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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

NPE-210S2 vs NPE-240S2

Condensing Tankless vs Condensing Tankless for specs, cost, and install fit.
Both are condensing tankless water heaters. Efficiency is nearly identical. All figures from published specs and EIA energy prices.

Performance

SpecNPE-210S2
Navien · Condensing Tankless		NPE-240S2
Navien · Condensing Tankless
UEF0.96identical
Max Flow Rate5.30 GPM5.80 GPMΔ 0.50 GPM
BTU Input180,000199,000Δ 19,000
But does it fit? Sizing guide

Physical dimensions

DimensionNPE-210S2NPE-240S2
Height27.40"identical
Width17.30"identical
Depth13.20"identical
Weight73 lbsidentical
Fit checked. Now the operating cost.

Operating cost

CostNPE-210S2NPE-240S2
Annual Operating Cost$239/yridentical
10-Year Operating Cost$2,390identical
Annual Energy176 thermsidentical

Costs vary by state. The NPE-210S2 ranges from $116/yr (ID) to $878/yr (HI). The NPE-240S2 ranges from $116/yr (ID) to $878/yr (HI).

Install requirements determine the upfront gap. Installation accessories

Installation requirements

RequirementNPE-210S2NPE-240S2
Voltage120Videntical
Amperage5Aidentical
Breaker15Aidentical
Vent TypeDirect Ventidentical
Vent MaterialCategory Iv Pvc Cpvcidentical
Condensate Drain—Yes
Same electrical requirements. Swapping between these units should not require electrical changes.

Warranty

CoverageNPE-210S2NPE-240S2
Heat Exchanger15 yridentical
Parts5 yridentical

Features

FeatureNPE-210S2NPE-240S2
Wi-Fi / Smart—Yes
Recirculation Ready—Yes

Decision split

Pick this one if...

Navien NPE-240S2

  • You want smart home / Wi-Fi control
  • You need higher flow (5.80 GPM)
Common accessories for this type of installation.

Common install considerations for gas tankless units

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

Condensate Neutralizer Kit Commonly required Check on Amazon (paid link)
Gas Flex Connector Commonly required Check on Amazon (paid link)
Venting Kit Commonly required Check on Amazon (paid link)
Full accessories list
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Related
Sources. ENERGY STAR, manufacturer spec sheets, EIA average energy prices.Methodology