Tankless hot water

[eastont]

I've been looking into this method of hot water. There is just the 2 of use living here and I don't see the economy of keeping 40 gallons of hot water at the ready. In checking about it seems that the best way is natural gas, but we don't have it. The electric will only raise the temperature about 45?F @ 1gpm, and the water coming in during the winter is approximately 40?F, so our "hot" water would be at best 85?F.

I'm thinking of keeping the existing hot water tank and use it as a holding tank with the water at about 70?F and then it would heat it to 135?F, which is plenty.

Another option is to go propane, it can go 55?F rise @ 3.5gpm, but the unit is 3 times as much as the electric.
I've been trying to cost compare, but it's so difficult because of the various parameters and gpm needs......how much is 1 gpm in a shower?

Anyone with extensive knowledge here? I'd appreciate any info.

Thanks

 

[PiratePast40]

Re: Tankless hot water

I can't say that I have extensive knowledge but I did look into just what you're talking about a few months ago. I was able to speak with several different suppliers at a home show and was a little shocked at their responses. For the most part, they were saying that it's simply not cost effective as a retrofit but with the energy credits, may be viable in a new construction or a rebuild scenario. The cost of purchase and installation of the tankless units was greater than the savings unless you needed to tear into the walls and replace your existing heater anyway. In order to claim the latest energy rebates/credits, you needed to have the equipment installed before the end of 2010.

There are other ways to increase the efficiency of your tank type water heater. Tank placement, insulating the pipes, and switching to gas are options.

 

[MTboatguy]

Re: Tankless hot water

I looked at many different models back in September due to the fact we needed a new heater and we were remodeling the Bathroom where the water heater resided, after talking to many, including a friend of mine that has one in the exact same environment I live, I decided to go with a standard water heater, the savings was nil on the tankless, in fact I would have had to put two inline to even hope to get any hot water out of them.

Our water runs out of the tap at approximately 35-37 degrees year around from our well, we have inline a 44 gallon pressure tank and our flow is 1.5gpm so it would raise it, but not enough for real hot water without two in the system. I put in a new 50 gallon lowboy tanked water heater and it only ran $319.00 of course I installed it myself..so the labor was cheap.

I think the tankless systems might work well in a moderate climate where your water is not quite so cold, and I think they will continue to improve in the future, but right now for me the technology is not advanced enough.

Gas and propane is not an option where I live, no gas lines and to put propane in would cost me a fortune, due to the fact they will not fill them during the winter, so would have to have a very large tank to make it through the 7 months they won't deliver.

I will add, we use modern water saver/restrictor devices in the showers, which bumps the pressure at the head, but it does take a while to fill my new 50 gallon Jacuzzi bath tub up!

 

[bigdee]

Re: Tankless hot water

I agree that tankless is not the way to go..payback time would be very long not to mention that the added complexity would increase maintenance costs. Insulation is a good way to increase effeciency as well as turning down the thermostats. Maybe you could reduce tank size but I wouldn't recommend it. I can turn off my conventional 50 gallon electric WH at my lake house and when I come back a week later I still have luke warm water becuse it is located inside the house and is insulated really well.

 

[df909]

Re: Tankless hot water

We have a tankless and are very happy with it. We've run the dishwasher and taken 3 showers within a few minutes of each other and we never ran out of hot water.

However, you should not use it if you have galvanized pipes as the water heater will clog up with gunk. We already had copper pipes so it worked for us. Ours is a natural gas- which brings me to another point. We had to install a dedicated 3/4" gas line just for the water heater because ours is a pretty good sized one. Last, they require electricity too. Luckily we replaced our electric panel at the same time and it's right next to the heater.

I think the biggest advantage is always having hot water. I like the idea of energy savings not for the money, but just to save from burning gas when we don't need to.

 

[KRS]

Re: Tankless hot water

Hard water will kill them !

 

[MTboatguy]

Re: Tankless hot water

We have a tankless and are very happy with it. We've run the dishwasher and taken 3 showers within a few minutes of each other and we never ran out of hot water.

However, you should not use it if you have galvanized pipes as the water heater will clog up with gunk. We already had copper pipes so it worked for us. Ours is a natural gas- which brings me to another point. We had to install a dedicated 3/4" gas line just for the water heater because ours is a pretty good sized one. Last, they require electricity too. Luckily we replaced our electric panel at the same time and it's right next to the heater.

I think the biggest advantage is always having hot water. I like the idea of energy savings not for the money, but just to save from burning gas when we don't need to.

You are in the perfect climate for one, your water comes out of the pipe at a reasonable temp, you have gas available and you have copper plumping, not much to go wrong there..glad it is working for you.

 

[texasabil]

Re: Tankless hot water

I had one and will never have another had it installed and 3 weeks later called another guy. he said they install them before your hot water heater to help ur heater not to run as long well wasted 600.00 good luck!!!

 

[sasto]

Re: Tankless hot water

You are in the perfect climate for one, your water comes out of the pipe at a reasonable temp, you have gas available and you have copper plumping, not much to go wrong there..glad it is working for you.

Well said MT....depends on the climate.

I think we will take the advice as well.

