how to make up for loss of baseboard linear footage

Discussion in 'HVAC Heating & Cooling' started by kdw72697, Mar 31, 2013.

  1. kdw72697

    kdw72697 New Member

    Messages:
    3
    Location:
    nj
    Hello, hoping the experts can help me figure out a heating issue.
    I plan to hire a local plumber to do the job, but at this point, I'm not even sure what I'd be asking him to estimate and/or do and I would like to clarify before I bring him in.


    I have a 14' run of cast iron hot water baseboard heater in my kitchen/dining room.

    Unfortunately (or fortunately, since I waited & saved many years to build my beloved deck!) I need to put a door to a deck somewhere on this wall.

    If I pull out this baseboard heater, I will be left with a mere 10' of 1990s slant-fin baseboard on the adjacent wall to heat the entire 14x24 room, which I am guessing will not quite cut it in Northeastern winters (NJ).

    I can possibly lose the 6' of baseboard to accommodate the door(s) and just have a few feet of new baseboard on either side, but I am not sure if that would be enough heat.

    If old-school radiators could work like hot-water baseboard, that might be an option (one which would look appropriate in my older house). But I don't know if they go beyond steam.

    I priced out radiant floor heating, which would be a fantastic option for this situation, but it's just too expensive for me at this stage of life (3 young kids, no $).

    So I am not sure how to proceed. In the meantime, we can hand our food out the kitchen window to the deck. :)
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    CI radiators work quite well with lower inlet water temps...much better than slant-fin. A CI radiator works quite well using IR radiant heating (some convection). A slant-fin works mostly by convection, and very little by radiation. Adding a door probably also means the room's heat loss will be higher, needing more heat to keep it warm than what you had. Now, what was there may have been more than what was needed. A heat load analysis is what you need to determine what's required to keep the room warm. Without knowing that, anything else is just a guess. Based on the water temp going in, you can calculate how much heat what you have now COULD produce (it's rarely on 100%), then compare that with CI radiators substituted for some of it.
  3. Dana

    Dana In the trades

    Messages:
    2,812
    Location:
    01609
    Is there any chance you can move the 14' over and replace the crummy fin-tube as part of the project? It usually comes in sections, and single sections longer than 6' are a bit unusual (and would be wicked-heavy). A typical 14' run is usually 6' + 6' + 2' bolted together, which can probably be truncated to a 6' + 2', or if there's space for a 12 footer where the fin tube now stands, a 6' + 6'.

    The BTU/foot ratings of 9-10" cast iron is typically the same range as fin-tube, but it's much nicer stuff, and is amenable to low-temp operation (unlike fin-tube), should you ever get a condensing boiler. It has far more thermal mass than fin-tube too, which both evens out the room temperature cycling, and helps keep the boiler's burn cycles long & efficient.

    Cast iron rads also work fine, as do modern Euro-style convecting panel radiators. If the room to room heat balance on that zone seems fine or needs tweaking, now's the time to figure out what to replace it with. Be sure that whatever replaces the "missing" baseboard that it has comparable heat output at some nominal temp. The derating with temperature curves for panel radiators and baseboards are similar, but big bulky high-volume very high mass radiators introduce another dynamic. You can do fine with comparable output "5 x 20" tall cast iron convective radiators (which usually fit under windows etc.) of comparable output such as the Burnham Radiant series. A 14' section of c.i. baseboard is good for ~5000-4800BTU/hr @ 150F AWT, which could be replaced by a radiator of ~50 sq.ft. equivalent surface area, such as a 20-section/ Burnham Radiant, which runs 45" in length. These are very nice rads that are often being scrapped during renovations in NY/NJ, sometimes available used for seriously cheap money, and they clean up fairly easily.

    Or you could see what there is in Euro-modern panel radiators of comparable size & output- they're usually cheaper than brand-new cast-iron, but not as cheap as reclaimed cast iron.
  4. kdw72697

    kdw72697 New Member

    Messages:
    3
    Location:
    nj
    Thank you both! It's so helpful to know what some of my options are.
    As a layperson I never thought about the fact that the 14' run would probably be a few pieces joined together! I will have to check and see.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    Imagine trying to pack and ship something that long and not bend or ding it!
  6. Dana

    Dana In the trades

    Messages:
    2,812
    Location:
    01609
    In fact they're usually assembled and painted/primed at the factory, then shipped as big long heavy awkward chunks, but usually field-reworkable if you need to add or drop a section. The seams between sections are usually pretty obvious close-up, but factory assembled under 3 coats of paint you may have to look closely. It's dead-obvious from the back side once you've pulled it out.

