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diyreader 04-25-2011 01:00 PM

Is a tankless water heater more efficient?
 
I plan to buy a water heater and am looking at getting a tankless one. I found several ones from noritz tankless water heater. are these tankless water heaters really more efficient than conventional ones?

Anyone are using it?

thanks

md2lgyk 04-25-2011 01:09 PM

In short, yes. I put a tankless in our house a couple of years ago and love it. But you have to be careful to get an appropriately-sized unit. And I'd stay clear of electric tankless heaters. They draw a LOT of current and could require a service upgrade.

diyreader 04-25-2011 01:24 PM

Quote:

Originally Posted by md2lgyk (Post 636121)
In short, yes. I put a tankless in our house a couple of years ago and love it. But you have to be careful to get an appropriately-sized unit. And I'd stay clear of electric tankless heaters. They draw a LOT of current and could require a service upgrade.

service upgrade? you mean for the electrical system? or, upgrade the water heater itself/


thanks

md2lgyk 04-25-2011 06:21 PM

I mean an electrical upgrade. I think most whole-house electric tankless heaters are 220 VAC. Never seen a bathroom with that.

broox 04-25-2011 06:37 PM

You use the word "efficient". My step-dad loves to tell people that good old electric water heaters are 100% efficient, and he is correct. All of the heat goes into the water, none of it goes up through the flue or vent. Just a thought.

TombstoneDW 04-25-2011 07:47 PM

I think it really depends on your usage. In terms of efficiency, if you're asking about cost of heating up water used then they are generally pretty good.

We've got a Bosch in our cottage that really serves our needs well. The pros are that you will never run out of hot water (unless you run out of NG or propane). We've had 12 people in a row take showers without an issue. It also works well because our need for hot water fluctuates. Having said this, the downside is that it takes a bit of time for the water heater to kick in - about 5-10 seconds, and then a while for the water to heat up. Where this comes into play are tasks like doing dishes - you have to let the water run for a bit before putting in the plug, otherwise the sink fills up with cold/cool water (we run off of a well, so the water comes out VERY cold).

Others may disagree with the above. There are some really good traditional tank water heaters out right now. I like how there appear to be more options in size nowadays, which means for a house with only 1-2 people, you could go with a smaller tank, meaning that you're not paying to heat a large quantity when your major usage times are mornings (showers) and late evenings (laundry), but you still get the benefit of readily available hot water.

Another thing to think about is cost and maintenance. I'm not aware of any utility companies that rent the tankless heaters, which means a fairly substantial upfront cost (good ones range in price from $1500 and up, if memory serves) and you have to pay for any repairs or maintenance. On the other hand, you can often rent a traditional water heater from the company with a maintenance contract that spreads the cost over a longer period. This can be costlier in the long run, as you pay the rate forever, and it doesn't really take long to cover the $600 cost of the water heater, but in return you get a peace of mind knowing that if something goes wrong somebody will come in to fix it and you avoid the possibility of a huge bill.

Just my 2 cents.

what-do-i-do 04-25-2011 09:15 PM

I purchased a rheem condensing tankless to replace my very old heater in the backyard. Tanklesss unit is going on the side of the house, out of the way. I have not installed it yet, (still) waiting on my friend a licensed plumber to install it.

I did have to call gas company to upgrade the gas meter because not enough capacity.

diyreader 04-26-2011 12:54 PM

Quote:

Originally Posted by what-do-i-do (Post 636496)
I did have to call gas company to upgrade the gas meter because not enough capacity.

it sounds like more work, :(

upgrade gas and eletrical, what else? I did not think of these.

thanks for the information.

Wildie 04-26-2011 01:27 PM

I considered a tankless water heater when i bought my house 4 years ago.

Electrical tankless would have required a service upgrade to 200 amps from 100 amps. This would have cost about $3000. Then, the cost of the tankless, itself.

My home has a natural gas service and I could have bought the NG tankless and the over-all investment would have been much cheaper.

Using a hot water tank in the winter is about 95% efficient for gas and 100% for electricity. This is because any heat loss helps to heat the house.
The negative aspect of these occurs in the summer because the heat loss cannot be used to advantage. In fact, can attribute to an increase in air conditioning costs. For this reason the heater should be installed in a utility room that isn't air conditioned.

I decided to stick with the rental, NG heater that only costs me $20/month and I have no maintenance costs, nor capital outlay.

vsheetz 04-26-2011 03:26 PM

I have a Bosch gas fired tankless. Installed it several years ago. We like it very much - endless hit water and considerably less cost to operate.

You have to consider usage scenario. It is just my wife and I so we are low usage making keeping a tank of water hot 24/7 an inefficient thing comparatively. Our water heater is located in the garage so it adds little to the heat load negative or positive.

I do not see where a whole house electric tankless would be cost effective. Gas, yes.

what-do-i-do 04-26-2011 06:34 PM

Quote:

Originally Posted by diyreader

it sounds like more work, :(

upgrade gas and eletrical, what else? I did not think of these.

thanks for the information.

I did not pay for the gas meter upgrade. I called the gas co. and asked them if my meter was ok for the additional demand of 199000btu's. A field rep came to my house calculated total demand and requested a new meter for my house.

I also need; a dedicated electrical circuit and gas line to new location about 13 feet from gas meter.


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