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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.

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Comments

1 We miss the woodstove from posted by Brent Ehrlich on 10/25/2012 at 02:01 pm

We miss the woodstove from our old cabin, but our current home is not set up for one, so we bought a Quadrafire a few years ago, which is direct vented. We get some of the aesthetics of the wood stove, and we have adjusted, for the most part, to the fan noise.

As noted, the lack of radiant heat can be a downside, but it has an upside too. The stove is completely cool to the touch. You could sit on the thing while it's blasting away. With two young kids, this has saved us a lot of anguish, as we have not had to put up gates or worry about additional fire protection.

We rely almost exclusively on the pellet stove and some ingenuity for heat and figure the stove paid for itself within the first three years. It's not an ideal solution, but it has been a great fit so far for our heating situation.

 

 

2 Heating with Wood Pellets posted by Dutch Dresser on 10/31/2012 at 04:30 pm

It's a pleasure to see an objective blog on heating with wood pelelts.  I'd like to offer a couple of comments on points made in the blog.  I am not an objective third party, I am a Director at Maine Energy Systems; we manufacture and distribute Austrian designed OkoFEN boilers under the name MESys AutoPellet boilers, and we deliver loose bulk pellets across the Northeast.

I'm not sure which pellet boilers are noisy, but ours are not.  There are two fans, one for combustion air and one for draft induction that are barely audible at the boiler, and certainly not audible upstairs.  The feed auger is silent.  A vacuum filled boiler will make the nooise of a vacuum cleaner for about ten minutes, once or twice a day depending upon fuel consumption, otherwise the boilers can't be heard from upstairs.

I don't track bagged pellet prices, but I have no reason to doubt the accuracy of the report here. As bulk deliverers, we have frozen the price of pellets for years at a time so that fuel price is a known for our customers.  Right now our prices are fixed through June 2014.

In many places, including Vermont, bulk deliverers are generally happy to fill multi-ton storage units for stove owners so they can break the polyethylene habit.  We call our solution the 3TX; it can be found on our website.  http://www.maineenergysystems.com/Pellestore_3TX.htm

For all the reasons stated so well above, I enjoy heating my housse with a pellet boiler and a playroom on my barn with a pellet stove.

3 Pellet stoves posted by Stuart Tarbuck on 10/24/2013 at 01:10 pm

I've been using a pellet stove (Enviro) for auxiliary heat for several years, both in my old house and the new one, and generally like it. My primary objection is the lack of radiant heat and the resulting reliance on a noisy fan.  As far as I know there is no current manufacturer of a radiant pellet stove. There was a company in Oregon (Snoqualimie Stove Works) who designed a very futuristic-looking one with a newly-designed burner but the extensive and expensive certfication process finally did them in and it was never brought to market.

My other small quibbles with pellet stoves are a) the reliance on the vagaries of the pellet manufacturers, whose prices continue to rise (nothing new there, of course!), whereas one can shop around for cordwood. b) the exorbitant cost of some replacement parts, especially the ignitor, which has to be replaced every couple of years or so.  The solution for the latter is to find out who actually makes the ignitor (known in the industry as a cartridge heater), get the part number directly off the ignitor and order it through a distributor. In the case of my Enviro EF5, the mfr. is Ogden Chromalox, P/N MXEJØ4A3293.  I bought two through an Ogden distributor for about $40 ea. including shipping, rather than about $150.00 each from an Enviro dealer!

These quibbles aside, pellet stoves are more efficient than wood stoves and they can be put on a thermostat if desired.  I rarely use the convection fan and, being an inveterate tinkerer, I'm planning to replace it with a lower-capacity unit at some point anyway. I mostly use mine to warm the house in the shoulder season, when the outside temperature doesn't dip too low. As my house (in coastal British Columbia) is very well insulated and has decent solar gain in the winter, this setup works quite well, as well as reducing my consumption of natural gas.

4 Pellet Stoves posted by Brent Ehrlich on 10/24/2013 at 01:36 pm

Hi Stuart,

There is a radiant-only solution: check out Wiseway in our GreenSpec product database http://greenspec.buildinggreen.com/product/wiseway-pellet-stove/wiseway-.... It looks a bit funky, so if you are trying to replicate a woodstove look, this probably won't work, but I like it. The unit uses no electricity. It is gravity fed and convection only. Cool product.

 

For a bit more info on pellet stoves, you can check out my blog from last year.

http://greenspec.buildinggreen.com/blogs/have-your-wood-or-pellet-stove-...

 

Brent

5 Pellet stoves posted by Stuart Tarbuck on 10/24/2013 at 02:06 pm

Thanks for the information. I had forgotten about the Wiseway stove. Certainly "a bit funky"; I don't think it  would suit my place but an interesting design for sure. Nice to see someone thinking out of the box, as all the other stoves are, marketing hype aside, "pretty much of a muchness."  Now maybe someone will come up with a gasification pellet stove, which would be 90+% efficient...

 

6 Whole Home Heat with a Wood Pellet Boiler posted by Andy Boutin on 06/25/2014 at 07:52 am

Like Dutch's post above, I would like to reiterate the fact that there is another solution: Wood Pellet Boilers. These are systems that connect to the piping and distribution in your home and allow you to use your radiant heat, baseboards or other current central heating system.

I have two wood pellet stoves and a pellet boiler (two pellet grills too, but that's another topic!) The first pellet stove I purchased in 2001 is a Quadrafire Castile Insert. It is so noisy it will drive you out of the room next door. In 2004 I got smarter about the purchase and put an Enviro Mini in our newly finished mud room. Great little stove that is much less noisy. Both have been reliable, but I do regret the Quadrafire purchase. Too noisy, less hopper volume and more prone to ash and clinker buildup.

In 2006 I started Pellergy LLC and began manufacturing a wood pellet conversion burner. I have been firing our Steam Boiler with pellets ever since! Central heat...Steam....with pellets! Last season I installed a Burnham MegaSteam boiler, a 3.5 Ton bulk pellet storage bin and our latest burner for a more convenient system. The MegaSteam is much easier to clean out, takes about 20 minutes, and our new burner systems all have air cleanout of the burn chamber to rid the system of clinkers. Burned 8.5 Tons of pellets in the boiler this past season, only touched the boiler once every 30-days to clean the ash from it. With bulk delivery directly to the 3.5 Ton bin, it is an easy way to heat your whole home.

That said, it is still a manual cleanout system and not for everyone. This year we are introducing the Pellergy Alpha Boiler. A fully automatic wood pellet boiler that self cleans its burn pot as well as the heating surfaces. It augers ash into a removable ash box that only needs to be emptied once per 2-3ton of pellets. The system is built in Austria and is absolutely amazing. The unit modulates down to 30% of its full output automatically and uses flame temperature thermocontrol to ensure 86% efficiency through all phases of modulation: No Lambda sensors to fail. Once per year maintenance takes less than 45-minutes.

We also have our bulk pellet storage systems, Pellergy conversion burners and a whole bunch of useful information up there (like savings calculators).


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