Rheem RTG-84XLN Outdoor Tankless Water Heater Review

Product Name:RTG-84XLN 8.4 GPM Low NOx Outdoor Tankless Natural Gas Water Heater
Power Source:Natural Gas
Use Type:Outdoor
Capacity:8.4 GPM
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The Quick Review

Considered the standard outdoor water heater for the standard home, the Rheem RTG-84XLN NOx is one of the most popular outdoor tankless heaters in North America. With a very adequate flow rate of 8.4 GPM, built by a premium brand in water heaters and backed by the industry leading 10 year warranty, the RTG-84XLN is one of the best outdoor heaters you can buy.


At 8.4 GPM, you have enough capacity to run two showers simultaneously, which is more than enough for the average home. Perhaps you cannot take two showers and run the dishwasher at the same time, so you’ll have to actively make that decision if your household plans to take two showers at once. Otherwise, you could run the dishwasher, the washing machine and a shower as well and be perfectly fine.


Since this tankless water heater requires a gas line hook up, you will require professional installation. We do not recommend an amateur attempt to install this unit as working with gas lines can be very dangerous. That said, for a professional, this installation is quite straight forward and shouldn’t run up a large labor bill. Many individuals on Amazon has reported that they were able to install it themselves with ease.


With a name like Rheem, value is built in with years of experience and thousands of happy customers.

The Misses

Most tankless water heaters take a while for the water to heat up when you turn on the faucets, and this unit is no exception. It can take up to 15 seconds (in the winter) for the water to heat up, which is slower than conventional electric water tanks. For a unit of this quality, we would expect them to innovate in this area.

In addition, 8.4 GPM can be somewhat limited, we would love to see Rheem come up with an 8.8 model, which is just enough for that last faucet.

Our Recommendation

We definitely recommend this product for any house with up to 2 bathrooms and large appliances. Be sure to check the price to see if a discount is available today.

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