Spend a buck to save a buck rings true for many homeowners, especially as cutting our carbon footprints seems to be equally important as cutting costs these days. Tankless water heaters are the buzz right now, and for good reason, too — my friend Lou Manfredini pointed out that the efficient water heaters can help reduce your total energy consumption by up to 30 percent. But that's only if you can foot the bill, since having one installed runs around $3,500. Yikes! My old water heater is on it's very last leg so I'll be making switch after it's heated its last drop of water. Do you already use a tankless water heater?