On Demand Water Heaters?????????

[JimR]

Does anyone have any knowledge of these hot water heaters? Cost to run vs tank type etc.? What brands are the best? TIA, Jim

 

[mahlers]

I have a couple of the Bosch 250 outdoor models, and so far I like them. While propane is getting expensive, they're a lot more cost effective to run than traditional electric tank heaters (and a little less expensive than traditional gas heaters). I went with outdoor tankless because of space considerations, and when I re-plumbed the house, I wanted the hot water right next to the bathrooms and kitchen. It was nice to only have to run a cold water pipe from one side of the house to the other (through a crawlspace). One thing that I'm going to do is plumb in small 2.5 gallon electric water heaters right after the tankless units. That smooths out the hot/cold/hot issues the tankless units have when you are doing things like washing dishes. The tankless units only turn on when there is enough flow, so you can easily run into issues when you're not running the hot water constantly. The little Ariston 2.5 gal units are only about $125, and they plug into a standard outlet - so I'll be adding those to my setup soon.

 

[SPYDERLK]

Does anyone have any knowledge of these hot water heaters? Cost to run vs tank type etc.? What brands are the best? TIA, Jim

Low flow point of use electric is good and quite manageable. House capable electric units will need at least 100A @ 220V to warm the higher flow used. They work at an escalating electronically controlled duty cycle as flow increases more and more above the amt needed to turn them on. Theyre great if you have the robust electric service where you need it.
larry

 

[JimR]

Low flow point of use electric is good and quite manageable. House capable electric units will need at least 100A @ 220V to warm the higher flow used. They work at an escalating electronically controlled duty cycle as flow increases more and more above the amt needed to turn them on. Theyre great if you have the robust electric service where you need it.
larry

I do have the power and open breaker spaces to run two 50amps for the heater.

 

[SPYDERLK]

I do have the power and open breaker spaces to run two 50amps for the heater.

That sounds like a 50A 220V circuit. If your feed water is very cold that power would give hot at about 1GPM. OK for a point of use faucet or a cool 2GPM trickle shower.
larry

 

[JimR]

That sounds like a 50A 220V circuit. If your feed water is very cold that power would give hot at about 1GPM. OK for a point of use faucet or a cool 2GPM trickle shower.
larry

That is actually a 100amp unit using two 50 amp breakers to run it. I believe the water flow is about 2.3 gpm's. I'll have to check it again. I've been looking at a few different brands. My oil based water heater is going bye bye.

 

[Doc_Bob]

The point of use electric are the norm in Kosovo. Work very well.

I have been told that the natural gas ones require a bigger supply pipe than the one that supplied the original 40 gallon heater.
Bob

 

[JimR]

The point of use electric are the norm in Kosovo. Work very well.

I have been told that the natural gas ones require a bigger supply pipe than the one that supplied the original 40 gallon heater.
Bob

I can't go with the point of use type heaters due to the hard to reach places that I would have to install them in. I need to go with a larger house type that is electric as we don't have gas.

 

[browns40]

Hi Jim,

First--I researched, but ended up going with the old tank heater... given the price of propane locally and the size unit I'd need, just would take a long time to get the return on it...

As mentioned earlier, the temperature of your water feed, and how many GPM you need will determine what set-up you need. In Maine our groundwater is so cold, most families need a dual set-up to keep pace with running a shower, doing laundry, dishes, etc. concurrently. A small household or single person would have different needs.

Most distributors will have a chart of groundwater temps for you to refer to.

I loved the idea of it, but just didn't see the payback, as the unit I bought went into a rental property. Good luck!

 

[JimR]

Hi Jim,

First--I researched, but ended up going with the old tank heater... given the price of propane locally and the size unit I'd need, just would take a long time to get the return on it...

As mentioned earlier, the temperature of your water feed, and how many GPM you need will determine what set-up you need. In Maine our groundwater is so cold, most families need a dual set-up to keep pace with running a shower, doing laundry, dishes, etc. concurrently. A small household or single person would have different needs.

Most distributors will have a chart of groundwater temps for you to refer to.

I loved the idea of it, but just didn't see the payback, as the unit I bought went into a rental property. Good luck!

Thanks for the information. My ground water is 60 degrees. I can bump it up easy enough with the right unit. My GPM's is around 2 GPM. So I don't need a really large unit. I'll be doing some research this week hopefully.

 

[Highbeam]

Don't fall for the propoganda. On-demand heaters aren't necessarily a money saver. They certainly save space which is valuable. They certainly don't have stand-by losses as a tank heater which may or may not be an issue depending on your usage style. If you only use water for one hour in the morning and one hour at night then gas fired on demand unit will deliver immediate savings. Consider where that lost energy is going.... into your home which is heated more often then not so the losses may not be lost.

It is actually very difficult to beat the efficiency of a plain old tank water heater. If your water heater is an indirect unit off of an oil boiler then great savings are available with either a tank or tankless heater since you can shut your boiler down in the summer.

 

[JimR]

Don't fall for the propoganda. On-demand heaters aren't necessarily a money saver. They certainly save space which is valuable. They certainly don't have stand-by losses as a tank heater which may or may not be an issue depending on your usage style. If you only use water for one hour in the morning and one hour at night then gas fired on demand unit will deliver immediate savings. Consider where that lost energy is going.... into your home which is heated more often then not so the losses may not be lost.

It is actually very difficult to beat the efficiency of a plain old tank water heater. If your water heater is an indirect unit off of an oil boiler then great savings are available with either a tank or tankless heater since you can shut your boiler down in the summer.

