# Adding Tankless Water Heater with Hot Water Tank



## WhatRnsdownhill

A properly sized tankless in ng or lp will not take but half a minute to come up to temp, the delay on getting hot water many times is the long pipe run to the faucet from the unit, but that is not the units fault, hot water heater or tankless....


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## cterrier

Thanks for the reply

Would it make a difference if it was an Electric Tankless Water Heater? Natural Gas or LP not avail.


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## WhatRnsdownhill

electric doesnt seem to have the same recovery that the gas units do, you would be better off with an electric water heater, if your renovating the house, you can put in a hot water return from the furthest hot water line in the house and make a circulating loop for the hot water, so you dont have to wait for the cold water to be pushed out by the hot water before you get hot water at the faucets or tub..


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## YerDugliness

cterrier said:


> Thanks for the reply
> 
> Would it make a difference if it was an Electric Tankless Water Heater? Natural Gas or LP not avail.


I use a electric HWOD for whole house use.

With HWOD you need to read the specifications on each model. The number of degrees it can increase the temperature of water varies depending on how many "tanks" (a small copper enclosure where the heater elements are located) and how many amps. You also need to know the temperature of your water as it enters the house or (preferably) as it enters the HWOD unit. If your water is only 55* at the point the HWOD gets it and that unit can only offer a 40* temperature rise, you'll not be happy in the shower. 

Also...a bit of advice learned the hard way...you need to install some sort of calcium/lime filter on the supply line to the HWOD unit. Mine is a Body Glove product (not affilliated with the line of sports clothing, I'm sure) and it has pellets inside that are designed to bond with the calcium in the water as it passes through the filter. That is important because scale/calcium can accumilate on the heating elements inside the tanks and they not only reduce the amount of available heat, they also increase the chances that you'll burn out the heating elements (I burned out two HWOD units before I managed to get it right, and that in a vacation home that was occupied only about 120 days/year). Since installing the calcium "filter" two years ago I have not burned out another unit.

My HWOD is centrally located in the house...but my washing machine is "downstream" of the kitchen sink. I usually take advantage of that to fill some sort of container with water (most often a kitchen tub in which I rinse my dishes), and as soon as the hot water gets to the kitchen sink I head for the laundry room and pull on the knob that starts the washing machine filling. It does take about 10, maybe 15 seconds for the hot water to get to either the bathroom or kitchen...and that is how long it takes to get fully hot, not just start warming up.

HWOD can be a great option for a vacation home and once I turned my vacation home into my full-time home I realized that with a little planning it's possible to raise a family with a HWOD. 

Cheers!

Dugly :icon_cool:


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## rjniles

Your wife might not agree the laundry room should be in the basement. Carrying laundry up and down stairs us a PIA.

Sent from my XT1095 using Tapatalk


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## user_12345a

i have zero experience with tankless but everything i've read and heard makes them seem like a bad deal.

A tankless unit could cost $3000 dollars installed.

They're loaded with proprietary electronics and other parts. The repair cost after warranty would be astronomical.

They also have maintenance requirements like flushing etc and if the power goes out, you have no hot water.

A regular gas tank would cost half as much or less to install (with a power venter costing $1500 or so installed), is reliable and can be fixed with industry standard parts the technicians keep on their trucks. No waiting a week for a part to come in.

There are 15 to 20 year old tank units which have never broke down.

A regular tank may only be 60% efficient vs the 90%+ of a tankless unit, but the energy used to heat water pales in comparison to what's needed for heating and cooling. It may be something like 10 to 20% of your total gas bill.

One failure, like a variable speed ventor motor costing $1000 in repairs will offset any savings.

The extra 1.5 to $3k for the tank could be put towards led light bulbs, more attic insulation, basement insulation, air sealing, etc. 

For the same money, the low tech solutions have the greatest roi.

Once you get into tankless water heaters, solar thermal, solar electric, geothermal heatpump, super high efficiency a/c, the initial cost is very high so it may take 10 years to get your money back and after that, you'll get a 5 to 10% return on investment. This is all assuming that the fancy product doesn't need expensive repairs and you keep the house for 20 years.

A $5 to 10 led light bulb may take 1 to 2 years to pay off and then you get a 50 to 100% return on investment for 10+ years. Same for air sealing.


