# Converting steam heat to hot water???



## beenthere (Oct 11, 2008)

I don't think your going to like the cost of new cast iron rads.
They are very expensive.
It is how ever possible to convert steam rads to hot water in many cases.

Hot water heat from cast iron rads is a very comfortable heat.
And yes, you can get your domestic hot water from the same boiler.

Why are you considering converting back to how hot water heat.


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## hvaclover (Oct 2, 2008)

Something that complicated needs an on site survey. Besides, the prices vary around the country. We have pros from all over. Post your location and see what happens.


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## Marvin Gardens (Sep 30, 2008)

I did a steam to hot water convert last year. We also put in some radiant floor heating. The boiler wasn't very efficient and we replaced it with 2 gas tankless hot water heaters. They got a lot of room when we removed the boiler and they love the system.


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## hvaclover (Oct 2, 2008)

Marvin Gardens said:


> I did a steam to hot water convert last year. We also put in some radiant floor heating. The boiler wasn't very efficient and we replaced it with 2 gas tankless hot water heaters. They got a lot of room when we removed the boiler and they love the system.


 

Yeah, but did they love the price:laughing:

Just being a smart arse. I only do warm air so I really have no clue on hydronics.


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## Marvin Gardens (Sep 30, 2008)

hvaclover said:


> Yeah, but did they love the price:laughing:
> 
> Just being a smart arse. I only do warm air so I really have no clue on hydronics.


The house was 1.4 mill.....don't think they cared. They never asked how much it was going to cost.

I felt like I was working for the government.


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## pcampbell (Feb 7, 2008)

Thanks, I am in NJ not sure why that isn't showing up on my profile thing!

As for reason, I do not like the way the hot air feels that much. 

I feel like the radiators should either be removed or be put to use :thumbsup:

How could you convert a single pipe system to hot water without changing the radiators anyway?

Maybe there's nothing wrong with the existing radiators, and nothing wrong with the steam heat. I've also just read that the hot air needs a lot more radiator surface area over steam for whatever reason.

Also I would like to get a Direct vented boiler (and was not sure if there's such thing as a DV steam boiler vs hot water?) if possible, eliminating the need for the chimney which, if we remove it, will let us use more space in our tiny house.

My understanding is that there was nothing wrong with the setup, they just switched from oil to gas and put the heat along with the A/C at the same time while they took out the oil steam boiler.

Sounds like I need to get some pros in to check it out...


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## beenthere (Oct 11, 2008)

A heat loss calc should be done. And then th2 rads measured to see if they are large enough to output that much heat using hot water instead of steam.
There is about a 35% loss in BTU output per sq ft of rad surface area when converting from steam to hot water.

If you convert to hot water, you can take advantage of an outdoor reset control, and reduce your heating cost.

A pound of 212°F steam contains a lot more heat then a pound of 212°F water.



New pipes have to be ran on single pipe systems.
The rad steam vents have to be plugged. And new vents have to be drilled and tapped.

A lot of people don't like hot air blowing on them, or the sudden hot then cold feeling an improperly installed forced hot air system can cause.


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## Marvin Gardens (Sep 30, 2008)

pcampbell said:


> Thanks, I am in NJ not sure why that isn't showing up on my profile thing!
> 
> As for reason, I do not like the way the hot air feels that much.
> 
> ...


The reason that water radiators need more fins than steam radiators is simple. Steam is over 220 degrees and water is only 140 or so. Hotter radiators put out more BTU's.

If you have gas go with a tankless for the radiators. It can be wall mounted and vented outside or even mounted outside.

I agree there is nothing like radiant heat. I just seems to warm up everything and if you get cold go and stand by the radiator.


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## pcampbell (Feb 7, 2008)

I am just so curious why contractors come in and think everyone is totally clueless. Maybe I act a little clueless because I want to see how they treat people.

I had a guy come in today to give me a quote on putting a boiler back in... and wanted to tell me I need a new gas line to the boiler, from the meter to the tune of $700. There is a 3/4" pipe and I'm curious what diameter he thinks you need to run for a 75,000 BTU boiler, but I didn't bother asking. At that point I was done with him.


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## beenthere (Oct 11, 2008)

Marvin Gardens said:


> The reason that water radiators need more fins than steam radiators is simple. Steam is over 220 degrees


On resi systems:
Steam is only over 220°F on systems with undersized pipes, or bad vents/traps.


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## j4galmom (Oct 16, 2008)

*Steam Radiators to Hot Water Radiators conversion*

Hi, I'm a single mom in NJ with 4 kids to keep warm, and no HVAC expertise - any help would be greatly appreciated!

