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Best 40 Gallon Electric Hot Water Heater

3 expert-curated picks ranked by performance, value, and long-term reliability

40-gallon electric hot water heaters serve 1-2 person households or installations where the 50-gallon doesn't fit. The capacity covers single-bathroom homes, secondary water heaters in larger residences, and rental properties where small footprint matters.

Top 40-gallon electric picks

Best overall: Rheem Performance Platinum 40-gal Electric

Two 4500W elements, UEF 0.93, 56-gallon FHR, 12-year warranty. EcoNet WiFi available. About $649 unit, $1,200 installed.

Best lifetime warranty: Rheem Marathon 40-gal Lifetime Electric

Polybuthylene tank cannot rust. Lifetime tank warranty. About $1,649 unit, $2,200 installed.

Best AO Smith / Lowe's: AO Smith Voltex 40-gal Electric

6-year warranty. About $549 unit, $1,100 installed.

Best budget: Rheem Performance 40-gal Electric

6-year warranty. About $499 unit, $950 installed.

When 40-gallon is the right capacity

  • 1-person households: comfortable margin
  • 2-person households with sequential demand: sized appropriately
  • 3-person households: tight, may run out during morning rush
  • Single-bathroom homes regardless of household size

Install considerations

40-gallon electric replacement is one of the simplest residential plumbing/electrical jobs:

  • Standard 30A 240V circuit. Verify the existing circuit doesn't share with other loads.
  • 10-AWG copper from breaker to unit.
  • 3/4" NPT cold and hot connections.
  • No venting required.
  • About 90 minutes for a plumber or 2-3 hours for a DIY first-timer.

Plumber labor: $300-$500. DIY-reasonable for any homeowner with basic electrical comfort.

Why upsize to 50-gallon

Three reasons households end up wanting 50 instead of 40:

  1. Adding household members (kids growing into teenage shower routines)
  2. Adding hot-water-intensive appliances (dishwasher, washing machine with hot wash)
  3. Discovering the recovery rate of electric is slower than gas

If you're between 40 and 50 gallons and have the closet space, 50-gallon is usually the better future-proofing choice. The cost difference is $100-$200 and the install is identical.

3 products
$949 – $1,795
Updated May 2026

Quick Comparison

# Product Brand Rating Price
1 Rinnai RU199iN Sensei Tankless Water Heater Rinnai 4.8 Check current price Amazon
2 Rheem Performance Platinum 50-Gallon Gas Water Heater Rheem 4.6 Check current price Amazon
3 AO Smith Signature Premier 50-Gallon Gas Water Heater AO Smith 4.5 Check current price Amazon