Hot Water Heaters: Conventional vs. Tankless - Tilted Forum Project Discussion Community

FEIGN · 03-25-2005, 06:45 AM

Hello to all, and thanks in advance for any replies.

I am looking into updating the hot water heater system in my house. It is currently a 30 gallon gas hot water heater. I am not sure if I should install a replacement tank water heater or go for the somewhat new tankless models that I keep seeing. Which is better, and are there any concerns with going tankless.

Thanks in advance.

absorbentishe · 03-25-2005, 08:16 AM

Rule of thumb on a tankless heater is get one that will support more than one thing running at a time. I was looking at these before, and the advice I got was to stay with a tank. Reasons... Calcium build up will reduce the amount of hot water (althought the years it would take to do this...), always hot water (with a tank), can run more than one appliance/shower at a time.

Although these were solid reasons not to get one, I wasn't totally sold on not getting one. I think I will get one in the future.

2sheds · 03-25-2005, 01:55 PM

fwiw, a local radio station has a call-in show about home buying, building, and that sort of thing. the host (david yates is his name - http://www.dreamhome.com) is a builder and has been saying a lot of good things about the tankless water heaters.

kazoo · 03-25-2005, 07:59 PM

Could you give us more info? Number of bathrooms in house, objections/problems with current system?

Charlatan · 03-25-2005, 08:02 PM

Tankless is better for the environment. You only heat what you need.

They have been in wide use in Europe for years.

c172g · 03-29-2005, 12:34 PM

We just built a house & I examined the tankless thoroughly. The biggest one I could find would heat enough water to run three appliances (fixtures) at a time. That probably sounds OK, but when you have the dishwasher going and laundry, you should not expect to wash your hands or face in much more than luke-warm water from what I was told. The three appliance one I was looking at could heat X number of gallons 70 degrees, which sounds fine unless you live in Michigan where the tap water is about 35 in the winter time. 105 degrees for a bath is marginal for most people, and again assuming nothing else is running.

It sucks to constantly heat 40 gallons of water and know that you are wasting cash, but we couldn't do it tankless unless we bought two of the three appliance units and then were very careful as to how our plumbing was setup. We have a three bedroom house with two baths currently and probably add a third when the basement is done. The cost of the units plus the plumbing nightmare (#1 should heat the dishwasher plus one bathroom and the kitchen sink, #2 to supply one bathroom, the laundry, and the utility sink, what about the third bathroom?) was enough to keep me conventional.

For a two bedroom apartment or small house I'd say go for it. Otherwise, get a gas fired tank & wrap that rascal with the blankets they sell for $30.

Cycler · 03-31-2005, 08:28 PM

My Dad works in the building industry and I commented on the tankless setup as he was taking me thru a new house. He said as many others have said here that the units just can't keep up with the demand of the appliances. My 2 cents, I like the idea but apparently it just isn't practical yet.

mazagmot · 04-02-2005, 06:27 AM

I've heard about small heaters that you can put near the appliance they will be used with, such as the bathroom, so you can always have a hot shower. I'm pretty sure that I've read about in here in the forum in conjunction with a programmable pad to automatically control the temp. Would a couple of small tankless heaters work in this sort of situation? Or could you set it up to have one run all the bathrooms/sinks and one run the washer and dishwasher?

Cycler · 04-02-2005, 08:08 AM

I am pretty sure you could set something up like this because some bathrooms/sinks are pulumbed with their own small tanked hot water systems I am not sure of the plumbing setup and logistics of going with the tankless system.

slant eyes · 04-02-2005, 11:34 AM

interesting enough, my brother and i spoke on this earlier. i can't speak for too many, but we wash most of our clothes in cold water as you should for colorfast-ness. i was told never to wash in hot water. so for us, that would leave the dishwasher. how hard would it be to just load the dishwasher before you shower. then turn the sucker on to run the night while you went to bed? it would save you lots of money from having to heat the tank all day.

plus, how many people wash thier clothes, their dishes, and take a shower at the same time?

