What limitations? I'll answer for you. There are no limitations. For a
one
bathroom home these are the business.

They are certainly a useful option for single bathroom homes and a
considerable improvement on a typical instantaneous combi. However, they are
not a panacea for all water heating problems.

They are have limitations. All products do. It is a case of matching the
limitations to acceptable parameters for the specific problems being
addressed.

Christian.