Tankless water heater!!

[growler]

Junk the electric and install gas. They'll probably still save money.

In theory I like the idea. But it can be hard to talk people out of something that they have already installed and spent a bunch of money on.

 

[kwired]

In theory I like the idea. But it can be hard to talk people out of something that they have already installed and spent a bunch of money on.

OP sounds like maybe they already upgraded to the 400 amp service, so kind of at point of no return. If I get asked to wire said water heater and they only have 200 amp service at the time, I will inform them what will be needed to get enough service to run their new heater. They can then decide if they want to proceed. Even if they have installed the WH already, they can have it removed and sell it for whatever they can get and take less overall expense than if they finish then decide it doesn't deliver enough hot water for their needs, takes too much maintenance, puts them on a high demand rate or some other undesired result.

 

[GoldDigger]

Don't forget that a small tank unit can provide an automatic limit to shower length as the water gets cold. The tankless encourages longer showers.
As a kid I lived in Parkmerced in San Francisco. Each block of "townhouses" had a common hot water supply in the central courtyard. They had a well insulated 1000 gallon or more tank fed by a bank of four tankless gas units.

 

[romex jockey]

Did it get replaced with tank style electric or gas?

simply a storge tank, as alluded to in this thread kwired

Was there demand metering? I could see demand metering factoring into commercial rates.

Yes.....

Right now gas is cheaper even in places with some of the lowest electric rates. Wasn't always that way

True....

The reason being a bigger pix>

~RJ~

 

[kwired]

simply a storge tank, as alluded to in this thread kwired

My question was.. was it electric or gas?

Answer yes to demand metering question - makes sense it became expensive to operate. Bet nobody considered that possibility when selecting this unit.

Otherwise energy laws of conservation still apply, it should take same energy to heat same volume of water same temperature, those laws don't factor in what that energy may cost.

 

[romex jockey]

My question was.. was it electric or gas?

sorry if i was not clear kwired....it was simply a non-fuled storage tank...perhaps i am calling it by the wrong name?

Answer yes to demand metering question - makes sense it became expensive to operate. Bet nobody considered that possibility when selecting this unit.

Especially the manufacturer(s) , which i am sometimes at odds with

For ex, all the hot tub folks quote national stats ,when customers ask what they cost to run

well, there's far more hot tubs south of me, than in the skibunny locale i do biz in

Otherwise energy laws of conservation still apply, it should take same energy to heat same volume of water same temperature, those laws don't factor in what that energy may cost.

True .....but this may be relevant to the trades before it is the public

methinks most of us riding that 'green wave', as well as this 'green deal' on the horizon know enough when to say something, and when not to....

Myself, i'm going to throw another armful of nice dry oak & ash in my wood boiler ,and watch the world spin on.....

~RJ~

 

[kwired]

sorry if i was not clear kwired....it was simply a non-fuled storage tank...perhaps i am calling it by the wrong name?

Maybe not wrong name, just misunderstanding of what you were trying to say. This is exactly what I have often said would be a good idea and did mention earlier in this thread. A storage tank ahead of the instant water heater or even one with heating but only to pre heat water to room temp or a little above. Then the instant water heater won't need quite so much energy demand to raise water temp the rest of the way at time of use. If you have ~55F incoming water like I do from my well it takes a lot more demand to heat it to ~120F then it would to heat it from 85-90F to 120F, and 85-90F in a storage tank won't lose a very significant amount of heat compared to same tank heated to 120 or so.

Especially the manufacturer(s) , which i am sometimes at odds with

For ex, all the hot tub folks quote national stats ,when customers ask what they cost to run

well, there's far more hot tubs south of me, than in the skibunny locale i do biz in

Energy label, not sure if these instant water heaters need the same labeling as other types, but if they do, would have a some average for energy cost that will be stated on the label. That only gives you cost of energy if that is your energy rate. It won't include demand charges, or take peak/off peak kinds of rates into consideration either, just assumes the rate stated is consistent year round.

Most consumers only see the one big number on the label - that unit's performance compared to whatever the other units it was compared to using same base rate. Since electric heat is 100% efficient the losses on the others are due to losses during storage, otherwise it cost same to heat same amount of water with time possibly stepping in with additional demand factors - oops label don't cover that.

True .....but this may be relevant to the trades before it is the public

methinks most of us riding that 'green wave', as well as this 'green deal' on the horizon know enough when to say something, and when not to....

Myself, i'm going to throw another armful of nice dry oak & ash in my wood boiler ,and watch the world spin on.....

Green is misunderstood. Lot of groups push green because it is "the right thing". They may have a point, but green doesn't automatically mean cost to own/operate something goes down. Often green is more expensive overall.

One's carbon footprint can be easily reduced without buying newest products out there and just better managing what you are using right now. But we are a spoiled society and want what we want and that in itself leads to a lot of waste in general.

