Tank water heaters aren’t anywhere near as ineffecient as we would assume. I know I thought they were pretty bad, but Technology Connections has done the math. I was surprised.
Comment on Heat-pump water heaters are a winner for the climate — and your wallet
Gork@lemm.ee 1 year ago
Yes, but water heater tanks are by themselves inefficient as it stores heated water regardless of it being used.
If I ever get a house (millennial lol) I’d want to have a tankless water heater. That way supply meets demand exactly.
BearOfaTime@lemm.ee 1 year ago
alvvayson@lemmy.world 1 year ago
Sorry, tankless is the worst.
You will always be using peak electricity, which comes from the least efficient gas peakers.
With a tank, you can heat with much greener and cheaper off-peak electricity.
Ghostalmedia@lemmy.world 1 year ago
Tankless water heater owner here.
My tankless heats up around the same time as my old tank. Although the tankless uses energy around the time we shower, cook, and do laundry. The tank generally replenishes just shortly after we do that stuff.
Also, our tankless is smart and begins to heat a recirculator at predefined times of the day / week - or it can learn your usage patterns and only start up then.
It’s also worth noting that tankless water heaters aren’t all electric. There are lots of different solutions - one being gas.
All in all, our utilities bill has gone down. My only gripe is that the devices are much more complex. So if something goes wrong, a lot of plumbers get confused. You needs to be half-plumber half-IT guy to troubleshoot a lot of new tankless machines.
BearOfaTime@lemm.ee 1 year ago
As a half-plumber, mostly-IT guy, I despise how tech is (very poorly) applied and implemented in devices like these. It’s always short-life tech attached to stuff that lasts 10-20 years, with complexity beyond necessity.
Lower tech would suffice just as well (think fewer integrated control boards and more external relays). Getting a replacement board in even a few years can be problematic.
Why does my furnace need a convoluted control board, when the primary control is the t-stat, and everything else could be done with a couple relays and a small, simple, timer circuit? Oh, that’s right, let’s make it harder/more expensive for the homeowner to repair.
Ghostalmedia@lemmy.world 1 year ago
I feel like that stuff could be done with a physical dial for temp and some version of this for recirculating. Image
alvvayson@lemmy.world 1 year ago
I have a tankless gas heater, too. Very common in Europe.
But let’s not pretend they are good for the environment.
They are not.
Ghostalmedia@lemmy.world 1 year ago
Agreed. I’m just saying that there lots of different tankless solutions, and something like peak electrical grid times do not impact all tankless systems in the same way.
IMHO, gas tankless systems are kind of the hybrid car of the water heater world, and electric tankless the pure EVs. They’re both better for the environment, but the gas tankless still produce carbon. You’re only cutting emissions but about 20%-30%.
Electric = zero emissions + doesn’t need to vent + free heating if you have solar + might require both a plumber and an electrician to do the install
Gas = often gets hotter faster and handles load better + can be cheaper if you have cheap natural gas + still produces carbon + needs a stupid vent
NaibofTabr@infosec.pub 1 year ago
Glowstick@lemmy.world 1 year ago
Hah i appreciate the effort but i ain’t watching a 22 minute video just to find out how efficient tank heaters are compared to tankless. It literally just needs to be a list of like 2 or 3 numbers
BearOfaTime@lemm.ee 1 year ago
Tech Connections is worth the watch, even on 2x speed. If you want the nitty gritty about efficiency, I believe it’s in the last 7 minutes or so (how it works is key, so the rest of the video is useful too).
He’s really good, and I despise 99.9% of videos because they waste time. He uses video to show things that would be more difficult to understand with words alone. That said, he chooses his words well, and is very clear and accurate.
chunkystyles@sopuli.xyz 1 year ago
Let me save you more of your precious time: tank water heaters are surprisingly efficient. No need to even think about numbers. Just remember that one fact.
BearOfaTime@lemm.ee 1 year ago
Tech Connections is worth the watch, even on 2x speed. If you want the nitty gritty about efficiency, I believe it’s in the last 7 minutes or so (how it works is key, so the rest of the video is useful too).
He’s really good, and I despise 99.9% of videos because they waste time. He uses video to show things that would be more difficult to understand with words alone. That said, he chooses his words well, and is very clear and accurate.
ExLisper@linux.community 1 year ago
I will add my 2 cents…
I hate tankless wather heaters. Every single one I’ve used was shit. It super hard to get the right temperature of water. Turn the heat up a bit: the gas burner goes to 11 and burning water goes out. Turn it a bit down: the gas stops completely and now cold water comes out. For some reason the also take lots of time to actually heat up so you’re wasting a lot of water. I’m sure you can buy a nice, new one that will work better but in my experience after some time they all turn to shit.
