Rheem Tankless Water Heaters — Gas, Electric & Condensing Models

Find the right Rheem tankless water heater for your home or business. We carry the full Rheem tankless lineup — from compact electric whole-home units (RTEX series), through high-efficiency non-condensing gas heaters (RTG series), super high-efficiency condensing models (RTGH series), and ThermaForce combi boilers — all fulfilled through our authorized dealer partner PlumbersCrib.

Browse by category below, or search by Rheem model number.

Tankless Buying Guides

Five honest guides written for homeowners who want to make the right decision the first time. No marketing fluff, real numbers and tradeoffs.

Start Here

Tankless Sizing Guide

Three-step process for sizing any Rheem unit — gas, electric, condensing, or combi. Climate zones included.
First Decision

Tankless vs. Tank

The honest tradeoff with a 20-year cost comparison. Sometimes a tank is still the right answer.
Fuel Choice

Gas vs. Electric Tankless

Capacity, install cost, operating cost — and which fits your home, climate, and existing utilities.
Efficiency Tier

Condensing vs. Non-Condensing

Efficiency, install cost, vent material, and the payback math that decides it.
Brand Comparison

Rheem vs. Navien, Rinnai, Noritz

An honest brand-by-brand comparison. Where each brand wins, including the ones we don't sell.
Specific Use Case

Outdoor Tankless Sizing

The full RTG outdoor lineup compared with model-by-model sizing for outdoor installs.

Choosing the Right Rheem Tankless Water Heater

The right tankless model comes down to three things: your fuel source, your home's hot water demand, and how energy-efficient you want the unit to be. Here's how the Rheem lineup breaks down — for the deep dive, see our complete sizing guide.

Gas vs. Electric

Gas tankless water heaters (RTG and RTGH series) deliver the highest flow rates — typically 6.8 to 9.5 GPM — making them the right choice for whole-home hot water in 2 to 5+ bathroom homes. They require natural gas or propane and proper venting. Electric tankless water heaters (RTEX series) install in tighter spaces, require no venting, and run on standard 240V wiring. The RTEX-24 and RTEX-27 can handle a 2-bathroom home in warmer climates, while the RTEX-36 supports larger applications. Full comparison →

Sizing by Bathroom Count

A practical rule: count the hot-water-using fixtures that might run at the same time, then size the unit by GPM. The Rheem RTG-70 series (7.0 GPM) covers most 2-bathroom homes. The RTG-84 and RTGH-84 (8.4 GPM) handle 2-3 bathrooms. The RTG-95 and RTGH-95 (9.5 GPM) cover 3+ bathroom homes. In colder climates with higher groundwater temperature rise requirements, size up one tier — what handles 3 bathrooms in Florida may only handle 2 in Wisconsin.

Condensing vs. Non-Condensing

Non-condensing models (RTG series) use a single heat exchanger with metal venting and are the lower-cost option. Condensing models (RTGH series) capture additional heat from exhaust gases through a secondary stainless steel heat exchanger, reaching up to 0.93 UEF efficiency, and can vent through standard PVC pipe — saving meaningful cost on long vent runs. The RTGH series typically pays back the price difference within 4-7 years through reduced gas consumption, and its 15-year heat exchanger warranty is the longest in the category. Full comparison →

When a Combi Boiler Makes Sense

Rheem ThermaForce combi boilers (RCBH and RHBH series) handle both space heating and domestic hot water from a single wall-mounted unit. They're ideal for whole-home renovations where you'd otherwise need both a furnace and a separate water heater, and they free up significant utility-room space. Models range from 99K to 199K BTU.

Popular Rheem Tankless Models

Rheem RTGH-95DVLN-3

The flagship condensing natural gas tankless. 9.5 GPM, 199,900 BTU, up to 0.93 UEF, 15-year heat exchanger warranty. Ideal for 3+ bathroom homes wanting maximum efficiency.

Rheem RTG-84DVLN-3

Mid-range non-condensing indoor gas model. 8.4 GPM, suitable for 2-3 bathroom homes. A strong price-to-performance choice for replacing a 50-gallon tank.

Rheem RTGH-SR10i IKONIC

Premium condensing tankless with built-in recirculating pump for instant hot water at the tap. Saves up to 12,000 gallons of water per year.

Rheem RTEX-24

Whole-home 24kW electric tankless. No venting required, compact wall mount. Works well for warm-climate homes, ADUs, or as a high-capacity point-of-use solution.

Rheem RTGH-95DVELN-3

The 9.5 GPM condensing model with built-in WiFi for EcoNet smart-home integration. Monitor and control hot water from your phone.

Rheem ThermaForce RCBH-L199i

Super high-efficiency condensing combi boiler — both space heating and domestic hot water in one wall-mounted unit. Ideal for whole-home renovation.

Why Buy from RheemTanklessOnline

RheemTanklessOnline.com is operated by LCP Supply alongside our flagship plumbing wholesale site, PlumbersCrib.com. Every order placed through our site is fulfilled by PlumbersCrib — an authorized Rheem dealer with full manufacturer warranty support, factory-direct pricing, and shipping nationwide. Talk to us before you order — proper sizing makes the difference between a happy install and a callback. Call 877-881-2742 for help selecting the right model.