The hot water heater is going in our home. We are looking for a replacement. There is a natural gas line right above the current water heater however the current one is electric. I was wondering opinions on tankless water heaters vs. water heaters with tanks and gas vs. electric. Gas where I am is cheaper but I am not sure how to actually compute how much cheaper. I was looking into a 110v 4 gallon per minute tankless but do they last a while?? It has a 6 yr warranty and is only 160 bucks. It has mixed reviews. Some say they are great and some say a water heater with a tank is the way to go. Any opinions?? Its not ready for replacement for a little while but I wanna do research before I am forced to get one because I absolutely need it. Thanks ahead of time.

Electric tankless is a no-no. You'd need some killer amperages to heat up water any decent amount.

Unless you're talking about something like an under sink mount that ONLY goes to the sink... but it doesn't sound like that's what you want. If you want to run a shower, you need gas. Also, don't pay attention to the GPM ratings unless they have temperature rise figures next to them. Measure your current cold tap water temp. Find out how much water your shower uses per minute. Measure your ideal shower temp. Make sure ideal shower temp - cold water temp < water heater temp rise figure at the GPM of your shower.

For reference: 240V/48A electric:
http://www.plumbersurplus.c...Heater/10377/Cat/474

Rise at 2.0 GPM 39°F - meaning if your cold water temp is 50 degrees, your hot water temp is 89F.

Gas:
http://www.plumbersurplus.c...r-Use/56631/Cat/1126

90° F rise / 2.1 gpm - " " your hot water temp is 140F.

Course, average shower uses more than 2gpm.

[This message has been edited by ryan.hess (edited 11-22-2008).]

Gas tankless is great.

Depending on how your house is set up you can cut costs on a tank by using your already heated shower water to preheat the incoming water.

Do you know why your tank is on the way out? I did a flush with CLR on ours and it cleaned out a lot of scale build up. Cleaned tanks run much better.

There is NO way you're going to get 4 GPM from a 110v electric. Not unless its like 400 amps. A 220 volt 80 amp will supply like 2.x GPM

If I were getting another, I would get a tankless, especially if you have gas. Not only for the $ savings, but for the much better flow rates.

Electric heating Vs gas, its about %50 cheaper to use gas, at least for air heating, I would assume water heating would be comprable, but rest assured, its a very large savings.

Also, to run an electric tankless, you will usually need 2 branches of 4 or 2 gauge wiring run to it to feed it. Sizeable units will not run on the 10-2 that is allready there for your tank heater.

Gas is probably the better choice if you can do it. But remember, with gas you need to have both a fresh air supply and a code-compliant exhaust flue, too. That may present a big problem in many existing homes.

I know its on its way out because it was installed in 1985 and we just bought the house and there are zero service records on it. The PO said they never had it serviced at all. The home inspctor said that it was a great model in its day but should be replaced ASAP. I wasnt sure about a electric one because this is our first home. I will look into gas ones going off what you guys said about the current draw. We are tryin to save money any where we can. We already plan to insulate the furnace ducting and hot water lines. Does that really make a difference??

quote Originally posted by Marvin McInnis: Gas is probably the better choice if you can do it. But remember, with gas you need to have both a fresh air supply and a code-compliant exhaust flue, too. That may present a big problem in many existing homes.

They do make (and I have one) power vent gas fired hot water heater. The exhaust flue is plastic pipe which can be vented out a sidewall or the roof. They are more expensive than a standard draft flue water heater. The power vent heaters can be put on a timer so they don't fire up at night for example when you aren't using it.

I hear they are great, but the payback on one is nearly forever on a retrofit.

I may do the same when my tank heater dies next year. I could care less about efficiency, and its for ease of install and no more worry about another tank dying in 10 years.

Tankless... get your hands on the recent Consumer Reports article on them. They weren't very impressed and found that any energy savings often got killed by high installation costs. They found it hard to get hot water at low flow rates, like shaving etc.

