Enviro redesigns EF2 pellet stove, raises efficiency 19%

Improved heat transfer led to major
improvement in efficiency without
any price increase of the EF2.

When the EPA began posting actual efficiencies on its list of certified stoves, all of sudden consumers could see which brands of pellet stoves were saving them more money in fuel costs and which weren’t. A popular pellet stove, the EF2, made by a prominent brand, Enviro, turned up at the very bottom of the list at 58% efficient, surprising many. The company had been advertising the stove at 87% to consumers.

Enviro appears to have redesigned the stove in an effort to avoid the distinction of having the least efficient stove on the EPA list. In July of 2016, Enviro tested their new version, the EF2-1, only a year after testing the older version, and it came in at 77%, nearly 20% higher than the old version. Now, due to greater scrutiny, they also advertise to consumers that the stove gets 77% efficiency. At the same time they lowered the emissions from 1.8 grams an hour to 1.4 grams an hour. Their carbon monoxide values also went from 25 grams an hour to 7 grams an hour, a dramatic improvement.

At 77% efficient, the new Enviro EF2-1 is one of the most efficient pellet stoves made by a major North American stove company. The average pellet stove is likely to be around 70% efficient, but this may rise as companies like Enviro compete to design higher efficiency stoves. One of Harman’s lower efficiency stoves, the Advance, tested at 67% efficiency. That stove is being discontinued, which could be partially due to its low efficiency. (Harman still claims that the stove is eligible for the federal tax credit for stoves that are 75% efficient or greater.)

The US Stove model 5660 is now one of the least efficient pellet stoves on the market at 62%, but the company still says that it is eligible for the 75% federal tax credit. St Croix makes two pellet stoves, the Hastings and Ashby, that each tested at 66% efficiency by EPA-approved test labs. However, the company website claims that the Hastings is 83% efficient and that its “efficiency ratings are verified by an independent lab.” The Hastings owners manual confirms that the independent lab rated the stove at 66% efficiency.  The tax credit is set to expire on Dec. 31, 2016.

The Enviro EF2-1 is also sold by Hudson River Stove Works under the brand names Chatham, Davenport and Kinderhook.  Despite the lab test showing the stoves are 77% efficient, Hudson River Stove Works continues to tell consumers that they are 85% efficient.  Unlike the manufacturers of automobiles and major appliances, there is nothing stopping wood and pellet stove manufacturers – or their retailers – from blatantly misleading consumers, as Hudson River Stove Works does.

The EPA has made efforts to bring more transparency by requiring manufacturers to post the test lab documents on their websites. These documents show additional details about the stove, including its carbon monoxide levels and emissions results at each burn rate. Enviro is one of the companies that complies with this rule and posts this information so that consumers can see testing information about the EF2-1 here.

In the November update to the EPA list of certified stoves, the EPA added a column for carbon monoxide, as all stoves tested after May 2015 have to test for and report their carbon monoxide emissions levels along with their particulate matter emissions and efficiency. However, the EPA has only input the CO test results for eight stoves as of December 14, 2016.  The EF2-1 at 7.4 grams of CO per hour has the lowest.  The five non-cat stoves with CO values range from 87 to 186. 

Wood and pellet stove companies that you can trust – and those you can’t

When it comes to listing accurate efficiency and BTU output on their websites, there are only a handful of companies that you can trust.

Updated on January 11, 2018 - For years, wood and pellet stove companies have listed exaggerated efficiencies and BTU output on their websites and brochures and no agency has challenged them for this practice.  Luckily, the EPA has started to list efficiencies on their list of certified stoves, so consumers have a easy way to check company claims.  

Most wood and pellet stove manufacturers use a variety of ways to say their stoves are more efficient than they actually are, and that they put out more heat than they actually do.  BTU output is the other area where manufacturers routinely report misleading data to consumers.  In the case of BTU output, even the EPA was willing to post those exaggerated numbers on its website, further contributing to the problem.

These issues are coming to light in the wake of new EPA regulations that require more accurate reporting and require manufacturers to post the test reports of independent labs that certify wood and pellet stoves.  Many stove manufacturers are not complying with the new rules and will not post their certification reports for consumers to see but some companies are complying.

