hot water tank element

[StupidSheet]

Hi, I did a search and after many hours of reading through some interesting threads I didn't find my answer. Many of you have used infloor heat in your shops which I intend to as well. Has anyone ever used a heating element for a hot water tank as your heat source? I know people use the whole htw setup but I haven't seen anyone use just the element yet.

Reason I ask is a friend recently showed me a pic of someone he knows that used this and said his bills are averaging around $35-50 a month. In Manitoba's cold climate that is pretty impressive. Is this what these tankless water heaters are basically doing?

Has anyone tried just the element? I will upload a pic of this setup when I get home tonight.

 

[philjafo]

At a factory I once worked at as a maintenance tech, we had built a wash booth that had two elements from water heaters in the open tank at the bottom. So I guess something could be built if you absolutely had to. However a water heater is a pressure vessel, and has the appropriate safety features engineered and built in already. Reasonably priced also. Make sure the water heater can provide the correct amount of btus that you need and change the t&p relief valve with a 30 psi one for a hydronic system and make sure you put in the rest of the safety features of a proper hydronic system. No need to reinvent the wheel. If a water heater can't provide enough btus there are electic boilers and tankless water heaters usually have higher btu output.

 

[StupidSheet]

Here is a pic of the setup he has.

 

[koditten]

I can not get the pic to enlarge. Details are not viewable by me. I'm interested in seeing this better.

Thanks

KO

 

[RECox286]

The heaviest electric element that I'm familiar with is 4500 watt.

Not knowing what kind of delta T you are trying to achieve, my first

thought is that 4500W, while a fair amount will only be a tickle,

where a KO is required. You also have a problem with the homemade

device in that there is high voltage connections which appear to be

visible on the device. I would steer you toward a higher wattage

point of use water heater that will be safer, and more effective in

doing what you are attempting. I think you are on the right track,

but just siderailed at the moment.

Good luck

Uncle Bob

 

[walleye catcher]

hey, i use a 5000w 240 v hot water element in a 1 1/2 black pipe, control by a baseboard thermostat, circ pump, and piping and this is an open system with a 3" abs expansion pipe on the down side of the pump, so you fill the floor and 1/2 way up the 3" expansion tube and turn on the 30 amp breaker and presto infloor heat. I have used pex and wirsbo piping with great success...very in expensive and simple...it is a kiss system (keep it simple stupid) and i have done probably 30 - 40 floors this way.

 

[walleye catcher]

is that galvanized piping to copper?? not a good set up galvanized will corrode black steel is better.

 

[walleye catcher]

you can purchase a element with a junction box on it. with enough room to terminate bx cable (armour sheathed)

 

[walleye catcher]

not sure how you pm me here...but im in manitoba and have used this successfully for years with out any call backs

 

[StupidSheet]

This isn't mine. This is a friend of a friend and supposedly it works great and is really cheap to operate. I want to put infloor heat in my shop but I don't want a $150 a month bill to go with it. This guy is running this setup for $35-50.

 

[walleye catcher]

This isn't mine. This is a friend of a friend and supposedly it works great and is really cheap to operate. I want to put infloor heat in my shop but I don't want a $150 a month bill to go with it. This guy is running this setup for $35-50.

hey you want to contact me? I dont want to post my email in the open. I have lots of good info for you. How do I contact you?

 

[hybred355]

I am wondering how big a floor will this set up heat?

 

[StupidSheet]

hey you want to contact me? I dont want to post my email in the open. I have lots of good info for you. How do I contact you?

I sent you a PM.

I am wondering how big a floor will this set up heat?

This guy's shop was right around 1000sq ft if I remember right. I can find out for sure.

 

[Alchymist]

Might want to look into pool heaters:

http://www.poolsupplyunlimited.com/...r15ILS/18233?gclid=CIjogeK2u7YCFcud4AodMX4A3A

or

http://www.little-giant.com/water-heating-products/pool-spa-heaters/electric-pool-spa-heaters.html

as examples. All sizes and variations available. Worth a look.

 

[jvitez]

Are you interested in this because the operating cost is cheap, or because putting it together (capital cost) is cheap?

If operating cost, heat input is heat input. Now much electricity you use depends on how much heat the garage loses. So an electric boiler, tankless electric water heater, or k type water heater will use very close to the same amount of electricity. The loses of hot water sitting in a tank are less important here as the heat is going into the same space you're heating anyway.

