About Best Tankless Heaters
Best Tankless Heaters is a research website for US shoppers with one job: help a household pick a tankless water heater whose documented flow rate, fuel and electrical requirement match its bathrooms, its climate and its utility hookups. We do not sell heaters, we do not install them, and we do not pretend to have run water through the units we list. What follows is a plain account of how the site is built so that you can decide how much weight to give it.
The single question we try to answer
Will this unit deliver enough hot water, at the same time, in your climate? That question has three documented inputs: the maximum flow a listing states in gallons per minute, the input it states in BTU per hour for gas or kilowatts for electric, and the temperature rise your inlet water forces on it. Our flow-rate calculator turns your fixtures and region into a required GPM and rise; the comparators show which listings state numbers in that range. Everything else on a card is supporting detail.
Where every number comes from
Each specification we display is copied from the exact Amazon listing text with the phrase it came from and a note of whether it was read from the title or the feature bullets. A GPM printed on a competing model, a manufacturer brochure for a different generation, or a figure we could infer from a model number is not used. When a listing states nothing usable, the card is scored on how completely the seller documented it and says so.
Gas numbers stay gas, electric numbers stay electric
A 199,900 BTU/h gas unit and a 36 kW electric unit both call themselves whole-house heaters, but they are sized under different rules, wired and plumbed differently and permitted differently. We keep the two families in separate comparators, we never convert BTU/h into kW on a product card, and the only place the arithmetic meets is the calculator, where the conversion is printed with its formula.
What we will not tell you
We publish no gas piping sizes, no venting layouts, no breaker or conductor sizes and no step-by-step installation sequence. Gas tankless heaters involve combustion, flue gases and fuel lines; electric units draw 75 to 150 amps. Both are permitted work almost everywhere in the United States, and the person who signs the permit is a licensed plumber, gas fitter or electrician who has seen your house. Our guides tell you which questions to bring to that person, and stop.
How the site earns money
Product links go to Amazon with an affiliate tag. If you buy through one we may earn a commission at no extra cost to you. The tag is not an input to any score, no manufacturer can buy a position, and a unit with no affiliate link would be ranked by the same formula as one with. The commission pays for the data collection described on the methodology page; it does not pay for opinions.
Corrections
Because every extracted value carries the sentence it came from, a correction is quick to check. Send the page, the ASIN and the listing text that contradicts us through the contact page.