Where the Ruud PROG40-36N RU62 fits
The 36,000-BTU/h natural gas version is the lowest-input standard tall 40-gallon natural gas model in this group. Its 19-inch tank diameter and 61½-inch height to the vent are useful starting points when the replacement must fit an existing narrow location. WHE checks the complete installation space before treating it as a direct replacement.
The photograph is Ruud’s representative tall Atmospheric family image. It shows the standard side-T&P arrangement; the exact dimensions and burner rating come from the model row below.
PROG40-36N RU62 specifications
| Exact model | PROG40-36N RU62 |
|---|---|
| Fuel and venting | Natural Gas; atmospheric natural draft |
| Nominal capacity / rated storage | 40 gallons / 38 gallons |
| Gas input | 36,000 BTU/h |
| First-hour rating | 64 gallons |
| Recovery | 36.4 gallons per hour at a 90°F temperature rise |
| Uniform Energy Factor | 0.58 |
| A — height to vent | 61½ inches |
| B — tank height | 58½ inches |
| C — tank diameter | 19 inches |
| D — height to gas connection | 14¼ inches |
| E — listed vent size | 3 or 4 inches; final vent sizing requires installation review |
| F — water-connection centers | 8 inches |
| G — height to side T&P valve | 52¼ inches |
| H — water-connection size | ¾ inch |
| Shipping weight | 127 lb; not filled operating weight |
| Base limited warranty | 6-year tank and parts; eligibility and exclusions apply |
Hot-water demand and comparable models
The PROG40-38N RU62 shares this model’s 19-inch diameter, 61½-inch vent height and 64-gallon first-hour rating, but increases listed recovery from 36.4 to 38.4 gallons per hour at a 90°F rise. The PROG40-40N RU62 changes more than the burner: it has an 84-gallon first-hour rating, a 19½-inch diameter and a 63¼-inch vent height. That extra height can matter more than the nominal 40-gallon label when connecting to an existing vent.
First-hour rating combines stored hot water and recovery under a standardized test. It is not a promise of continuous delivery at that rate. Tell us about back-to-back showers, tub filling and appliances used at the same time so we can compare the heater with your actual peak demand. Incoming water temperature and fixture flow also affect the result.
Fit, gas supply and atmospheric venting
For a replacement in a narrow closet, allow for more than the 19-inch cylinder. The side relief valve, discharge piping, gas connection and access to the drain all use space outside that measurement. A tank that passes through the doorway may still leave too little room to work on the burner or disconnect the plumbing.
Order the factory natural gas version and verify that fuel on the delivered rating plate. A propane heater is a separate configuration, even when its tank looks similar. WHE checks the available gas supply against the selected input and the other appliances; the manual prohibits changing the heater to another fuel.
This atmospheric heater uses natural draft through a suitable vent system. WHE checks the draft hood, connector, complete vent route, combustion-air supply and any shared appliances. The sheet’s “3 or 4 inches” entry is not a stand-alone instruction to pick either pipe size. A power-vent or direct-vent installation needs a separate suitability review.
This guide covers the standard side-T&P model with top water connections. It does not specify the separate TT top-relief-valve or AX side-water-connection version. We plan the relief discharge, shutoffs, thermal-expansion provisions and any pan or drainage work around the actual installation.
Care, features and warranty
The family includes Ruud’s Guardian combustion shut-off system, a low-NOx burner, an anode rod and a brass drain valve. “Low NOx” does not mean ultra-low NOx, and the combustion shut-off feature is not a water-leak shutoff. Keep the air openings and service areas accessible and follow the supplied maintenance instructions. Sediment-control features do not eliminate maintenance.
Ruud lists a six-year limited tank and parts warranty. The linked residential certificate distinguishes eligible single-family use from other installations and excludes labor and reinstallation costs. Keep the purchase record, model and serial number. ProtectionPlus is an optional tank-warranty extension; it is not included base coverage or an automatic extension of parts and labor. Confirm the certificate supplied with the unit.
Which manufacturer figures this guide uses
Specifications here follow Ruud’s October 2025 sheet, RU-PROA-ATM-SS-10.25. The family web table still uses an older Energy Factor column. Those EF figures are not interchangeable with the UEF values in the current sheet. Confirm the delivered rating plate, EnergyGuide and supplied instructions before installation.
Frequently asked questions
Does the 38,000-BTU version deliver more hot water in the first hour?
Ruud lists the same 64-gallon first-hour rating for the 36,000- and 38,000-BTU natural gas versions. The 38,000-BTU model has a higher listed recovery rate. Compare the complete ratings and gas-supply requirements, rather than assuming every increase in input changes first-hour output.
Is PROG40-36N RU62 natural gas or propane?
This exact model is natural gas, with 36,000 BTU/h input. For the other fuel, compare Ruud PROG40-32P RU62 as a separate selection. Do not assume equal dimensions or performance, and do not convert this heater to another fuel.
Does a 40-gallon label mean 40 gallons of rated storage?
No. Ruud lists 40 gallons nominal and 38 gallons rated storage for this model. Its 64-gallon first-hour rating is a separate performance measure that includes recovery during testing.
How much height does this tall model need?
The tank itself is 58½ inches high; the drawing lists 61½ inches to the vent. The installation also needs space for venting, water piping and service. Those dimensions alone do not establish the required enclosure height or clearances.
Can WHE quote a replacement from photos?
Clear photos of the data plate, entire heater, vent, gas connection and surrounding space help us start. We confirm the fuel, fit, demand and installation scope before finalizing equipment and pricing. An existing 40-gallon tank alone does not establish compatibility.
Plan a Ruud replacement with WHE
Water Heating Experts helps homeowners in Palm Beach Gardens, Jupiter and nearby Palm Beach County communities compare equipment and installation needs. See our gas water heater installation service, Ruud model guides and complete model catalog. Include the full model number when requesting an estimate so the proposed fuel, burner and connection arrangement are clear.
Official Ruud documents
- Professional Achiever Atmospheric family page
- Specification sheet RU-PROA-ATM-SS-10.25, October 2025 (model table on page 2)
- Residential gas FVIR use and care manual AP14328-5, May 2017
- Residential six-year limited warranty certificate AP16826-2
Specifications checked October 17, 2026. Use the instructions and warranty supplied with the delivered heater.