Heat pump and tankless water heaters compared on the certified rating, not the brochure claim.
Uniform energy factor, first-hour rating and tankless gallons-per-minute. HeatPick reads official ENERGY STAR certification records and ranks 240-volt heat pump water heaters, 120-volt heat pump water heaters and gas tankless water heaters with the weights printed on every page. 3 categories, 119 products, 32 head-to-heads.
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Heat pump water heaters and gas tankless water heaters, scored from official ENERGY STAR certified ratings.
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Buying guides
How it works
1. The maker's spec table
Every scored figure comes from an official ENERGY STAR certified-product record, linked on the product card. If a figure is not published we show "Not listed" and score it at the category minimum, so an unpublished number never outranks a published one. We do not use installer quotes, retailer listings or brochure first-hour claims in place of the certified rating.
2. Different jobs, different weights
240-volt and 120-volt heat pump water heaters are weighted toward official uniform energy factor, first-hour rating and certified storage volume. Gas tankless models emphasize uniform energy factor, maximum gallons per minute and minimum activation flow, plus whether ENERGY STAR lists the model as connected-capable.
3. Match it to your home
A higher first-hour rating or max GPM is not automatically the right heater for a small household. 120-volt heat pump models are scored separately from 240-volt models because they use a different circuit and the official first-hour ratings are often lower. Gas tankless units need correctly sized gas supply, venting and a licensed installer. Follow the maker's electrical, condensate, venting and temperature-limit instructions. Then check the price on Amazon. Commissions never change the order.