Tankless water heater

Limited-Time · Dec 13, 2011

Thinking of upgrading to a Propane fired on demand water heater. Does any one know the energy usage (cost wise) difference between that and an electric water heater?

GA_Boater · Dec 13, 2011

Re: Tankless water heater

Every water heater has the info on a sticker. And it's hard to give without info from you as size, demand, etc. I would look at mfg. web sites where they post what you are looking for. Just a thought.

bigdee · Dec 13, 2011

Re: Tankless water heater

IMO adding insulation to your conventional WH makes the most sense. It will cost the same amount to heat the water in either unit, you are only saving the thermal energy lost during standby periods. The higher cost of the tankless WH and the reliability and maintenance will eat up what little you may save. I have a 50 gallon electric that is insulated as well as the hot water pipes in my lake house. I always turn off the power (only in case of leaks) before leaving and when I go back a week later I still have warm water! I have tried leaving it on to see what the difference would be and did not notice any significant change in my Kw usage. I see that your from the Carolina's too so the moderate climate helps too if it is in a crawlspace (even better if in a conditioned space).

marauder11 · Dec 13, 2011

Re: Tankless water heater

Ok if your just refering to a tank style old school hot water tank it will cost you more to heat the water compared to a tankless hot water heater. The tankless models are more efficient. Some up to 98% also they are multi stage fired. So if your running your tap and are using say .5 gal a minute your tankless will only fire say 30% of it max output because that is all you need to get the water to temp.Where a tank style fire full and that is it. you also really do get endless hot water as long as you stay between the range of you units gpm. In the end I as a plumber would go to a tankless just because i can do the maintenace. If your handy you can do the yearly flushing ect. Parts are more and i would do my homework on brands. I have had issues with one where i have removed the original and replaced it only to have to replace the control board and other stuff on the second unit. Lemons in everything . They have gotten alot better and reliable.

bruceb58 · Dec 13, 2011

Re: Tankless water heater

I have switched from a propane tank water heater to a tankless propane water heater a few years ago.

If you do this, you have to make sure that the venting distance is minimal or you are going to pay a fortune in venting. There are some new heaters out that use plastic pipe venting and operate on a similar theory to a condensing home heater. Make sure your gas line is sized sufficiently. These things need a huge line.

I figured my propane savings would amount to a payback in 3 to 4 years. I installed my system myself with a total cost including plumbing at around $1200 or $900 after the tax credit. I had a propane water heater that was on its way out and they run around $500 so the delta was $400. I figured $100 savings per year. If you aren't already due for a water heater, your payback period will be longer.

My propane runs around $4/gallon.

Some of the Pros for the heater:
1) Storage where my old heater used to be.
2) Never run out of hot water.

Cons:
1) Water heater is further away so takes longer for hot water to reach faucets. You can use certain type of recirculators but they are pricey(I bought one recently)
2) Won't heat water if power is out
3) No emergency water storage.
4) Need to de lime semi annually if you have hard water. This is necessary to keep their efficiency

MTboatguy · Dec 13, 2011

Re: Tankless water heater

A lot of things are going to depend on your location and your average water temp coming into the house, I know I looked seriously at tankless a little over a year ago, and our water is way to cold coming out of the well, so much so, that I would had to have doubled up with two larger tankless to make sure we had the water needed. I ended up putting in a new 50 gallon conventional heater and I have added a supplemental inline heater where needed. I had to put the supplemental in due to the size of the Jacuzzi bath I installed. Now in hindsight, I would have probably pursued a different solution, for right now it is working out fine.

Limited-Time · Dec 13, 2011

Re: Tankless water heater

Thanks for the replies. A little more info. I currently have a conventional electric tank water heater. So that's my base line. Also the incomming water temperature varies from the low 60's to the 80's from winter to summer.

MTboatguy · Dec 13, 2011

Re: Tankless water heater

Your incoming temp would work just fine with one of the new tankless, my problem was, that my incoming temp stays right at 38 degrees year around, so it was a long ways to bring it up to an acceptable temp for our use..

bigdee · Dec 13, 2011

Re: Tankless water heater

http://www.consumerreports.org/cro/...eaters/overview/tankless-water-heaters-ov.htm

bruceb58 · Dec 13, 2011

Re: Tankless water heater

When I calculated my energy use, I compared propane to propane. You will have to compare electricity to propane. I know for me, since propane is probably 3 times the cost of natural gas for my area, I can get more savings than what Consumers Reports was calculating. You have to figure the difference between electric heater to propane tankless.

There is one other supposed benefit to the tankless and that it is supposed to last longer than a tank water heater if taken care of(deliming). Not sure if that will be the case or not for me.

