Cast Iron Baseboard vs Standard Copper
Richie921
| Posted in Energy, Heating & Insulation on
Hey guys. Thinking ahead here to my heating system. I’m going to be using hot water heat and was wondering which system would be better to use, cast iron baseboard or the standard coppoer fin? The existing system is steam radiators but I’m going to be removing the whole thing. We are doing a roof raise and I want to have the same heat system throughout. Also, I can convert my existing boiler (only five years old) to hot water but I don’t think it will be big enough for the whole house. Would I be better off converting it and getting a second boiler splitting the zones between the two or replacing it with one big boiler? Thanks
Richie
Replies
The only heat as comfortable as cast iron base, is radiant floor. Many of the 1960s vintage homes that we work on have almost continuous outside perimeter cast iron base. These usually use a water temperature of 140 to 145 degrees instead of 180 like most of the fin tube setups.
If you can afford them and don't mind the look, they are great!!
agreed!
Cast iron baseboard - less noisy and you get a radiant component that isn't there with fin-tube.
Not an expert but I would suggest one boiler, not two - look at the Weil McClain Ultra3 with indirect water heater for domestic - great combination (I have it).
Jeff
While the "standard" current residential hot water finned copper tube convectors will work, and if sized properly for the space and water supply conditions, will provide excellent comfort at little cost. They are rather flimsy. I prefer the cast iron versions, but beyond the durability, the work equally well.
As far as converting your existing boiler from steam to hot water, that can be done easily enough. Primarily it invloves different controls. You should seek a local expert to do this. The drawback will be that it (a steam boiler) is not intended for condensing operation so you will have to operate it at no less than 140 return temperature to prevent flue gas condensation that will corrode the cast iron boiler. Therefore, it will operate at 80 to 82% AFUE, at best.
Using some boilers to provide domestic hot water by means of an indirect water heater is an excellent plan. Note that I said SOME boilers. A single stage, converted steam boiler does not fall in that category. A right sized, condensing modulating boiler, operating at as low supply temperature as will meet the heating load, will be the most efficient. Most, including the Weil McLain Ultra (a very good boiler, BTW), will have built-in controls that include a "DHW override", that will divert all the capacity to the indirect water heater at a call for hot water and will adjust the supply temperature up to meet the demand. Practically an endless supply of hot water and at a more energy efficient way thatn any affordable water heater will ever produce.
So, if you decide to get a new modulating condensing boiler (I would) and you decide to use cast iron baseboards (I would) and size them for low water supply temp (say 130 degF, I would) and couple this boiler with an indirect water heater (I would) you will end up saving 10 to 15% of the fuel cost for heating, and probably 20 to 30% of the fuel you use to make hot water. The boiler will cost you up front as will the IWH and associated pumps, and the CI BB will cost more up front. That's your dilema. Pay more now, once or pay more every day for years.
Given the facts, is there any real reason to convert from steam to hot water?
"Ask not what the world needs. Ask what makes you come alive... then go do it. Because what the world needs is people who have come alive."
Howard Thurman
The OP seems to have decided on that plan before posting, so I didn't go there. My personal choice would be to keep the steam, and spend the time/money necessary to replicate the the existing CI steam radiators. US sources are scarce and foreign sources are pricey. But I like old steam systems, regardless of practicality.
IF the OP wants to convert the existing boiler, the answer is NO.
IF the OP wants to upgrade to a high efficiency, low temperature supply hot water system, I can't really find fault in that. In others words, the answer is YES. But upgrading to a high efficiency boiler is the key difference. CI vs Cu/Al fin tube is immaterial.
Thanks for the additional clarifications Tim.
Be advised that early models of the Ultra 3 have had a few glitches (all usually fixed by reps/techs).
Jeff
Keep your radiators. They can be used for hot water. I love my radiators. There's nothing better for drying out you and your workclothes after a cold wet day.In my opinion they take up less wall space. If you don't like the look, make covers for them
Maybe. Steam rads can't be used for water. The columns on steam rads are not connected to each other at the tops.
and ... they are inevitably too small.
I've never heard that before, i believe you but i have two i converted in my house with no problems and have seen it and done it in other homes. Maybe a Pa thing, who knows.
Hydronic (hot water) systems need a lot more heat transfer surface area because of the way that hot water transfers heat vs. steam - review 'latent heat' etc.
Jeff
Hey guys...sorry it took me so long to reply. My computer was being repaired. I was looking into the cast iron base more and found it to be really expensive (like 35 to 40 dollars per foot) when compared to copper base. Now I'm thinking about radiant floors. What is your opinion on this type of heat? I've never experienced it. Does it perform well? The house will have hardwood throughout except the baths and kitchen (ceramic tile) and the bedrooms (carpet). How does the cost of a radiant system compare to cast base and copper base? Thanks.
Before you give up on the cast baseboard heat, go to a salvage yard for building materials or maybe a regular scrap yard and you are likely to find them.
Unless they have been smashed, they are usually in good shape.
Sandblast them and repaint a nice color to match your decor..and you are in business.
Look real carefully for freeze cracks in a junk yard radiator. The cracks can be hard to see. You may want to pressure test them before installing them to find that you installed a heavy piece of scrap iron to be replaced.
Yeah, be prepared for some work if you go with the junkyard variety. I salvaged some out of an old remodel to use in my kitchen. It was a comedy of errors. It wasn't until I had them in the house that I discovered that I had two varieties of baseboard that didn't fit together. Then I went through all the trouble of air testing only to discover that I still had leaks when I put the water on--an old plumber told me that you can't air test old iron because the rust plugs the air holes. (I figured out that I could test them with water more reliably) I got the leaks fixed, finally--it was a matter of really thoroughly cleaning the old push nipples. A whole house full of recycled radiators would be a serious project, and you better have some patience.
Yes, By all means test them first!
I am thinking of all the perfectly good cast baseboard that we scrapped because nobody wanted them. What a waste!
Edited 2/5/2009 10:40 pm ET by BoJangles
Don't ask Riversong about radiant heated floors!!!!But I think he is taking a break because he feels we don't worship him enough!!!