Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Moving in-set radiators out of walls to improve efficiency?

Options
dbrant
dbrant Member Posts: 2
Hi all,
We have several steam radiators that are in-set into the walls (see picture). I've had a suspicion that this placement of radiators is extremely inefficient, since half of the radiator is literally heating the siding of the house, and the cavity that holds the radiator should really be filled with insulation instead, with the radiator being fully inside the room.

The pipes in the basement that lead to these radiators are easily accessible and exposed, so theoretically it should be easy enough to move these radiators inward, and fill in the wall.

My question is whether this theory is valid, and whether such a project would be worth it. Would I gain a good amount of efficiency by moving the radiators out of the walls?


Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited April 2022
    Options
    The theory is valid. The piping on steam system must conform to certain parameters. You don't want to cause a problem with condensate returning to the boiler, leaving the radiator.

    Also... more important... How are you going to close those curtains with a big ole' radiator in the way?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    Options
    It's very valid. I had a much smaller version of yours in my small bathroom. I removed it and insulated the hole and the result was no apparent difference in the comfort of the room (there might have been some net difference of course with the heat coming from the hall to make up for whatever was coming out of the radiator).

    Whether it's worth it is a tougher question. What if it only saved $20 per year? Or $5? Myself, I just hated the idea of that cold hole in my wall so the decision was philosophical for me regardless of cost vs effort.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    GGrossreggi
  • ChrisJ
    ChrisJ Member Posts: 15,693
    Options
    Aren't those convectors?

    If it's a convector it needs the cover and the interior to act has a chimney so to speak, and pull air through it. You would need to buy all new, or used radiators that are the correct sizes.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    In_New_EnglandHap_Hazzard
  • GGross
    GGross Member Posts: 1,048
    Options
    ChrisJ said:

    Aren't those convectors?


    Definitely looks like a recessed wall convector. They would need to build it a little cabinet or purchase a new one.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,529
    Options
    looks like convectors to me
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited April 2022
    Options
    I have seen those as convectors with five or six 1/2" tubes with metal fins connected to a manifold at either end... I have also seen a flatish cast iron block of some design that connects like a standard radiator. Both use the same concept of the "chimney effect" to accelerate air past the heating elements located near the bottom half of the cabinet.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • mattmia2
    mattmia2 Member Posts: 9,655
    Options
    looks like it has already been retrofitted once. might be a cabinet inside a cabinet and you might be able to insulate behind it.
    reggi
  • ScottSecor
    ScottSecor Member Posts: 855
    Options
    I cannot prove it, but I think you would not reduce your fuel bill enough to notice. Just for reference, we have removed about thirty free standing radiators or hot water baseboard emitters over the years that were replaced with Sunrad style recessed radiators. The customer wanted more floor space, not have to look at those 'ugly' radiators, never kick another radiator in the dark again, etc. As a matter of fact, we did a builders house years ago and the majority of the brand new house was fitted with Sunrad style recessed cast iron radiators instead of hwbb. I loved the design so much, I happen to have one in my kitchen (with almost no wall space).

    Whenever we install a recessed Sunrad type radiator (new addition or retrofit mostly) we install a piece of 1/2" rigid foil faced foam behind it. To date, no one has ever complained that they were using more fuel.
    PC7060ethicalpauldelcrossv
  • Greybeard
    Greybeard Member Posts: 17
    Options
    What ScottSecor said. Shove a sheet of rigid foil faced foam in the back of the enclosure and call it a day. I use some behind free-standing radiators.
    delcrossv
  • mattmia2
    mattmia2 Member Posts: 9,655
    Options
    I suspect air sealing the recess will do far more than insulation.
    ethicalpaul
  • BobC
    BobC Member Posts: 5,478
    Options
    The cost of moving those convectors will never be paid for in fuel savings, it will help some but not nearly enough. Adding thin reflective insulation in back of those and sealing up the box so nothing escapes out the back or up into the wall cavity above will cut losses a lot at little cost.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    delcrossv
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    Options
    I agree with Bob C. I plan on using 1/2 thick duct insulation for the recessed convectors at my church. It is rated to be exposed, which most board insulations are not. If you want you could bond a layer of heavy foil to the insulation with duct insulation spray adhesive.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,007
    Options



    Try this. If you can get behind the unit easily. You can just staple it in place.

    delcrossvHap_Hazzard
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    Options
    No. This will not change the efficiency of the convector. No matter what you do to it, you still get the same number of BTUs per cubic foot of steam condensed. This is a physical constant that can't be changed. All you can change is the amount of steam it condenses, thus the heat output, per hour by increasing or decreasing the airflow. Effectively, this makes the convector bigger or smaller in terms of its EDR.

    Any change from the designed configuration, short of installing a fan, will probably result in a reduction in EDR. Convector enclosures are designed to optimize air flow through the convector. The best thing you can do to insure optimal airflow is to remove the cover periodically, vacuum up all the dust and cobwebs that have accumulated, and put the cover back on.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,526
    Options
    I’m with Bob C. as well. 
    Retired and loving it.
    Dave in QCA
  • pedmec
    pedmec Member Posts: 975
    Options
    Work on these a lot in the Boston area. Always see them installed with foil face paper backing behind the convectors with the foil facing the convector. Can't imagine that of the hundreds that I've seen that the installation would not work as intended and if there was a better way they would have done it. i figure that a lot of the old buildings (easy over 100+ years old) that there in would have changed it if it wasn't a good application. god knows they have had plenty of time to test it.
  • ChrisJ
    ChrisJ Member Posts: 15,693
    Options
    pedmec said:
    Work on these a lot in the Boston area. Always see them installed with foil face paper backing behind the convectors with the foil facing the convector. Can't imagine that of the hundreds that I've seen that the installation would not work as intended and if there was a better way they would have done it. i figure that a lot of the old buildings (easy over 100+ years old) that there in would have changed it if it wasn't a good application. god knows they have had plenty of time to test it.
    They work, sure.
    But so did the coal fired snowman boilers.

    The in wall convectors could be improved on greatly but it's just not cost effective to modify once they're in place.

    For example, radiators installed inside of the heating space next to an insulated wall works quite a bit better.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    ethicalpaul
  • gerry gill
    gerry gill Member Posts: 3,078
    Options
    No you won't increase the efficiency. You have two types of heat at play here. Radiation and convection. You get none of the radiation due to the cabinet. It is really the radiation heating the outside wall. You won't get that heat anyways. What you get is convection air current heat. If you want to increase the efficiency, increase the height of the cabinet. (not really practical under a window)
    gwgillplumbingandheating.com
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Jakek
    Jakek Member Posts: 55
    Options
    I had a similar situation which I documented in this thread.

    A year later I can say the room still looks much, much better but there's no change in comfort in the room and/or fuel savings. The old radiator was leaking slightly between the fins so it probably was worth it regardless.
  • gassyman
    gassyman Member Posts: 5
    Options
    I am an enthusiastic reader and fan of HeatingHelp.com, and though I have worked in HVAC throughout my career, it was with limited formal training. Because of this, I find it easier to see thing from a homeowner's or customer's perspective. My impression of the original question was that the word efficiency was being applied to the entirety of the building, not limited to the heating system. I think the insulation behind the convector is the answer. It would be interesting to see thermal images of the outside of that wall during heating season.
    Larry Weingarten