These suddenly trendy appliances burn small pellets - about the size of a pencil eraser - that are made of compacted sawdust and sold in 40-pound bags. Expect to pay $3,000 to $5,000 for the stove and the installation, which takes two or three hours.
And hurry: These stoves are going fast.
"A lot of our manufacturers are out of stock," says Bill Ryan, owner of the Stove Shop in Phoenixville. "We're also backlogged six weeks on installation."
Ryan says most people use pellet stoves to heat the family room and the rooms nearby so they can turn the thermostat on their furnace way down. You'll need about 3 tons of pellets each winter at about $300 a ton.
Solar panels. Generally not a choice for home heating, except among gung-ho eco-pioneers. Still, there's plenty of sun in the Delaware Valley to heat your household's water or even generate maybe half of its electricity.
A solar hot water system costs about $6,000 to buy and install. It takes just a couple days once you have the permits and materials in hand, but the backlog for panels can be a month or two.
The average solar-electric system costs about $65,000 and could require six months' lead time or more to line up permits and order solar panels.
Pennsylvania is about to launch a program that will cover up to 35 percent of the costs to buy and install either type of system. (See "Green Stuff for Greening.") Visit to check other states' incentives and plug numbers into a calculator for estimating costs.
Geothermal heat pumps. These systems circulate fluid through pipes in the ground, where the temperature stays in the 50s all winter. Then, they convert the underground heat into hot-air heat for your house. In summer, the relatively cool ground temperature turns the system into an air conditioner.
It's not too late to install one. You'll need just a week or two to have wells dug and get the system pieced together, according to Dave Valek of Hannabery HVAC, an Allentown company that does geothermal installations through a Maple Glen office locally.
Valek said a typical home system would cost about $25,000 (provided you've already got hot-air ductwork) with a payback of maybe 8 to 12 years. The one big catch: "You've got to be able to get a 40-foot rig into the back of your yard where you're going to dig."
The Web site is the go-to spot for all things geothermal.
Wind power at home. Alas, largely a fantasy unless you live on a farm. The problem is that wind turbines - the preferred term for home windmills - make noise and sit 30 feet up in the air.
"Municipalities and homeowners' associations have issues," says Kevin Yingling, an energy planner for the state of Delaware.
Still, the barriers to home wind power are falling. French designer Philippe Starck introduced a sleek home turbine at a design show in Milan, Italy, this spring. Closer to home, the borough of Ocean Gate in Ocean County, N.J., has passed a law allowing turbines for homes that meet certain setback requirements.