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Rinnai RUC98iN Review 2021: Good Choice or Not? [January Updated]

Having a tankless heater for your home is always an added advantage for your needs. Choosing a proper tankless heater means that you can get instant hot water. Having the Rinnai RUC98iN is one such product that you can get. There is nothing better than having the RUC98iN available for your needs.

However, if you are just about to purchase the product, you must have deep knowledge about it. Here, we have come up with a complete review of the Rinnai RUC98iN that you can always go through. We hope that going through his review will always help you to understand more and then purchase it.

1. Less Energy

One of the biggest advantages of RUC98iN Rinnai Tankless Water Heater is that it can always use less energy. When we compare it with any other regular models available, the energy consumption is almost 50% lesser than others.

This is mainly because the water can easily pass through the heating coils just before it will reach the distribution lies. So it always consumes lower energy.

2. Less Space

There is an added advantage because of the design of the Rinnai RUC98iN. The product is designed for the on-demand water heater. This makes the tankless water heater much more compact.

Thus, the space consumption is much lesser than most of the products. Moreover, it does not feature any tank. This is the reason why it can consume less space. 

3. Continuous Supply

The one thing that we liked the most about the product is the continuous water supply. Most of the traditional heaters take time to heat the water and then can provide you. But it is not the same for the RUC98iN. It can offer a continuous supply of hot water without any delay at all.

4. Safe and Clean

Another advantage of using the RUC98iN Rinnai is that the product is completely safe and clean. The tank-based heaters may not be safe to use when the stored water is unused.

In such a case, it is not a proper way of using the heater. It may lead to severe diseases. It does not have a tank at all and thus, it is completely safe to use at any time.

5. No Fire Problems

One of the biggest advantages of using this Rinnai Ultra Series Water Heater is that there are no fire problems with the heaters. The tank-based heaters may have overheating problems. This mainly happens when the heater is poorly maintained. However, this Rinnai water heater has a standard safety feature that reduces fire problems.


1. Condensing Technology

Most of the heaters from Rinnai have advanced technology for heating the water. But at the same time, the Rinnai RUC98iN includes a condensing technology. This allows efficient water heating a notch that can deliver it more efficiently. Thus, it is far more efficient to deliver your hot water faster.

2. High Energy Factor

Another important feature of the product is the energy factor. We have found that the product includes an energy factor of 0.96.

3. Dual Venting

The one unique feature of this Rinnai Ultra Series Water Heater is that it can give you the best venting options. You can get two options including concentric and PVC. 

4. Design

Just like any compact heater, this tankless water heater also saves up space. Because it is slim in design, the product can be very compact to use.

RUC98iN Problems

The RUC98iN includes a simple mechanism and a smart operation of work. It specifically works more like any other product from Rinnai and the performance is always good.

However, at times, you may feel that the product is not working properly. In such a case, there will be error code for display. In case of such a display, it is always essential that you inform the professional to work on the problems. We have covered around 36 Error Codes for Rinnai Tankless Water Heaters in a separate article.

The one important feature of purchasing any product from Rinnai is that you can get a professional service. For this, all that you need to do is to register the product with a service professional.

In case the error code shows up, the issues will be sent directly to the office. This will allow the technician to contact you and get prepared in case you need a service or there is any damage to the product.

To avoid any type of problem, the one important thing that you need to consider is maintenance. Any water heater requires proper maintenance. The tank-based heaters require more maintenance while the requirements for the tankless ones are less.

At the same time, Rinnai offers professional maintenance for all the products. In case you are facing multiple problems with the product, the ideal thing to do would be to flush the Rinnai RUC98iN. You can follow the manual guide to properly flush it.

Energy Efficiency

Most of the products available from Rinnai offer a decent energy factor. As a result of this, most of the latest models include a UEF of 0.95. The Rinnai RUC98iN is another impressive product from the manufacturer and it can easily reach up to 0.96.

This is mainly because the product meets with certain criteria and the gas consumption is very low. So even if you are present in the cold areas, the energy becomes highly efficient to work with. So you can always opt for it. 

Star Rating

Measuring a star rating for any product will mean that it has to meet certain criteria. As a result of this, the product must meet all the certain criteria. The Rinnai RUC98iN comes with a specific performance setup and it allows you to get proper requirements.

Moreover, the product can always meet the Energy Star Blue logo and as a result of this, it is always handy to use the product. Thus, the electricity consumption is also low for the product.


Installation is an important factor to consider while choosing any tankless water heater. Thankfully, the Rinnai RUC98iN nails the requirements and gives you proper results. The heater includes a condensing technology.

