Tankless water heaters have been common in Europe for more than 10 years, and they’re catching on in Canada for the same reasons they’re popular on the other side of the Atlantic. Reduced energy consumption, smaller physical size and continuous hot water output are the three reasons homeowners choose tankless, and the Rinnai RL75i is one model I’ve examined, used and approve of.
Tankless water heaters eliminate the heat loss that inevitably comes from tank-style heaters as they sit full of hot water, even between uses. These are called “standby energy losses” and eliminating them is the main reason tankless water heaters are more efficient than tank-style models. They heat water only as a hot water tap is turned on somewhere in your house. Internal sensors detect flow as soon as water moves through pipes, igniting natural gas or propane that heats water for the second or two that it’s flowing through the unit. As soon as the hot water tap is shut off, the flame stops too. You only heat the water you actually demand.
Saving space is another issue. While a typical 60-gallon tank-style water heater takes up more than 70 cubic feet of space, the RL75i model I tested occupies only about 2 cubic feet. The small physical size of this tankless heater means it’s easier to install the heater closer to faucets that are used most often. A closer location means less wasted time and less water down the drain waiting while hot water actually hits your faucet or tub after turning them on.
The RL75i I set up in my test shop was designed to use propane and it work flawlessly during many ON/OFF cycles. Operating temperature of the heater was easy to adjust, the fit and finish of the unit is excellent, just as you’d expect from a Japanese product. The RL75i is a mid-efficiency model delivering an 82% conversion efficiency and connected to a vertical or horizontal vent. Higher efficiency Rinnai condensing tankless heaters delivering as much as 96% efficiency are available, too.
Cost for the RL75i runs between $1500 to $1600 and includes a five year residential warranty covering parts and labour. The heat exchanger itself is warranted for 12 years. If there’s a higher quality, better warranted tankless water heater out there than this one, I haven’t found it yet.