I believe the Geo Spring Hybrid Heat-Pump water heater to be the most efficient and affordable. It cut my gas bill here in Florida by 76%.
Please read my blog post here on the GreenHomeGuide website.
My wife and I are in a home we purchased in August which was built in 1975 and we are the second owners of the house. The hot water heater appears to be an original fixture (slight exaggeration). It is almost 20 years old and was maintained very frequently by the previous owners. However, it is Oil Heated, drains our supply of heating oil, is nasty, seemingly inefficient and probably going to die anytime now. What are the best, most efficient and cost effective options to consider when the time does come to replace this? Our eventual goal is to replace the oil all together but the furnace is only 8 years old. Thanks for your responses.