 

[bruceb58]

Re: Tankless hot water

I have one and it works well. I am on propane and with the cost of propane here, I felt the cost savings would pay back after 3 or 4 years. You do need to have a very large gas line and the venting can be very expensive if it has to go very far. Mine vents immediately out a wall. If you have to vent up through a roof it is probably not worth it. I also de-lime mine with vinegar every 6 months to keep it running more efficiently so that is something you have to keep in mind. In my case I had to replace a 50 gallon propane water heater anyway so the delta price wasn't too bad.

The downside is no hot water if you lose power because even though it uses gas, it needs electricity for all the control circuitry.

Another upside is I have more storage where the old hot water heater was.

 

[dozerII]

Re: Tankless hot water

When we did the complete rebuild on our house we went with the so called best tankless system we could find Navion. $3500. The biggest waist of money I ever spent. Granted it doesn't use a lot of gas, but boy does it waste water. We live in an area where water is in short supply, and having to wait with the tap running for 90 seconds to get hot water makes me mad. I have had to have the computer replaced 3 times, as well as boxes of other parts, under warranty. If this thing ever comes to costing me money, it is coming off the wall and straight to the scrap yard.

 

[eastont]

Re: Tankless hot water

Thanks, I guess the answer to my question is simple, if I'm not living in California forget it. I called the city water works yesterday and they said the water temp was 1?C or 33.5?F, and warmest it gets is 21?C or 70?F. So it's not a possibility.

Maybe I should look into a propane hot water tank....hmmmmmmmm

 

[bruceb58]

Re: Tankless hot water

When we did the complete rebuild on our house we went with the so called best tankless system we could find Navion. $3500. The biggest waist of money I ever spent. Granted it doesn't use a lot of gas, but boy does it waste water. We live in an area where water is in short supply, and having to wait with the tap running for 90 seconds to get hot water makes me mad. I have had to have the computer replaced 3 times, as well as boxes of other parts, under warranty. If this thing ever comes to costing me money, it is coming off the wall and straight to the scrap yard.

Don't blame the tankless water heater for wasting water. Blame the guy that installed it so far away. Since you rebuilt your house, why didn't you mount it closer to where it gets used?

Also sounds like you paid way to much. I paid $900 for one of the largest units made and around $300 of other stuff to hook it up. Along with the $300 tax credit, it cost me $900 total.

 

[bruceb58]

Re: Tankless hot water

I called the city water works yesterday and they said the water temp was 1?C or 33.5?F, and warmest it gets is 21?C or 70?F. So it's not a possibility.

Mine has a rating of 3.9gpm with a 75 degree temp rise which would probably work ok for you on the coldest day. Just remember that the lower the flow, the larger the temp rise. If you blast the water, the lower the temp rise will be once you hit the heater's full gas draw. Mine probably never runs fully on unless there are two showers going at the same time in the winter.

I also have a house up in Tahoe and definitely would not put a tankless water heater there. The water heater is inside the house and since I am heating the house constantly anyway in the winter, the heat wasted from the water heater is just helping the house stay warmer.

 

[dingbat]

Re: Tankless hot water

I find this discussing interesting seeing the prevalence of "point of use" tankless systems in Europe. No experiance outside observations

 

[rbh]

Re: Tankless hot water

Eastont,
The old guy down the road from us has a metal tank next to his wood stove in the basement, from there it goes into a little 20 gallon electric hot water heater.
In the winter he is never out of hot water, and he gets his water from a creek (gravity fed) so he has to keep the cold water tap open so the pipe does not freeze up at the dam, as it is only a foot or so below the surface before it goes underground.

 

[Tim Frank]

Re: Tankless hot water

Just had a Rinnai installed a couple of months ago and it is absolutely great.

It is a nat gas unit, but they are available for propane.
It will deliver 5 GPM at 75deg rise.

Specs aside, we are really pleased with what it actually does....you never run out of hot water.

But they aren't cheap, and it will not actually pay for itself....ever.

And Bruce is bang on...if you have to run a lot of water before you get hot, the piping layout is the problem.

 

[I Am Mello]

Re: Tankless hot water

My vote...NO!
#1 they need a bi-yearly service that is expensive if done by a professional (which few people know about)
#2 If its gas...you have one more hole going thru the roof to exhaust
#3 It does have a life expectancy. it will go out. You can buy a regular heater many times over for the cost of one "GOOD" point of use or tankless.
#4 Do what I did.. Go to your local hardware place, get a timer (for electric only) and set it for your use. Mine goes on 2 times a day for 30 minutes each time. We have pleanty of water. (me, the wife who showers in HOT water only, and 11 yr old girl)
Just my humble opinion
I Am mello

 

[dozerII]

Re: Tankless hot water

Don't blame the tankless water heater for wasting water. Blame the guy that installed it so far away. Since you rebuilt your house, why didn't you mount it closer to where it gets used?

Also sounds like you paid way to much. I paid $900 for one of the largest units made and around $300 of other stuff to hook it up. Along with the $300 tax credit, it cost me $900 total.

You bet I'll blame the tankless system. It is mounted exactly halfway between the two water usage areas. 10 feet to the kitchen, and 10 feet to the bathroom, all hot water pipes are insulated, the thing is a pile of crap.

 

[Tim Frank]

Re: Tankless hot water

You bet I'll blame the tankless system. It is mounted exactly halfway between the two water usage areas. 10 feet to the kitchen, and 10 feet to the bathroom, all hot water pipes are insulated, the thing is a pile of crap.

Seems like a lot of water to be running if the unit is working properly.
Has it been checked out properly?