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Comment by phil21 | Hacker News Reader

The best investment in my comfort and upgrading my home was two redundantly configured Navien continuous water heaters.

Never worry about running out of hot water ever again. If I’m gone on a trip for 2 weeks my hot water bill is zero. Due to having overcapacity, whenever I have guests staying with me no one ever has to worry about simultaneously using showers or any other hot water at all. I run out of water pressure before I do heating capacity.

If one breaks I just schedule a repair or replacement for weeks in advance and have to limit folks to 2 simultaneous showers at any given time. Hasn’t happened yet.

I will never go back to a tank based water heater unless outright forced into it. It’s one of those “TiVo like” upgrades to your lifestyle you never knew you needed until you have it.

Certainly not cheap, but also not prohibitively expensive if you can find a competent installer who doesn’t overcharge.

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> If I’m gone on a trip for 2 weeks my hot water bill is zero

You mention other advantages, but money isn't one. You're limited to 100% efficiency with tankless.

Although an idle hot water tank can waste ~70W (~1.7kWh) of power, this is way more than made up for by using a heat pump. Plus tankless strains the grid a lot more than any system with a buffer built in.

Two reasons I decided not to go with tankless:

1. Can’t have recirculation pump to supply hot water instantly throughout the whole house.

2. Significantly higher energy bill compared to heat pump.

An additional bonus is the heat pump cools my garage in the summer.

1 sounds like a huge inefficiency?

Why?

In SE Asia, tankless is generally placed closer to where it comes out.

Recirculation pump means that you're paying to keep your pipes from getting cold.

Recirculating works fine with these, if I chose to do it. They both have a tiny hyper-heated insulated tank for the purpose so they can trickle a hot water loop to the furthest destination. They also have a recirc mode which would barely show up on your monthly energy bill.

If I was building new construction I’d do it, but the upgrade just isn’t worth it for me at the moment since it would require drywall repair and running another return line for relatively minimal benefit.

Note as others have pointed out: this setup is not to save money, it’s entirely quality of life as the primary metric under consideration.

Is this unusual in the US? I think almost everyone in the UK for years has been installing ‘combi’ boilers, which are ones that heat the water in radiators and also heat water on-demand.

In my geographic area (coldest part of the lower 48 that isn’t an mountain) everyone heats water with natural gas which is cheap as hell anyways so we all have tank style water heaters.

A lot of US houses have forced air for heat (I guess because it combines well with cooling).

How often do your water boilers break? :O

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