If you live near a reliable source of feed corn, wheat, cherry pits, sunflower seeds or other biomass fuels, it might be worth investing in a pellet stove that can burn more than one type of fuel. But just because your stove burns pellets doesn't mean you can toss any pellet-sized fuel in the hopper, though -- the stove must be designed to safely and efficiently handle the different burn characteristics of each fuel. Burning fuels your stove isn't designed for can lead to inefficient or unsafe burns, and in many cases it'll void the warranty too.
Choosing a multi-fuel stove also lets you hedge your bets so you're not hanging on the price of just one fuel source, which can vary greatly depending on season, demand and availability. Although multi-fuel stoves almost always fall into the pellet stove categories, wood stove owners can diversify their heat sources -- a little bit, anyway -- by making or buying biomass briquettes.
The largest and best-reviewed multi-fuel stove in this report -- and the top runner-up in our pellet stove category -- is the Quadra-Fire Mt. Vernon AE (Est. $4,240). The Mt. Vernon AE stove comes preprogrammed to burn wheat, sunflower seeds and corn in addition to pellets, and Quadra-Fire dealers can reprogram it for optimal burning efficiency of other fuels as specs become available.
With a maximum heat production of 53,300 BTU per hour -- enough for up to 2,900 square feet -- and an 80-pound hopper, the Mt. Vernon AE can run all day or night during a deep freeze without needing a refill. Owners do report some reliability issues, particularly with the auto-igniter, and sometimes the "smart" features are a little too smart, like an auto-shutdown cycle that kicks in if you lower the stove's set point too much. Then you have to wait until the stove has shut down and gone through its auto-clean cycle before you can restart it.
With all that said, however, the Quadra-Fire's features still make it the best multi-fuel stove we've evaluated. It comes with a 7-day programmable thermostat and intermittent pilot ignition. It's also compatible with zone heating, and that auto-clean cycle reduces the chance of burn-back into the top-loading hopper.
If the electricity goes out, the Mt. Vernon AE can be run from a 12-volt automobile battery, and it's approved for use in mobile homes. Minimal clearances for the Quadra-Fire Mt. Vernon AE are 8 inches front and back and 18 inches on both sides; the hearth need extend only a few inches on each side of the stove.
The Mt. Vernon AE took top ratings for clean burning, easy maintenance and good visibility (so you can check on the fire) in a comparative test from the Alliance for Green Heat. In fact, it had the highest overall score of the five stoves rated in the test, and most users say that when it works, it's the most efficient pellet stove they've used. They also write that the most common complain about this stove -- constantly having to replace the igniter -- can be fixed by either resetting the stove's computer or plugging it into a surge protector.
However, a number of owners also say that Quadra-Fire's customer service became unhelpful as soon as the stove went out of warranty. That makes the Mt. Vernon AE a great example of how important it is to have a friendly, accommodating stove dealer nearby; even when the manufacturer isn't helpful, a good dealer can help with everything from installation to maintenance and troubleshooting.
You also need to stay on top of regular maintenance, which is easier with the Mt. Vernon than for many other pellet stoves. Make sure you vacuum around the auger and use high-quality pellets to prolong the stove's usual trouble-free performance.
The best inexpensive multi-fuel stove we found is the Quadra-Fire Classic Bay 1200 (Est. $2,700), which can burn pellets or shelled corn. This stove has an 80-pound hopper, puts out up to 51,600 BTUs, and is advertised as heating 1,000 to 2,700 square feet. Users tend to use it for houses of 2,000 square feet or less.
As with the Quadra-Fire Mt. Vernon AE, the biggest concern customers voice about the Classic Bay 1200 is the company's dubious customer service -- so if you're going to buy this stove, make sure you have a friendly, reliable local dealer that can help you with replacement parts or service. The safety-conscious should also be aware that if the Classic Bay 1200's igniter goes out (which users say it does with some frequency) and the stove keeps feeding fuel into the unlit firepot, it can create a hazard.
When the Classic Bay 1200 does work, though, customers feel like they're getting a really good bargain. They say you can help this stove along by staying on top of the maintenance and burning the highest quality pellets you have available to you. Because the Classic Bay 1200 isn't the most efficient or reliable stove out there, you're usually best off using it for supplemental heat or a backup in case the power goes out -- but it remains a good enough deal to be an attractive, lower-cost choice.
If you want a multi-fuel heater that can integrate with your home's existing ductwork, consider the Fahrenheit Technologies Endurance 50F (Est. $4,000 and up) forced-air furnace, which puts out up to 50,000 BTUs and has a two-speed blower built in. Even if that 600/800-cfm blower isn't powerful enough for your home's current duct layout, you can install the furnace with direct ducting or add an optional diffuser to use it as a stand-alone stove. Be warned that in some states, you might not be able to run a solid fuel furnace as your only heat source; sometimes keeping your old furnace as a backup is enough to get around this. Always check local regulations carefully.
In addition to the usual wood pellets, the Endurance 50F can also burn grain pellets, dried cherry pits and shelled corn, and the electronic ignition paired with a massive 112-pound hopper (with an optional extension to 250 pounds) means you can set the thermostat and forget it for up to 60-some hours, depending on the burn rate for whatever fuel you're using. Just like a conventional furnace, the Endurance 50F is thermostat-controlled and will turn itself off when not needed, then come back on again when you need a shot of heat.
User feedback on the Fahrenheit Technology Endurance 50F is relatively limited, despite it having won a coveted Vesta Award in the "renewable fuel central system" category in 2007. Users that do offer their opinions, however, are almost uniformly thrilled with the unit's solid engineering and steady, reliable performance. They also like that the furnace's ability to work with ducting means they can keep the mess or dust of pellets confined to the basement, instead of front and center in the living room.
Owners say the daily and weekly upkeep on the Endurance 50F is very easy: The self-cleaning firepot automatically discards clinkers (another type of waste from pellets), and the huge ash pan only needs to be emptied weekly, if that. You will need to clean the exhaust port, heat exchange baffle and air filter every month, though. We did see some complaints about components going out on this stove -- unfortunately, a reality of any pellet stove -- but users also say that Fahrenheit Technology's customer service is fairly helpful.