I'm confused. It sounds like you're advising me not to get a tankless water heater then? I mean, I understand that up-front costs are high and it takes a long time before you start recouping money, but I get the feeling you're saying just go with a regular tanked water heater. For example, if that's the case (and I apologize if that's not what you meant), then when would you guys recommend tankless water heaters?
The financial "payback" of a tankless= never (maybe even 2x never for a single person household.
)
Tankless solutions can make sense when space is at a premium, cases where buying back another 5 square feet of floor area is considered worth the upcharge.
Like I said, I like the "on demand" nature because I'm just one guy, I sort of like the fact that it seems more efficient and therefore less wasteful, and I don't want to be pitching water heaters into landfills.
A heat pump water heater is less wasteful than a tankless. The standby losses get recovered using less than 1/4 the amount of electricity that it would have taken to re-heat the water with a resistance element to maintain temperature (the way a plain old tank does), and on average heating the water actually used takes only about 1/3 amount of electricity of an electric tank, with 2/3 of that heat drawn from the room. In a humid basement the larger fraction of that heat taken from the room is the "heat of vaporization" of the water condensed from the room air. During a PA winter when the indoor & outdoor air is drier it takes that heat from the heating system, lowering the room temperature in the process. But the lower room temperature also reduces the heat lost through the walls to the cold outdoors- it's not a simple model. During the summer it takes some of the load off the air conditioning or dehumidifier (assuming you use a dehumidifier to control basement mold.)
But if local electricity prices are substantially lower than the national the financial payback might be "never" with a heat pump vs. a plain old electric tank too.
I haven't looked into that at all, but I told him that I sort of didn't want a tank in my home. To me, that's the biggest benefit of a tankless unit, in addition to the on-demand function, of course. Is that something I should just ignore?
Explain more why you don't want a tank(?).
The leak risk is a non-starter- tankless units can (& do) leak too. Tank lifespan for glass lined tanks is largely a function of the number of deep thermal cycles (that induce mechanical stresses) and total volume of water that moves through the tank. With a water softener it will go longer than with hard water (which eventually can eventually fill the tank with scale.) An electric tank in a 5 person household taking daily showers might only last the 10 year warranty period, but for a single person household 25+ years is likely.
So yes, you should probably recalibrate the
perceived higher risk of a tank and ignore it. The actual risk is quite small. There is a higher fire risk to gas appliances vs electric, and some people perceive that risk to be higher than it actually is as well. In reality most people have more serious risk factors to deal with than floods from failing tanks or fires from gas leaks, both of which can be mitigated.
For example, I noticed that in every thread on tankless water heaters, Dana immediately pushes people towards a hybrid water heater, just like in this thread. Literally anyone who asks any question about a tankless water heater immediately is recommended to get a hybrid water heater. That's not helpful at all. Sorry.
That isn't political- the arguments for heat pumps vs. tankless are both functional & financial. And the perceived benefits of a tankless (for those who haven't experienced tankless water heaters) are usually bigger than reality.
Any carbon emissions issues are
way in the background (even for those who care deeply about it), especially for a water heater serving a single person household. If one is seriously concerned about the carbon issues there are almost always more effective places to apply that money in an existing house than the water heater. A very few locations in the US have begun banning the use of fossil fueled mechanicals in
new construction, but they won't be digging up the gas mains any time soon (probably not within the lifecycle of a gas water heater anyway.)
For MOST people a heat pump water heater is simply a
better solution than a tankless. It provides much higher flow when needed (filling tubs, etc), and it costs less to operate, install & maintain than a tankless. As it happens it's also more efficient and has a lower carbon footprint than a tankless. I bring it up a frequently because it's not even been on the radar as a solution for many people. The down side to heat pump water heaters is the slow recovery time and lower first-hour gallons than a tankless. But those are only an issue for 4+ person households (who may need more than 50 gallons of buffering capacity), and a complete NON-issue for a single person household (unless you have a huge spa tub to fill, which would also be an argument against tankless solutions.)
FWIW: I neither hate nor love tankless water heaters- but I
do understand them pretty well. I lived for well over a decade with a gas fired tankless water heater (in cold-water MA) and it was fine despite a few quirks. The biggest drawbacks for us were perceptibly slower fill times for tubs, poor (but tolerable) temperature control in a shower when other appliances (notably the clothes washer) was in use making intermittent draws during a shower, poor temperature control (including summertime flame-outs) at
very low-flow at sinks, and the inability to deliver hot water to intermittent short draws from the dish washer. It had some maintenance issues- I replaced the flame detector a couple of times, had to clean up & un-stick a temperature control valve once, but it was retired still working. Despite the quirks it was fine overall, and might have kept it if I needed the space. Newer/better gas tankless designs have mitigated some inherent quirks, but not completely.
During major revisions of the heating system the tankless was replaced by a 48 gallon "indirect" water heater, (supplemented by a ~50% efficiency drainwater heat recovery heat exchanger returning heat going down the drain back into pre-heating the incoming potable stream.) Strangely enough, I'm using a (different model) tankless water heater as the hydronic boiler, heating only heating system water in the tankless directly, heating the potable water through the indirect's heat exchanger. There are some quirks to using a tankless water heater as a heating system boiler too, but it's been pretty reliable for over a decade now, the only maintenance issue being cleaning out the tiny screen filter at the inlet once every year or two. (Had there been inexpensive stainless fire-tube heat exchanger boilers with bigger turn-down ratios on the market then I probably would have used one of those instead.) I'm OK with this tankless application too.