 

[StupidSheet]

Might want to look into pool heaters:

http://www.poolsupplyunlimited.com/...r15ILS/18233?gclid=CIjogeK2u7YCFcud4AodMX4A3A

or

http://www.little-giant.com/water-heating-products/pool-spa-heaters/electric-pool-spa-heaters.html

as examples. All sizes and variations available. Worth a look.

I wonder how that would work.

Are you interested in this because the operating cost is cheap, or because putting it together (capital cost) is cheap?

If operating cost, heat input is heat input. Now much electricity you use depends on how much heat the garage loses. So an electric boiler, tankless electric water heater, or k type water heater will use very close to the same amount of electricity. The loses of hot water sitting in a tank are less important here as the heat is going into the same space you're heating anyway.

Basically both, I was told the initial cost was cheap and to run it was cheap. I don't know if this would be any cheaper to run than a boiler in the exact same building but thought I would ask if anyone else has tried it. I am going to talk to my friend and see if I can go take a look at this setup and get some more info.

 

[walleye catcher]

that unit is only 1.5 kw way too small...u need at least 5kw for a small floor. An electric heating element is $30

 

[Alchymist]

that unit is only 1.5 kw way too small...u need at least 5kw for a small floor. An electric heating element is $30

They are available in many sizes - here's one at 11KW -

http://www.little-giant.com/assets/docs/swimmax-wiring-diagram.pdf

Now, by the time someone builds a housing for a water heater element, adds the relays and safety devices, how much time and $$ will be invested? To top it off, no UL approval. One does what one will do, I guess.

 

[jrfiero]

This is a cool idea!

I run a 30 gal tank with a convertible 3800/5500 watt lower element which I've pretty much decided to leave on 3800. Description here http://www.garagejournal.com/forum/showthread.php?t=185015 .

Two other advantages in building this tankless system is it takes less room and weighs a lot less.

Safety? Bah.

Jonas

 

[Highbeam]

The set up won't save energy. Whether the element is in a real HWT or is scabbed into a section of pipe, it will still have to run the same amount to heat the space. No operating cost savings.

Is it cheaper than just buying a HWT? Probably, but the HWT has other benefits and safety features. You can buy a small HWT with the same wattage element and not loose the floor space.

 

[StupidSheet]

The set up won't save energy. Whether the element is in a real HWT or is scabbed into a section of pipe, it will still have to run the same amount to heat the space. No operating cost savings.

Is it cheaper than just buying a HWT? Probably, but the HWT has other benefits and safety features. You can buy a small HWT with the same wattage element and not loose the floor space.

I definitely won't be buying a hot water tank to heat my shop. I've heard from more than a few that it is very inefficient and the tanks don't last. I will either do something like this or a tankless boiler I'm thinking.

I disagree with you about using as much energy. This system is heating the water in smaller amounts.

 

[Alchymist]

I definitely won't be buying a hot water tank to heat my shop. I've heard from more than a few that it is very inefficient and the tanks don't last. I will either do something like this or a tankless boiler I'm thinking.

I disagree with you about using as much energy. This system is heating the water in smaller amounts.

Not happening. To raise the floor to a given temperature from a given temperature takes "X" amount of BTUs. Regardless of how those BTUs are obtained ( assuming electrical heating of water) it matters not how it's heated, the energy consumed remains the same. Only "difference" might be heat loss of a stored water tank, but even then it's minimal if the tank is in the same area as the heated space. TNSTAAFL.

 

[anthony666]

the trick with electric heat is to run it up during off peak hours a few degrees above target and then just let her radiate during the day to below target temp

insulate as much exposed pipe as possible because you wanna keep the heat in the slab .. you'll rapidly lose a lot of heat from exposed pipe, yes it's inside your space but you want it to radiate slowly from the slab not spill out uncontrolled, thermal mass is your friend

think of it this way, if you're in a house with a wood stove it starts to get real cold as soon as the fire is out .. if you're in a house with an insert in a big brick or stone chimney it takes many hours after the fire is gone before you start to feel it because the heat soaks into the chimney and then works it's way out slowly

so a few dollars spent on a timer is gonna save you tons if you're in a place where power is cheaper in the wee hours

 

[Highbeam]

I definitely won't be buying a hot water tank to heat my shop. I've heard from more than a few that it is very inefficient and the tanks don't last. I will either do something like this or a tankless boiler I'm thinking.

I disagree with you about using as much energy. This system is heating the water in smaller amounts.

Well, we'll have to agree to disagree. Just about everything you said here is false and demonstrates your funamental misunderstanding of heating systems.

You do realize that a tankless boiler is just a miniature hot water heater dont you?

 

[StupidSheet]

Well, we'll have to agree to disagree. Just about everything you said here is false and demonstrates your funamental misunderstanding of heating systems.

