LIVE image

What to like and what not to like about pellet stoves and pellet boilers.

Our Quadrafire pellet stove, which we can operate even during a power outage. Click to enlarge.
Photo Credit: Alex Wilson

We have a sort-of love-hate relationship with our pellet stove. My wife leans more toward the latter, while I see the benefits outweighing the negatives. In this column I’ll outline the primary advantages and disadvantages of pellet heating.

Advantages of wood pellet heating

Regional fuel. The fuel is—or can be—local or regional in origin. At a minimum it’s not fuel that’s coming from places where they don’t like us—like the Middle East. When I’m buying pellets, the source is a significant consideration. I’m willing to pay slightly more to have my pellets come from nearby plants in Jaffrey, New Hampshire or Rutland, Vermont.

Carbon-neutral. The life-cycle of wood pellet production and use can—and should—be close to carbon-neutral. With natural gas, propane, or heating oil we’re taking carbon that was sequestered underground millions of years ago and releasing that as a greenhouse gas into the atmosphere (where it contributes to global warming). When we burn wood pellets we’re still releasing about the same amount of stored carbon into the atmosphere, but that carbon was sequestered in the wood fiber over just a few decades, and if we’re managing our woodlands properly (replacing harvested trees with new ones) the entire life cycle results in almost no net carbon emissions.

Relatively clean-burning. Wood pellets are a lot cleaner-burning than cordwood. This is because pellet combustion is aided by a fan that supplies a steady stream of air to the burn pot. When I first start up my pellet stove—as the electric heating element heats up the pellets to start the combustion—there’s some smoke produced, but once the pellet stove is operating there is no visible smoke being generated. (This is a reason to set the temperature differential on the control relatively high—so that it won’t cycle on and off too frequently.)

Infrequent stoking. Pellet stoves have integral bins that can be filled every few days in cold weather, and most pellet boilers have stand-alone bins that hold several months’ worth of pellets. Regular stoking isn’t required—unlike with a wood stove. If a pellet stove is your only heating system in a space (as is the case with our apartment) how long you can go away depends on the energy efficiency of the building, expected outdoor temperatures, the volume of pellets your stove or bin holds, and the thermostat settings. With our pellet stove, we can go away for about three days in the coldest Vermont weather as long as I leave the thermostat set fairly low.

Convenient. With a pellet stove you don’t have to handle firewood. I’m sure I’ve cut, split, stacked, and burned a couple hundred cords of wood over the decades, and I know that it’s a lot of work. With pellet stoves you’re still handling the fuel—usually 40-pound bags of the rabbit-food-size pellets—but it’s more convenient than dealing with firewood.

Economical. Pellets are less expensive than heating oil, propane, or electric-resistance heat, so you can save money if you would otherwise use those fuels. You may save more money with a pellet stove by heating only a few rooms instead of the whole house—though there are often ways to do that with other heating system as well.

Disadvantages of wood pellet heating

Noisy. There’s no getting around the fact that pellet stoves are noisy. There are typically two fans: one to supply combustion air to the burn pot and another to circulate heated air into the room. I find the noise annoying; my wife hates it. It’s certainly a far cry from a silent wood stove in our living room. There’s a Wiseway Pellet Stove that supposedly operates passively, but haven’t seen one in operation yet. Pellet boilers are noisy too, but they’re typically in the basement or a separate building, so it’s not a problem.

Electricity dependent. When you lose power a pellet stove or pellet boiler can’t operate (unless you have one of those new Wiseway stoves). This is an important consideration not only in rural areas prone to power failures, but also more generally in an age of global climate change with more intense storms forecast. With our own Quadrafire Mt. Vernon AE pellet stove, I bought a kit that allow me to operate the DC fans using a 12-volt automotive-type battery during a power outage. It won’t auto-start using the DC power, so you have to start it by hand with kindling or starter paste, but at least it can be used to keep a space warm when the grid is down.

Comfort. Pellet stoves don’t deliver radiant heat. I love pulling up a chair in front of our wood stove on a cold winter night and sitting down with a good book. That radiant heat seems to warm you inside and out. Pellet stoves—at least the one we have—don’t heat up in the same way and radiate heat. Nearly all the heat is delivered by fan-forced convection. It’s just not as pleasant.

Plastic bags. Unless you get pellets delivered in bulk you produce a lot of polyethylene plastic waste from the bags. The first two years we had our pellet stove I was able to buy bulk pellets that were delivered in reusable thousand-pound totes that sat on pallets. I had to carry the pellets upstairs in five-gallon pails, but at least I didn’t generate all that waste. Unfortunately, the company that had delivered those totes disappeared, and I had to switch to the more typical 40-pound plastic bags (which we reuse as trash bags). I believe that as pellet heating becomes more common, bulk delivery of pellets will become more available.

