# Rheem 18kW Tankless Water Heater *Published: 2025-03-04 | Updated: 2025-03-04 | Source: https://shopsavvy.com/products/rheem-18kw-tankless-water-heater* --- **Brand:** Rheem **Price Range:** $99.99 - $682.35 across 31 retailers ## Pros - Effectively provides hot water for a home with multiple bathrooms and simultaneous uses, such as showers and laundry. - Compact design saves space, making it suitable for replacing larger tank systems. - Installation is straightforward for DIY enthusiasts; offers significant space savings. - Provides consistent hot water with no temperature fluctuations after the initial setup. - Offers significant cost savings compared to traditional tank water heaters. - The tankless model eliminates stagnant water issues, contributing to a sense of cleanliness. - Accompanies a value kit that simplifies water flow adjustment and initial troubleshooting. - Positive feedback on performance from users over several months. - Supports multiple simultaneous hot water sources effectively. - Maintains user satisfaction with the performance and efficiency of the model. ## Cons - Requires significant amperage and larger wiring, which may need panel upgrades. - May struggle to reach optimal temperatures through smaller pipes in cold weather. - Filling a bathtub might exceed the heater's output capacity; controlled flow is advised. - Installation, if not DIY, can be costly due to electrical and plumbing modifications. - Additional components like valve kits and fittings can increase overall cost. - Brief waiting period for hot water to reach certain faucets after turning on. - Requires annual maintenance for hard water flushes, potentially needing professional service. - Some homes might need an inline recirculation pump for optimal performance. - Difficulties with providing instant hot water for simultaneous showers and other uses without additional equipment. - Installation location challenges in colder climates noted by some users. ## About This Product This tankless electric water heater is ideal for mid-range whole-home applications. This unit is ideal for single shower applications in the Midwest. The Rheem Performance tankless electric water heaters offer a continuous, endless supply of hot water. A lower kilowatt unit can provide hot water on demand for single or multiple point-of-use applications while a higher kilowatt unit could provide hot water for a whole house depending on the inlet ground water temperature. Tankless electric water heaters save space, save energy, save money, and require no venting. The sleek, compact size, 90 percent smaller than a tank, allows you to save space and place the unit wherever you want, including under a sink. Tankless units only draw energy when hot water is flowing, while traditional tanks are constantly drawing energy to keep the water in the tank at the desired temperature. Rheem's self-modulating technology can save Up to 50 percent on your water heating bi... ## Last Seen Prices | Retailer | Price | Availability | Last seen | Store's standard terms | |----------|-------|-------------|-----------|------------------------| | [Aikocol](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/E4UJlfZLPmaxOwCzclWL?source=shopsavvy&medium=product-page) | $99.99 | In Stock | 2025-04-11 (may have changed) | | | [Amazon](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/b2100dab-e989-eafc-8853-5f684638b4f0?source=shopsavvy&medium=product-page) | $264.82 | In Stock | 2025-03-04 (may have changed) | | | [Wayfair](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/YNiGK9GzPvhR3QZfX78L?source=shopsavvy&medium=product-page) | $384.67 | In Stock | 2025-04-11 (may have changed) | 30-day returns · free shipping on $35+ | | [retailers/miamiwaterheater](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/YEmu44QjifbQmEV3AC9x?source=shopsavvy&medium=product-page) | $399.95 | In Stock | 2025-04-11 (may have changed) | | | [retailers/bigbigmart](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/ab1847a5-a25a-424f-ec05-1ece66fb6e3f?source=shopsavvy&medium=product-page) | $401.42 | In Stock | 2025-04-11 (may have changed) | | | [joojet](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/7frZTMyqsBruk088rXRV?source=shopsavvy&medium=product-page) | $426.93 | In Stock | 2022-07-27 (may have changed) | | | [retailers/faucetdirect](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/2aa52f30-455f-6df7-1979-cd7303601035?source=shopsavvy&medium=product-page) | $449.00 | In Stock | 2025-04-11 (may have changed) | | | [retailers/bigfrogsupply](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/e0118c12-4b1d-7854-f65f-69e984cf1281?source=shopsavvy&medium=product-page) | $449.00 | In Stock | 2025-04-11 (may have changed) | | | [hvacdirect.com](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/e35b8fc9-7643-aa48-7f27-9b5818621647?source=shopsavvy&medium=product-page) | $449.00 | In Stock | 2025-04-11 (may have changed) | | | [Newegg](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/97ce9152-80d5-c934-642b-1726d0d88ab6?source=shopsavvy&medium=product-page) | $449.00 | In Stock | 2024-12-22 (may have changed) | 30-day returns | | [Rheem Tankless Online](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/OBATwVlVeXApzMm5VABd?source=shopsavvy&medium=product-page) | $449.00 | In Stock | 2022-07-27 (may have changed) | | | [retailers/neobits](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/4a7df2e1-2772-9041-ca98-329dbd8248ca?source=shopsavvy&medium=product-page) | $458.08 | In Stock | 2025-04-11 (may have changed) | | | [Wholesale Water Heaters & More](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/wnEuNKdxnfRJpep324y1?source=shopsavvy&medium=product-page) | $459.00 | In Stock | 2022-07-27 (may have changed) | | | [retailers/tanklesswaterheaterdepot](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/yDL7Y0H6ypL1JBWOmVs2?source=shopsavvy&medium=product-page) | $459.95 | In Stock | 2025-04-11 (may have changed) | | | [Rheem Tankless Heaters](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/q2cKybKWGU5E3mkbZN2N?source=shopsavvy&medium=product-page) | $459.95 | In Stock | 2022-07-27 (may have changed) | | | [Zoro Tools Industrial Supplies](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/Dd2QJlrABgQOQg0h4LHA?source=shopsavvy&medium=product-page) | $477.01 | In Stock | 2022-07-27 (may have changed) | | | [Zoro](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/Kg3Qzt17k4ZR5ZiR3iGS?source=shopsavvy&medium=product-page) | $486.99 | In Stock | 2024-12-22 (may have changed) | | | [afsupply.com](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/9LBH1VFFTqbrPDLN0W1e?source=shopsavvy&medium=product-page) | $534.25 | In Stock | 2025-04-11 (may have changed) | | | [Home Perfect](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/2S0m2NSPPsyWVP68NWSB?source=shopsavvy&medium=product-page) | $534.25 | In Stock | 2025-04-11 (may have changed) | | | [retailers/sears](https://shopsavvy.com/api/redirect/products/473Bt8gJbKCrd3Vw3M98/offers/f974af6e-01ac-8bb0-18f9-aa861942b9c3?source=shopsavvy&medium=product-page) | $536.64 | In Stock | 2025-04-11 (may have changed) | | *Store terms are each retailer's standard return and shipping policy from ShopSavvy's retailer research; 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