My pesent water heater setup is a storage tank type that is run as a seperate zone off the oil burner. Now that oil has gone through the roof. I refuse to pay these (explicit) word another dime. My options are going back to an electric storage type water heater or an on demand style. We use hot water off and on all day. That is why I think the on demand type would work out better for us.

 

[jinjimbob]

Don't fall for the propoganda. On-demand heaters aren't necessarily a money saver. They certainly save space which is valuable. They certainly don't have stand-by losses as a tank heater which may or may not be an issue depending on your usage style. If you only use water for one hour in the morning and one hour at night then gas fired on demand unit will deliver immediate savings. Consider where that lost energy is going.... into your home which is heated more often then not so the losses may not be lost.

Our 75 gallon propane water heater is in the house, but the walls are vented greatly, next to the furnace, similar to being in a garage, in a small room.

If there isn't much water use, only 2 people living in a house, wouldn't an on demand produce savings?

I would like to convert all our propane to electricity, but I'm not sure if the costs savings for the furnace and water heater would be high enough.

 

[JimR]

Our 75 gallon propane water heater is in the house, but the walls are vented greatly, next to the furnace, similar to being in a garage, in a small room.

If there isn't much water use, only 2 people living in a house, wouldn't an on demand produce savings?

I would like to convert all our propane to electricity, but I'm not sure if the costs savings for the furnace and water heater would be high enough.

This should give you an idea of what I use to use for oil. I would fill my 275 gallon oil tank sometime in April or May. I would need to fill it up by early November. I figure that to be six months of hot water for 250 gallons of oil. That is over $1000 now. That amount of money will pay for my on demand heater, breakers, wire and I would be willing to bet a years supply of hot water. Of course no one has come forward to say what it costs to use one of these and I can't get a straight answer from any of the local plumbing supply houses.

 

[SPYDERLK]

Of course no one has come forward to say what it costs to use one of these and I can't get a straight answer from any of the local plumbing supply houses.

It will depend on how fast youre running the hot water. If enuf to need 100% from a house capable unit~3gpm -it will cost $2-3 an hour. We are talking 25 or 30 KW demand at full bore on these.
larry

 

[JimR]

It will depend on how fast youre running the hot water. If enuf to need 100% from a house capable unit~3gpm -it will cost $2-3 an hour. We are talking 25 or 30 KW demand at full bore on these.
larry

Hi Larry, Thanks for the info. My well is 565 feet deep and only pumps about 2gpm. I figure the cost would be a little bit less as I wouldn't need a really big unit that you would normally need for a house that has 3-4 gpm. All three bathrooms have 1 gallon a minute shower head on them.

 

[Kays Supply]

I am a plumber in Illinois. My supply house has been after me for several months to take the installation class from the instant water heater company they sell, so I can install them. I have been putting them off. After several months I finally got my supplier to admit that if the unit is serviced by a qualified tech, as required for warranty, it will cost more than a tank type over the live of the heater. Heat exchanger has to been cleaned regularly to get proper heat transfer. This is for the brand he has. I would expect something like this for other brands. I have also installed other brands for people and they have flow controls in them. They will maintain hot water but if more that two taps are open, you only get a trickel from all of them. I am still waiting to be impressed.

 

[jwstewar]

We moved into our house in early May. We had the builder install a Noritz tankless water heater. So far we are thrilled with it. Used to be we would run out of water if both kids would take a bath and then either Monica or myself would try to take a shower. Now we can run the dishwasher, washing machine, the kids take a bath, and then both of us can take a shower w/o any issues. Usually 2 or 3 (sometimes 4) of these happening at one time. Ours is propane fired. Of course, we haven't had it long enough to know about cost or reliability. We had a 40 gallon tank before in the old house. So far we are happy with our decision to spec the tankless heater. I'm thinking about a small point of use one to put in the pole barn at my clean-up sink.

 

[Highbeam]

The standby losses are the only actual daily financial benefit to tankless. Both systems still spend energy to heat the needed number of gallons. The tank heater is arguably more efficient at actually converting energy into hot water since the ondemand heater requires rapid heat transfer. Electric is always 100% efficient at heating and the newer tank units are of course better insulated.

If the hot water is used constantly or regularly then your stand by losses approach zero as the water heater is effectively a pipe. If your uses are very intermittent then the tank has a lot of dead time to lose heat and this is the time when a tankless gets a slight advantage.

On and off all day, get a proper tank.

Very intermittent use, consider the tankless.

The side benefits of a tankless might be very valuable to you. Endless hot water and space savings are the big ones. These tankless units cost a lot to install and maintain, and they don't work when the power goes out. In the event of an emergency you have a reservoir of drinking water as well with the tank.

Lastly, do you really want an endless supply of hot water? I would propose that this could lead to abuse of your energy supply. If you really do want it I have seen homes with two water heaters to provide enough reserve for the high demands.

 

[heehaw]

if we go away for a wk-end, i always turn the gas valve to pilot on the water heater, lets say on friday night, Sunday evening when we return, i turn it back on, when i remember, and the water heater has "never" come on when i did that. several times i have forgotten to turn it back on, and the wife and i take showers/baths till tuesday evening before someone gets a cold shower and i remember to turn it back on...an i have the cheapest 40 gallon natural gas water heater i could find..i do have loflow shower heads..so we don't use a great deal of water when showering, but in my case, i can't see where a tankless water heater would save me anything.
heehaw