Rheem SPEX48
0.96 UEF DOE CCD · 2026-09-19Grade E: where this UEF sits among the 271 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
An electric tankless unit, very small draw pattern (small units - a single bathroom, or a point-of-use heater under a sink).
Checking the Rheem SPEX48? This electric tankless unit uses 615 kWh of electricity a year at the very small draw pattern, the standard daily hot-water usage DOE tests against. That figure is equal to its class median of 615 kWh, a difference of 0 kWh. It ranks 77th lowest of 271 models in its class.
Energy use per year
615 kWh a year
Computed by this site from the registry's UEF and the federal test's daily hot-water draw for this draw pattern. What it costs depends on the electricity rate where you live.
That is equal to the median of 615 kWh for the 271 models registered in the same heater type and draw pattern; it ranks 77 of 271, lowest energy first.
Solid line: this model (615 kWh). Dashed line: the class median.
Min 562 kWh Median 615 kWh Max 649 kWh
What it costs to run where you live
What the registry files
- UEF (Uniform Energy Factor) how much hot water you get for each unit of energy the heater uses
- 0.96 DOE CCD · 2026-09-19 Compared only with other models registered as an electric tankless unit at the very small draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- Very small DOE CCD · 2026-09-19
- Maximum Gallons Per Minute how many gallons a minute it can heat while running continuously
- 0.5 gal/min DOE CCD · 2026-09-19
What it costs to install
$1,306–$1,838 installed
Not a quote — a modeled range of what installers have charged for this class of unit; your price will vary with labor rates, access, and local code requirements.
Escalation indexes: equipment (BLS PPI) latest available: August 2026; labor (BLS ECI) latest available: April 2026 to June 2026.
NLR REMDB (BLS PPI/ECI escalated) · 2026-04-01Safety record
No CPSC recall names this model.
Checked against the CPSC recall database. CPSC does not publish a model-level match for this product category, so this list is curated by hand from the manufacturer's recall filings.
CPSC · 2026-09-24What these figures mean
How this compares
The closest models in the same class — same fuel, type and draw pattern.
Keep going
How every figure on this page is calculated
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Find what replaces your water heater
Enter the model number off your old unit and see what is on file today, with the yearly cost difference.
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Find a water heater that fits
Three questions — fuel, hot water need, install space — narrow every model on file to the ones that fit.
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What a water heater costs to run
Prices a unit's efficiency against your own utility's filed tariff for your ZIP code.
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How to size a tankless water heater by GPM
Answered from what models in this size actually file.
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Water heaters
Every model on file with the Department of Energy, by heater type.
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All electric tankless water heaters
Electric instantaneous units, sized by flow rate rather than tank gallons.
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Every Rheem model on file
What this brand files, by heater type.
UEF 0.96 · Grade E Price it on your ZIP
This site calculates the 615 kWh figure; the registry does not publish it. It combines two inputs: the registry's UEF, the ratio of hot water delivered to energy used, and the DOE test's daily hot-water draw for this draw pattern. For this model the UEF is 0.96. The registry data come from the DOE CCD, retrieved 2026-09-19. The figure holds only at that test draw, and energy use at your own daily draw is not available here. The class is the 271 models registered as an electric tankless unit at the very small draw pattern. Among them, this unit ranks 77th for lowest energy use, which places it in the second-lowest quarter of its class. The steps behind the number are set out in how the annual cost is calculated.
The very small draw pattern covers small units: a single bathroom, or a point-of-use heater under a sink. The 615 kWh figure describes use at that scale only. The registry lists this unit's maximum flow rate in gallons per minute as 0.5. A home that needs hot water for several bathrooms is outside the draw pattern behind that figure. Energy use for this model at a larger draw pattern is not available in this data. If you are confirming a like-for-like swap, you can find a same-class replacement by model number. If the need is a different size or fuel, the selector by fuel, space and size covers other classes. The rank of 77th applies only within this class of 271 models and says nothing about units in other classes.
This text states no running cost. The cost of 615 kWh of electricity depends on your own utility tariff, and that rate is not part of the registry data. The cost calculator on your own ZIP applies your local electricity rate to this figure. Because this unit sits at its class median, as stated above, its calculated cost at the test draw matches that of a median model in the class on the same rate. A model elsewhere in the class would differ only by its own gap from 615 kWh. The installed-cost range appears in its own block on this page, with its source and date. It is a modeled range, not a quote, and this text does not restate it.
DOE CCD · 2026-09-19