and Co2 levels varied more in the wood stoves (91 to 370 g/kg )than fireplaces(15 to 30 g/kg).No2 levels remained relatively stable throughout the burning cycle. The POM (polycyclic organic matter) emission samples from wood combustion were higher than in other residential heating fuels which is of greater environmental concern.This study involved a bioassay analyses to discover that the ash had no significant toxicity.Subsequent studies involved testing variables such as:
- air/fuel ratio
- secondary air
- physical arrangement of fuel
- firing rate
- combustion temperature
- equipment design
The Hall and DeAngelis study published way back in 1980, was found to be one of the most comprehensive at that time and they concluded that conditions are more favorable for complete combustion in a fireplace than in a wood stove. Potentially hazardous compounds such as aldehydes and POM emissions from greater residential wood burning in wood stoves, is cause for worry about local ambient air quality.
It is thirty nine years later and we are still perfecting the wood stove. Today we trust manufacturers,like Travis Industries, to invest in research and development in order to deliver the safest products for our customers. According to Travis representatives, the company invested 1.2 million dollars in research and testing last year alone.
Here are some of the properties of the Travis, Lopi brand of wood burning stoves. The Lopi brand has made consistent innovations to provide an advanced combustion system that allows you to conserve fuel by burning less wood for longer periods of time. They refer to this system as the Hybrid Fyre.
The Hybrid Fyre received the EPA's award for best green product in 2011 and continues lead the way in innovative burn technology.
So what makes the Hybrid Fyre so efficient and safe?
Secondary air tubes combined with an insulated baffle slow down the fire and a catalytic combustion chamber incinerates any left over particulate, burning up to 99.5% of the flue gasses and all but eliminating any carbon monoxide. The bypass damper allows for smoke free start-ups and reloads when open, which assists with overnight burns when closed. Room air is drawn through the cast iron air convection chamber for maximum heat transfer and efficiency. Hot air is circulated through your room through natural convection.
You can, of course, add a quiet, massive, optional 400 CFM fan that will boost heat circulation through the room and/or choose the GreenSmart automated wood igniter to start your fire with a push of a button.
We are grateful to our manufacturers who continually test and improve the products we provide to our customers. Follow this link on our website for a complete list of the wood stoves we offer.