10/24/2012 03:08 pm ET Updated Dec 06, 2017

Ask Mr. Green: What's the Best Type of Furnace?

Hey Mr. Green,

We were considering converting from an oil-run furnace to one powered by natural gas. But now we're unsure, after reading Sierra's article about the pollution caused by the fracking process that companies use to extract natural gas. Do you have suggestions for a greener -- yet affordable -- replacement for our furnace?

--Susan in Guildhall, Vermont

In Vermont and other tree-abundant places, a wood-burning heater may actually be the best affordable choice for reducing the harms caused by extracting and burning fossil fuels. But wood has these virtues only if it's sustainably harvested and used in Energy Star appliances: Typical wood-burning stoves can emit enough dangerous particles to affect air quality, which is why some places ban the burn.

As for picking your poison -- natural gas or oil -- gas was once considered safer, because burning it emits about 30 percent less carbon dioxide per unit of heat than burning oil does. Also, the natural-gas industry hasn't smeared the seas with legendary spills like BP's Deepwater Horizon.

But with the fracking boom, natural gas has lost its eco-favorite status. Fracking ruins landscapes and poisons water and people. 

Whatever you end up choosing for your heater, try to cut waste: Proper insulation, caulking, and duct sealing can work wonders. Turn the thermostat down to 55 or 60 degrees when you're away or sleeping, and don't ever set it higher than 68. Taking efficiency measures can cut your heating bill by more than 30 percent.


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Got a question? Ask Mr. Green!

--illustration by Little Friends of Printmaking

This article originally appeared in Sierra magazine