# go from hot water heating to forced air



## alex333 (Jun 9, 2008)

My house has hot water heating with in-wall cast iron radiators. The boiler is probably 50 years old although expansion tank and some other parts have been replaced some time ago. I am planning to install central air with duct work. Does it make sense to install hot air system along with ac and get rid of hot water heating? How much extra would I pay to install hot air along with ac? Also, comfort wise and monthly bills, does it make since to get rid of hot water system?


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## pcampbell (Feb 7, 2008)

I am not a huge fan of forced hot air. It will come down to a lot of things, personal preference. Duct location, etc. Forced air tends to be very dry but you could get a humidifier. Also if your cold air vents are going to be on the ceiling, this works wonderfully for A/C since the cold air sinks, but not that well for hot air which rises. We also have in wall cast iron radiators, but they are steam. The previous owner took out the boiler but we would like to get them going again eventually.

If you get rid of the heat, are you going to rip out all of the radiators. How much work is that going to be compared to keeping the old boiler, vs getting a new boiler.


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## NateHanson (Apr 15, 2007)

I would not recommend replacing FHW heat with FHA. It's not as consistent or as comfortable in my experience. Also it's loud.


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## geo fan (Jun 12, 2008)

*compermise*

hot water is quite and comfortable the real benifit to forced hot air is you can condition it with filters humidifiers and rgf's which if done will make it more comfortable energy costs will go up inless you install a dual feul heat pump-condensing gas or the mack daddy geo thermal heat pump
a good compermise is to run 2 1"pipes from the boiler location to the air handler this will alow you to easily install a radiator in the ductwork called a hydro coil in the future or install a heat pump and have your boiler as second stage back up 50 years is time to start making plans and remember there will be asbestos insulation in that boiler so when its disturbed have your children out


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## javan (Jun 9, 2008)

I have forced hot air and would love to go to a hot water system, but the investment is just too great right now.

How water is so much more comfortable and quiet, compared to the hot air. I am assuming that you are doing this so you can have AC.

We just use ceiling fans and one small window A/C unit and that works ok.


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## Piedmont (Nov 1, 2007)

I also don't like forced air. I haven't met anyone who liked them over a forced water system. With water systems the fluid takes time to heat/cool giving a more consistent heating, doesn't just turn on/off instantly like forced air. I find with forced air you're either too hot or too cold depending when the blowers turn on/off and their start-up can be noisy. They also can lose a lot of energy through ducts, it's not easy to locate duct leaks like it is for a water system (a water system it's very easy). I also prefer window ac units to central air conditioning. Although a central air unit more efficient when you consider duct loss I think them less efficient in the end. Window ac units have no ducts you get 100% of their cooling (I think them more efficient in the end) and can easily control the temps of the room. But, although I prefer window AC units they're not for everyone (lugging them around, and they're noisier). Our house just takes a single window unit to keep our house cool, and having it cool our house it runs constantly so it also keeps our humidity down. So, I'd stick with the water heating and add window ac units if you can. Doesn't sound like your house is very new the way you're talking, may need several window units and if your house is very old its electricals may not handle them.


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## DUDE! (May 3, 2008)

I wouldn't want the forced hot air either, spend time in three houses that have it, seems you get it all at one time. I have hot water radiator heat, use a couple room air conditioners. My sister just added central air to their house, they have oil fired hot water for heat, only thing I can say about that is I'm glad I don't have to lug that heavy air conditioner no more. Might be off here but if I was looking to replace my furnace, I'd look into those geo thermal units you hear about. just my two cents


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## pcampbell (Feb 7, 2008)

one thing someone mentioned which i agree with which is nice is having the air filter on the blower. we catch all kinds of junk in there. i love our central A/C but would like to get rid of the heating aspect of it for radiators.

i also really like the direct vented room furnaces. these things are like 14 stage so the blower goes quiet frequently giving off less heat to maintain a consistent temperature. and also have a humidifier and filter built in.


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## vivibae (Aug 2, 2008)

Is it possible to have CAC and radiator heating? Excuse me if my question doesnt make sense. I am house shopping and found a house that I am interested in, but it has radiator heating. I read in other sites that the radiator heating is more comfortable then forced air, but we would like to get central air. Depending on the responses will probably help me make a decision on this house. I appreciate any help. Thank you.


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## pcampbell (Feb 7, 2008)

yes they would just be 2 completely separate systems.


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## Tommy Plumb (Oct 7, 2006)

Keep the radiators but defiantly change out that old boiler.


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## DUDE! (May 3, 2008)

my sister's cape has hot water radiator heat, they added central air, she did "lose" a first floor closet to get the duct work up to the second floor. I guess you would need to consider space requirements for ductwork.


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## Wildie (Jul 23, 2008)

Someone mentioned that high registers for a/c are no good for heating. My home, built without a basement, has the duct work in the attic, connected to registers in the ceiling.
I have found that this is superior to floor registers.
Floor registers blow the heat to the ceiling, whereas the ceiling registers blow the heat down, where its needed.
Its my opinion that floor registers are a throw-back to the old gravity furnace concept, and this concept should be revisited.
A common complaint of forced air heating was that you got a blast of cold air before the heat came out. 
This doesn't happen on my H/E furnace. I believe its because the blower comes on in stages.


