Retailers say BTU
output can be most confusing issue
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| Glenn Robinson is one of many retailers struggling to help consumers avoid relying on manufacturer claims about BTU output. |
Updated on Jan, 7, 2021 - Glenn Robinson has been selling and installing pellet, wood
and coal stoves in Pennsylvania for 11 years, and one of the biggest problems he faces is sizing the stove. “I became
tired of false information from manufacturers about how many BTUs
they claimed their stoves put out” he said in a recent interview. “Customers see these exaggerated BTU numbers
from a small stove and think it will heat their home, but it won’t. The result is that the stove is undersized
and there is premature wear and tear.
One model from a big name brand would only last for 3 – 4 months before
needing repair or even full replacement,” he said.
Glenn is not alone in identifying exaggerated BTU listings
as one of the biggest problems consumers face in buying a stove. Scott Williamson, a Massachusetts pellet
installation and repair technician says that he sees stoves “all the time that
are being run on high 24/7 and pellet stoves just aren’t designed to do
that.” Both installers say that under
sizing of pellet stoves is one of the biggest problems, and urge customers to
consider larger (higher BTU output) stoves if they live in average size homes
in the northern half of the country and plan to use the stove a lot.
Buying a pellet stove can be a confusing process for
consumers (but as of 2021 high efficiency pellet stoves and installation costs are eligible for a 26% federal tax credit!) Retailers are likely to push the brands they sell and manufacturer
websites don’t tell the whole story.
Objective, third party reviews are rare and often outdated. Consumer Reports did a pretty good review
in 2009 but used very limited criteria and didn’t test for durability. The Alliance for Green Heat (AGH) also
undertook third party testing in 2015 and issued a detailed online report
on some issues including BTU output, maintenance and efficiency. (Like Consumer
Reports, AGH conducted completely independent testing by purchasing all the
units and doing all of our own testing.)
This blog identifies and discusses six rules for consumers
to keep in mind when buying a pellet stove, with a focus on sizing. This is not an exhaustive list but it’s a
good place to start: 1. Don’t undersize, 2. Beware of cheaper stoves, 3. Look
for range of heat output, 4. Understand maintenance requirements of the stove,
5. Look for cleaner stoves and 6. Beware of stoves with no efficiency on the
EPA list
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| AGH tested six popular pellet stoves. Almost all performed well during intensive 30 day testing, but did not live up to some manufacturer claims. |
Pellet stoves can be a very effective and affordable way to
provide primary or secondary heat for your home without the smoke that wood
stoves often create in the hands of the typical user. Wood stoves require lots
of work on the fuel side of the equation, but pellet stoves involve more work
on the appliance side of the equation.
The Alliance for Green Heat also monitors advertising of
pellet stoves and has found over the years that the great majority of companies
vastly overrate the amount of heat their stoves put out. The EPA list
of certified wood and pellet stoves is not perfect but it remains the best
source of BTU output for consumers.
Most EPA-certified pellet stoves are listed as producing a
maximum of 25,000 – 40,000 Btu and minimum of 7,000 – 13,000 Btu. The average
pellet stove on the EPA list, according to data provided by third party test
labs, put out a maximum of approximately 31,800 Btu and a minimum of
approximately 10,050 Btu.
The stove with the highest maximum Btu on the EPA list is
the Harman P68 at 53,500 Btu (advertised at 71,200 Btu input). When a stove
manufacturer lists Btu input, it refers to amount of Btus in the fuel, if you
were to get 100% of those Btus into the room.
But the average pellet stove is around 73% efficiency, which means you
will get 73% of the fuel’s potential heat into the room. (This is similar to the AFUE – the annual
fuel utilization efficiency – that is used on gas and oil boilers and
furnaces.)
The stove with the lowest maximum Btu is the Thelin Gnome
pellet stove that puts out up to 9,000 Btus.
However the company advertises three times that - 27,000 Btus - without
any explanation. Manufacturers usually
exaggerate Btu, thinking that it will make their stoves more attractive, but in
the case of the Thelin Gnome, there are people looking for stoves to heat very
small places and the exaggerated Btu output may make them think even the Gnome
is too big.
Here are six critical things for consumers to keep in mind
when purchasing a pellet stove:
1. 1. Don’t
undersize. If the stove is going to be your primary heat source you will
likely need a medium or large pellet stove, even if a smaller unit advertises
high BTU output. Ignore BTU numbers on
manufacturers websites and literature and check the EPA list. The maximum output for pellet stoves is in
the 30,000 – 50,000 range, enough to heat all or most of a small or medium
house in most climates. “Don’t plan to run the stove all the time at its
highest setting,” warns Scott Williamson “or you will be calling someone like
me to fix it quicker than you think.” When we tested six popular pellet
stove models, we calculated an output of no more than 21,000 BTUs, far
below what the EPA listed and even farther below what manufacturers claimed.
It is possible to oversize the stove and
that can be a problem, but is not nearly as common as under sizing. “For example, the
Harman P68 is notorious for being installed in small areas like mobile homes
but they gunk up when they aren't allowed to get up to temperature for a bit
before they shutdown,” says Scott Williamson.
