[swiftcoder]

... I may be out of touch with US water usage, but just how much hot water does the average household use?

They quote $2,500 10-year savings vs oil. I have my hot water piggybacked on the oil-fired condensing boiler unit that's also used for my central heating, and I doubt I burn more than $250/year total on the hot water side of the equation (in a 4-bed, 4-bath house).

[thekraken57]

hot water is a huge piece of home energy. DOE had this study that showed more energy for water heating than electric car charging in a home with both. Just look at the total energy use on the energystar sticker of a standard water heater. https://www.energy.gov/eere/vehicles/articles/fotw-1307-sept...

[swiftcoder]

I do not understand how this is possible in general. For example, I use ~3,600 litres of oil to heat through the winter, and the same boiler consumes less than 300 litres to produce domestic hot water for the other six months of the year.

That places my central heating on the order of 5-10x higher energy expenditure than my domestic hot water - this does not seem atypical in my area, and apparently data for the entire EU is similar (60% heating, 15% hot water): https://ec.europa.eu/eurostat/web/products-eurostat-news/w/d...

[maxerickson]

It's comparing it to EV charging. I expect part of the point of the linked study is to examine readiness as more people adopt EVs.

With the heavy use of direct combustion for home heating in the US, heating wouldn't be hugely interesting in that context. I consume more natural gas for heating each month in the winter than I do for hot water annually.

[swiftcoder]

> It's comparing it to EV charging

"Space heating" is also on the same graph, and it's nearly 1-to-1 with water heating. Which seems odd

[maxerickson]

Yeah, I expect that's small portable heaters rather than whole house.