Current electric tanks are much faster heating and hold that heat very well. It will run you 400-500 for the premium ones and I strongly recommend them. I had one of the top end ones from Home Depot at my last house and it would recycle from stone cold in about 20 minutes. I think it was a 50 gallon one. My electric bill dropped noticeably after it went in.

Gas needs more than a gas line. If you don't have a suitable vent stack for it, then you'll have to have that done and it can add allot of cost.

------------------
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(Jurassic Park)

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Gas tankless is the way to go. Prices are continuing to come down. Where it gets expensive is if you retrofit and pay somebody else to do it. You already have a gas line, so some of your cost will be reduced. You do need to get a unit that will operate more than one appliance at a time. What I mean by this is, if you are showering and running the dishwasher at the same time, or a dish washer and a washing machine, some of the units will not handle the load. It will take a couple of years to recoup the startup cost but with a lifespan of 10-15 years, you will recoup it and much more. Also try to avoid an electric start one. get one with a pilot light. If power goes out you will lose hot water even if it heats with gas.

Jim

Ok. Went to the stores and all 3 said that the on demand water heaters where no good unless I was gonna spend about 1500 on the equipment. I was looking online and I seemed I could have gotten away a ton cheaper with that option than that price. I think I am going to end up going with a 40 gallon gas water heater. Thanks for all the advice/opinions regardless.

If you want to save some money, you can drain your water heater, and replace the sacrificial anode and heater element(s). You're talking less than $50 to get it back up to almost new. If it's rusting on the inside, hit it with a rust remover and rinse thoroughly. The new anode will prevent/stop additional corrosion.

Yea, you can get a really good tankless for more in the neighborhood of 500. Just take your specs, and look around online. You're going to have the same work in installing a tank or tankless, and frankly, if you get a direct vent model, its not that hard if its near a side or back wall where you can just pop through. Just follow the installation specs.

I dont know why people think "installers" are so golden, I know some people who are HVAC tecs, I wouldnt let change my oil. Just because they charge $150 an hour, doesnt mean they know any more than you would after breezing through the manual.

quote Originally posted by 86GT3.4DOHC: Yea, you can get a really good tankless for more in the neighborhood of 500. Just take your specs, and look around online. You're going to have the same work in installing a tank or tankless, and frankly, if you get a direct vent model, its not that hard if its near a side or back wall where you can just pop through. Just follow the installation specs. I dont know why people think "installers" are so golden, I know some people who are HVAC tecs, I wouldnt let change my oil. Just because they charge $150 an hour, doesnt mean they know any more than you would after breezing through the manual.

quote Originally posted by 86GT3.4DOHC: Yea, you can get a really good tankless for more in the neighborhood of 500. Just take your specs, and look around online. You're going to have the same work in installing a tank or tankless, and frankly, if you get a direct vent model, its not that hard if its near a side or back wall where you can just pop through. Just follow the installation specs. I dont know why people think "installers" are so golden, I know some people who are HVAC tecs, I wouldnt let change my oil. Just because they charge $150 an hour, doesnt mean they know any more than you would after breezing through the manual.

But it does mean they're working as a licensed contractor who has to be compliant with building codes.

I will be doing all the installation myself and my gfs father will help me. No worries about install cost. But the tankless is also more expensive to install going on what the guys at the store said.

Yes, tankless is more expensive. Just think as if you were installing a water heater into a house that didn't have one.

The unit... $900
Exhaust... $100 (price goes up the further away from an outside wall you mount it)
Gas line...$100
Intake PVC...$75
Plumbing...$100 (I used PEX and quick connectors to connect up to the old copper lines).

You can end up spending a lot to install. I installed my own and comparing month to month I saved about 30% over the old gas water heater.

I really like the unit. It is not the same as having a tank of hot water. There are things you have to do differently. But you have all the hot water you will ever need.

Plus, I like the space savings.

Some people leave their old water tank in the house and hook up the tankless after this tank. That way, incoming water will sit in the tank and warm up to room temp. This would be good for winter, but I haven't had an issue here with enough hot water (and our cold water is really cold).

