HHT and Ravelli agree to release efficiency for 5 stoves

In response to a Freedom of Information Act request filed by the Alliance for Green Heat, Hearth & Home Technologies (HHT) and Ravelli released actual efficiency numbers for several of their popular pellet stove models.  Efficiencies ranged from 56% to 76%.

Wood and pellet stoves certified after May 2015 must test for and disclose their efficiency to consumers, as required by new EPA regulations. Prior to these regulations, stove manufacturers claimed that any available efficiency data was confidential and they generally did not provide it to consumers.  However, many companies provided the efficiency data to the EPA as part of the certification process. 

The Alliance for Green Heat, based on its legal counsel, argued that the EPA could not keep efficiency data it collected prior to May 2015 confidential because it was based on emission data, and emissions data cannot be confidential.  In July 2015 the EPA declined to release the efficiencies to the Alliance, in keeping with its longstanding practice that they would keep all data confidential if it was submitted as Confidential Business Information (CBI).  

Originally, the Alliance had asked for the weighted average efficiency as well as the efficiency from each of the four burn rates that labs use to test stoves.  The Alliance agreed to drop the request for the individual burn rate efficiencies and only request the average.  Based on that change, HHT and Ravelli agreed to allow the EPA to release their efficiency numbers to the Alliance with some conditions.

The EPA provided a final response with a data sheet (pdf) attached.  The efficiency numbers (HHV based on B415.1) from that data sheet are:

Company        Model                         Efficiency

HHT                Accentra 52i insert    76%

HHT                Mt Vernon E2            75%

HHT                Mt Vernon AE           71%

Ravelli             RV100                       70%

Ravelli             RV80                         56%

The Alliance requested efficiency information for these particular models, along with several others, because we were in the process of independently testing a selection of pellet stoves.  The Alliance was also attempting to convince the EPA to change their policy and disclose all efficiency data, even if that efficiency data had been marked as Confidential Business Information.  The Alliance argued   

The Ravelli RV80 Ceramica
is far cleaner than the original
RV80. The new, improved
efficiency is not yet posted on
the EPA list.

that efficiency was of such basic importance to consumers and that keeping it confidential served no useful purpose. That attempt was unsuccessful.  The Alliance is not appealing.

The five newly released actual efficiency numbers are not included on the EPA’s list of certified stoves, where about 25% of the stoves have actual efficiencies listed.  Except for one of the Ravelli’s, these five stoves all have around average or above average efficiencies.   The Ravelli RV80 was only 56% efficient, but  Ravelli has a updated version of this stove, the RV80 Ceramica, that has much lower grams per hour. (In response to this post, the EPA found that they had mistakenly omitted posting the efficiency of the RV80 Ceramica and said they would post it soon.)  Virtually all stoves claim to be 75% efficient to be eligible for the $300 federal tax credit, and EPA listing or disclosure that reveals the stove is not even 60% efficient does not appear to deter manufacturers from continuing to claim eligibility for the tax credit.   

Note: A representative of Ravelli replied to this blog saying that the RV80 is now out of production.   The Ravelli representative said that the updated RV80 Ceramica has an efficiency "over 75%." We asked Ravelli to support the "over 75%" figure with a lab report.  EPA regulations require companies to post lab report on their website for any stove tested under the 2015 NSPS.  Some companies comply, and others resist this level of transparency.

Study of pellet stoves shows environmental advantages - and corporate exaggerations

An independent assessment of popular pellet stoves conducted by the Alliance for Green Heat  found that pellet stoves, unlike most wood stoves, can achieve low levels of emissions in real world settings that are in line with laboratory results.   

The Alliance for Green Heat ran a battery of tests on popular pellet stoves designed to approximate how they would perform in the real world.  The group found that half of the stoves operated as clean at the end of the thirty-day test than they did at the beginning and the others were only slightly dirtier.

All six stoves, from the least to the most expensive, operated well, and produced enough heat for a small to medium- sized home in most of the United States.  One of the biggest differences was that the three more expensive stoves tested (above $4,000) needed very little weekly cleaning and maintenance.  The less expensive stoves ($1,200 to $3,300) needed daily or at least bi-weekly cleaning of their burn pots and glass.

The study also found a lack of accepted reporting standards, leading to exaggerated claims about efficiency, BTU output and pellet hopper size on manufacturer websites and promotional literature. 

The Alliance for Green Heat tested the stoves to give consumers better tools and make better purchasing decisions.  The study is part of a yearlong Pellet Stove Design Challenge that assesses the state of existing pellet stove technologies.  The Design Challenge will culminate in a competition for the cleanest and most efficient stoves, modeled after the Department of Energy’s Solar Decathlon.

Approximately one million American homes are heated with pellet stoves, more than twice the number that have solar panels.  In Italy alone, 2 million households heat with pellets. Pellet stoves often serve as primary heat sources, enabling homes to eliminate or drastically reduce fossil heating fuel.  Last year, about 40,000 pellet stoves were sold in the U.S. and they may outsell wood stoves in the near future.

The Alliance tested the England Stove Works 25-PDCVC, the Enviro M55 insert, the Harman Accentra 52i insert, the Piazzetta Sabrina, the Quadra-Fire Mt. Vernon AE, and the Ravelli RV80.  The group assessed each stove on its cleanliness, efficiency, maintenance, heat output and visibility of glass.  The overall winner was the Quadra-Fire Mt. Vernon AE, which received top marks in three of the five categories.  The Harman Accentra received top marks in two of the five categories.

The results of this study underscore that pellet stoves tend to burn substantially cleaner than wood stoves in real world settings, but it challenges the notion that pellet stoves generally have higher efficiencies than wood stoves.  The efficiencies of the six stoves were low to medium, which is partially the result of companies not having to test and report actual efficiency numbers. 

“Our testing confirmed that pellet stoves are an effective and affordable renewable energy technology,” said John Ackerly, President of the Alliance for Green Heat. “We hoped to see higher efficiencies, but efficiencies should improve in coming years,” Ackerly added.

Click here to read the full report on our website.
Click here to download a PDF of the report (the PDF does not have all the links and photos that the online version has).
Click here to download a PDF of the background materials to the report.

The Alliance for Green Heat promotes modern wood and pellet heat as a low-carbon, sustainable and affordable residential energy solution. The Alliance works to advance cleaner and more efficient wood heating appliances and focuses on low and middle-income families.  Founded in 2009, the Alliance is a 510(c)(3) non-profit organization based in Maryland.