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## user_12345a

> Appreciate any opinions. Don't think I want to increase the size of hot water tank as that IMHO is dying technology and won't be long before Fed. Gov't makes regulations against using them.


if your federal government had any sense they wouldn't ban them.

They would raise efficiency standards and let the manufacturers figure it out.

Your regular tank is 58 to 65% efficient. Regular tanks can be tweaked with ventor motors and spark ignition, more insulation to bring it up to 70%+.

In fact rheem already has a 70% efficient tank model.

There are also condensing tank water heaters which achieve 90%. Would cost you probably as much as a tankless but at least the repair costs would be reasonable.

...and you have a reserve of hot water. Being able to have a hot shower when you've lost power for a day and have no heat is nice.

I actually favour direct vent and natural draft style inefficient tanks over power vent or high efficiency power vent because they work without any electricity. (pilot ignition Gas fireplaces do too)

Hopefully your government won't ban those to make a political statement. 



Think about having alternative sources of energy for when the power goes out (and it will because the infrastructure is aging and being neglected by utilities), not just "going green".


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## Flannel Guy DIY

my one piece of advice is to install the tankless heater as close to the appliance as possible.


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## YerDugliness

Flannel Guy DIY said:


> my one piece of advice is to install the tankless heater as close to the appliance as possible.


Good advice...although additional insulation on the pipes will help a lot if it hasn't already been done.

Here is what I think, after using a whole-house HWOD for about 8 years now:

1.) If you are using electricity to heat with a HWOD, you WILL burn out heating elements if you have hard water...unless you follow this advice. The fix for that is a large calcium "filter" offered for sale by the company that makes my HWOD (I think the manufacturer of the calcium filter is "Body Glove"). Before I got my Body Glove I was burning out a HWOD every two years and I was only spending about 90 days a year in the house. After installing the Body Glove I have not burned out a heater in over 3 years and that includes 2 years of full-time residence (I live by myself, but use a LOT of water!!). The B-G "filter" has a paper element, which I think is just for particulate filtration, and also has a perforated "tube" that runs the length of the element that has what looks like chunks of quartz inside it. Apparently whatever the material is that looks like quartz bonds chemically with the calcium. I no longer get that calcium "haze" on my glassware that we are all familiar with.

2.) Rather than a single whole-house unit (mine is said by the manufacturer to be sized for a small "lodge"), I think that multiple smaller units placed near the point of use would be preferable. I have two "zones" in my home that would benefit...the kitchen, which is right across a wall from the laundry room, and the bathroom area. My whole-house unit can keep up with two concurrently active areas of water usage, but at what cost? It uses two 60-amp circuits...that has to make that meter spin!! I've visited a friend with a *single* "small zone" HWOD and I can attest that when one is in the shower and the water is turned on in a different zone, you'll learn all about a "cold water sandwich"!...not to mention that the smaller single zone heaters were not "temperature output limited" as is my whole-house unit, so there was a risk of scalding, too.

Bottom line...if you have more than one area where hot water will be needed, you need either one VERY large and power hungry HWOD, or you need more than one of the smaller units at the various areas of use throughout the house. The next time I pursue one of these retrofits, I'll go for the multiple smaller single point of use HWOD units.

One note of interest...the current demand on this whole-house HWOD unit is so high I had to upgrade from 100amp service to 200amp service, and that was VERY expensive because the home in which I live is almost 100 years old and I was told by the POCO that my home would not bear the stress from the weight of the large lines necessary to carry 200 amps overhead, so we had to go with underground for the electrical service. All in all the changeover probably ran $2K after all the labor from the dishonest electrician was taken into account (he spent almost all of his time on the phone but I got charged for that time to the tune of $90/hour for him [$60/hr] and his helper [$30/hr] :surprise: ).

I know I'll never recoup all that $$$...but at least I don't have to continue pouring more money into keeping a tank system warm when I am not present, which can be for rather large amounts of time. I accept that there will never be a "payback" day for my system...but I like what I have and have already kissed all those $$$$ goodbye and am looking forward to a future with lower bills.

Cheers!

Dugly


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## dgghostkilla

I'm going to add a tankless heater better return in the long run


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