 

[MAC702]

Maybe not wrong name, just misunderstanding of what you were trying to say. This is exactly what I have often said would be a good idea and did mention earlier in this thread. A storage tank ahead of the instant water heater or even one with heating but only to pre heat water to room temp or a little above. Then the instant water heater won't need quite so much energy demand to raise water temp the rest of the way at time of use. If you have ~55F incoming water like I do from my well it takes a lot more demand to heat it to ~120F then it would to heat it from 85-90F to 120F, and 85-90F in a storage tank won't lose a very significant amount of heat compared to same tank heated to 120 or so.....

Okay, now I get it, too.

This is known as a tempering tank.

 

[norcal]

A few years ago we did a tankless install for a 9 unit place , 200A 4-40's. The manufacturer had convinced the landlord via ROI. The poco changed out the 15KV to a 50KV pole pig. The thing ran constantly, the poco billage tipped into and stayed in 'commercial rate'.:slaphead:

The 'heating guys' determined storage tanks as remedy.....

~RJ~

Seems foolish to supply hot water to tenants, like a master meter for electric there no incentive to conserve. There is nothing like having to pay for what you use to change your habits. hmy: When I last visited my aunt & uncle in Germany they had meters for hot and cold water for each unit in their apartment building, but they do things different there, like 400V 3Ø for the range....

 

[Frank DuVal]

A house with gas service installed an electric tankless?

About as smart as a house in the neighborhood I grew up. It had an electric range, gas hot water tank and an oil fired furnace!:?

I know as electricians we think of electric first, but gas is just like running rigid conduit.... And sizing the pipe like we size wire....

And a gas tankless can be run on a generator, while the generator for a 120 amp service to an electric tankless.......

 

[gadfly56]

A house with gas service installed an electric tankless?

About as smart as a house in the neighborhood I grew up. It had an electric range, gas hot water tank and an oil fired furnace!:?

I know as electricians we think of electric first, but gas is just like running rigid conduit.... And sizing the pipe like we size wire....

And a gas tankless can be run on a generator, while the generator for a 120 amp service to an electric tankless.......

I'm completely with you on this. The only downside I can see for gas is that there may be an upsize needed for the regulator and the feed line into the house.

For electric, just the kW-hrs is going to be gruesome, and if the local POCO has smart meters and tiered or demand pricing for residential...hoooo, boy!

 

[MAC702]

...The only downside I can see for gas is that there may be an upsize needed for the regulator and the feed line into the house....

I've installed several of both gas and electric tankless units. The biggest PITA for installing the gas tankless is the larger flue, often a condensing one. A couple times, I convinced them to move the water heater to a new location on an exterior wall and near the gas meter. It's a lot easier to put a new flue through the wall, and to run cold and hot water lines than to upgrade existing gas pipes and flues.

 

[gadfly56]

I've installed several of both gas and electric tankless units. The biggest PITA for installing the gas tankless is the larger flue, often a condensing one. A couple times, I convinced them to move the water heater to a new location on an exterior wall and near the gas meter. It's a lot easier to put a new flue through the wall, and to run cold and hot water lines than to upgrade existing gas pipes and flues.

I did not even think of the flue size. We have a standard 40-gallon tank, and the flue is 4" IIRC. What is the size needed for a tankless install?

 

[MAC702]

I did not even think of the flue size. We have a standard 40-gallon tank, and the flue is 4" IIRC. What is the size needed for a tankless install?

Typical would be a 5" concentric assembly. The inside tube is the exhaust and the outer tube is the makeup air. The inside flue will have condensation and needs a drain.

 

[Adamjamma]

In my example, with two teenagers in the house, the tank hot-water duration limitation was their main concern.

In my own case here in UK... when we switched from tanked to tankless, with four daughters... peace came because they could all take their long showers, and the monthly bill went down... so though the cost was high, just the lack of bickering made it worthwhile...

 

[kwired]

In my own case here in UK... when we switched from tanked to tankless, with four daughters... peace came because they could all take their long showers, and the monthly bill went down... so though the cost was high, just the lack of bickering made it worthwhile...

If duration of showers goes up enough because the hot water is virtually endless, the monthly bill will go up.

 

[romex jockey]

Seems foolish to supply hot water to tenants, like a master meter for electric there no incentive to conserve. There is nothing like having to pay for what you use to change your habits. hmy: ..

Most of the apartment dwellings on my turf started out as older large farmhouses w/ barns that ended being parsed out into as many 'cubby hole' rentals as possible. Unfortunately ,as this happened over decades of time, the 'lectrical infastructure didn't always follow suit, so we are left with many 'partially exclusive' dwellings that have an outlet or two on the next guy's dime.

For ex, we're always getting calls for a tripped breaker, where everything in the apt is plugged into ONE receptacle.....:happysad:

In my own case here in UK... when we switched from tanked to tankless, with four daughters... peace came because they could all take their long showers, and the monthly bill went down... so though the cost was high, just the lack of bickering made it worthwhile...

I had an uncle that raised 4 girls, don't think the man ever saw the inside of his bathroom....~RJ~