This will allow the heater to be easily installed. Moreover, it comes with dual options. So you can always choose either the PVC venting option or the concentric venting option. This will allow any heater to work properly with the safety measurements.

The one thing that you should always keep in mind is that the installation must be done by a professional. Rinnai allows the warranty to be valid only when you take the help of a Rinnai Trained professional to install the heater in your home. For more on warranty, you can check this link.

However, this is not all. The initial installing option is much more because it requires a complete plumbing setup. For this, you can take the help of any local plumber to get the job done for you. It always takes less time to complete.


1. The one big benefit of using the Rinnai RUC98iN Ultra Series is that the product can be used by a professional. The mechanism is simple and if you know any professional, it can be easily installed without any problems.

2. The other big benefit of purchasing it is that it can save you a lot of money. The product may have a high cost while purchasing, but it consumes very low electricity and gas consumption. So it can always save up a lot of money.

3. This water heater mostly works in silent operation. While we compare it with other products, the Rinnai RUC98iN runs in a smooth operation and it can save up a lot of money.

4. The one feature that we liked the most about it is that the heater includes temperature control. There is an adjustable thermostat present that allows you to change the temperature. You can easily adjust the thermostat dial and then set up the temperature according to the requirement.


1. The High GPM trigger is only set at 10 GPM.


The natural gas heater works in this mechanism and this will not allow the heater to work well with lower pressure. In such a condition, you need to adjust the thermostat according to the temperature that you require. Just increase to a suitable temperature.

2. Drop-in Temperature


This happens mostly when the heater is connected with multiple faucets and then all of them are running. You can leave the heater to default and after a few seconds, you will start getting back the warm temperature.

3. Takes Time to heat


The Rinnai RUC98iN works very fast when it comes to heating the water! This may happen once in a while when you are not using the heater for a long time. In such a situation, it is important to flush the heater and then wait for a few minutes. You will be able to get back the default functions of the heater in no time.

Comparison Appliances

When we compare the RUC98iN with the other products available in the market today, there are not many products that can be as comprehensive as this one. There are a lot of heaters available in the market now and most of them are smaller in size. Naturally, the capacities of such products are much lower than others. 

But in the case of the RUC98iN, the heater is much decent in the size. This allows you to save up money because of the performance and the daily running costs. There are not many reasons to worry about the product. Thus, we would always prefer to go ahead with the Rinnai RUC98iN as it has compatible options along with your needs.

Also, we have a detailed article on Best Rinnai Tankless Water Heaters in case you want to have more options.

Frequently Asked Questions

Q1. Why am I not Getting Hot Water instantly?

A1. You may face a situation when you have just turned on the heater and you are not getting hot water. Hang on for a while. Though the heaters are designed for providing you limitless water, it takes some time to set up. So if you give just a few minutes, it will allow the heater to work much more efficiently than any other service at the same time.

Q2. Can I get the hot water without power?

A2. The Rinnai RUC98iN is a specific tankless water heater that works on both electricity and gas. Though it has a combination heating option, it does not work without power. Moreover, there is no storage tank present with the unit. So you cannot expect hot water to be flowing out of the faucet even when there is a power cut or no power supply is provided.

Q3. What is the frequency of maintenance for the RUC98iN?

A3. Coming to the maintenance of the product, the RUC98iN work according to the frequency of your use and how well it can perform. There are two types of maintenance provided for this Rinnai Water Heater when it comes to playing.
The first type is to opt for a professional who would clean the debris and the contaminants present in the drainage pipe. The other type of maintenance is regular flushing. So you can expect both the maintenance to be working at a span of 6 months.

Q4. Why is Smoke coming out of the RUC98iN?

A4. The only place the smoke can come out from it is the exhaust of the product. This is mainly because the temperature of the exhaust is significantly hotter than the outside air. This allows the heater to condensate quickly and will give you water vapour. However, there is no reason to panic about such issues.

Q5. How long can the RUC98iN provide me proper service?

A5. Most of the products from Rinnai come with decent maintenance and performance. This allows the Rinnai RUC98iN to work much faster than most of the other heaters present. As a result of his, the heater can easily last for 20 years and can serve you more. This will, however, depend on the level of contamination present on your locality and how much you maintain the product.

Final Verdict

The Rinnai RUC98iN is a top buy from the manufacturer. There are a lot of positive features that will impress you while you are using the product. Considering the complete review and after testing the heater, it is evident that we have liked the whole features and performance of the Rinnai RUC98iN Ultra Series Natural Gas tankless water heater.

You can look for more information present above that will guide you to understand whether to purchase the product or not. However, if you are facing any problems while using the product, you can always choose to mention it in the comments below.