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Heater Types

Heat Pump Water HeatersHigh-efficiency electric replacements and hybrid tanks.Condensing Tankless Water HeatersCondensing whole-home flow with venting constraints.Gas Tank Water HeatersStraight swaps when gas storage is still the fit.

Plan Your Swap

Sizing guideCapacity, first-hour rating, and temperature-rise fit.Accessories hubInstall extras, code-adjacent parts, and paid-link accessory picks.Upgrade from NHP50Replacement candidates and projected operating-cost delta.Upgrade from NHP65Replacement candidates and projected operating-cost delta.Upgrade from NHP80Replacement candidates and projected operating-cost delta.Upgrade from NPE 210S2Replacement candidates and projected operating-cost delta.Upgrade from PROE50 T2 RH95Replacement candidates and projected operating-cost delta.HPTA 50 2 vs HPTA 80 2Side-by-side specs, efficiency, and fit differences.HPTS 50 2 vs NHP50Side-by-side specs, efficiency, and fit differences.NHP120 vs PROPH80 T2 RH400 30Side-by-side specs, efficiency, and fit differences.NPE 210S2 vs NPE 240S2Side-by-side specs, efficiency, and fit differences.

Guides & Data

California heat pump guideLocal rates, rebates, and operating costs.Colorado heat pump guideLocal rates, rebates, and operating costs.Massachusetts heat pump guideLocal rates, rebates, and operating costs.Oregon heat pump guideLocal rates, rebates, and operating costs.Washington heat pump guideLocal rates, rebates, and operating costs.DOE 2029 standardsWhat changes in 2029 and which product classes move first.

Brands

A.O. Smith Water HeatersPublished models, product lines, and brand coverage.Bradford White Water HeatersPublished models, product lines, and brand coverage.Navien Water HeatersPublished models, product lines, and brand coverage.Noritz Water HeatersPublished models, product lines, and brand coverage.Rheem Water HeatersPublished models, product lines, and brand coverage.Rinnai Water HeatersPublished models, product lines, and brand coverage.Takagi Water HeatersPublished models, product lines, and brand coverage.
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Comparison

HPTS-50-2 vs NHP50

Heat Pump vs Heat Pump for specs, cost, and install fit.
Both are heat pump water heaters. The HPTS-50-2 is more efficient (UEF 3.80 vs 3.46). The HPTS-50-2 saves $19/year to operate. All figures from published specs and EIA energy prices.

Performance

SpecHPTS-50-2
A. O. Smith · Heat Pump		NHP50
Noritz · Heat Pump
UEF3.80Δ 0.343.46
Capacity46 gal47 galΔ 1 gal
First Hour Rating65 galΔ 7 gal58 gal
kW Input4.50 kWidentical
The HPTS-50-2 leads on efficiency. But does it fit? Sizing guide

Physical dimensions

DimensionHPTS-50-2NHP50
Height63"58.30"Δ 4.70"
Width22"Δ 6"28"
Depth22"Δ 6"28"
The HPTS-50-2 is taller. Fit checked. Now the operating cost.

Operating cost

CostHPTS-50-2NHP50
Annual Operating Cost$143/yrΔ $19/yr$162/yr
10-Year Operating Cost$1,430Δ $190$1,620
Annual Energy831 kWhΔ 107 kWh938 kWh
10-year modeled difference is $190. At this scale, local energy rates, usage patterns, and install costs matter more than the efficiency delta.

Costs vary by state. The HPTS-50-2 ranges from $92/yr (ND) to $346/yr (HI). The NHP50 ranges from $103/yr (ND) to $390/yr (HI).

$19/yr separates them. Install requirements determine the upfront gap. Installation accessories

Installation requirements

RequirementHPTS-50-2NHP50
Voltage240Videntical
Amperage22AΔ 1A23A
Breaker30Aidentical
Condensate DrainYes—
Same electrical requirements. Swapping between these units should not require electrical changes.

Warranty

CoverageHPTS-50-2NHP50
Tank10 yridentical

Features

FeatureHPTS-50-2NHP50
Wi-Fi / SmartYes—
Noise Level45 dBΔ 9 dB54 dB
RefrigerantR-134aidentical

Decision split

Pick this one if...

A. O. Smith HPTS-50-2

  • Minimizing energy cost matters (saves $19/yr)
  • You need quiet operation (45 dB vs 54 dB)
  • You want smart home / Wi-Fi control
  • Peak efficiency is the priority (UEF 3.80)

Pick this one if...

Noritz NHP50

  • Your ceiling or space is under 63"

Neither if...

  • Your home only has 120V service and you cannot upgrade the panel
  • Your install space is under 700 sq ft of open air
Common accessories for this type of installation.

Common install considerations for heat pump units

What is required depends on your existing installation, local code, and installer preference.

Thermal Expansion Tank Often required by code Check on Amazon (paid link)
Water Heater Drain Pan Often required by code Check on Amazon (paid link)
Earthquake Straps (Seismic Restraints) Often required by code Check on Amazon (paid link)
Full accessories list
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Related
Sources. ENERGY STAR, manufacturer spec sheets, EIA average energy prices.Methodology