A few companies stand out for providing the same efficiency numbers to their consumers as the independent test lab provided to the EPA.  They are: Blaze King, Jotul, Kuma, J.A. Roby, Seraph, Travis and Woodstock Soapstone.  Consumers can trust the efficiency numbers that these companies post on their websites and in their promotional materials.  

The same is not true of other companies, including many leading brands.  Most companies list efficiencies using the European (LHV) method, which can produce efficiencies of more than 100% and make their stoves appear 5 - 8 points higher than they actually are.  But some companies go further, publishing efficiencies that are 15 - 29 points higher than they actually are. 

The largest stove maker in the country, Hearth & Home Technologies (HHT), that owns Dutchwest, Harman, Heatilator, Quadra-Fire, Vermont Castings and others brands, published test lab reports for all their brands, several weeks after this blog first came out (in May 2016), which noted that they had not complied.  The company also says that actual efficiency numbers from independent test labs are recorded in the owners manuals in their stoves.  The result is that consumers see the exaggerated LHV efficiency on the brochures and website and then see the real number, often 5-10% lower, in the fine print of the owners manual.

HHT companies provide their lab reports on pages like these for Quadrafire, Harman.  For those and other HHT brands almost all the lab reports pre-dated the new EPA regulations, so actual efficiencies and BTU output are not included.  HHT has declined to voluntarily disclose efficiencies, like companies such as Jotul and Hearthstone have done.

One of the foremost experts in the hearth industry Dr. James Houck, an adjunct faculty member at the University of Portland in Oregon, used to work for Omni Test labs, the most well known test lab in the US.  He says, “Many of the pellet (and cordwood) stove efficiency values have been produced by commercial labs which optimized conditions and calculation methods." 

A wood stove test lab.

Under the new EPA stove regulations, known as New Source Performance Standards (NSPS), labs may be more restrained from optimizing conditions and calculation methods and will be producing more accurate efficiency and BTU output numbers for consumers.  Still, labs are under pressure from their clients to produce the best possible emission, efficiency and BTU numbers, or they may take their business to a lab they think can produce the best numbers.

The new EPA rules are requiring the test labs to produce more accurate BTU output data, which is crucial for consumers to right size the appliance for their home.  The result will be that BTU figures posted by the EPA after May 2015 when the new rules began will be lower than the figures posted before May 2015.  

The EPA has not started enforcing some of the provisions of the 2015 regulations which are being ignored by many companies. And, its enforcement capabilities are slim, a fact that is not lost on the industry that it regulates. State agencies could help enforce the new regulations, particularly for manufacturers based in their states and if stakeholders in the state pressure them to do so.

Under the new rules, an independent lab testing the St. Croix Hastings pellet stove reported that it produced 7,000 – 27,000 BTU per hour.  However, the St. Croix website says the stove produces up 40,000 BTU per hour.  Many manufacturers used to use the BTU input, which is the amount of BTUs available in the fuel, rather than the BTU output from the stove.  But The EPA has been recording estimated and often exaggerated BTU figures on its list of certified stoves for many years and it will be a slow process for them to start recording more accurate BTU figures from new test reports.  The Alliance for Green Heat has urged the EPA to remove all exaggerated BTU data from their list of certified stoves and only post actual BTU output that is determined by an independent lab using an approved calculation.

“The problem with companies using all manner of efficiency and BTU calculations is there is a disincentive to report more accurate numbers that would make your stoves look less efficient and less powerful,” said John Ackerly, President of the Alliance for Green Heat, a consumer focused wood heating non-profit organization.  “The new EPA rules are starting to change what gets posted on its list of certified stoves, but manufacturers can still virtually post whatever they want on their websites and no state or federal agency monitors that, as they do with cars and most consumer appliances,” Ackerly said.

Some companies are beginning to post their lab reports on their websites, so consumers who want extensive technical details can have access to them.  The reports are dense, often long and hard to digest, but can provide useful insights for those who want very detailed, technical information.  Blaze King, Enviro, Kuma and St. Croix were the first to post test lab report for all their stoves.  Jotul and HHT companies Quadrafire, Harman, Vermont Castings, Heat & Glo, Heatilator, Majestic and Eco-Choice now post them as well.   For some companies, such as St Croix, those test lab reports reveal that they have far higher efficiency and BTU numbers in their promotional materials.  Lab reports can also help consumers understand what air settings or power levels their stove is likely to be cleanest, dirtiest, most efficient and least efficient.

