> The future is in completely abandoning residential gas infrastructure...
Gas tankless water heaters are still sometimes a cost-efficient per-therm choice if you are already plumbed for gas [1] [2].
I've yet to find a calculator that figures the TCO (including costs that are externalized today, like pipe losses to the environment) between tankless water heaters using natural gas, propane, resistive electric, induction electric, and heat pump versions of those types, though. There are many different situations, so what is overall systemically efficient in one situation will not be suitable for another.
It would come as little surprise to most HN readers that I have a number of very expensive resistive air heaters that we call computers laying around for my work, so in my particular situation, a heat pump water heater works extremely well. However, I'm still unsure of the TCO after all the maintenance and repair is accounted for over the decades I will own the heat pump as it is undeniably more complex than more common water heaters. So I will give a nod to resistive water heaters as a likely good TCO choice in most situations after all costs are said and done [3].
Heat pump water heating works with surprisingly low temperatures. For example, if your basement naturally approaches 45-50 degrees from the walls, that's plenty to keep a 50-80 gallon tank heated without drawing heat from the rest of the house in the winter. During the other seasons, any incidental cooling is of course a benefit.
Gas tankless water heaters are still sometimes a cost-efficient per-therm choice if you are already plumbed for gas [1] [2].
I've yet to find a calculator that figures the TCO (including costs that are externalized today, like pipe losses to the environment) between tankless water heaters using natural gas, propane, resistive electric, induction electric, and heat pump versions of those types, though. There are many different situations, so what is overall systemically efficient in one situation will not be suitable for another.
It would come as little surprise to most HN readers that I have a number of very expensive resistive air heaters that we call computers laying around for my work, so in my particular situation, a heat pump water heater works extremely well. However, I'm still unsure of the TCO after all the maintenance and repair is accounted for over the decades I will own the heat pump as it is undeniably more complex than more common water heaters. So I will give a nod to resistive water heaters as a likely good TCO choice in most situations after all costs are said and done [3].
[1] https://www.ruud.com/products/water-heaters/tankless-water-h...
[2] https://www.waterheaterleakinginfo.com/gas-vs-electric/
[3] https://www.physicsforums.com/threads/is-induction-heating-m...