Thursday, July 31, 2014

AGH Comments to the EPA on New Stove Data

The EPA is in the process of posting everyone's comments.  As of Monday, August 4, they have posted comments by Rick Kurkeet from Intertek Labs, Stuart Clark from Washington Department of Ecology and several anonymous ones.  They can be found here and ours are posted below.

Alliance for Green Heat
Comments on the
July 1, 2014 Notice of Data Availability
Regarding EPA’s Proposed Standards of Performance for New Residential Wood Heaters, New Residential Hydronic Heaters and Forced-Air Furnaces, and New Residential Masonry Heaters
Docket ID No. EPA-HQ-OAR-2009-0734

July 31, 2014

The Alliance for Green Heat (Alliance), appreciates the opportunity to comment on EPA’s July 1, 2014 Notice of Data Availability (NODA) regarding the agency’s proposed New Source Performance Standards (NSPS) for wood heating devices.[1]  The Alliance is an independent non-profit organization that works with environmental and forestry organizations, air quality experts, the wood and pellet stove industry, and others in the wood burning community to promote high-efficiency wood combustion as a low-carbon, sustainable, local and affordable heating solution.  The Clean Air Act requires EPA to review and revise, if appropriate, the NSPS at least every eight years.  As we explain in the original comments we submitted on the Proposed Rule, the Alliance strongly supports EPA’s decision to update the standards for wood stoves and to require a number of previously unregulated wood heating devices to reduce their emissions.  We also believe that the new standards, which reflect significant improvements in wood heating technology, are both appropriate and long overdue.  We offer the following additional comments in response to EPA’s July 1, 2014 NODA.

First and most importantly, it is imperative that, going forward, all stoves be required to complete a test at the lowest possible burn rate setting.  The data released in the NODA provided a vital insight that few people know: 80% of non-catalytic stoves cannot be successfully tested at the Category 1 burn rate (0.8 kg/h or less).  Under the current EPA test method, Method 28, these stoves have been allowed to test at the higher Category 2 burn rate, as long as they can successfully complete a test at 1.0 kg/h or less in Category 2.

The possibility of avoiding testing a stove at the lowest burn rate—which is when emissions of PM and other toxics are often the highest—has apparently created a loophole that has incentivized some manufacturers to design their stoves so that they fail to hold a flame for a sufficient amount of time in Category 1, so that they can be tested at the easier-to-meet 1.0 kg/h burn rate in Category 2. 

If EPA finalizes its proposal to certify stoves based on only the highest and lowest burn rates[2], this potential loophole could become even more important.  EPA should clarify in the final rule that all stoves certified under the new NSPS must be capable of being tested at their lowest burn rate, and that stoves that cannot successfully complete a test burn at their lowest rate will no longer be eligible for certification.

This will still allow stoves to be tested at 1 kg/h but assures that the consumer cannot operate the stove at a lower burn rate.  We are not opposed to allowing stoves to use a minimum burn rate of up to 1.15 for cordwood testing, but again, they must be successfully tested at their lowest burn rate.  Otherwise, the proposal to raise the minimum to 1.15 kg/h could just enlarge the loophole of stoves testing at higher burn rates than consumers could operate them.

Second, it has become abundantly clear in recent months that more and more manufacturers are using the K list to make minor changes in their stoves to ensure 5 more years of sales life before retesting.  While the K list provides an important function, it is now being used to significantly delay retesting of what could be a majority of EPA certified stoves.  One of the results of this is that manufacturers can avoid testing at their lowest burn rate and avoid releasing their efficiency data until 2019 for many or most or in some cases, all of their stoves. For this reason, we again urge the EPA to require that B415.1 efficiency numbers using HHV be submitted to the EPA within 6 months of promulgation. 

The data released in the NODA confirmed previous data sets, that the efficiency range of pellet stoves is far wider than wood stoves.  These certified pellet stoves ranged from 62 to 80% efficient with a standard deviation of 8.5, double the standard deviation of non-cats and four times the deviation of cat stoves.  Because of this wide variation of efficiencies, it is in the public interest to require efficiencies be released as soon as practicable.  Manufacturers already have efficiency data for most or all of their stoves so there would not be any significant burden to them.

In addition, we note that the data provided in the NODA appears to establish that an emission rate of 1.3 g/h is already being achieved by some sources in the source category using cord wood.  The Alliance continues to support EPA’s proposed approach of allowing stoves to be certified with either crib wood or cord wood during the first phase of the NSPS, and to require certification with cordwood thereafter.  In addition, the Alliance recommends that EPA continue to gather test data on cord wood emission rates for non-catalytic stoves over the next five years and consider revisiting the emission limits in the NSPS if additional data suggest that the NSPS should be adjusted for non-catalytic stoves. 

Finally, the Alliance has published a blog post that addresses a range of issues related to the data released in the NODA.  We have appended this post to these comments and request that EPA consider it along with our other comments as it finalizes the Proposed Rule.

                                                                                    /s/ John Ackerly
                                                                                    Alliance for Green Heat

[1] Standards of Performance for New Residential Wood Heaters, New Residential Hydronic Heaters and Forced-Air Furnaces, and New Residential Masonry Heaters, Notice of Data Availability, 79 Fed. Reg. 37,259 (July 1, 2014) [hereinafter “NODA”].
[2] See Proposed Rule, 79 Fed. Reg. 6,329, 6,367 (Feb. 3, 2014).


  1. I do feel that certain loop holes in the test procedures need to be addressed, but my concern is that with tighter emissions the cost per appliance will also go up. This will force people with limited income to continue burning older non EPA certified units as well as creating more of a market for these older stoves. It's all great to require more stringent standards as well as more frequent testing, but this just drives up the price per stove for those that can least afford it. I also refer to the Libby, MT change-out where the air quality improved dramatically after all the older stoves were removed and the users educated on how to use these cleaner stoves the following year. All this happened with current EPA standard stoves

    1. Old burner can easily be upgraded ..
      I have no finanual interest in this product , but it deserves a mention .

  2. Can anyone tell me if the tests differentiate between particle sizes ? i.e. do the tests count PM10, PM2.5 ONLY ?
    Also , is any other work done on the nature of emissions .....a burner releasing more fly ash and no VOC's or carbon based particulate is much more preferential than one releasing moderate amounts of VOC's and Carbon based particles yet next to zero fly ash .