Rennai tankless or Rannai tankless is actually spelled Rinnai, it is commonly misspelled as Rennai condensing or Rannai condensing. Here are some more spelling errors for Rinnai tankless water heater.

1. Rennai Tankless
2. Rinai Tankless
3. Renni Tankless
4. Rinni Tankless

For the Record it is Rinnai.

Here are some Rinnai Facts

- Uses concentric venting which results in only one hole drilled in your wall but this results in a reduction of venting options.
- Lowest failure rates.
- 10 years parts and labour warranty
- Made in Japan
- 8.0 GPM hot water production on most units
- More than 30 million units installed world wide
- No pilot light (direct electronic ignition)

This picture is an example of the vent pipe that a Rinna tankless uses.  Basically there is a pipe inside a pipe, one directs exhaust gases out of the house, while the other allows fresh air to flow in from outside directly to the combustion chamber.

So for the record it is Rinnai.

See Also:

1. First Rinnai Condensing Tankless
2. Solar Water Heater and Tankless Update
3. Rinnai Concentric Venting