You don’t have those issues with a tank. My heat pump is set up to heat the water during 1 hour in the night and that’s enough for the rest of the day. Super simple, efficient and cheap.
FishFace@lemmy.world 1 year ago
This is a bit trickier with heat pumps because they are not very good at delivering a lot of heat energy quickly, especially if you need a large temperature increase because you enjoy a nice hot shower (I have my boiler set to heat water to 65 degrees for a comfortable temperature at the shower head, though could set it a bit lower.) There are various ways around this but a common one is storing water so you don’t have to heat it quickly or using an old-fashioned electric shower so that the heat pump doesn’t need to be oversized. You don’t get the extra efficiency of a heat pump, but showers aren’t the majority of domestic energy consumption; heating is.
There are other arguments for water tanks, of course - as a millenial you may not be thinking about a house with a large family, but it’s similarly inefficient, even with a gas boiler, to heat water on demand for many bathrooms and radiators all at once and you’re better off having a (large!) water tank. “Inefficient” here not in terms of the amount of gas used, but the amount of boiler.
Ghostalmedia@lemmy.world 1 year ago
Just make sure to do your research. And by that I mean, make sure to hire a plumber that is very familiar with tankless systems.
I have a tankless, and I like it, but I’ve learned that you need a plumber who is super familiar with tankless systems, and specifically, your brand of tankless.
Tankless systems are much more complex than a big dumb tank of water with a temp sensor. If your plumber doesn’t know how to troubleshoot the electronics, recirculating system, valves, etc, it can be frustrating - and you could be stuck without hot water for a while if something goes wrong.
partial_accumen@lemmy.world 1 year ago
Tankless is crazy LESS energy efficient than a tank heat pump water heater. Why? In tankless you’re having to CREATE THE HEAT. With heat pump tank you don’t. You’re citing the inefficiency of storing a tank of hot water, but the insulation on a decent (not garbage) hot water heater is really really good! The heat loss through the insulation is VERY small. You could turn off the water heater entirely and come back days or possibly weeks later and the water is still hot.
FunkyMonk@kbin.social 1 year ago
As older millennial too who has worked on the house allot this is true, pilot been off while working on shit and can still get a few hot showers in for days of sparing use with water in that tank even if the heat source was stone dead.
Ghostalmedia@lemmy.world 1 year ago
I assume that the person above is referring to a natural gas tank system and not a heat pump tank system.
That all being said, this is something that the department of energy has studied. Depending upon household use, a tankless option can be much more energy efficient.
Here is a gas tank system compared to a gas tankless
energy.gov/…/tankless-gas-water-heater-performanc…
SpaceNoodle@lemmy.world 1 year ago
You still have to create the heat for a water tank, too …
KinNectar@kbin.run 1 year ago
A heat pump pulls heat from the ambient air and accumulates it in the tank, unlike a conventional water heater which uses combustion or a resistance heater to generate the heat from an energy source. That is why heat pumps are generally much more efficient than other types of water Heaters, including on-demand Heaters which have a very high instantaneous load.
Heat pumps do have their weaknesses though, specifically they lose efficiency the colder the ambient temperature is, so if you live in the arctic circle this might not be the technology for you.
db2@sopuli.xyz 1 year ago
Can confirm, I hooked up an electric on demand for the time it takes for a single shower, it was stupidly expensive. It used way more power than a tank would to deliver hot water in a weeks time (math is fun). I boxed that pos back up and plan to sell it.
phoneymouse@lemmy.world 1 year ago
Heat pumps lose efficiency far above arctic temperatures. Below 40F, the efficiency drops quickly.
Semi-Hemi-Demigod@kbin.social 1 year ago
A tankless needs to heat water extremely quickly, which needs a lot more energy. More energy than you can get out of electric heat for a whole house, so most of them are gas.
I guess you might be able to put a bunch of small electric tankless heaters at each hot water tap, but that's a lot more electrical work and points of failure.
dual_sport_dork@lemmy.world 1 year ago
That, and each one of those tankless heaters requires its own dedicated 15 or 20 amp circuit so if you install a shitload of them all over the house you’re going to fill up your breaker panel really quickly.
SpaceNoodle@lemmy.world 1 year ago
Conversion of electricity to heat is 100% efficient.
Revan343@lemmy.ca 1 year ago
Not if it’s using a heat pump
Lantech@kbin.social 1 year ago
In my case, the heat pump is in the basement. So in the summer it's great. It dehumidifies and cools the basement. However in the winter, it's cooling the basement too. So the gas furnace kicks on to heat the basement back up. There's a push-pull there.
However, I have solar, and an excess of electricity credits from it.
So what I've done is put it in high-demand mode which uses more electricity and less heat pump, reducing the push-pull issue.
In the summer I'll put it back in pure heat pump mode.