Charlatan · 04-02-2005, 04:33 PM

One of the apartments I stayed in in France had one for each floor of the apartment. They were in the utility cupboards in the bathroom on each floor... My friend in the UK had one in her flat... she had one installed in the bathroom... a small one, so she always had hot water and another that worked for the rest of the system.

splck · 04-02-2005, 11:48 PM

From what i've seem in Europe, I'd go with the tankless (I love endless showers). It costs less per year to run...

Charlatan · 04-03-2005, 05:25 AM

If I was building from sratch I would definately use one or two... Starting from sratch would give you the flexibility to have independant plumbing for upstairs and downstairs or some combination like that...

soundmotor · 04-10-2005, 07:19 PM

Quote:

Originally Posted by slant eyes

interesting enough, my brother and i spoke on this earlier. i can't speak for too many, but we wash most of our clothes in cold water as you should for colorfast-ness. i was told never to wash in hot water. so for us, that would leave the dishwasher. how hard would it be to just load the dishwasher before you shower. then turn the sucker on to run the night while you went to bed? it would save you lots of money from having to heat the tank all day.

plus, how many people wash thier clothes, their dishes, and take a shower at the same time?

We've done the eval & will be ditching the tank for tankless. We currently have a 120 gallon, stone lined tank that costs a fortune to keep hot. We never run the dishwasher when we shower as the water pressure drops. Tankless should fit the bill nicely.

soundmotor

magnum_xxxl · 04-11-2005, 02:00 PM

I'm a draftsman, basically I draw what the Designer tells me to, but wev'e been doing alot of tankless system lately. The usual for us is:

2500 sqft (air conditioned) or less - one large tankless sytem
2500 - 3500 sqft - two tankless systems (1 near master bath, 1 near Kitchen/Utility)
3500 & above - one at each bath, one near kitchen, and one at utility if not close to the kitchen.

ggadgit · 04-12-2005, 03:22 AM

The main thing I heard to look out on tank less hot water heaters is hard water, as it will leave deposits in the system. Personally if I was building a house I think I would look at a solar hot water heater maybe backed up with a small tank less hot water heater.

mazagmot · 04-12-2005, 05:16 AM

magnum, do you add that many heaters because you need to, or because a client who can afford to build a house that large wants to ensure they always have hot water, come hell or high water?

braisler · 04-12-2005, 06:43 AM

The other good thing about larger house builds with multiple heating units is that you only need to run one set of pipes carrying cold water all through the house. Each zone can have local plumbing to deliver hot water to the taps closest to the water heater supply. Less pipe costs less money and has lower heat loss over the run. If you have a 4000 sqft house, you are likely to have at least one hot water outlet that is more than 50 feet from the tank hot water heater. Even if you insulate that pipe, you are still going to have heat loss over that kind of run. You will also have a much shorter lag time from when you turn on the hot water tap to when it actually flows hot.

When and if I have the chance, I am installing a tankless system in my house. The house we just bought last year had the tank hot water heater JUST replaced by the previous owner. We thought about going tankless even so, but thought that would be a waste having an almost new tank model already.

black94lt1 · 04-12-2005, 12:06 PM

Go with a tank, tankless do not keep up with the demands of most people, too many points of use.

On a lighter note, it is a water heater, not a hot water heater. If you had hot water, you would not need to heat it!

magnum_xxxl · 04-13-2005, 12:46 PM

Quote:

Originally Posted by mazagmot

magnum, do you add that many heaters because you need to, or because a client who can afford to build a house that large wants to ensure they always have hot water, come hell or high water?

Personally, home size aside, what most of our builders suggest is a unit near the kitchen/utility area, & one at Mstr Bath, anything after that is client request. But everything does lead back to size of home & usage expectations. I wouldn't personaly suggest which way to go without seeing the layout of the house & talking with the owner about their lifestyle.

irseg · 04-13-2005, 02:35 PM

Quote:

Originally Posted by black94lt1

On a lighter note, it is a water heater, not a hot water heater. If you had hot water, you would not need to heat it!

Hehe I'm glad someone else notices that besides me.

It's right up there with "ATM Machine", "PIN Number", etc.