J.

[This message has been edited by jaskispyder (edited 11-24-2008).]

quote Originally posted by turboguy327: I will be doing all the installation myself and my gfs father will help me.

Nothing wrong with that, but if you change the type of tank you will have to pass a city/county plumbing inspection on the completed installation. In some locations, you may even need a building/remodeling permit before you begin. What happens if you just do it and don't tell anybody? Probably nothing, unless you have a fire in your home and discover that the absence of an inspection of your plumbing installation voids your homeowners insurance.

Yup, it is a good idea to check with your insurance and the city. For me, it was a $400 savings by plumbing (gas and water) myself.

quote Originally posted by Formula88: But it does mean they're working as a licensed contractor who has to be compliant with building codes.

Ya think? I worked on a house last summer, the furnace was installed by the leading HVAC company in town, they vented it directly below a large 6' window section. Not only did that mean that all you get to see out of that room 4 months of the year is a large cloud of 'steam', but also is in direct violation of building code, which mandates exhaust vents to be, I believe, 36" away from any opening.

Just because they work for a company, doesnt mean jack, other than if they kill you, thier insurance will likely pay your next of kin damages.

quote Originally posted by theogre: Tankless... get your hands on the recent Consumer Reports article on them. They weren't very impressed and found that any energy savings often got killed by high installation costs. They found it hard to get hot water at low flow rates, like shaving etc. Current electric tanks are much faster heating and hold that heat very well. It will run you 400-500 for the premium ones and I strongly recommend them. I had one of the top end ones from Home Depot at my last house and it would recycle from stone cold in about 20 minutes. I think it was a 50 gallon one. My electric bill dropped noticeably after it went in. Gas needs more than a gas line. If you don't have a suitable vent stack for it, then you'll have to have that done and it can add allot of cost.

Not only low volume (there is a certain flow rate to trigger the tankless heaters on), but also large volumes of water, it will not keep up.

I have seen several small Ma & Pa restaurants install tankless heaters (they say to save money and space) only to find out it will not keep up the heat with the water volume needed to run a restaurant dish washer (typically piped in at 3/4" and average use of 50 gallons of water per hour).

quote Originally posted by Formula88: But it does mean they're working as a licensed contractor who has to be compliant with building codes.

You hope anyway.

Id still rather do it myself.

quote Originally posted by FrugalFiero: They do make (and I have one) power vent gas fired hot water heater. The exhaust flue is plastic pipe which can be vented out a sidewall or the roof. They are more expensive than a standard draft flue water heater. The power vent heaters can be put on a timer so they don't fire up at night for example when you aren't using it.

Marvin is talking tankless, you are talking about a tank unit.

Kevin

quote Originally posted by Wichita: Not only low volume (there is a certain flow rate to trigger the tankless heaters on), but also large volumes of water, it will not keep up. I have seen several small Ma & Pa restaurants install tankless heaters (they say to save money and space) only to find out it will not keep up the heat with the water volume needed to run a restaurant dish washer (typically piped in at 3/4" and average use of 50 gallons of water per hour).

That really isnt relevant to a household decision. The GPH doesnt matter so much as the flow rate, if that makes any sense. A tank heater will have trouble supplying high GPH, as they will run cold when the tank is 'emptied', but it will supply a higher flow rate, pretty much as big of pipe as you can put in there. A tankless will supply as many GPH as you want, assuming you stay below its flow rating.

At any rate, you're not going to use that much water in a residental application, the only 3/4 pipe your going to find is in the distribution, since you're not supposed to run more than one outlet on a 1/2" pipe, but the outlets wont neccessarially use even the full 1/2".

Bottom line, if you size it properly, for the flow rate you expect, it will have no problem giving you hot water, and it will never run out. Example, I cant even fill my whirlpool tub in my house with a tank heater, just installed last year, runs out of hot water even filling it with 'warm' water about %60 full. The heater was installed before we got the house, I would have gone with tankless, even with pure electric I could have made it work.

