Unlimited hot water

[PineRidge]

I wanted to share one of my latest projects with you all. Our water heater was going on 13+ years and was affording us less and less hot water. We have no chimney or B-vent for the furnace or water heater to vent to so the furnace and the original water heater both vented out the side of the home via PVC pipe. The original tank was a AO Smith Power Shot and was at best 80% efficient. Conventional gas or propane water heaters maintain a specific amount of water 40, 50, or more gallons of water at a specific water temperature 24 hours a day so there is wasted fuel.

After some consideration we decided to go with a American on demand tankless heater and since there are 3 adults in the home we opted for a 199,000 BTU at 95% efficient unit. A on demand heater has no storage tank like its conventional counterpart. It only heats water when there is an actual demand and does so immediatly so there is little waste.

Sice the original water heater was still functioning we decided to do the install over a period of a few days working on it for an hour or two when we had the time. Once the final connections were made and the tankless heater thoroughly tested we then took the original AO Smith tank off line.

With the on demand heater whenever a hot water faucet is turned on the heater senses the flow through the heater and immediately fires the burners. We have well water and as such the digital readout indicates the inlet water temperature at 59 degrees F. The outlet temperature is currently set to 140 degrees F but is easily changed via the keypad on the front of the heater. I have no prior experience with tankless heaters but I can tell you that it's a real pleasure having an unlimited supply of hot water and it's nice not to be wasting fuel heating water when you don't need it, or away from the house.


On demand tankless water heaters are by no means new technology, they have been used in Europe for some 20+ years. I was surprised that when in Home Depot picking up some copper fittings the gal checking me out asked what my project was and when I mentioned tankless heater went on to say that she had lived in overseas for years and enjoyed having all the hot water she ever wanted. She went on to say that she couldn't understand why they weren't in widespread use here in the US to which I replied big price difference!

 

[Bob77064]

That's a very neat installation. We have a tankless water heater and have been very happy with it and the gas bills.

 

[scott_vt]

Good Mornin Mike,
Very nice job on the installation, we can see youve done this before !

For years I have been thinking of doing the same and getting rid of that power user electric that I have ! We have propane on site so it would be an easy enough convert.

Any idea on propane usage ? Thanks for sharing your project !

 

[dave1949]

Looks, good. From the photos, I can't tell if the plywood is in direct contact with the block wall, but if it is, and depending on the humidity level in your basement, you'll want to watch for moisture and mold gathering on the backside of the plywood.

The only complaints I've heard from people with on-demand heaters is, because it takes a certain flow rate to turn them on, it's hard to get a dribble of hot water. The other is that a few have had condensation freeze-ups where the exhaust exits the pipe outdoors in really cold weather.

Do you think you can determine the change in your gas usage (eventually) compared to the old unit?

 

[PineRidge]

Good Mornin Mike,
Very nice job on the installation, we can see youve done this before !

For years I have been thinking of doing the same and getting rid of that power user electric that I have ! We have propane on site so it would be an easy enough convert.

Any idea on propane usage ? Thanks for sharing your project !

Thanks Bob and Scott.

There are some factors that would determine your usage Scott. The size of tankless heater you purchase American offer 3 that are dependent on how much hot water at any given moment you need. IE: 1 or two people taking showers at the same time with another appliance such as a clothes washer using hot water. And of course the cost for propane in your area. your results may vary....

 

[1fastbob]

Couple of comments....I would be a good idea to insulate your hot water lines to make it even more efficient. Also a water softener is recommended as well water will eventually coat the heat ex-changer with scale requiring de-scaling or replacement. I will soon be installing a similar system in my home. I am NOT looking forward to a water softener and the feeling it gives the water when applying soap in the shower (slimy).

 

[V1Rotate]

I also have a tankless hot water system, however, mine also makes the heat for the baseboard radiators. I absolutely love the system, it is very cheap to run.
On my unit (and I suspect others) there is a gas valve that acts like a throttle, if there is only a small demand for heat or hot water the gas valve only opens part way so as to only provide enough flame to heat the small amout of water flowing through it. As the demand for heat or hot water inreases, the gas valve opens more, that way almost no heat is wasted.

 

[jinman]

On demand tankless water heaters are by no means new technology, they have been used in Europe for some 20+ years. I was surprised that when in Home Depot picking up some copper fittings the gal checking me out asked what my project was and when I mentioned tankless heater went on to say that she had lived in overseas for years and enjoyed having all the hot water she ever wanted. She went on to say that she couldn't understand why they weren't in widespread use here in the US to which I replied big price difference!

Mike, I always know that your projects are gonna be top-notch. That is a very nice install.:thumbsup:

I'd say the on-demand hot water systems used in Europe are common because of the cost of energy. We forget how spoiled we are to have cheap electricity and cheap fossil fuels in this country. If you double or triple the cost of energy here, the price of efficient low-consumption products will start to look much cheaper.

 

[dmccarty]

On demand water heaters do not work real well if one only has electric, which is one reason they are not used.

Then there is the cost of the units themselves. For us, the payoff on the tankless vs tank water heater was around 13-15 years at a minimum.

I thought for sure we would put in a on demand water heater when we built the house, but we only have electric, and because of the extra cost of tank less, we just went with an 80 gallon water heater. A big advantage for the tank water heater is that it provides a water supply in power outages. We have tapped that tank a couple of times. 80 gallons of water will last us quite a long time.

Later,
Dan

 

[s219]

I think the latest craze are hybrid systems, which have both an inline heater and a small reserve tank. I forget the reasoning behind it, but its supposed to give even better usability.