You do realize that a tankless boiler is just a miniature hot water heater dont you?

Yes you are right I don't know much about these types of heating sytems. I thought a tankless boiler was basically very similar to the picture I posted, just done up right with a nice enclosure.

What I do know is I won't be using a complete hot water tank as I know for a fact that is not the proper way to go or are they as effecient. I've talked to at least 3 people here that have tried it and have since switched over to a boiler.

 

[anthony666]

You do realize that a tankless boiler is just a miniature hot water heater dont you?

by that logic a corvette is just a miniature school bus

 

[VHF]

Reason I ask is a friend recently showed me a pic of someone he knows that used this and said his bills are averaging around $35-50 a month. In Manitoba's cold climate that is pretty impressive.

Must be a very well insulated building or very low electric cost! At $0.10/kWH you would only be able to run a 4500W element for 111 hours out of the month. That's only about a 15% duty cycle.

A 4500W element only puts out 15,300 BTU/hr. At a 15% duty cycle I don't think that is going to do the job to keep a garage warm in a cold climate. Maybe would keep a well-insulated garage above 40F.

Consider that a typical forced air furnace is 60,000 BTU/hr and might run at a 30% duty cycle on a moderate winter day (approaching 100% duty cycle as it gets colder outside until the "design temperature" is reached.)

As has already been mentioned, as far as efficency is concerned, it really doesn't matter if you have a bare element, a tank, or an electric boiler. Electric heat is all the same, 100% efficent at the point of use at converting electric power into heat (nothing is lost up a chimney.)

How fast your building looses heat determines how much heat you need and how much it will cost you to keep it warm.

 

[Sureshot]

Yes you are right I don't know much about these types of heating sytems. I thought a tankless boiler was basically very similar to the picture I posted, just done up right with a nice enclosure.

What I do know is I won't be using a complete hot water tank as I know for a fact that is not the proper way to go or are they as effecient. I've talked to at least 3 people here that have tried it and have since switched over to a boiler.

Don't dig your heals in too deep. I think the way to look at it is the thermal mass. 40 gallons of water is 350 ponds for simple math. A slab in a 24x24 garage is likely in the realm of 27k pounds although someone is free to correct me as I think that is low. You are not gaining or losing much thermal mass compared to the thousands of pounds the slab weighs.
I think if you had all the info on the water heaters etc you would see it is more the size of the heating element and peoples comfort level with a factory heater or a home made setup like yours.
I would have no problem using your setup in the right application and you could easily tee in for solar to supplement in the fall and spring or wood/propane boiler for the worst of winter.

 

[StupidSheet]

Ok so as I was saying about a hot water tank be effecient. That was probably the wrong choice of words. What I should've said was it isn't very cost effective. From what I've been told from a few people is it costs a lot more to operate than a boiler systen and that HTWs aren't designed to be used in that way and burn out(bad choice of words again) quicker requiring replacement of the tank. That is the reason I doubt I would ever go with a HWT.

Thanks for a lot of the informative replies. By the sounds of it though, no one has ever tried to use just the element by itself so no one can positively tell me if this works well or not.

 

[philjafo]

Must be a very well insulated building or very low electric cost! At $0.10/kWH you would only be able to run a 4500W element for 111 hours out of the month. That's only about a 15% duty cycle.

A 4500W element only puts out 15,300 BTU/hr. At a 15% duty cycle I don't think that is going to do the job to keep a garage warm in a cold climate. Maybe would keep a well-insulated garage above 40F.

Consider that a typical forced air furnace is 60,000 BTU/hr and might run at a 30% duty cycle on a moderate winter day (approaching 100% duty cycle as it gets colder outside until the "design temperature" is reached.)

As has already been mentioned, as far as efficency is concerned, it really doesn't matter if you have a bare element, a tank, or an electric boiler. Electric heat is all the same, 100% efficent at the point of use at converting electric power into heat (nothing is lost up a chimney.)

How fast your building looses heat determines how much heat you need and how much it will cost you to keep it warm.

Basic math says it won't work very well, but if you sure everyone else is wrong, go ahead and build your tankless water heater (that's basicly what your trying to build). Let us know how it works for you, I've been wrong before but a btu is a btu, and 15,300 likely won't be enough to keep up.

 

[jvitez]

I think the big negatives about using tank type water heaters for in-floor radiant heat comes from folks using NG fueled water heaters. Low temps case condensation in the flue which leads to rust.

