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Best Whole House Tankless Water Heater
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Rinnai RUC98iN Review ~ Gas Tankless Water Heaters

If you are looking for water heater that are tankless and using only natural gas, then we have come up with the best proven one for you. Yes, Rinnai has manufactured the superb quality Tankless water heater with great specifications and we have found it as per the super quality standard from the ones we reviewed.

Rinnai brings tankless water heating to one step ahead with condensing technology and delivers more efficiency than ever before. You can enjoy all the same tankless benefits that you are expecting from Rinnai, plus even greater energy savings. It features 95% Thermal Efficiency Natural gas or propane Indoor Installation. Read on to learn how the Rinnai Ultra Series Natural Gas Tankless Water Heater is the perfect water heating solution with all the safety features and minimal maintenance.

Enjoy hot water when you need it, not when you don’t

With this Rinnai product, you don’t have to worry about running out of hot water any more. Their innovative technology provides an endless supply of hot water whenever and wherever it’s needed, even for simultaneous uses at multiple fixtures. You will trust its performance in the events of back-to-back showers and baths. Also do not worry when you have laundry and dishes at the same time. Just forget about the problems and enjoy the hot water. No longer have you needed to prioritize activities and scheduling hot water with this amazing water heater.

Eco-friendly: This tankless technology offers the maximum energy efficiency, helping to conserve natural resources. And with higher standards for lower CO2 emissions, they contribute to a healthier environment.

Minimum wastage: Being compact in heat exchanger design and far longer product lifespan and recyclable parts is the synonym of minimum wastage and greater usability.

Great performance with greater savings

The natural gas tankless water heaters work by heating cold water as it passes through your pipes. Internal sensors detect when cold water needs to be warmed, and natural burners trigger a heat exchanger that will get your water to just the right temperature before sending it through the tap.

The performance is quite good as it functions so quietly and efficiently due to its design features.

Efficient Design: We have reviewed Rinnai as one of the best and its design contributes to it. The tankless technology features durable heat exchangers to provide maximum efficiency and gives you average to 60 percent energy saving than the traditional tanks.

Save energy: The tankless technology is what, it operates only when hot water is needed, with pilot light and no storage tank to heat and reheat water, thus enabling you save on energy and utility costs. It uses an electronic ignition means there is no standing pilot light that will constantly use energy.

One time investment and all time saving: It is a near about zero maintenance product means just invest your amount at the time buying and it will not cost you maintenance for parts or any services frequently. This is, as per the experts, the best thing in any big equipment.

Personalize your efficiency: This Rinnai Tankless Water Heater gives you options at the time of installation as per your needs giving you more efficiency.

Long time promise: Every part of a Rinnai Tankless Water Heater is replaceable. You can get any of its components exchanged easily, if needed, which is better than replacing the entire system.

Save space with a compact design

Best Whole House Tankless Water Heater
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Maximum output at minimum space: These wall-mounted models of Rinnai can be installed on interior or exterior walls with size of a small suitcase or smaller giving you free space for other valuable purpose.

Flexible installation: Its installation is kind of flexible giving you independence of moving it as per your need such as crawl spaces and attics etc.

Gas used:

The Rinnai RUC98iN is a sleek and highly efficient gas tankless water heater that uses both natural gas and propane and comes with multiple venting options.

Heating Capacity:

The standard model of the Rinnai RUC98iN is capable of heating water to temperatures of 95 to 140 degrees Fahrenheit. In fact, the commercial model can provide water as hot as 185 degrees Fahrenheit. It uses 0.75-inch MNPT water and gas connections rather than the regular 0.5-inch connections found in most homes.

Installation Guide:

It is somewhat difficult to install and requires maintenance by certified Rinnai repair personnel so as not to void its warranty. So it is recommended to get it installed or re-installed by a certified Rinnai repair staff only.

Rinnai Warranty Details:

For Residential: Limited 12-year on heat exchanger, 5-year on parts, 1-year on labor (5-year optional on labor)

For Commercial: Limited 5-year on heat exchanger, 5-year on parts, 1-year on labor (2-year optional on labor)

Measurements and Specifications

The Rinnai Ultra Series Natural Gas Tankless Water Heater shows the following specifications:

Item model number RUC98iN
Item Weight 82 pounds approx.
Product Dimensions 10 x 18.5 x 26 inches
Voltage 120 volts
Flow Rate 9.8 GPM
Water Consumption 9.8 gallons
Size Twin Pipe/Ultra


  • It serves multiple bathrooms simultaneously
  • High flow rates are perfect for large homes
  • Can be converted to propane if you don’t like natural gas


  • Slight flow delays at the tap (Negligible)
  • GPM decreases as water temperature climbs
  • System requires careful installation with many bells and whistles

The Bottom Line:

Best Whole House Tankless Water HeaterBy reviewing all the aspects of Rinnai as well as other rivals, we came to the bottom line that despite a very few problems, the Rinnai water heater is one of the strongest and most worthwhile natural gas tankless water heater on the market. That’s why we picked it as the best whole house tankless water heater. You will like it after the installation as it has beautiful, sleek design, not making noise and giving quite good performance. Also the other Rinnai models, are great suitable choice for most of them with a lesser price tag. But all in all, the Rinnai is the best brand for it in terms of service, maintenance, and of course the quality.

  • Our Rating
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