All current tankless units have different efficiency ratings. They can range anywhere from 60 to an amazing 98 percent. This can of course come with some positives and Negatives. The highest rated efficiency of a tankless system is called the Navien which is 98% efficient. Since the unit uses the heat so effectively it can actually be vented with plastic pipe as the exhaust gases are at a very low temperatures. This unit is one of the first to utilize a condensing heat exchanger giving the unit its amazing efficiency rating.

It has been approved by CSA and thus can be used and sold in Canada and Ontario, which it has been for more than a year now. Before you settle on this unit there are some negatives of this hot water heater. This system has the highest failure rate of all other systems, motherboards are constantly failing causing no heat situations for customers. There has also been been reported a failure with a rubber gas hose off the valve which needs to be replaced. This in turn could possible remove the Ontario TSSA approval and the Canadian wide CSA stamp. 2009 should be an interesting year for Navien.

Currently the best tankless system is the Rinnai it doesn’t have the greatest efficiency rating but it still stands at 84%. If efficiency was a test and that was your mark you would be bringing home an A and that’s something I wish I received more often.

See Also:

1. Rinnai R85
2. Tankless Installation Time