AO Smith offers 5 40 gallon water heaters models in the lineup we track. This page is the AO Smith-specific cut of the broader 40-Gallon Water Heaters water heaters category — same product class, narrowed to the AO Smith catalog only.
<p>AO Smith's water heaters lineup is one of the most-shopped in the category — and there are concrete reasons it stays that way year after year. This page is the complete index of every AO Smith water heaters model we currently track, with verified specifications, current Amazon pricing, aggregated ratings, and head-to-head comparison links against the strongest competitors in each price tier. Before you start filtering, the next several minutes will give you the context you need to make a confident pick.</p> <h2 id="brand-overview">About AO Smith in water heaters</h2> <p>On warranty length...
For the complete AO Smith lineup across all sub-types and capacities, see the AO Smith Water Heaters hub.
If you're cross-shopping 40 gallon water heaters beyond AO Smith, the following brands also ship in this category:
The 40-gallon water heater is the volume size for 2–3 person households — second only to 50-gallon in residential install volume. The 40G saves $30–$80 upfront vs the 50G and fits the same standard 22"-diameter footprint with slightly less height. For 1-bathroom homes and smaller households, 40G is often the right sizing.
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