Long said its important to use dry wood. Green, wet wood produces excess smoke, one of the main concerns of outdoor wood furnace opponents.

Long said a larger unit was sold to the Town of Jay Highway Department. That allowed them to spend only $94 on fuel oil last year, as they used wood to replace 1,500 gallons of fuel oil.

Adirondack Hardware also carries Enviro pellet stoves and two lines of high-efficiency monitor heaters.

In Plattsburgh, Hulbert Brothers salesman Lance Hulbert said the company switched its fuel-oil boiler to a propane gas unit last year.

"We saved $10,000 last year, with fuel oil at $3.50 a gallon," he said.

That's a good alternative for people who don't want to put in the extra work of chopping wood, Hulbert said. He recommends using a 500- or 1,000-gallon tank. Companies usually offer lower prices for larger orders, he said.

A new propane boiler usually works at 98 or 99 percent efficiency, Hulbert said, while fuel oil boilers usually operate at about 83 to 85 percent efficiency.

One big seller for Hulbert Brothers has been BioBricks, brick-shaped blocks of compressed wood.

"It's like a big pellet you can burn in your wood stove," Hulbert said. "They're going out faster than we can bring them in."

Hulbert Brothers Heating Specialist Larry LaValley said each brick burns about the same as three sticks of wood. The bricks are twice the density of cordwood.

An information sheet indicates a 48-cubic-foot pallet of BioBrick delivers the same amount of heat as a cord of hardwood (with 21 percent moisture content). That means more heat into the home rather than up the chimney in the form of steam.

LaValley said the company also sells pellet stoves, but has been having trouble keeping any in stock, as they sell as fast as they come in.

Hulbert Brothers has seen extraordinary sales for this time of year, LaValley said, almost all on alternative-energy units. He said they've sold one oil boiler since June.

Hulbert said it's important to pay attention to the efficiency rating of equipment, as some stoves are as low as 50 percent. People also need to learn how to properly cure their wood. Many beginners will chop and place it right in the stove, which can lead to increased creosote buildup and eventually set a home on fire.

The company offers wood gasification units, which feature a second chamber to ensure gases produced as fuel burns are captured for combustion. LaValley said a lower-end wood boiler operates around 50 percent efficiency. The wood gasification units operate at almost 90 percent efficiency, he said.