When you make an important purchase you want to do a little looking around to make sure that what you buy is a smart choice. It is perfectly natural to want to compare tankless water heaters before making your purchasing decision. The question is what do you compare?
But before you start pouring over the tankless hot water heater reviews, you need to be clear what you need in your home. Do not be content if the review or the product blurb says it is a whole house heater. It may not be a whole house heater for your house, and that is what matters.
To know your needs you need to think about what appliances you use simultaneously. This maximum demand is all that matters for instant hot water heaters. Once you have worked it out (by looking at the booklets that come with your appliances, by looking on the Internet for sensible estimate or by filling gallon jugs from your taps for a minute), you will have a gallon per minute figure. This is what you are searching for in the reviews - any unit you buy must be able to meet this need.
Tankless gas hot water heaters and oil powered ones will come with an efficiency rating that should be in the region of 85 percent or more for a modern unit. This efficiency is probably the second most important thing to look at when making your comparisons. It will give you an indication of how much the unit will cost to run. Of course the other thing you must look at is the overall price - you will have to decide what you can afford!