You are making a new hot water heater purchase - the time has come to compare gas hot water heaters. Just like any other big purchase these days - cars, home cinema, PCs - it comes with a whole new vocabulary to learn so you can make sense of the reviews.
So what are the basic figures to look out for? After all, if we wanted to become experts we would have trained as a gas fitter.
With tankless gas water heater I'd say there are two fundamentals that you need to be aware of. The first is efficiency and is about the technology of the unit, the second is capacity and is about the suitability of the unit for your home.
Efficiency for tankless gas hot water heaters is easy. Old units were sixty, sixty five percent efficient. That was not so good. New units should use what they like to call condensing technology to achieve upwards of ninety percent efficiencies. Not all use the best energy saving technology, but you should look our for one that does.
The second figure that matters for instant hot water heaters is capacity - it is expressed in gallons per minute. To make a sensible decision you need to know what your maximum demand is. If a unit can meet this you will have no problems with it. Do not oversize unless you have to - it just does not make sense.