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Most US homes use the hot water tank, which keeps 40 - 60 or so gallons of water hot 24x7.
Most UK homes use on-demand tankless heaters.
Just wondering why they are not popular in the US.
 

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Most US homes use the hot water tank, which keeps 40 - 60 or so gallons of water hot 24x7.
Most UK homes use on-demand tankless heaters.
Just wondering why they are not popular in the US.
We have more room.

In Germany I got cold water sandwiches with these things.

Tanks are simpler & only lose 75w/255 BTUh continuously.
Depending on what you pay per kWh or for NG, the breakeven point for the annuity you are paying to the PoCo vs. the lump sum & install for a tankless
may be years away.
 

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Tanks are simpler & only lose 75w/255 BTUh continuously.
Which comes out to 1.79KWHs per day, and 53.79 KWHs per month. So around 90 to 100 bucks a year in stand by loss.

A 40 gallon tank water heater may hold 40 gallons of hot water. But it only provides around 30 gallons of stored hot water. As around 10 gallons of that water is cooled by the cold water coming in through the dip tube. That loss can easily add up to another 100 dollars a year, in reheating water you already paid to heat.
 

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Tanks are cheap to buy, cheap to run and last for years with little to no maintenance.
 
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Tanks are cheap to buy, cheap to run and last for years with little to no maintenance.
Most last for many years, some barely make it out of warranty.
 

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Which comes out to 1.79KWHs per day, and 53.79 KWHs per month. So around 90 to 100 bucks a year in stand by loss.

A 40 gallon tank water heater may hold 40 gallons of hot water. But it only provides around 30 gallons of stored hot water. As around 10 gallons of that water is cooled by the cold water coming in through the dip tube. That loss can easily add up to another 100 dollars a year, in reheating water you already paid to heat.
And after I wrapped insul around it I got it down to 50w.
5 minutes on vs. 5 hrs off, instead of 5 minutes on for 7 hrs. off.

At the time I measured it 40 yrs ago, I didn't multiply it out to a per year price. Back then I didn't plan ahead.:(

I guess it's worth it to me to avoid a once/day cold water shower sandwich.

And, I'd think the reliability of a complex on-demand system is less than a simple tank but now that you mentioned it, I guess I'll have to go looking for MTBF numbers for both. :(
 

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I can only speak from personal experience. Our 40 gallon tank water heater was EOL (14 years) so I needed to spend possibly $600 to replace it. It was electric and heated water while we slept, went to work, went to church, etc. I had our propane guys install a 320 gallon tank and connect it to our 22k generator, gas logs, "canning" stove in the basement and to a new Rinnai tankless water heater. The Rinnai cost (at that time) about $1300 complete, so it was an additional $700 in actuality. My electric bill reduced noticeably, and we only have a gas fill up once a year, unless we run the gas logs too much. The water heater heats only when you make a demand, and doesn't have a pilot light to run all the time. Maintenance is miniscule. Just back wash it with vinegar once a year and it heats water till the cows come home.
Yeah, there is a cold water plug when it has been sitting a while, but it can be overcome with a recirculation system made for tankless heaters. All in all, I recommend them. Oh, the exhaust is PVC, so it is very energy efficient.
 

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The tankless hot water system needs a beefier energy supply system. In the U.S. a typical tankless electric water heater needs two 30 amp branch circuits. In some cases the meter and panel (and service from the power company) had to be upgraded. How much would it cost you to have your gas line dug up to install a fatter pipe for a tankless gas heater?
 

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The tankless hot water system needs a beefier energy supply system. In the U.S. a typical tankless electric water heater needs two 30 amp branch circuits. In some cases the meter and panel (and service from the power company) had to be upgraded. How much would it cost you to have your gas line dug up to install a fatter pipe for a tankless gas heater?
The gas line from the gas company wouldn't need to be dug up. They might have to install a larger(higher CFH) gas meter, but not the gas line.
 

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And after I wrapped insul around it I got it down to 50w.
5 minutes on vs. 5 hrs off, instead of 5 minutes on for 7 hrs. off.

At the time I measured it 40 yrs ago, I didn't multiply it out to a per year price. Back then I didn't plan ahead.:(

I guess it's worth it to me to avoid a once/day cold water shower sandwich.

And, I'd think the reliability of a complex on-demand system is less than a simple tank but now that you mentioned it, I guess I'll have to go looking for MTBF numbers for both. :(
Sow how did you over come the cooling effect the cold water has on the stored hot water in the tank. That makes youhave to pay to reheat water that you already paid to heat. Which is about 121 watts everytime you use hot water for laundry, showers, or baths.

1 shower a week, adds up to 6.292KWHs a year, to reheat that water. Multiply that by how ever many people there are in your household. Same with the number of loads of laundry you do using the warm setting o your wash machine.
 

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The devil is in the details & I think I can avoid that particular devil in this case.

A hot bath is more comfortable to me than a cold one. More generally, we have NG & elec. to make us comfortable.

Therefore, whatever we pay per year for NG & elec. must be what our comfort is worth to us.

BTW, I’m also more “comfortable” if I can repair our elec. & gas appliances by myself. :)
 

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The devil is in the details & I think I can avoid that particular devil in this case.

A hot bath is more comfortable to me than a cold one. More generally, we have NG & elec. to make us comfortable.

Therefore, whatever we pay per year for NG & elec. must be what our comfort is worth to us.

BTW, I’m also more “comfortable” if I can repair our elec. & gas appliances by myself. :)
People can pay as much as they want for personal comfort. Nothing wrong with that. But, they should direct others a way from other types of systems, that they have very little experience or knowledge about.