How do these things work? I'd imagine they must use a massive amount of energy while they're running--think of how long it takes to heat a pot of water on a red-hot stove burner, and a tankless heater would have to do that almost instantly for as long as the water is flowing. I guess it would be a little better overall though, since a regular heater still has to keep the tank hot regardless of whether you're using any hot water or not.

nofnway · 04-13-2005, 11:11 PM

I've recently had a chance to look over the spec sheets on the
Rinnai tankless and found that for larger loads they can run 1, 2, or3 units plumbed together through a manifold system and adjust the amount of heated water to meet the demand of the house. if you need just a little hot water only one runs....need more the next one kicks in and so on...

portereight · 04-15-2005, 05:28 AM

We have a tankless system and have had zero complaints. Our system consists of a heat exchange coil for domestic hot water that runs through our boiler. The heating capacity of this system is virtually identical to most of the gas fired on demand systems. The fears that it cant keep up are unwarranted. How often in your home do you REALLY run the dishwasher, clothes washer, and have a couple of people taking showers while you try to wash your hands?
The best thing about tankless is that you never run out of hot water. You can take as many long showers as you like and there will always be hot water for the next person.

dman2 · 05-07-2005, 11:56 AM

I have heard nothing but good things about tankless systems. They advertise them on the radio sometimes as being able to take a shower as long as you want without losing hot water. A friend of mine said that they do not get as hot as a traditional gas/electric water heater. There has to be some sort of adjustment that can be made. How hot do you need water anyway?

I say, out with the old and in with the new. Tankless sounds good to me.

japhyryder · 05-12-2005, 03:37 AM

I am now looking forward to having to replace my tank with a tankless when the time comes. That advise about water hardness makes sense, if you have hard water you probably should have a water softener also.

03-25-2005, 06:45 AM	#1 (permalink)
FEIGN Upright Location: NEW JERSEY	Hot Water Heaters: Conventional vs. Tankless Hello to all, and thanks in advance for any replies. I am looking into updating the hot water heater system in my house. It is currently a 30 gallon gas hot water heater. I am not sure if I should install a replacement tank water heater or go for the somewhat new tankless models that I keep seeing. Which is better, and are there any concerns with going tankless. Thanks in advance. __________________ Remember, where ever you go, there you are.

03-25-2005, 01:55 PM	#3 (permalink)
2sheds Crazy Location: dfw - texas	fwiw, a local radio station has a call-in show about home buying, building, and that sort of thing. the host (david yates is his name - http://www.dreamhome.com) is a builder and has been saying a lot of good things about the tankless water heaters. __________________ Depression is just anger without enthusiasm. It’s having an empty beer bottle but no one to throw it at.

03-25-2005, 07:59 PM	#4 (permalink)
kazoo Psycho Location: Where the night things are	Could you give us more info? Number of bathrooms in house, objections/problems with current system? __________________ There ain't nothin' more powerful than the odor of mendacity -Big Daddy

03-25-2005, 08:02 PM	#5 (permalink)
Charlatan Getting it. Super Moderator Location: Lion City	Tankless is better for the environment. You only heat what you need. They have been in wide use in Europe for years. __________________ "My hands are on fire. Hands are on fire. Ain't got no more time for all you charlatans and liars." - Old Man Luedecke

03-31-2005, 08:28 PM	#7 (permalink)
Cycler Float on.... Alright Location: Where the wind comes sweeping down the plains, i.e. Oklahoma	My Dad works in the building industry and I commented on the tankless setup as he was taking me thru a new house. He said as many others have said here that the units just can't keep up with the demand of the appliances. My 2 cents, I like the idea but apparently it just isn't practical yet. __________________ "I'm not even supposed to be here today." "I assure you we're open."

03-25-2005, 08:16 AM	#2 (permalink)
absorbentishe Boy am I horny today Location: T O L E D O, Toledo!!	Rule of thumb on a tankless heater is get one that will support more than one thing running at a time. I was looking at these before, and the advice I got was to stay with a tank. Reasons... Calcium build up will reduce the amount of hot water (althought the years it would take to do this...), always hot water (with a tank), can run more than one appliance/shower at a time. Although these were solid reasons not to get one, I wasn't totally sold on not getting one. I think I will get one in the future.