Complex. Unlike wood stoves, pellet stoves have moving parts that can wear out and that require maintenance. There are blowers, temperature sensors, an auger to deliver pellets, and other components. Most retailers recommend annual servicing, which can add significantly to the total operating cost of a pellet stove or pellet boiler.

Less control over the fuel. If you have a woodlot you can cut and split your own firewood. That’s not the case with pellets. Pellet factories use massive presses to extrude wood fibers through dies to create the pellets. Do-it-yourself pellets aren’t an option.

Not always cheaper. While pellets are less expensive than most other fuels, they may not be cheaper that natural gas or air-source mini-split heat pumps. Use our Heating Fuel Cost Calculator to compare costs per unit of delivered heat. In the Northeast, pellets typically track with heating oil—going up when heating oil prices spike, though generally remaining significantly lower. If you can order pellets in bulk rather than buying them in 40-pound bags, there may be some savings—but not all that much. And there have occasionally been shortages of pellets, driving prices up substantially.

Bottom line

Pellets are a mixed-bag, but they offer enough advantages in many situations to warrant consideration. They provide a user-friendly option for relying on a relatively local, renewable fuel source. If Europe is any indication, the use of pellet heat in the U.S. is likely to increase significantly in the years and decades ahead.

Check out the high-performing, low-emitting pellet stoves that we've found in our GreenSpec section.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.

If you enjoyed this article, sign up for BuildingGreen email updates:

*

Comments

1 The calculator isn't somethin posted by Nadav on 10/03/2010 at 04:00 am

The calculator isn't something you download--it runs online. See the link towards the end of the story.

It estimates water collected off the cooling coils, regardless of what type of air handling unit they're in. An enthalpy wheel would change that calculation.

2 Appears to be a good tool. Wh posted by Bazeeth Ahamed on 09/28/2010 at 11:19 am

Appears to be a good tool. Where from I can download it? If the fresh air is treated by a centralized FAHU. Does the quantity gives condensated collected from FAHU? What about the condensate in FCUs? What if enthalpy wheels are used for heat recovery?

K.M. BAZEETH AHAMEDwww.greenbuilding-me.com

3 This is a very impressive too posted by Brian Koles on 09/27/2010 at 09:01 am

This is a very impressive tool. Those who find it useful may also want to check out the various ROI calculators available on the Resources page at www.GreenTechBuyer.org. While every project is different, and the metrics aren't perfect, they may be useful for estimating startup costs and payback for green projects. I hope this helps.

4 This is more a question than posted by Yumiko on 10/11/2010 at 01:13 pm

This is more a question than a comment: Is this tool applicable for residential use? If it is, how would I determine the indoor relative humidity? If it is not, where can I find a similar tool for residential projects?

5 RH calculator posted by Skip Steller on 07/13/2013 at 01:42 pm

I tried your new RH calculator, but the GPH condensate appeared to go DOWN, not UP, when I increased the inside RH, with all else remaining the same.  And when I  decreased the inside RH it resulted in an INCREASE GPH condensate. I could understand this if one is supposed to fill in the DESIRED inside RH, but not the actual RH.  Or, perhaps I'm just looking at something wrong.

 

Add comment

Login or register to post comments

— Share This Posting!

About the Authors

 

Recent Discussions

posted by atwilson
on Aug 19, 2015

Cynthia, yes that's correct; there is...

posted by cynthia.crawford
on Aug 19, 2015

Alex-Sorry- I meant to say sprayed- fiberglass. Thank you for your answer in any case, for both foam and fiberglass. It's the first time I've...

posted by atwilson
on Aug 18, 2015

Cynthia, Spider is a spray-fiberglass product, not a spray-foam, but neither material could be considered rodent-proof. In our home, rodent entry...

Recent Comments


Getting to Know Spider Insulation

Alex Wilson says, "Cynthia, yes that's correct; there is formaldehyde in mineral wool (urea-extended phenol formaldehyde). I'm not as worried about that as many others..." More...

Cynthia Crawford says, "

Alex-Sorry- I meant to say sprayed- fiberglass. Thank you for your answer in any case, for both foam and fiberglass. It's the first time I've...

" More...

Alex Wilson says, "Cynthia, Spider is a spray-fiberglass product, not a spray-foam, but neither material could be considered rodent-proof. In our home, rodent entry at..." More...

Cynthia Crawford says, "Since sprayed foam doesn't require boric acid, how does it prevent rodents from entering a building or burrowing into the fiberglass? They certainly..." More...


7 Tips to Get More from Mini-Split Heat Pumps in Colder Climates

Wendy L'Ecuyer says, "1. We've had a few assessments for a mini split installation in a master bedroom/ensuite. Some have recommended a 9000 BTU unit, the others a 12000..." More...