Rheem tankless water heater

Comparison of Rheem Tankless Water Heater Price & Costs | Rheem System Buying Guide

How much is a Rheem tankless water heater going to cost, installed in your home? The average price for a Rheem electric water heater is between $370 – $2,100 with professional installation. The cost for a Rheem natural gas or propane gas system is between $1,950 – $3,000 for most, with prices for the Performance Platinum tankless heaters reaching $3,500.

Rheem Tankless Price Ranges for Main Series
Series Models Included Price Range (Including Installation) Budget Level
Performance 9 – 3 to 36kW $370 – $1,500 Low-Medium
Professional Classic RTEX 9 – 4 to 36kW $400 – $2,100 Medium-High
Natural Gas/Propane (1)
Mid-efficiency 70/84/95 Indoor & Outdoor $1,650 – $2,100 Average
Professional Prestige 84/90/95 Indoor & Outdoor $1,950 – $3,000 Medium-High
Performance Platinum Indoor 84/90/94
Outdoor 84/94
$2,200 – $3,500 High
The model numbers generally refer to the maximum GPM, or Gallons per Minute. “84” is 8.4 GPM, 90 is 9.0 GMP and so forth. 
(1) Both non-recirculating and recirculating water heaters are available in these series. Some have built-in recirculating pumps, and others offer optional pumps. See the Series descriptions below for details.
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Overview of Rheem Tankless Water Heaters

Rheem has a tankless water heater for you – in fact, there are likely several Rheem models that will meet your needs. The brand manufactures two lines of electric water heaters and three lines of natural gas and propane water heaters.

And Rheem is considered one of the most reliable brands available today.

Here are the five lines and what they offer.

Rheem Performance Tankless Electric Water Heaters

This is the most affordable Rheem tankless water heater line. They do an adequate job for lower unit/installation cost than most of the other Rheem tankless water heater lines.

Nine models are produced from point-of-use, single-outlet sizes to whole-house electric tankless water heaters. Depending on the size of your home or apartment, the 3kW to 13kW are considered single-outlet models. Install them to provide hot water for a bathroom faucet, shower, the laundry or a dedicated use like a hot tub or small heated swimming pool.

The larger models, 18 to 36 kilowatt electric water heaters, are designed to serve 2-3 bathrooms, and possibly 4 when they’re not all being used at once. These are considered whole-house water heaters.


But before you choose an electric whole-house tankless water heater, consider how much hot water you need, the temperature of the incoming water and the cost of electricity.

Why? In the north or where electricity is very expensive, installing a gas tankless water heater might make more sense. It probably will, in fact, especially if you intend to be in the home for more than the next few years.

And about the temperature of the incoming water, the colder the water is entering your home, the less GPM of hot water the unit can produce.

If you’re a DIY enthusiast with experience, the Rheem Performance tankless water heaters start at less than $200. The largest models, the 27kW and 36kW, cost between $475 and $550.

Keep in mind they have to be plugged in or wired to a circuit. The hot water line needs to be cut and connected. But that’s about it. No venting, and that means lower installation cost, a major reason to consider an electric tankless water heater.

Rheem Professional Classic Series Electric: RTEX

This Rheem electric water heater series is a little hardier. It’s 9 models range from 4kW to 36kW, so yes, there are single point-of-use models and whole-house options.

Rheem Professional Classic Series Electric

The quality of the Professional Classic RTEX Series is higher than the Performance Series, so hence the higher cost. The units run about $160 for the 4-kilowatt heater to more than $800 for the largest models. Those are great DIY options. Expect to pay about $225 to more than $1,000 for professional installation based on the electrical requirements.

Tankless Mid-efficiency Direct Vent Indoor and Outdoor Units

These are the most affordable Rheem gas fired tankless water heaters. The efficiency ranges are in the low 80s, so they aren’t Energy Star certified. But the lower cost makes them a good choice if you don’t use a high volume of hot water and/or you don’t plan to live in your current home long-term. They’re also a good fit for warm climates where the incoming water is above 65F.

Three models with maximum GPM of 7.0, 8.4 and 9.5 are produced, but as we’ve said, unless you live in a warm climate, expect a GPM of about half the maximum. The temperature of the incoming water – water coming from a well or, more typically, being pumped through pipes just a few feet underground, significantly affect the amount of hot water your tankless water heater can produce.

These units are sold at Home Depot and many other local and online sellers in a range from about $700 to $1,000. That’s the water heater only, not any installation supplies or venting materials for indoor installations. A plumber will charge another $750 to $2,100 based on the installation factors including the vent.

Rheem Professional Prestige Series Condensing Series

These are some of the most popular Rheem tankless water heaters. Sizes are max GPM of 8.4, 9.0 and 9.5, so they can serve 3-4 outlets/bathrooms at once. If your household uses a lot of hot water, consider these units.