2. 2. Beware
of cheaper stoves. There are some good budget wood stoves on the market,
but with pellet stoves, you are more likely to get what you pay for than with
wood stoves. “If you want a reliable
stove that puts out a lot of heat, we urge customers to ignore pellet stoves
under $2,500,” says Glenn Robinson. Scott
Williamson generally agrees but has seen some basic stoves like the Pel Pro in particular holds up very well.
3. 3. Check for
range of heat output. Most stoves
can put out about 3.5 times more heat at their highest setting, compared to
their lowest. Some stoves have a tiny
range, putting out only 1.5 times more heat at their highest setting. If you live in a more moderate climate, in the
early fall and late spring, you may want just a little heat, and still have the
capacity for much greater heat output on the coldest days and nights of
winter. All other things being equal in
a stove, you may want a stove with a larger range of heat output and you can
check the range of all stoves on the EPA list
of certified stoves. In our tests, we
found that the Enviro M55 insert ran continuously for an impressive 49 hours on
its lowest setting with a tested hopper size of 60 pounds and it ran for 22
hours on its higher setting. However,
with a 37-pound hopper, the Englander 25 PDVC only rain for 15 hours on its
lower setting and 13 hours on its highest setting, indicating a very low turn
down ratio.
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4. 4. Understand
maintenance requirements. If you don’t clean your stove regularly and have
it professionally serviced once a year, don’t expect high BTU output. Most consumers get subpar performance from
stoves and have to repair them more often because they are not maintaining
their stoves according to the owner’s manual.
Pellet stoves are not like wood stoves: they have lots of moving parts
and need cleaning of the burn pot and inside the stove on weekly, and depending
on the stove, a daily basis. Pellet
stoves that are not cleaned regularly can lose 10% or more of their efficiency
– and their heat output, and lead to costlier repairs. Understand the daily,
weekly and annual maintenance requirements from the start and don’t put them
off. When we tested six popular pellet
stoves, we found that the three more expensive ones (Harman, Quadra-Fire
and Enviro) could go for a week or more without cleaning the burn pot. However, the Englander, Ravelli and Piazzetta
needed daily burn pot cleanings.
5. 5. Look for
cleaner pellet stoves and ones that are 2020 certified. Pellet stoves
are far
cleaner than wood stoves, even if they both have the same particulate
matter in grams per hour. Particulate
matter is the tiny stuff that smoke is made out of and pellet stoves should not
have any visible smoke after the 3-minute start up. The average pellet stove used to put out
about 2 grams of particulate per hour.
But since the new EPA regulations took effect in 2015, pellet stoves have become even cleaner and more efficient. As of April 2020, more than half of the 2020 certified pellets stoves emit 1 gram or less per hour. This makes pellet stoves more
suitable in more densely populated suburban and even urban areas. Choosing a cleaner pellet stove means a
cleaner flue pipe and cleaner air around your and your neighbors’ homes. You can now easily search for the cleanest pellet stoves on the EPA's new searchable database.
6. 6. Beware of efficiency numbers on manufacturer and retailers websites. As with BTUs, manufacturers routinely
exaggerate the efficiency of their stoves on their websites, so if
efficiency and saving money is important to you, check the EPA list of stoves
for efficiency ratings. Until May 2020, many companies still hadn't even reported their efficiency to the EPA, but thanks to new regulations, all companies have to test for and disclose their efficiency. Pellet stoves range
from 58 to 87% efficiency, so do your homework and check the EPA list. As of Jan. 1, 2021, consumers can get a 26% tax credit when buying and installing pellet stoves that are 75% efficient or higher. Click here for more details.Do not rely on Manufacturers Certificates that claim their stoves are eligible for a federal tax credit without first checking the efficiency on the EPA's searchable database of certified heaters. Even large companies that make good quality stoves like Jotul and QuadraFire have claimed that stoves as low as 66% efficiency are eligible for the tax credit. The credit is supposed to be for stoves over 75% efficiency.
The EPA used to allow companies to calculate efficiency based on a
default of 78% efficiency, even though most pellet stoves are below that,
explains Ben Myren, who runs one of the stove test labs approved by the EPA.
The result is a 5-10% exaggeration of some stoves on the EPA site, something
that the EPA has not publicly acknowledged. (Some incentive and change
out programs - Maryland, Massachusetts and New York - require that
the stove have an efficiency listed on the EPA list to get the full rebate.)
Appreciating these six factors are likely to help you make a
better decision, but we also encourage consumers to rely on feedback from
friends, neighbors and others who own pellet stoves. One site that can be helpful for research is hearth.com.
A final note of caution is to take advertised hopper size with a grain
of salt. Most manufacturers also
exaggerate hopper size. Of the six
models we tested, Harman and Ravelli exaggerated their
hopper size by 15 – 18%, while Enviro didn’t exaggerate at all. Choosing a stove with an advertised hopper
size of 50 – 60 pounds can be a good idea, as it means the hopper will likely
hold 45 – 55 pounds and you can empty an entire 40 pound bag in it when its
low.
