Your right in the fact that a newer home will consume less energy that most older homes. New homes also take about 15 years to payback their impact on the environment in energy savings. It's always Greener to use what is already there and that's the existing older home. I don't know about where you are but here the newer ones are built farther out in areas that require driving and don't have as good of access to public transportation or biking/walking opportunities If your spending an extra $100 on gas each month but saving $100 on utilities it's a wash. One other option is to buy an older home and utilize the FHA Energy Efficient Mortgage. This allows you to finance 5% over the purchase price for energy upgrades. This requires no additional qualifying and can go over appraised value. You get to save energy from day one and also the house is more attractive to buyers when you go to sell..