And there are solutions for low flow rate switching.

If you compare apples to apples, saying you would install a gas heater, either way, the tankless will not run you that much more, and it will save you money. If you try comparing oranges to apples, running an electric tank or a gas tankless, then you could still probably justify it, but its not a no-brainer. As for running an electric tankless, unless you are mounting near the electrical pannel, you may run into trouble getting enough juice to it.

quote Originally posted by Lambo nut: And this statement, even referring to a tankless unit, is inaccurate. Kevin

How about, "if you want to run a shower, without the electric company having to kick in auxiliary nuclear power, you need gas."

The average home uses ~1 kilowatt.

This electric tankless is pretty well equipped to heat a shower, plus a little extra: http://www.accentshopping.c...duct.asp/P_ID/149441

It uses the power of 27 homes while it's heating, and even then it's barely enough to run little more than one shower at one time. You'll probably need to upgrade your service panel. If your water heater draws 120 amps then most of a 200 amp panel is used.

It would take a lot of electricty to run, if the water coming in the house was near freezing, and one was trying to run three water outlets at once.

I went a step above that, and installed this in my house.

http://www.e-tankless.com/s...ess-water-heater.php

I've had it for two plus years now, without a single problem what so ever. Have two daughters, one 13, the other 10, and a 5 year old son. Had to do something, because the 30 gallon tank heater would not keep up! I can run three outlets at once in the summer no problem, and two, sometime three in the winter. Two showers going at the same time, will only have a slight decrease in flow, but the water temp will maintain with no problems. I know it is overkill, but this thing just idles along for what we need it for. If something does happen to it, I would probably go with the next size smaller, as the 300 amp service suggestion was not in place when I bought the current unit, but like I said, no problems. We have gas heat, so the only other major draws, are the oven and the A/C. We just don't bake a cake in the winter when we are showering.

Kevin

quote Originally posted by ryan.hess: How about, "if you want to run a shower, without the electric company having to kick in auxiliary nuclear power, you need gas." The average home uses ~1 kilowatt. This electric tankless is pretty well equipped to heat a shower, plus a little extra: http://www.accentshopping.c...duct.asp/P_ID/149441 It uses the power of 27 homes while it's heating, and even then it's barely enough to run little more than one shower at one time. You'll probably need to upgrade your service panel. If your water heater draws 120 amps then most of a 200 amp panel is used.

They had those on Woot for $250 a week ago. I damn near bought one just to hang on to.

The average home has a 200 amp service, 48 kilowatts. The average tank water heater is breakered for 30 amps.

Hell my central furnace pulls 20kw, with my water heater and my dryer running, and everything else im still fine. Not that I think you could even get more than a 200 amp service without someone asking a lot of questions.

That tankless unit at 27 Kw could run almost 3 showers at once. And they are on demand, which means that you're only going to pull 27kw when you have the thing maxed out.

Theres nothing wrong with electric water heating, other than its not the cheapest. Any electric water heater is going to be sized for the flow output its rated for. If you happen to have your water heater near the load center, it wouldnt be anything to run a few feet of 4 gauge wire and throw in a couple more breakers. But it would definitely be cheaper to run with gas. Guessing though, I would say running a gas tank vs electric tankless would probably be relatively equal in cost. But, if you're running the gas and vent, theres no extra work to put in the tankless.

It will always be cheaper to run gas on an equal basis, but there is nothing fundamentally wrong with electric water heating.

[This message has been edited by 86GT3.4DOHC (edited 11-25-2008).]

quote Originally posted by 86GT3.4DOHC: They had those on Woot for $250 a week ago. I damn near bought one just to hang on to. The average home has a 200 amp service, 48 kilowatts. The average tank water heater is breakered for 30 amps. And the average home does not use 1kw/day. I live by myself in a 1600 sq foot house, and without HVAC I still use 500 kwhr a month. Thats more allong the lines of 16 Kwhr a day. Thats spring\fall when im not running heat or AC. If the average home used 1 Kwhr, most people would be paying about four dollars a month for their electric bill

You're mixing up kW (power) and kWhr (energy).

