They test the exhaust and say - see there is carbon monoxide and lock out the furnace. 

http://ca.reuters.com/article/domesticNews/idCAKCN...Ontario will be spending $5.4 billion to cut the carbon footprint and phase out natural gas for heating. 

To prevent the sentiment build up you could put a water softener & carbon filter on the house, it's a nice added feature for the tenants and they have to pay for the salt monthly.  

@Kevin Carbon is hosting the South End PacificNW Real Estate Meetup, and looks like it is going to be on Monday the 31st of August.  

@John Carbone: On your taxes, you'll be able to classify it as second/vacation or investment, regardless of the mortgage docs. 

You want a smoke/carbon monoxide detector there. 

And a few Bucks Donated every now and then to an Animal Shelter might ease your thoughts a bit, because they do need help and cannot really fend for themselves.Kind of like owning a 747 and planting trees for Carbon Credits--an Offset for your mind.Good Luck!

@John Carbone Also keep in mind that real estate prices are sticky.

When I've looked at places in Carbon County, I don't factor in any/much appreciation when calculating returns. 

This also means less climate-changing emissions for your house than other forms of heating would produce because it doesn't release any carbon dioxide into the atmosphere when used correctly.