Kara Jennings, Sizing & electrical editor

I'm the person on the team who likes the boring tables. Every tankless heater has a flow chart: so many gallons a minute at a given temperature rise. The headline GPM on a listing is usually the friendliest case. What I want to know is what comes out of the shower in February, when the water reaching your house is properly cold.

On electric models I add things up: kilowatts, total amps, how many double-pole breakers and what wire size the manual calls for. A whole-house electric unit can ask for more than many panels have to spare, and I'd rather you learn that from a guide than from an electrician's quote.

Then there is the warranty, and I read the exclusions first. Plenty of the warranties I go through exclude scale damage or depend on installation by a licensed professional. That is why I also write the maintenance and descaling guide, with the flushing intervals the manuals give.

I write the guides on sizing, electrical requirements, installation, install cost and maintenance, and I edit some of Christine's. None of these heaters has run in my house for the site. My part is the reading, the arithmetic and the side-by-side comparison.