An electric heater should be much better. It's a pretty well closed system, and as stated before all electric heat is 100% efficient at point of use. But main neg is low input. I agree, 4500W isn't much in Manitoba's winter, unless the space is really really really well insulated and air sealed, or really small.

 

[jrfiero]

Ok so as I was saying about a hot water tank be effecient. That was probably the wrong choice of words. What I should've said was it isn't very cost effective. From what I've been told from a few people is it costs a lot more to operate than a boiler systen and that HTWs aren't designed to be used in that way and burn out(bad choice of words again) quicker requiring replacement of the tank. That is the reason I doubt I would ever go with a HWT.

Thanks for a lot of the informative replies. By the sounds of it though, no one has ever tried to use just the element by itself so no one can positively tell me if this works well or not.

Walleye Catcher said he'd done 30-40 systems like this, and had plenty of information for you.

I put in a link to my post about my system which uses a 30gal tank with a convertible 3800/5500 element, and here's another link to some thoughts on my tank. http://garagejournal.com/forum/showthread.php?t=189861

If you're going to ask questions you should read the answers.

 

[StupidSheet]

Walleye Catcher said he'd done 30-40 systems like this, and had plenty of information for you.

I put in a link to my post about my system which uses a 30gal tank with a convertible 3800/5500 element, and here's another link to some thoughts on my tank. http://garagejournal.com/forum/showthread.php?t=189861

If you're going to ask questions you should read the answers.

Yes I'm trying to set up a time to contact him. I will look through your post, who knows maybe I will be converted.

This thread was started just to see if anyone has done anything similar to the picture I osted as I was told it is very cheap to operate. I have very little information about it and am skeptical. I did not intend this to be tankless being better or hot water tank being better thread. As many of you can tell I have very little knowledge on either. I have been told on a few occassions that hwt are no good to use but as some of you have stated this is not the case. I guess I will read some more about what's available and then make an informed decision. All I know is I don't want to have $150 monthly electric bill to heat my shop in the winter so I'm looking for the cheapest possible way. That's why the system I posted the picture for peaked my interest.

 

[Highbeam]

That's fine, but just know that all electric heaters will cost you the same amount of money to run. Step back and consider that it takes a certain amount of energy to maintain a certain temperature in your garage. You buy electricity by the killowatt hour which is a fixed amount of energy. You're consume however much of this energy is needed whether you spend it through a tankless boiler, a tank heater, or even an electric furnace.

If it costs 150$ for the electricity then it costs 150$. There's no free lunch.

 

[jrfiero]

Yes I'm trying to set up a time to contact him. QUOTE]

As you may know, you can send anyone a private message by clicking on their screenname at the left of their posts and selecting "Send a private message to ..." He mentioned he didn't want to publicly post his email, so the private message function of this forum is the way for you two to set up a conversation.

And, I think I started my first post in this thread with "This is a cool idea," so I don't mean to seem all negative.

 

[jvitez]

That's fine, but just know that all electric heaters will cost you the same amount of money to run. Step back and consider that it takes a certain amount of energy to maintain a certain temperature in your garage. You buy electricity by the killowatt hour which is a fixed amount of energy. You're consume however much of this energy is needed whether you spend it through a tankless boiler, a tank heater, or even an electric furnace.

If it costs 150$ for the electricity then it costs 150$. There's no free lunch.

Very well said!

 

[Sureshot]

I stumbled across someone doing this a few days ago. Same homemade system in SW Manitoba and he said $160/month.

 

[StupidSheet]

That's fine, but just know that all electric heaters will cost you the same amount of money to run. Step back and consider that it takes a certain amount of energy to maintain a certain temperature in your garage. You buy electricity by the killowatt hour which is a fixed amount of energy. You're consume however much of this energy is needed whether you spend it through a tankless boiler, a tank heater, or even an electric furnace.

If it costs 150$ for the electricity then it costs 150$. There's no free lunch.

So an electric furnace heating a shop or a HWT heating a shop or electric construction heater would all cost the same to heat the space?

 

[anthony666]

So an electric furnace heating a shop or a HWT heating a shop or electric construction heater would all cost the same to heat the space?

radiant heat isn't just about producing btu's, it's about how you manage and utilize those btu's

you can heat a bunch of air and have it leak out of every crack and stratify in the highest altitude where it's wasted .. or you can heat a large thermal mass which will slowly warm everything in your shop and continue to do so for hours making you very happy

stick with your original plan

 

[Alchymist]

So an electric furnace heating a shop or a HWT heating a shop or electric construction heater would all cost the same to heat the space?

The cost PER BTU would be the same. How you managed the heat produced could vary.