03-29-2005, 12:34 PM	#6 (permalink)
c172g Crazy Location: Michigan	We just built a house & I examined the tankless thoroughly. The biggest one I could find would heat enough water to run three appliances (fixtures) at a time. That probably sounds OK, but when you have the dishwasher going and laundry, you should not expect to wash your hands or face in much more than luke-warm water from what I was told. The three appliance one I was looking at could heat X number of gallons 70 degrees, which sounds fine unless you live in Michigan where the tap water is about 35 in the winter time. 105 degrees for a bath is marginal for most people, and again assuming nothing else is running. It sucks to constantly heat 40 gallons of water and know that you are wasting cash, but we couldn't do it tankless unless we bought two of the three appliance units and then were very careful as to how our plumbing was setup. We have a three bedroom house with two baths currently and probably add a third when the basement is done. The cost of the units plus the plumbing nightmare (#1 should heat the dishwasher plus one bathroom and the kitchen sink, #2 to supply one bathroom, the laundry, and the utility sink, what about the third bathroom?) was enough to keep me conventional. For a two bedroom apartment or small house I'd say go for it. Otherwise, get a gas fired tank & wrap that rascal with the blankets they sell for $30.

04-02-2005, 06:27 AM	#8 (permalink)
mazagmot Crazy Location: S. Korea	I've heard about small heaters that you can put near the appliance they will be used with, such as the bathroom, so you can always have a hot shower. I'm pretty sure that I've read about in here in the forum in conjunction with a programmable pad to automatically control the temp. Would a couple of small tankless heaters work in this sort of situation? Or could you set it up to have one run all the bathrooms/sinks and one run the washer and dishwasher? __________________ d^_^b Got my headphones on.

04-02-2005, 08:08 AM	#9 (permalink)
Cycler Float on.... Alright Location: Where the wind comes sweeping down the plains, i.e. Oklahoma	I am pretty sure you could set something up like this because some bathrooms/sinks are pulumbed with their own small tanked hot water systems I am not sure of the plumbing setup and logistics of going with the tankless system. __________________ "I'm not even supposed to be here today." "I assure you we're open."

04-02-2005, 11:34 AM	#10 (permalink)
slant eyes Psycho Location: cali	interesting enough, my brother and i spoke on this earlier. i can't speak for too many, but we wash most of our clothes in cold water as you should for colorfast-ness. i was told never to wash in hot water. so for us, that would leave the dishwasher. how hard would it be to just load the dishwasher before you shower. then turn the sucker on to run the night while you went to bed? it would save you lots of money from having to heat the tank all day. plus, how many people wash thier clothes, their dishes, and take a shower at the same time? __________________ no man or woman is worth your tears - and the one who is, won't make you cry question authority, don't ask why, just do it!

04-02-2005, 04:33 PM	#11 (permalink)
Charlatan Getting it. Super Moderator Location: Lion City	One of the apartments I stayed in in France had one for each floor of the apartment. They were in the utility cupboards in the bathroom on each floor... My friend in the UK had one in her flat... she had one installed in the bathroom... a small one, so she always had hot water and another that worked for the rest of the system. __________________ "My hands are on fire. Hands are on fire. Ain't got no more time for all you charlatans and liars." - Old Man Luedecke

04-02-2005, 11:48 PM	#12 (permalink)
splck it's jam Location: Lowerainland BC	From what i've seem in Europe, I'd go with the tankless (I love endless showers). It costs less per year to run... __________________ nice line eh?

04-03-2005, 05:25 AM	#13 (permalink)
Charlatan Getting it. Super Moderator Location: Lion City	If I was building from sratch I would definately use one or two... Starting from sratch would give you the flexibility to have independant plumbing for upstairs and downstairs or some combination like that... __________________ "My hands are on fire. Hands are on fire. Ain't got no more time for all you charlatans and liars." - Old Man Luedecke

04-11-2005, 02:00 PM	#15 (permalink)
magnum_xxxl Tilted	I'm a draftsman, basically I draw what the Designer tells me to, but wev'e been doing alot of tankless system lately. The usual for us is: 2500 sqft (air conditioned) or less - one large tankless sytem 2500 - 3500 sqft - two tankless systems (1 near master bath, 1 near Kitchen/Utility) 3500 & above - one at each bath, one near kitchen, and one at utility if not close to the kitchen.

