Draft-July 23, 2010--- Company Names Removed

Pellet Stove Manufacturers: ICR Answers to Question G

Question G. Please provide a list of characteristics that are critical for pellet fuels used in the 

units you manufacture (e.g., moisture content, ash content, dimensions, etc.) and why you think 

so.

1. Redacted

It is important that the pellet fuel is of premium grade. Ash content should be no more than 

3%, dimensions need to be consistent in length and preferably 1⁄4” diameter X 3⁄4” long. 

Ideally moisture content should be 5-7 percent. Fuel of substandard value contributes to 

clogging of the auger system, possible burn back issues, incomplete burn in the firepot and 

excessive maintenance for the unit.

2. Redacted

Our stoves are design for wood pellets low in moisture and low ash content. The typical size 

of the pellet fuel is 1⁄4 inch round and less than 3⁄4 inch in length. 

[redacted some product specific info...]

3. Redacted

 Dimensions – Our stoves are designed to use pellets 1⁄4” maximum diameter and no 

longer than 3⁄4”. We base our feed rates on this. This also minimizes jams.

 Ash Content – Ash over the PFI Standard could cause auger jams in our units.

 Sodium Content – This must be kept to its lowest level to eliminate corrosion and metal 

degradation.

 Additives – The cleanest burning pellets have no additives.

 Fines – Fines above 1% can cause auger jams.

 Chlorides – Keep as low as possible to eliminate corrosion.

4. Redacted

The most critical characteristics for pellet fuels that are used in the pellet stoves we 

manufacture are going to be: ash content, fines, moisture content and length.

Ash content is considered most important, as a lower ash content keeps the burnpot area 

cleaner for a longer period of time, thus allowing a cleaner bum between cleanings. The most 

common operational problem for the home user is a dirty bum, and generally this is related to 

maintenance. The lower ash content will allow for users who do not follow regular 

maintenance schedules to get a clean bum, longer.
Draft-July 23, 2010--- Company Names Removed

Pellet Stove Manufacturers: ICR Answers to Question G

Fines are also very important, as they tend to clog the augers in pellet stoves. In addition, 

fines tend to build up in the bumpot; they do not allow as much airflow, and thus do not 

promote proper combustion. 

Moisture content is very important for the efficiency of the unit (allowing more BTUs per lb. 

of fuel), as well as performance. As with any wood that is burnt, dry wood pellets will bum 

hotter and cleaner, and thus a low moisture content is preferred. 

Length is important for the auger feed systems of pellet stoves, as well as for consistency of 

bum. A consistent length of pellet fuel will prevent maintenance issues in stoves and will 

allow for a more even bum. Ideally, if we were talking about a perfect world with an ideal 

fuel, the fuel would be the exact size across the board, and manufacturers such as ourselves 

would have a steady, even bum all the time. A steady fire bums cleaner, thus reducing 

emissions. 

With this said, I would like to point out that pellet stoves are much cleaner, on average, than 

wood stoves and, due to the increased efficiency over wood stoves, that advantage is even 

more pronounced. As much as any manufacturer wants the pellet industry to provide a 

perfect product, I believe it must also done practically, as it is in all of our best interests to 

keep this fuel affordable. If the restrictions upon pellet manufacturers were to become cost 

prohibitive, that would drive up the price of the fuel and keep it from becoming a preferred 

heating method to some consumers. Particularly in this economy, where our country needs to 

continue to develop products like pellet stoves for energy independence, it is my hope that if 

we err, we err on the side of less stringent standards. As a stove manufacturer, of course it is 

in our best interest to have the best pellet available; however, if pellets become unaffordable 

due to excessively strict standards, then nobody wins, as we will not have a customer base for 

our product.

5. Redacted

We recommend the use of premium pellets based on the pellet fuels institute standards listed 

below:

Density: Consistent hardness and energy content (minimum 40 lbs/cubic foot)

Dimensions: Length (1.5” maximum) and diameter (1/4”-5/16”) to assure predictable fuel 

amount and to prevent jamming.

Fines: Limited amount of sawdust from pellet breakdown, to avoid dust while loading and 

problems with pellet flow during operation. (Amount of fines passing through 1/8” screen no 

more than 5% by weight.)

Chlorides: Limited salt content (no more than 300 ppm) to avoid stove and vent rusting.

Ash Content: Important factor in maintenance frequency.

Moisture Content: Less than 8%
Draft-July 23, 2010--- Company Names Removed

Pellet Stove Manufacturers: ICR Answers to Question G

The reason for recommending a pellet that meets these standards is that quality of fuel 

greatly affects the operation of the stove, the maintenance schedule of the stove increases in 

frequency by using a poor quality fuel, Currently it is difficult for the end user to determine 

the actual quality of the fuel and always blames the stove when it isn’t burning correctly. 

6. Redacted

Ash Content, Moisture Content, Fines, Species of Wood, and Overall dimensions are all 

important to the operation of our pellet units. Variability of these characteristics has no doubt 

been the biggest challenge to our end users (and therefore the manufacturers) over the last 

several years. When the customer becomes accustomed to the performance, heat output and 

maintenance intervals required by a specific fuel...and then those qualities change, the 

customer is forced to modify or alter how they use and maintain their appliance. This isn’t 

necessarily the issue between “West Coast” and “East Coast” fuel which we’ve dealt with for 

years, but variability of quality and consistency within regions and sometimes within brands 

which makes it difficult to keep up with. We’ve done all we can do to educate our customers 

on visual cues which might suggest they need to alter the operation of the units or increase 

the maintenance intervals but more consistency and control of the composition and 

performance of the fuel would:

 Greatly increase the satisfaction of our customers.

 Greatly reduce warranty/customer service cost for manufacturers.

 Result in finer tuned, cleaner burning more efficient appliances.

 Reduce the R&D costs of developing new units.

7. Redacted

Information not provided. 

8. Redacted

 Density: consistent hardness and energy content (minimum 40 pounds/cubic foot).

 Dimensions: length (1 Y2" maximum) and diameter (1/4" x 5/16") to assure predictable 

fuel amounts and to prevent jamming.

 Fines: limited amount of sawdust from pellet breakdown to avoid dust while loading and 

problems with pellet flow during operation (amount of fines passing through 1/8" screen 

no more than .5 percent by weight).

 Chlorides: limited salt content (no more than 300 parts per million) to avoid stove and 

vent rusting.

 Ash content: less than 1%.

9. Redacted

Information not provided.