Richard Dreyfus in Tin Men
Now that the stimulus bill has passed and the word about tax credits and weatherizing incentives is out, you can bet that the tin men selling "insulating" siding and new "energy efficient" vinyl windows will be out in force to sell you stuff that "pays for itself in three years" and that "the government will pay most of the cost anyways". Except these are two of the least cost-effective measures that you can take, and can significantly decrease the value of a house if they destroy its character and charm.
click here to go to working illustration gizmo
The National Trust for Historic Preservation put out a neat little interactive gizmo last year that suggests what you should be (and shouldn't bother) doing.
And when the window guy comes to call (he will), say no. The National Trust says:
There is an epidemic spreading across the country. In the name of energy efficiency and environmental responsibility, replacement window manufacturers are convincing people to replace their historic wood windows. The result is the rapid erosion of a building's character, the waste of a historic resource, and a potential net loss in energy conservation. Typically replacement windows are vinyl, aluminum, or a composite with wood, and none will last as long as the original window. Repairing, rather than replacing, wood windows is most likely to be the "greener option" and a more sustainable building practice.
They have a tip sheet on how to fix and seal wood windows; download a PDF here.
In 2002 the Rocky Mountain Institute did a study of the different things you can do to save energy in your home, and listed them in order of cost-effectiveness. The numbers are probably no longer relevant (savings would be a lot greater now) but the order is- replacing windows still costs a lot of money in relation to what it saves in fuel and carbon emissions, as does gutting the house to insulate walls. Low hanging fruit like insulating attics and caulking make a lot more sense. Download the PDF here
We covered much of this in order of effectiveness on Planet Green:
Green Your Home for Winter: Where To Start
Green Your Home for Winter: Get a Programmable Thermostat
Green Your Home For Winter: Stop the Air Leaks
Green Your Home For Winter: Insulate Your Water Heater
Green Your Home For Winter: Add Attic Insulation
Green Your Home For Winter: Install Efficient Showerheads
Green Your Home For Winter: Weatherize Your Windows
Green Your Home for Winter: Install Faucet Aerators