For me it was an easy decision since I had to replace my water heater anyway. For someone who has a relatively new heater, it may not be worth it depending on the energy savings.

destroyer_85_golf · Dec 13, 2011

Re: Tankless water heater

tankless water heaters are not a direct drop in for a tank water heater. That being said they do offer fairly decent energy savings. A tankless water heater is basically a small boiler as it has a input BTUH (British Thermal Units per Hour) of say 400,000 BTUH where as your standard newer tank water heater only has a input of 40,00 BTUH, but as someone else in here said most of the new ones will modulate so that they only use enough gas to get the discharge water up to temp. dont bother adding a water heater blanket they dont do anything as long as you have a newer water heater they are well insulated. If you can get your hands on a Rinnai that is the brand that we install around where im at but its only available to profesionals. the cost is fairly substancial seeing as how a decent unit is almost 2k. Rinnai also offers heaters so if it looses gas it will start a electric coil to keep things from freezing. Im a plumber and if i had to make a recomendation i would go with a good A.O. Smith power vent they have high efficiency ratings and are cheaper to install and buy. I happen to have a A.O. Smith in my house now its a 1995 and its still going strong.

destroyer_85_golf · Dec 13, 2011

Re: Tankless water heater

sorry also forgot to mention if you go with a tankless water heater, go into a supply house and have them size it to your house. IE you need to know how much your faucets and shower heads will flow how many bathrooms and so on.
if you post the info on here i can size one for you .

bruceb58 · Dec 13, 2011

Re: Tankless water heater

destroyer_85_golf said:
A tankless water heater is basically a small boiler as it has a input BTUH (British Thermal Units per Hour) of say 400,000 BTUH where as your standard newer tank water heater only has a input of 40,00 BTUH, .

Not sure where you get your info but there are really no household tankless water heaters that are 400K BTU. Most are just shy of 200K. Rinnai are available on Ebay and other places on the net. They are less than $1000 as well.

Fishing Dude too · Dec 14, 2011

Re: Tankless water heater

An electric tankless has an X deg gain, where a gas fired will heat to a set point. I have looked into both tankless, feel the savings would not be there at either place. It's up to you, oh and their life span is only 5 years compaired to 10 on a tank waterheater.

bigdee · Dec 14, 2011

Re: Tankless water heater

Fishing Dude too said:
An electric tankless has an X deg gain, where a gas fired will heat to a set point. I have looked into both tankless, feel the savings would not be there at either place. It's up to you, oh and their life span is only 5 years compaired to 10 on a tank waterheater.

A+ It is alot cheaper to improve your thermal losses for a few bucks than it is to spend 1500. With electricity at .12/kw it only costs around $2 a week to maintain a well insulated idle water heater. Just for LAG I put a data-logger on my WH to see how much it cycled in a one week period while the house was unoccupied.......total energised time during the week was 4.16 hrs. This was 168 hours,if you live in the house the idle time is going to be less......remember,the tankless WH only saves during idle times. This is just more of the green energy hype......these things have been in use in Europe for decades but they are smaller and installed close to the faucet some houses have several. The European lifestyles are also different than ours ie; 2 minute showers,washing in cold water etc.

bruceb58 · Dec 14, 2011

Re: Tankless water heater

bigdee said:
remember,the tankless WH only saves during idle times.

Actually, the claim is that they are way more efficient during the heating phase as well.

In Southern California Tier 3 electric costs including the generation charge is $0.23/kwh. I would probably hit Tier 4($0.27) with an electric. That is why there are not many electric water heaters in So Cal.

In the end, the only way to know if the cost of switching is worth it is knowing both the electrity price vs propane price in South Carolina. Until both of those are known, you can't calculate what any savings might be.

bruceb58 · Dec 14, 2011

Re: Tankless water heater

Fishing Dude too said:
An electric tankless has an X deg gain, where a gas fired will heat to a set point. I have looked into both tankless, feel the savings would not be there at either place. It's up to you, oh and their life span is only 5 years compaired to 10 on a tank waterheater.

Tankless water heater lifespans are estimated to be 20 years...not 5.

bigdee · Dec 14, 2011

Re: Tankless water heater

bruceb58 said:
Actually, the claim is that they are way more efficient during the heating phase as well.

In Southern California Tier 3 electric costs including the generation charge is $0.23/kwh. I would probably hit Tier 4($0.27) with an electric. That is why there are not many electric water heaters in So Cal.

In the end, the only way to know if the cost of switching is worth it is knowing both the electrity price vs propane price in South Carolina. Until both of those are known, you can't calculate what any savings might be.

"they" is wrong.....it takes the same amount of electrical energy to heat water, tank or no tank.....it is claims like this that are targeting the naive.

.23 cents/kw......you need to move east son!!!!

bruceb58 · Dec 14, 2011

Re: Tankless water heater

bigdee said:
"they" is wrong.....it takes the same amount of electrical energy to heat water, tank or no tank.....it is claims like this that are targeting the naive.

.23 cents/kw......you need to move east son!!!!

No thanks! There is a reason its expensive to live here! Its worth it!

My electric bill for a 3000sf house is only $67 and is even lower in the summer.

jasoutside · Dec 14, 2011

Re: Tankless water heater

Hey LT, this might be worth looking into...

http://www.geappliances.com/heat-pump-hot-water-heater/

I spent some time weighing everything out and decided to go with one of these ^^^. With the cost of LP, and my busy family of five, I couldn't see the savings on a tankless.

I've only had it in for a couple of months now, but at the moment, I seem to have some pretty favorable numbers coming back.

Just thought I'd make mention of it. Cheers man

Tankless water heater

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