Rheem Professional Prestige Series Condensing Series

Both indoor and outdoor models are produced. Indoor units have a higher installed cost because they have to be vented. But in cold climates with the risk of freezing, they are a better choice.

Outdoor units are easily the affordable choice in warmer climates. You’ll save $400-$1,000 on installation with an outdoor unit, and the climate won’t affect the potential GPM water flow – in fact, when it’s hot outside, the climate is a bonus for energy efficiency.

The Pro Prestige Series water heaters are manufactured in models with and without recirculation. If you are adamant about having instant hot water and aren’t averse to an extra $500-plus in installation costs, then sure, go with a tankless water heater with a recirculation pump and piping.

If you can live with 30 or so seconds of cool water while waiting for the hot water to arrive, skip the recirculation option and save some cash. Units alone cost up to $1,450.

Performance Platinum Condensing Water Heaters

This is Rheem’s top of the line. Most units have built-in recirculation pumps to provide you with instant hot water at the outlet(s) of your choice. To save on standby heat loss, recirculation water heaters are usually outfitted with timers, so that the instant hot water is available when you want it most, say from 6am to 8am and in the evening.

Performance Platinum Condensing Water Heaters

Units are offered from 160,000 BTU/8.4 GPM to 199,000 BTU 9.4 GMP. Cost is around $1,000 to $1,500 for the water heater only depending on size and whether it is recirculating.

Expect another $1,000 minimum to $2,000 or so to install the water heater, vent it and run pipes that allow for proper recirculation. Both indoor and outdoor models are available in this line.

Understanding Your Rheem Tankless Hot Water Heater Options & Model Codes

Rheem is straightforward about labeling, usually using the maximum gallons per minute, or GPM, of gas models. A model 84 offers up to 8.4 GPM. A 94 delivers up to 9.4 GPM.

Just keep in mind the importance of the term “maximum.” In most climates, you can expect 50% to 65% of the max, but those figures are still good enough to provide continuous hot water to 2-4 outlets.

Rheem electric tankless water heaters are labeled by the kW per hour of electricity that they consumer. The 3/4kW units produce up to .5 gallons per minute (GPM), OK for one low-flow bathroom faucet. The 36kW largest units can produce up to about 6.0 GPM when the incoming water is fairly warm. In cool climates, expect 2.5 to 4.0 GPM depending on incoming water temperature.

  • Performance Tankless Electric: 3/6/8/11/13/18/24/27/36 kilowatts per hour, 0.5 to 6.0 GPM all climates.
  • Professional Classic Series Electric: RTEX-4/6/8/11/13/18/24/27/36/ kilowatts per hour, 0.5 to 6.0 GPM all climates.
  • Professional Prestige Series Gas: 160,000, 180,000 and 199,000 BTUs. Indoor/outdoor, natural gas and propane. 8.4, 9.0 and 9.5 GPM maximum.
  • Performance Platinum Condensing Series Gas: 160,000, 180,000 and 199,000 BTUs. Indoor/outdoor, natural gas and propane. 8.4, 9.0 and 9.4 GPM maximum.
  • Tankless Mid-efficiency Non-condensing Series Gas: 160,000, 180,000 and 199,000 BTUs. Indoor/outdoor, natural gas and propane. 8.4, 9.0 and 9.5 GPM maximum.

Condensing vs Non-condensing – A condensing water heater has a secondary heat exchanger that transfers heat out of exhaust gases to raise the temperature of incoming water. That makes it easier to heat to the desired temperature, and boosts GPM. It also lowers operating cost – makes the unit more efficient.

Condensing units cost quite a bit more, but if you use a lot of hot water, one of them will pay you back the extra cost in 3-10 years.

Indoor vs Outdoor – In warm climates, we suggest you consider an outdoor water heater. The installation cost is quite a bit lower, and the outdoor temperatures don’t significantly reduce energy efficiency.

In cold climates, an indoor unit might make more sense. Talk with the installer about options and the cost of each, so you can compare real installation costs head-to-head.

Recirculation – There’s no cost advantage with recirculation. In fact, the equipment, installation and operating costs will be higher. It’s all about instant hot water. If you’re willing to pay for it, that’s a nice convenience.

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Warranty Information

Rheem electrical tankless water heaters are backed by a 1-year heating chamber warranty – the heating element and reservoir. The rest of the parts are covered for 5 years. This is an average warranty for electric water heaters across the industry.

Rheem gas tankless water heaters are covered with a 5-year parts warranty and a 12-year heat exchanger warranty for residential units. It’s just 5 years on a commercial installation. This is slightly higher than average. For comparison, Navien’s best heat exchanger warranty is 15 years. Rinnai’s is just 10 years.

Corporate Contact Details

Rheem is a very large company, part of Paloma Industries.

Rheem’s mailing address: 1100 Abernathy Road, Suite 1700 Atlanta, GA 30328

You can also try the Contact Form on the Rheem website.

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