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## Mike Warner (Jul 6, 2007)

I'm going the opposite way, from 45 year old forced air to hot water heat. I'm running copper fin-tubed baseboards baseboards, connecting them with Pex tubing to a manifold. I've got a 93% efficient wall-hung modulating/condensing boiler that will also heat my indirect fired hot water heater. I'll get rid of the conventional old (15 year) hot water heater and my 40% efficient forced air furnace. This is all DIY. I've been designing this since February 2007. I used the free "The Radiant Advantage" from Embassy systems for heat load calculations for starters. You then have to figure out head loss calculations and balance your zones. Its pretty involved for a do-it-yourselfer, so you need at least a year figuring things out. It is a steep learning curve.

A high efficiency forced air furnace would have been much cheaper (maybe $2000 compared to $9000), but read the other posts and you'll see that hot water heat is preferred. I'm just a baker, and I needed to take out three loans for this. I had all the ductwork for forced air. You have all the radiators for hot water, plus they are all piped. That will save you at least $2000. It might be worth paying a professional two or three hundred bucks to consult on replacing your boiler with a newer one.

Good luck whatever you decide.


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## Wildie (Jul 23, 2008)

Mike Warner said:


> I'm going the opposite way, from 45 year old forced air to hot water heat. I'm running copper fin-tubed baseboards baseboards, connecting them with Pex tubing to a manifold. I've got a 93% efficient wall-hung modulating/condensing boiler that will also heat my indirect fired hot water heater. I'll get rid of the conventional old (15 year) hot water heater and my 40% efficient forced air furnace. This is all DIY. I've been designing this since February 2007. I used the free "The Radiant Advantage" from Embassy systems for heat load calculations for starters. You then have to figure out head loss calculations and balance your zones. Its pretty involved for a do-it-yourselfer, so you need at least a year figuring things out. It is a steep learning curve.
> 
> A high efficiency forced air furnace would have been much cheaper (maybe $2000 compared to $9000), but read the other posts and you'll see that hot water heat is preferred. I'm just a baker, and I needed to take out three loans for this. I had all the ductwork for forced air. You have all the radiators for hot water, plus they are all piped. That will save you at least $2000. It might be worth paying a professional two or three hundred bucks to consult on replacing your boiler with a newer one.
> 
> Good luck whatever you decide.


 Its said that h/w heat is more even. The problem is ducting for a/c.
There's no reason that that you can't have both.
My brother-in-law had an old h/w system that needed to be replaced, so he opted forced air heating with central a/c.
I use a programable thermostat and have it set drop back a couple of degree's at night. 
We like it cooler at night.
Is this an option with h/w heating?


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## Mike Warner (Jul 6, 2007)

Wildie said:


> Its said that h/w heat is more even. The problem is ducting for a/c.
> There's no reason that that you can't have both.
> My brother-in-law had an old h/w system that needed to be replaced, so he opted forced air heating with central a/c.
> I use a programable thermostat and have it set drop back a couple of degree's at night.
> ...



You can have programmable thermostats with hot water heat. A friend has programmable thermostats with hotwater heat which he can monitor and reset over the internet.
You have to have ducting AND some type of piped radiation. Ducting for central a/c and either radiant floors (Pex in a poured slab is most efficient, it can run at 120 degrees), radiators or baseboard. I've heard of hot water heat exchangers inside the ducting, and even though it may be a good application in a few circumstances, I doubt if it is as efficient as the other hot water configurations. I really don't know, I've never looked in to it. Where I live is dry and hot in the summer, so I opt for a swamp cooler, which is more efficient (I think) than central a/c. Also, in my case in an older home, I've had to retrofit baseboard radiators and plan to run them at 150 degrees at the coldest 0 degree design day. The modulating/condensing boiler with an outside temperature sensor will automatically reduce the maximum 150 degrees down to a lower more efficient temperature when it is not as cold outside.


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## Wildie (Jul 23, 2008)

Mike Warner said:


> You can have programmable thermostats with hot water heat. A friend has programmable thermostats with hotwater heat which he can monitor and reset over the internet.
> You have to have ducting AND some type of piped radiation. Ducting for central a/c and either radiant floors (Pex in a poured slab is most efficient, it can run at 120 degrees), radiators or baseboard. I've heard of hot water heat exchangers inside the ducting, and even though it may be a good application in a few circumstances, I doubt if it is as efficient as the other hot water configurations. I really don't know, I've never looked in to it. Where I live is dry and hot in the summer, so I opt for a swamp cooler, which is more efficient (I think) than central a/c. Also, in my case in an older home, I've had to retrofit baseboard radiators and plan to run them at 150 degrees at the coldest 0 degree design day. The modulating/condensing boiler with an outside temperature sensor will automatically reduce the maximum 150 degrees down to a lower more efficient temperature when it is not as cold outside.


 I'm unfamiliar with the term "swamp cooler'. Would this be a condenser that is lain in a swampy area?
Are these Fahrenheit temperatures?


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## Mike Warner (Jul 6, 2007)

Look up swamp cooler on the internet. Fahrenheit.


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## Mike Warner (Jul 6, 2007)

If it were Celsius then that convert into 302 degrees fahrenheit. I mean no offense, but do a little of your own homework.


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## Wildie (Jul 23, 2008)

Merci beucoup! Mike! I hope that you won't offended that I'm offended.


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## geo fan (Jun 12, 2008)

*They still make swamp fans*

I thought those things went out in the 70's.
nothing like adding humidity to the air to cool off , ahhh nice and clammy


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## Steven62 (Aug 21, 2007)

Nope, still around and going strong. If you live in a dry climate, they are the right type of cooling, not for everyone or every climate for sure!
I now live in Southern Missouri, and a swamp cooler (evaporative cooler) would probably drown you!


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## Wildie (Jul 23, 2008)

Sounds to me as if a 'swamp cooler' would be a wonderful source of 'Legionaires Desease' if it were not maintained properly!


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