Is the Ruud PROE20 S2 RU right for your installation?
The Ruud PROE20 S2 RU is the smallest nominal-capacity model in this Standard Electric family. Ruud lists 19.9 gallons, a 31½-inch tank height and a 17-inch diameter. It is a conventional electric storage water heater with the sheet’s standard 240V, dual-element configuration, rather than a plug-in miniature sink heater.
This model needs careful demand planning. A small physical footprint can be useful, but it also limits the stored reserve available for showers or other overlapping uses. WHE asks which fixtures it will serve and how they are used before treating it as a suitable replacement. It should not be assumed equivalent to a 30- or 40-gallon tank simply because the same element wattage is listed.
Image note: Ruud supplies one tall-tank photograph for this family. It is a representative manufacturer image; this short model has different proportions. Use the dimensions above to judge fit.
Ruud PROE20 S2 RU specifications
| Exact model | PROE20 S2 RU |
|---|---|
| Manufacturer classification | Short electric storage tank; indoor installation |
| Nominal capacity | 19.9 gallons |
| Rated storage | Not listed in the linked specification sheet |
| First-hour rating | Not listed |
| Uniform Energy Factor (UEF) | Not listed |
| Standard supply / elements | 240V AC, single phase; two 4,500W elements, non-simultaneous operation |
| Recovery at a 90°F temperature rise | 21 gallons per hour with the standard 4,500W configuration |
| A — tank body height | 31½ inches |
| B — height to water connections | 31½ inches |
| C — tank diameter | 17 inches |
| Water connections | Top; ¾-inch NPT, shown on 8-inch centers in the series drawing |
| Required supplied external blanket | No required-blanket footnote on this model’s specification row |
| Approximate shipping weight | 62 lb; not the filled operating weight |
| Base limited warranty | Six years tank and parts for eligible single-family residential use; written terms apply |
Rated storage, first-hour delivery and UEF measure different things. They do not by themselves establish a number of showers or a household’s energy bill.
Dimensions, connections and replacement fit
Ruud’s row gives both tank height A and height to water connections B as 31½ inches. We preserve those two labels instead of adding a guessed connection height. Verify the supplied drawing and actual fittings for a tight installation. The 17-inch tank diameter still needs additional room for a pan, plumbing and maintenance.
Ruud does not attach a required external-blanket footnote to this model’s row. Do not add another model’s blanket dimensions or assume an optional accessory is included. The exact supplied equipment and instructions govern the finished installation.
WHE checks the full delivery route, supporting surface, drain pan, nearby pipes and access to the front panels, drain valve and anode. The tank dimensions are not minimum installation clearances. We also review water pressure, thermal expansion and temperature-and-pressure relief discharge as part of the scope.
Compare nearby Ruud models
| Model | Nominal / rated gallons | First-hour gallons | Body height × diameter |
|---|---|---|---|
| PROE20 S2 RU (short) | 19.9 / unlisted | Unlisted | 31½ × 17 in. |
| PROE28 S2 RU95 B (short) | 28 / 26 | 45 | 30 × 19¾ in. before blanket |
| PROE30 M2 RU95 (medium) | 30 / 27 | 45 | 37½ × 20¼ in. |
The linked sheet leaves rated storage, first-hour rating and UEF blank for PROE20 S2 RU. Those values are unlisted, not zero, and the family’s 0.90–0.93 UEF range should not be assigned to this model. The 28-gallon blanket model lists 26 gallons rated storage and 45 gallons of first-hour delivery, but requires a substantially wider insulated installation. The medium 30 has 27 gallons rated storage in a 37½-inch-high body with a 20¼-inch diameter. Either comparison requires actual space and demand checks.
WHE sizes around peak use, including shower flow, tub volume and overlapping appliances. These standard configurations share 21 GPH recovery at a 90°F rise; a larger tank does not automatically reheat faster.
Electrical configuration and installation planning
Standard power is 240V AC, single phase, with two 4,500W elements operating one at a time. Ruud notes special-order electrical options; the ratings here are for the standard configuration.
WHE checks the delivered nameplate and wiring diagram against the available circuit. These conventional tanks have no combustion flue or heat-pump condensate system. If considering relocation from an attic to a garage, send photos of both locations for an estimate.
Maintenance and warranty
The series sheet lists stainless steel elements, an anode, Ruudglas tank lining, an EverKleen diffuser and a brass drain valve. Follow the supplied manual for sediment maintenance and anode inspection; the diffuser does not make the heater maintenance-free.
The linked AP16826-2 certificate (September 2014) provides six-year limited tank and parts coverage for eligible single-family use by the original owner, and lists one year for other locations. Labor, removal and reinstallation are excluded. Confirm the supplied certificate and retain your records. ProtectionPlus is a separate extension.
Manufacturer documentation and product-image notes
The specifications above come from Ruud’s May 2024 PROE RU N Rev. 16 specification sheet, linked from its Professional Achiever Standard Electric family page. Sources checked October 17, 2026.
The webpage’s model table uses the older Energy Factor label and shows 0.95 on many rows. EF and UEF are different measures; this guide uses the linked sheet’s model-specific UEF values. The webpage also describes a copper upper element while the sheet says stainless steel upper and lower elements. The sheet is the basis here, with the supplied nameplate and parts documentation checked for the actual heater.
For the 19.9-gallon model, the sheet leaves rated storage, first-hour delivery and UEF unlisted. The efficiency range elsewhere on the family page is not a verified rating for this model.
Ruud also links the general AP9029-12 use-and-care manual (January 2015) and six-year limited warranty certificate. Use these references alongside the exact instructions delivered with the unit. A family photo or optional feature mentioned elsewhere on the page does not establish an included accessory.
Local installation help
Water Heating Experts helps homeowners in Palm Beach Gardens, Jupiter and nearby Palm Beach County communities compare fit and hot-water demand. Send photos of the existing label, full installation and surrounding space. Start with our Ruud installation page, review our electric water heater service, or compare the full model catalog. Availability and the complete installation price are confirmed with your estimate.
Ruud PROE20 S2 RU FAQs
How much water does the PROE20 S2 RU store?
Ruud lists 19.9 gallons nominal capacity. Its current linked table does not publish a separate rated-storage figure, so this guide does not substitute a guessed value.
What are its UEF and first-hour rating?
Ruud’s linked specification sheet does not list UEF, first-hour rating or a separate rated-storage figure for PROE20 S2 RU. This guide does not estimate them. The row does list 19.9 gallons nominal and 21 GPH recovery at a 90°F rise.
Do both 4,500W elements run at the same time?
Not in Ruud’s standard configuration. The sheet specifies non-simultaneous operation, meaning the controls operate one element at a time. This is not a standard 9,000W simultaneous heater. WHE verifies the nameplate and circuit before installation.
Does the series name guarantee smart controls or automatic leak shutoff?
No. The documents used for this guide do not establish Wi-Fi or automatic leak shutoff as included features of this exact standard model. The webpage mentions System Sentinel only for selected configurations; it is not assumed included here.
Does the six-year warranty include labor?
No. Ruud’s linked certificate excludes labor, removal and reinstallation costs. The six-year tank and parts term is for eligible single-family use; the certificate sets different terms for other installations. ProtectionPlus is a separate extension, not the base warranty.