As a DIY site, we want people to feel free to ask how to work on and repair even on demand water heaters/tankless water heaters and boilers.
 

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People can pay as much as they want for personal comfort. Nothing wrong with that. But, they should direct others a way from other types of systems, that they have very little experience or knowledge about.

As a DIY site, we want people to feel free to ask how to work on and repair even on demand water heaters/tankless water heaters and boilers.
They seem to feel free to ask about anything, short of brain surgery. :D

Would an average DIY'er tackle repairing a tankless heater?
Maybe.

Should they?
I wouldn't, even with schematics, the source code for the computer, a whole bench full of test equipment, etc.

If I had the factory service manual in front of me, maybe, but these manuals sometimes call for test fixtures that are hard to get.

Industries do not want DIY'ers to succeed, it is money out of their pockets. :(

And some OEMs put booby traps into their devices to punish the plucky DIY'er. Who's to stop them?
 

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Most US homes use the hot water tank, which keeps 40 - 60 or so gallons of water hot 24x7.
Most UK homes use on-demand tankless heaters.
Just wondering why they are not popular in the US.
They are popular when they are needed. I install them an a semi regular basis. They have more parts to break, which are expensive, making them generally disposable. The better "tankless" models still have a small tank inside. Condensing, non-modulating tanks are only slightly less efficient, and have standard parts that are readily available.
 

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They seem to feel free to ask about anything, short of brain surgery. :D

Would an average DIY'er tackle repairing a tankless heater?
Maybe.

Should they?
I wouldn't, even with schematics, the source code for the computer, a whole bench full of test equipment, etc.

If I had the factory service manual in front of me, maybe, but these manuals sometimes call for test fixtures that are hard to get.

Industries do not want DIY'ers to succeed, it is money out of their pockets. :(

And some OEMs put booby traps into their devices to punish the plucky DIY'er. Who's to stop them?
Electric on demand heaters are stupid simple, and very easy to DIY repair if you have the tools to deal with the larger wire sizes.

Some natural gas tankless and most tanks are also very simple for the DIY'r. The more popular tankless, like Navien, are fairly complicated, even for a tech, but they post FULL and very complete manuals on their website. (they also come with them.)

I've never seen a "DIY trap" on any unit, hvac or boiler. Poor design, maybe, but never anything intentional. OEM don't make money on the labour of service calls unless they have their own repair company. (they are usually out competed by all of the third party vendors.)

I had our propane guys install a 320 gallon tank...
...
The water heater heats only when you make a demand, and doesn't have a pilot light to run all the time. Maintenance is miniscule. Just back wash it with vinegar once a year and it heats water till the cows come home.
Yeah, there is a cold water plug when it has been sitting a while, but it can be overcome with a recirculation system made for tankless heaters. All in all, I recommend them. Oh, the exhaust is PVC, so it is very energy efficient.
Just to be clear for others, that 320gal is for propane, and not the hot water heater, . Most people already have a tank, or natural gas.

You also need to clean the fire side once in a while. At the very least you'll change the flame rod and electrode when it stops working and errors out. Many of the tankless models make it hard to clean the fireside though, due to their compact size.

I prefer models with buffer tanks. It prevents the cold water sandwich.

Not all tankless are condensing. Some are not, and use metal vent, or are ventless.

The tankless hot water system needs a beefier energy supply system. In the U.S. a typical tankless electric water heater needs two 30 amp branch circuits. In some cases the meter and panel (and service from the power company) had to be upgraded. How much would it cost you to have your gas line dug up to install a fatter pipe for a tankless gas heater?
None. Most gas meters have no issues with the capacity of a single instant hot water heater. Some like Navien also can be retrofitted in place of a mid efficient tank, using the same venting and gas pipe. (engineered that way.) At the worst, for most people it's a new vent and a portion of the gas line in the house may need to be upgraded.

If you need multiple heaters, then the utility upgrades the meter for free, to a certain size. I've only had to upgrade the service once past that. That was to install a generator, on a house that already had 5 boilers, fireplaces, ranges, and a NG firepit. The generator needed more pressure then the regulator could provide. (the meter was a tad small too.)
 

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Which comes out to 1.79KWHs per day, and 53.79 KWHs per month. So around 90 to 100 bucks a year in stand by loss.

A 40 gallon tank water heater may hold 40 gallons of hot water. But it only provides around 30 gallons of stored hot water. As around 10 gallons of that water is cooled by the cold water coming in through the dip tube. That loss can easily add up to another 100 dollars a year, in reheating water you already paid to heat.
My whole Electric bill for hot water is only $120 a year with a HPWH. Not possible to have anywhere near $100 in standby loss. Plus it dehumidifies my bsmt for no extra cost. The 10 gallons of hot that is cooled by incoming water is also warming up the incoming water by the same amount so your have zero actual loss there,certainly not $100 of loss. IMO a superior hot water solution to either a regular electric or a tankless.
 

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My whole Electric bill for hot water is only $120 a year with a HPWH. Not possible to have anywhere near $100 in standby loss. Plus it dehumidifies my bsmt for no extra cost. The 10 gallons of hot that is cooled by incoming water is also warming up the incoming water by the same amount so your have zero actual loss there,certainly not $100 of loss. IMO a superior hot water solution to either a regular electric or a tankless.
High end tanks like that have much thicker insulation. HPWH are far more complicated mechanically. Lots to break on them. They also don't have the greatest COP. Better then resistive heat as long as they are in a conditioned space, but no where near the same $ cost compared to NG or even propane and oil. (unless you have ridiculous delivery fees)
 
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