Chuck This is a typically practiced technique of providing hot water in Europe. As you may already know, electricity is more costly then LP gas, so consider the alternative. Instead of adding LP gas, have you considered installing a Solar hot water heating system to your home? A properly designed system with ample storage could eliminate the need for either electricity or LP gas to heat your water. The solar system would consist of a flat plate collector on your roof sized properly for your home. A glycol solution would be pumped to the collector, heated and return to the storage tanks(s) where the heat is transferred to the water. The storage tank could also be fitted with electric heat as a back up system incase of limited sun light to heat the glycol solution. In the long run, the solar hot water system will save you money but initially will have a greater up front cost.