Earlier this week I saw a news report about how scores of SUV owners are desperately trying to trade-in their gas-guzzlers for smaller, more fuel-efficient vehicles. Most who try are getting below Blue Book value because car dealers believe they’ll be hard to resell. In light of $4-a-gallon fuel prices, this probably doesn’t come as a shock to anyone. But it should make you think about the other “SUVs” in your life and work.

I heard someone say that the one upside to rising energy prices is that it forces us to change our habits. And while I don’t wish this cost burden on any of us—particularly since it’s hitting at every turn, from soaring food expenses to higher airline fees—one glance at the growing number of walkers and cyclists in my neighborhood shows that the point is valid. The question is, when it comes to other areas of our lives—such as housing--will we learn now or be forced later?

Now is the time to think about tomorrow’s what-ifs for your homes. Even if the save-the-planet side of going green doesn’t appeal to all Americans, there’s no denying the influence the wallet can wield. As costs continue to climb, homes will go the way of the automobile: Too-large, resource-squandering houses will be offloaded in favor of size-appropriate, energy-efficient models. The first hybrid cars captured the attention of early adopters and eco-celebrities. Now nearly everyone is clamoring for one.

Chances are more and more homeowners will begin opting for the hybrid house instead of the 10-mpg McMansion. What will you choose to build? Act now unless you want the homes you’re selling today to be the unwanted and unsold SUVs of the future.