04-12-2005, 03:22 AM	#16 (permalink)
ggadgit Tilted	The main thing I heard to look out on tank less hot water heaters is hard water, as it will leave deposits in the system. Personally if I was building a house I think I would look at a solar hot water heater maybe backed up with a small tank less hot water heater.

04-12-2005, 05:16 AM	#17 (permalink)
mazagmot Crazy Location: S. Korea	magnum, do you add that many heaters because you need to, or because a client who can afford to build a house that large wants to ensure they always have hot water, come hell or high water? __________________ d^_^b Got my headphones on.

04-12-2005, 06:43 AM	#18 (permalink)
braisler Addict Location: Midway, KY	The other good thing about larger house builds with multiple heating units is that you only need to run one set of pipes carrying cold water all through the house. Each zone can have local plumbing to deliver hot water to the taps closest to the water heater supply. Less pipe costs less money and has lower heat loss over the run. If you have a 4000 sqft house, you are likely to have at least one hot water outlet that is more than 50 feet from the tank hot water heater. Even if you insulate that pipe, you are still going to have heat loss over that kind of run. You will also have a much shorter lag time from when you turn on the hot water tap to when it actually flows hot. When and if I have the chance, I am installing a tankless system in my house. The house we just bought last year had the tank hot water heater JUST replaced by the previous owner. We thought about going tankless even so, but thought that would be a waste having an almost new tank model already. __________________ --- You do not really understand something unless you can explain it to your grandmother. - Albert Einstein ---

04-12-2005, 12:06 PM	#19 (permalink)
black94lt1 Tilted	Go with a tank, tankless do not keep up with the demands of most people, too many points of use. On a lighter note, it is a water heater, not a hot water heater. If you had hot water, you would not need to heat it!

04-13-2005, 11:11 PM	#22 (permalink)
nofnway Insane Location: under the freeway bridge	I've recently had a chance to look over the spec sheets on the Rinnai tankless and found that for larger loads they can run 1, 2, or3 units plumbed together through a manifold system and adjust the amount of heated water to meet the demand of the house. if you need just a little hot water only one runs....need more the next one kicks in and so on... __________________ "Iron rusts with disuse, stagnant water loses its purity and in cold water freezes. Even so does inaction sap the vigor of the mind" Leonardo Da Vinci

04-15-2005, 05:28 AM	#23 (permalink)
portereight Crazy	We have a tankless system and have had zero complaints. Our system consists of a heat exchange coil for domestic hot water that runs through our boiler. The heating capacity of this system is virtually identical to most of the gas fired on demand systems. The fears that it cant keep up are unwarranted. How often in your home do you REALLY run the dishwasher, clothes washer, and have a couple of people taking showers while you try to wash your hands? The best thing about tankless is that you never run out of hot water. You can take as many long showers as you like and there will always be hot water for the next person.

05-07-2005, 11:56 AM	#24 (permalink)
dman2 Insane Location: Georgia	I have heard nothing but good things about tankless systems. They advertise them on the radio sometimes as being able to take a shower as long as you want without losing hot water. A friend of mine said that they do not get as hot as a traditional gas/electric water heater. There has to be some sort of adjustment that can be made. How hot do you need water anyway? I say, out with the old and in with the new. Tankless sounds good to me. __________________ I have to exercise in the morning before my brain figures out what I'm doing. ~Marsha Doble

05-12-2005, 03:37 AM	#25 (permalink)
japhyryder no one special Location: Charlotte, NC	I am now looking forward to having to replace my tank with a tankless when the time comes. That advise about water hardness makes sense, if you have hard water you probably should have a water softener also. __________________ It's only entertainment, someone's sick idea of a joke.