Both are gas tank water heaters. Efficiency is nearly identical. The XG40T09HE40U0 saves $5/year to operate. All figures from published specs and EIA energy prices.
Performance
| Spec | XG40T09HE40U0 Rheem · Gas Tank | XG50T09HE40U0 Rheem · Gas Tank |
|---|---|---|
| UEF | 0.65Difference: 0.01 | 0.64 |
| Capacity | 38 gal | 48 galDifference: 10 gal |
| First Hour Rating | 81 galDifference: 4 gal | 77 gal |
| BTU Input | 40,000identical | |
But does it fit? Sizing guide
Physical dimensions
| Dimension | XG40T09HE40U0 | XG50T09HE40U0 |
|---|---|---|
| Height | 63.75" | 62.75"Difference: 1" |
| Width | 19.50"Difference: 2" | 21.50" |
Fit checked. Now the operating cost.
Operating cost
| Cost | XG40T09HE40U0 | XG50T09HE40U0 |
|---|---|---|
| Annual Operating Cost | $358/yrDifference: $5/yr | $363/yr |
| 10-Year Operating Cost | $3,580Difference: $50 | $3,630 |
| Annual Energy | 263 thermsDifference: 4 therms | 267 therms |
10-year modeled difference is $50. At this scale, local energy rates, usage patterns, and install costs matter more than the efficiency delta.
Costs vary by state. The XG40T09HE40U0 ranges from $174/yr (ID) to $1312/yr (HI). The XG50T09HE40U0 ranges from $176/yr (ID) to $1332/yr (HI).
$5/yr separates them. Install requirements determine the upfront gap. Installation accessories
Installation requirements
| Requirement | XG40T09HE40U0 | XG50T09HE40U0 |
|---|---|---|
| Voltage | 0Videntical | |
| Vent Type | Natural Draftidentical | |
| Vent Material | Category I B Ventidentical | |
| Condensate Drain | Noidentical | |
Warranty
| Coverage | XG40T09HE40U0 | XG50T09HE40U0 |
|---|---|---|
| Tank | 9 yridentical | |
| Parts | 9 yridentical | |
| Labor | 2 yridentical | |
Features
| Feature | XG40T09HE40U0 | XG50T09HE40U0 |
|---|---|---|
| Wi-Fi / Smart | Noidentical | |
| Self-Cleaning | Yesidentical | |
Common accessories for this type of installation.
Common install considerations for gas tank units
What is required depends on your existing installation, local code, and installer preference.
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Related
Sources. ENERGY STAR, manufacturer spec sheets, EIA average energy prices.Methodology