I currently have an oil-fired steam furnace and radiator system that is rapidly declining. I've gotten estimates to replace my oil furnace with a similar oil-fired furnace steam system (a Burnham high efficiency unit) for $6,600 - *is that a decent price?* 

I also have gas coming into my house for my water heater. I've thought of converting to gas, but have been told that gas systems can't heat steam as effectively as oil. *Is that true?*

I've also considered converting from oil-fired steam heat, to gas-fired hot water system - but don't know if that would require me to replace all my 90 year old radiators. *Can you run hot water through radiators? Would I have to replace piping to do so? Would this cost me more than the $6,600 for the new oil-furnace?*

Thanks everyone!


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## beenthere (Oct 11, 2008)

Converting to hot water can cost more to do.

Depends on the condition of the pipes, you may need a lot of pipe alterations to convert.

Plus, not all steam rads can be converted to hot water.
So yes, it could cost more.

Gas can make steam just as efficiently as oil. Who ever told you it can't, is either feeding you a line of BS, or doesnt know much about gas.

Gas could prove much more economical for you to use. 
Plus, with gas, you pay for what you did use, not for what you will use.

As far as price. 

It can vary greatly from one area to the next.
Proper steam boiler piping takes time. 
The new boiler will most likely have more controls/safeties then your old one has, code requires additional ones that were not required when your old boiler was installed.


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## j4galmom (Oct 16, 2008)

*Thanks!*

Thanks "Been There" - I had a feeling that the oil company trying to sell me the new oil furnace might be snowing me with their "gas doesn't heat a furnace as well as oil" pitch.

I'm going to stick with the steam heat. I simply can't afford a conversion right now, and given that my radiators are 90 yrs. old I doubt they'll handle hot water. 

I am going to check out the gas option, since it is already running into my house, and I hate having an oil tank in my basement!

Again - thanks for the help!


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## pcampbell (Feb 7, 2008)

from NJ - if you are using PSE&G or anyone, price per therm is somewhere around $1.50 - the cost of Oil is about 50% per BTU last time I checked.


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## beenthere (Oct 11, 2008)

At $1.50 a therm, if a gas steam boiler was only 78% efficient, an a oil boiler is 80%, oil would need to be less then $2.16 a gallon to be as cheap to heat with.


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## mattedfred (Oct 24, 2008)

Marvin Gardens said:


> I did a steam to hot water convert last year. We also put in some radiant floor heating. The boiler wasn't very efficient and we replaced it with 2 gas tankless hot water heaters. They got a lot of room when we removed the boiler and they love the system.


hey marvin,

how do find the tankless water heaters? how efficient are they when they are used to heat radiant floor heating systems? i am considering either an electric boiler, NG hot water heater, NG boiler and tankless.


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## pcampbell (Feb 7, 2008)

FWIW We gave up on the steam system. I am going to rip out the radiators and sell them, and seal up where the old recessed radiators sat, and I imagine that alone will make a huge difference in the amount of cold air entering our home.


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## Marvin Gardens (Sep 30, 2008)

mattedfred said:


> hey marvin,
> 
> how do find the tankless water heaters? how efficient are they when they are used to heat radiant floor heating systems? i am considering either an electric boiler, NG hot water heater, NG boiler and tankless.


The lady I did it for loves it. Don't know how efficient they are compared to other systems. She had just bought the house and had nothing to compare it to. The boiler was ancient and I imagine they had some serious energy bills. The house is about 4000 sg ft and is 4 stories including a walk out basement.

Hydronic heating is much more efficient that air heaters. They warm up the floor and that can stay warm for a long time even with the heat off.

After I got her system in I had to go back and remove a temporary gas line in her basement and run one into her new kitchen. The floor was nice and warm even with the tile floor which is usually much cooler. I could have laid down on the floor and had a nice nap if it weren't so hard.


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## mattedfred (Oct 24, 2008)

thanks marvin, 

i was wondering why the decision was made to install tankless water heaters as opposed to tanked heaters or a new boiler? tankless heaters are only more efficient when they aren't running as in when there isn't a demand for hot water. i would think that installing a tankless heater for radiant heating as well as domestic hot water would create more demand?


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## Marvin Gardens (Sep 30, 2008)

mattedfred said:


> thanks marvin,
> 
> i was wondering why the decision was made to install tankless water heaters as opposed to tanked heaters or a new boiler? tankless heaters are only more efficient when they aren't running as in when there isn't a demand for hot water. i would think that installing a tankless heater for radiant heating as well as domestic hot water would create more demand?


I'm thinking the same thing. I tried to get her to consider a high efficiency tanked water heater for her system but she insisted on a tankless.

At first we tried to do one tankless for everything but that was not putting out enough heat so we had to add a second tankless for the radiators and floor heating. The other does the domestic hot water.


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## mattedfred (Oct 24, 2008)

thanks marvin, have you installed radiant heating using tanked water heaters before? how would you compare them to boilers?


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## Marvin Gardens (Sep 30, 2008)

mattedfred said:


> thanks marvin, have you installed radiant heating using tanked water heaters before? how would you compare them to boilers?