Lab reports from testing that was done prior to 2015 usually do not have efficiency numbers or have been whited out.  Some of the posted lab reports are from as early as 1989, are hundreds of pages long and by test labs that no longer exist such as EEMC, Lokee Labs and Northwest Testing.

Advice for consumers:  Beware of efficiency and BTU output claims on websites and promotional literature of wood and pellet stove manufacturers.  The only companies who accurately report their efficiencies on their websites that we are aware of are Blaze King, Kuma and Seraph, Travis and Woodstock Soapstone.  The EPA’s list of certified wood stoves contains more and more actual efficiency numbers and is one of the few reliable places for efficiency information.  Many companies are still holding out disclosing lab reports to consumers.  If you want to be certain you are buying a higher efficiency stove, buy one that discloses their actual efficiency and actual BTU output on the list of EPA certified stoves.  For more information on this topic and a list of stoves that have actual efficiency numbers, check our blog post, A Review of Wood and Pellet Stove Efficiency Ratings.

(This blog will be periodically updated as more data becomes available or if the companies mentioned reply to queries)

Consumer Reports on Reliability of Gas Furnaces & Pellet Stoves

Alliance for Green Heat, Updated on Nov. 30, 2017 - Wood and pellet stoves are a secondary fuel of choice for many of us who primarily heat with oil, propane or electricity. But when it comes to cost savings, gas furnaces provide the cheapest form of fossil fuel heat. Choosing a reliable brand of furnace is still important, and the December 2012 issue of Consumer Reports advised consumers to think twice about York furnaces which broke down about twice as often as other brands.

Bryant, Trane and American Standard furnaces needed repairs the least often, according to the Consumer Report survey of 32,251 appliances bought by subscribers of the magazine. Many other brands, including Carrier, Rheen, Ruud and Lennox, held up nearly as well. Consumer Reports also has excellent general advice about purchasing a gas furnace.

Consumer Reports has never done a large survey of wood or pellet stove reliability, although they did test and review 6 pellet stoves in February 2011. The magazine gave highest rating to the Harman P68, which, at $3,900, was also the most expensive of all the pellet stoves they reviewed. A close second to the Harman was the Napoleon NPS40 which cost only $2,350, and rated higher than 3 other more expensive models from Lopi, Enviro and Quadrafire. At the bottom of the list was Summers Heat 55-SHP10L, made by Englander, but that model only cost $1,300 and is often considered a good value.

Consumers Reports has never tested wood stoves, so don't subscribe thinking you will find any ratings or recommendations for wood stoves. Both wood and pellet stoves deserve far more attention from consumer organizations as there is little reliable third party testing and reliability surveys. The testing that Consumer Reports did of pellet stoves in 2010 did not include efficiency, reliability, noise levels for pellet stoves or how much electricity the stove drew.  The Alliance for Green Heat tested six popular pellet stoves in the fall of 2015.  In our tests, the Quadra-Fire Mt. Vernon AE got the highest overall score, followed by the Harman Accentra insert.

Like Consumer Reports, we purchased pellet stoves without the knowledge of the manufacturer to maintain independence and then put them through a battery of tests.  The Italian Piazzetta Sabrina scored the highest on efficiency and the Enviro M55 insert did very well on heat output.  If you are in the market for a pellet stove, see our 2017 "6 Tips to buy the right a pellet stove."

 The Alliance is also pursuing actual efficiency data of pellet stoves from the EPA, who initially declined to release the actual efficiencies of popular pellet stoves.  The Alliance asked the EPA for a final determination on this matter and still hopes that the EPA will release this data.

Wood stoves are inherently more reliable and often need little repair, other than cleaning the chimney annually and replacing the gaskets every few years. However, the durability of many wood stoves, while a selling point, can also be a drawback because many people keep their old, inefficient and polluting stoves for too long, not realizing that newer ones can save them up to 50% on fuel cost and be far better for their health.