500 kWhr per month = 694 watts power consumption ~1000w.

I *think* the current electrical code is you can't have more than 80% of your service rating in the breaker circuits. So 200 amp service, and you add a 120 amp tankless heater, you've only got 40 amps to power the rest of the house...

quote Originally posted by 86GT3.4DOHC: Not that I think you could even get more than a 200 amp service without someone asking a lot of questions.

My home that was completely rebuilt in 1998 has 400 amp (220 volt, single phase) service. No problem as long as the local electric utility has adequate capacity in place to supply it.

My previous home in Oklahoma City actually had 200 amp, 220 volt, 3-phase (delta) service. It's the only residence I've ever seen with 3-phase service.

quote Originally posted by ryan.hess: You're mixing up kW (power) and kWhr (energy). 500 kWhr per month = 694 watts power consumption ~1000w. I *think* the current electrical code is you can't have more than 80% of your service rating in the breaker circuits. So 200 amp service, and you add a 120 amp tankless heater, you've only got 40 amps to power the rest of the house...

Yea, you caught that before I changed it. I reread your post and realized what you meant.

Marvin, what in the world would you need 400 amps for?
My fathers house we built was 5000 sq ft and was only 200 amp. My current house with a 20kw electric central furnace and no gas access is only 200 amp. I cant even imagine how I could hook up enough crap to pull 400, much less fathom the electric bills that would cause.

When we were building our house we thought about tankless but we did a lot of research and many people complained about how you cant run 2 sorces of water at once with a tankless. Like the dishwash and clother washer at the same time. So we went with a gas 50gal hot water heater. During the summer when we dont run our furnace we only use 1MCF of gas thats $14 per month and we have 5 people living here who take showers every day and at least 1 load of dishes and 2 loads of laundry per day so I think the cost of the gas one is not to bad

quote Originally posted by 86GT3.4DOHC: ... what in the world would you need 400 amps for?

Reasonable question, but you might just as well ask the same about 200 amp service. Sixty years ago, a new house (like my parents') with 100 amp service was considered extravagant by some. Service level has to be provisioned for peak load, rather than average load. If you have 400 amp service and never use all of it, so what? On the other hand, if you have only 100 amp service but discover that you need more to run everything in your house and shop, adding capacity will probably be very expensive.

We have a large house with four bedrooms and four bathrooms (and unfinished space for a fifth bed and bath in the basement), a big kitchen, my office in the basement (with four computers and two satellite data systems that run 24/7), two zoned HVAC systems (and provisions for a third in the future), a wiring closet just for communications stuff, and a large, well lighted, heated and cooled workshop with a stationary air compressor, a welder, etc. In our case, I think the local electrical code played a part, too. With all of the above we were approaching to the code limit for 200 amp service so our architect recommended that we go ahead and install 400 amp service, which was the next step up from 200 amp. I think the incremental cost to install 400 amp vs. 200 amp service was only about $100 (new construction), and the rate from the electric utility is the same. And remember: "Anything worth doing is worth overdoing!"

Even though our house has a theoretical peak capacity of ~90 KW, it is relatively energy efficient and our average base load during the winter is only about 2 KW (we have natural gas heat) rising to perhaps 5 or 6 KW during the summer cooling season. Of course, there are intermittent demand peaks much higher than that.

[This message has been edited by Marvin McInnis (edited 11-26-2008).]

I like the Takagi units myself. You can get a reasonable idea of pricing from Pex Supply:

http://www.pexsupply.com/Ta...ndid=96&brand=Takagi

I'm actually using a Takagi Jr. for a radian floor hydronic heating system in a small office. The unit is very compact, and they have all the bits and pieces at Pex Supply to do direct vent.