I am not a boiler guy. I have fixed them but have never installed one and never did a radiant system on them.

I have done several tanked water heaters with hydronic heating and it has worked well. I keep the temperature down around 100 and that seems to do well. The key is to get a large tank like a 120 gallon one. This way there is a lot of storage and the heater can keep up on colder days.


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## beenthere (Oct 11, 2008)

Keep in mind.
That a water heater used as a boiler. Won't pass code in many areas/states. As not all of them are approved as a comfort heating appliance.

When reselling the home.
An inspector could catch it. And you would have to have a boiler installed before selling the home.


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## pcampbell (Feb 7, 2008)

beenthere said:


> A heat loss calc should be done. And then th2 rads measured to see if they are large enough to output that much heat using hot water instead of steam.
> There is about a 35% loss in BTU output per sq ft of rad surface area when converting from steam to hot water.
> 
> If you convert to hot water, you can take advantage of an outdoor reset control, and reduce your heating cost.
> ...


I am looking at the radiator and.... where is the steam vent? Is that part of the little valve that allows one to control the flow? On mine they seem to be located in the middle (height wise). There also seem to already be a plug at the top of the radiator.

I took a quick look at the radiators and there's certainly a hole on the opposite side of the steam pipe suply/return that is plugged (for a HW return I assume). I am already half way through the process of ripping out the steam pipes, and it is something I want to do anyway. They are probably too big for hot water anyway. What would be the correct diameter for hot water? 1/2"?


How do you think I can go about figuring out if the existing steam radiators will be big enough for hot water?

What is the difference really, between something like a Rinnai, and a Trinity Ti (which is rated for use as a boiler)?


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## yuri (Nov 29, 2008)

If you don't like the feel of your current furnace there are much better ones out there now. Lennox make a 95% efficient G71MPP which can be used as modulating or a 3 stage furnace and gives you MUCH longer cycles and more comfort. I assume you want to keep a furnace for an air handler so you still have A/C. You can then go with a tankless water heater and have the best of both worlds.


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## beenthere (Oct 11, 2008)

Steam vents are usualy at the half way, or 1/3 height.

Go to Burnhams web site, and down load their rad size chart.

Can't tell you the difference.


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## Yoyizit (Jul 11, 2008)

*Decent price*

Get at least 5 bids, do your dot plot

..........x.......x.xx........x
$0.....$1.....$2.....$3.....$4
^relative price^

throw out the outliers at $1 and at $4 and figure the cluster in the middle is the true price of the job in your zip code in Feb., '09.
http://www.google.com/search?client=safari&rls=en-us&q="median+income"+zip+code&ie=UTF-8&oe=UTF-8


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## pcampbell (Feb 7, 2008)

I did some research, and it sounds like the radiators might be on the small side.

I wonder if we should look into radiant floor heat. I think though, that in this case we would need to very well insulate the joist bay below the radiant tubing, because our basement is on the cold side.


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## pcampbell (Feb 7, 2008)

yuri said:


> If you don't like the feel of your current furnace there are much better ones out there now. Lennox make a 95% efficient G71MPP which can be used as modulating or a 3 stage furnace and gives you MUCH longer cycles and more comfort. I assume you want to keep a furnace for an air handler so you still have A/C. You can then go with a tankless water heater and have the best of both worlds.


We are not entirely opposed to a high efficiency forced air furnce but...

How much does the unit cost if I were to install it myself?

The advantage I see of getting rid of the furnace upstairs would be getting heat from low on the living area, as opposed to blowing from the top with cold floors. This is probably our biggest complaint. REALLY cold floors. We've tried heating the basement, and it really does not do much, other than make our heating bill very high. I also insulated the ceiling of the garage (above our living room), and it didn't seem to help much. But I have the feeling that if I used foam insulation ($$$) it would probably do a much better job.

When you do a hyrdonic install with a tanked heater, where does the return water go?


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## tk03 (Sep 30, 2008)

Did you do a heat loss calculation? That is the start. I have run into very few jobs where the steam rads will not heat as a water system. It is cheaper to tighten up the home then changing the radiation. if the cast iron rads can't heat radiant will not heat without back up heat.
Get a heat loss
Size the radiation
You have a good application for a condensing boiler if possible

Remember cast iron radiation decreases heat loss as it has more radiant heat than convection. The more air currents the greater the heat loss. 

Check out this link for more info on heat loss and radiator sizing.
www.comfort-calc.net/home-page.html
There is a heat loss info section and also tech menu


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## yuri (Nov 29, 2008)

Lennox won't sell their units to anyone but their dealers. These are very high end units and need PROPERLY laid out and sized ductwork. Cannot see your setup so I cannot comment on the ductwork. We sell and install them for around $6,000 w/o major ductwork modifications.


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