AO Smith Conservationist 40-Gallon Electric Water Heater (ENT-40)

Model ENT-40
4.0/5 from 520 ratings
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Price as of Apr 2026
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Status
Legacy / Replacement Reference
Wattage
4500
Fuel Type
Electric
Tank Type
Tank
Energy Factor
0.92
Warranty Years
6

AO Smith Conservationist 40-Gallon Electric Water Heater (ENT-40) Review

The AO Smith Conservationist 40-Gallon Electric (ENT-40) is the smaller-capacity sibling of the ENT-50, designed for 1-2 person households or installs where 50-gallon dimensions won't fit. Mainstream Conservationist tier between AO Smith's budget ProMax and premium Signature Premier lines.

Specs: 40 gallons stored, two 4500W heating elements, UEF 0.93, 52-gallon first-hour rating, 6-year tank and parts warranty. ENERGY STAR certified. Glass-lined steel tank with self-cleaning dip tube on sub-models. Magnesium anode rod, polyurethane foam insulation.

The 40-gallon electric capacity (52-gallon FHR) covers 1-2 person households with sequential demand. For 3+ person households, the 50-gallon Conservationist or upgrade to AO Smith Voltex heat-pump is the right choice. Like-for-like 40-gallon electric replacement is one of the simplest residential plumbing jobs.

Right buyer: Lowe's-channel shopper replacing an existing 40-gallon electric tank in a 1-2 person household with 5-8 year ownership horizon. About $549 at Lowe's, $1,100 installed. For longer ownership, the upgrade to AO Smith Voltex heat-pump (massively lower operating cost) or Rheem Marathon (lifetime warranty) usually pays back.

Full Specifications

Brand
AO Smith
Model Number
ENT-40
Status
Legacy / Replacement Reference
Wattage
4500
Fuel Type
Electric
Tank Type
Tank
Energy Factor
0.92
Warranty Years
6
Capacity Gallons
40
First Hour Delivery
52

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