    If there's room for the whole 14 footer where the 10' of fin-tube currently resides, it's going to be easier & cleaner to adjust the plumbing to fit rather than break open & rework the 14-er. They're assembled with push-nipples between the sections that are quite tight, and it takes a block of wood and a sledgehammer to pop it apart (careful not to crack the casting or break off any of the fins), and you'll have to tap them for pipe fittings where the push-nipples were. Make sure you have the necessary tools and fittings before banging it apart, eh?

    New the stuff is usually well north of $50/foot sometimes north of $90/foot, which is many times cost of fin-tube, but it's oh-so-much nicer as a heat emitter, so it's worth making some effort to keep it in service if you can. Used I've seen it running as cheap as $15/foot, but $20-30/ft is more typical. If it turns out you can't really use it, keep it intact and sell it as baseboard, not as scrap- it has real value. In good shape should be able to get at least $200-300 for it selling it on craigslist or similar- a scrapper would give you maybe $20-25, provided YOU hauled it in. Even in pretty rough shape it still has value, since it can usually be cleaned up and re-painted.

    See: http://www.younits.com/baseboard-radiators-c-163_166_172.html?pto=750&pfrom=500&brand=140

    http://philadelphia.craigslist.org/for/3718826445.html


    http://hudsonvalley.craigslist.org/mat/3684329108.html

    http://jerseyshore.craigslist.org/app/3711385699.html


    BTW: The older Sunrads are nearly identical in every respect to the Burnham Radiant- and this guy is unloading a 22 section unit for $200, which is the right range for replacing 14' of 9"-10" c.i. baseboard. (If your baseboard is taller or shorter, say so.)

    http://newjersey.craigslist.org/mat/3609048929.html

    They look like this:

    [​IMG]

    Since they're only 5" thick they can be mounted flush to the wall (preferred), but were often cut into kneewalls or under windows (more heat loss out the wall that way.)

    Even if it's all scarred up a quick sand-blast cleanup makes them paintable to better-than new standards. I've seen people even use glossy automotive bake-on finishes color-matched to their decor, but cans of high-temp primer & paint can still work well for the low-budget DIYer. If you're not super picky and can go with a random off-white a cooperative independent auto-body shop will usually give you a very nice clean-up & paint service on them for $100 (order of magnitude), sometimes less, if you're willing to wait for the next time they paint a white car.

    It's better to use one that was previously used in a pumped hydronic rather than steam application, but it's not essential. The steam units will have more crud & corrosion in them, so you'd be wise to add a filter to the loop when using radiators previously used in steam systems.
  7. kdw72697

    kdw72697 New Member

    Messages:
    3
    Location:
    nj
    That Craigslist radiator is EXACTLY what I was looking for, but I had no idea what they were called nor how to search for them! Thank you!!

    I *think* I see the seams...there is a LOT of paint on these, though.

    The slant-fin run is only 8'. The 14' wall is about 13' of CI.

    Trying to attach photos...

    new baseboard on left, CI on right. Door would go in place of current window:
    photo 3-19.JPG

    I think this is a seam:
    photo 1-23.jpg

    Attached Files:

  8. Dana

    Dana In the trades

    Messages:
    2,812
    Location:
    01609
    The middle picture is definitely a seam between sections. When you pull it from the wall and lay it face-first you'll see the bolts keeping the sections together, as well as the cast-fins for enhanced convective heat transfer, etc., and probably the manufacturer's name/model cast into it somewhere (or not.)

    Putting a SunRad or Radiant with ~3/4"-1" clearance from your wainscot would look totally appropriate in that room, and function slightly better than cutting it into a cubby, or you could remove the section of wainscot and some casing-trim around it- just be sure to maintain the air-tightness of the wall and allow at least 3/4" of back-side clearance for reasonable backside convection. The radiator itself has 5 channels for convection anyway, but leaving the backside clear & convecting transfers less heat to the wall than if it was in full contact. (Some folks even put in foil-type radiant barrier on the wall to help reduce that loss.)
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