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Radiator Reflector Panels - Thoughts?

I was just wondering what everyone thinks about putting Aluminum Radiator Reflector Panels behind their steam radiators in order to reflect more of the heat out into the room instead of the wall absorbing the heat. From my reading on this subject I understand this is done a lot throughout Europe and with success. Thoughts???
Crown Boiler Bermuda Series model: BSI103, BTU output: 85,000, single pipe steam system

Comments

  • BrianT1077
    BrianT1077 Member Posts: 108
    Crown Boiler Bermuda Series model: BSI103, BTU output: 85,000, single pipe steam system
  • vaporvac
    vaporvac Member Posts: 1,520
    @BrianT1077 , I have used similar and one can really feel the difference. I actually bought mine in England years ago where is is sold for that purpose. It was applied with wallpaper paste. Somewhere there's some IR pics from a few years ago, where on of the pros experimented with two side-by-side rooms. It was obvious, but I already suspected as much. ALL my old semi-recessed rads had a reflective metal piece custom installed originally, so this isn't a new concept.
    Thanks for the Empire State Building info., @Dan Holohan ; I wasn't aware of that detail.
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
    BrianT1077
  • SWEI
    SWEI Member Posts: 7,356
    Bubble wrap definitely works. If I were remodeling and wanted longevity, I'd probably use XPS and polished aluminum sheet metal.
    BrianT1077
  • BrianT1077
    BrianT1077 Member Posts: 108
    Well tonight I thought I would try some Reflectix in the dining room behind the radiator. I stapled it to the wall. I will do the other rads over the next few days. Stuff is actually very easy to use. Think I should trim off the part that covers the molding? Thoughts?




    Crown Boiler Bermuda Series model: BSI103, BTU output: 85,000, single pipe steam system
    LionA29
  • marcusjh
    marcusjh Member Posts: 79
    This brings back memories for me. Long ago, my Dad read an article somewhere about reflecting heat back into a room with aluminum reflectors. So he took some cardboard, lined it with aluminum foil, and tacked it to the wall behind his radiator. The cardboard was from a large box, and he scored the top of it so it angled over the top of the radiator. I remember the top of the reflector eventually resting down on top of the radiator, and getting really hot. I think his room was the only one that had one, and 'm not sure it worked very well for him. He finally got rid of it in the 90's.

    I always wondered if one of those heat generated fans would work on a radiator, but I'm not sure if they get hot enough (aren't they for wood stoves?).
    BrianT1077mvickers
  • LionA29
    LionA29 Member Posts: 255
    Looks fine, I used the foil faced styrofoam.
    BrianT1077carlboiler
  • rosaliedipietro2
    rosaliedipietro2 Member Posts: 16
    Would a piece of sheet metal work well?
    mvickers
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    Anything which includes some insulating value is better than just sheet metal.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    @rosaliedipietro2 I suggest you read your messages, that's the envelope at the top of the page.
  • random12345
    random12345 Member Posts: 469

    Would a piece of sheet metal work well?

    Forget sheet metal. Too expensive, and not that great. Aluminum foil. Either tape it to the wall with aluminum high temp flue tape or get some craft wire, shape it into a rectangle and then take sheets of foil and put it over that like you would spread a cloth canvas over a wood frame. Place the foil wrapped frame behind the rad. As far as I can tell aluminum foil has one of the highest infrared reflectivities of any material at the wavelength of light emitted by a steam radiator that is at 215 F.

    https://sciencedirect.com/science/article/pii/S2215017X1930373X

    According the Wien's displacement law, a steam rad at 215 F (374 K) emits peak blackbody radiation at around 7731 nm. According to the article above, the total reflectivity of aluminum foil is nearly 100% at 2500 nm. It should be even higher at longer wavelengths. At least that's my understanding.

    I've tried it, and the walls behind my rads are no longer hot. It works.
    BobC
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    Anything which includes some insulating value is better than just sheet metal.
    Depends what the goal is. If the goal is to reflect radiant IR back into the room instead of letting the wall absorb it, insulating material is irrelevant.

    This was part of the Empire State Building's heating retrofit a few years back, part of what got them a LEED Gold rating.

    was the other part a healthy donation to LEED? 😂
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    My point is to use something more than just sheet metal, like the aluminized bubble stuff, foil faced insulation, etc.

    Regarding infrared reflectivity, I have to take the Sgt. Schultz plea, " I know nothing"...probably about a lot of other subjects, too.


    carlboiler
  • hot_rod
    hot_rod Member Posts: 22,120
    I think the more polished the better. I bought some mirror finish contact paper to build a solar oven once. Any dust or rain deposits really cut down on the power.
    Be interesting to find an old mirror at a second hand shop to compare to the bubble foil

    We found the same issue with reflective foil under radiant staple up. Once it got a layer of dust, the reflectivity was gone, output dropped 

    Plus the mirror would show where the painting missed🥴


    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • dabrakeman
    dabrakeman Member Posts: 552
    I use the carboard and aluminum foil method on a couple radiators. No tacking in place. Couple times a season I will just reach behind the radiator, pull it out and wipe off any dust with a dry cloth and reinsert behind the radiator. Infinitely customizable, easy to maintain and cheap. I also keep them a bit in from the outer edges of the radiator so as to not be very visible.
    mvickers
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    I wonder if using a dry cloth could cause static electricity which could attract dust to the foil?
  • random12345
    random12345 Member Posts: 469

    I use the carboard and aluminum foil method on a couple radiators. No tacking in place. Couple times a season I will just reach behind the radiator, pull it out and wipe off any dust with a dry cloth and reinsert behind the radiator. Infinitely customizable, easy to maintain and cheap. I also keep them a bit in from the outer edges of the radiator so as to not be very visible.

    Even easier if it works. My rads are very close to the wall. I was concerned the cardboard wouldn't handle the heat.
  • dabrakeman
    dabrakeman Member Posts: 552
    No issue with level of heat and safety with cardboard. Closer the radiator is to the wall likely the higher the potential gains.
  • random12345
    random12345 Member Posts: 469
    edited October 2022
    Ok. Maybe I'll give it a try...
  • bhiggins
    bhiggins Member Posts: 7
    When I had a boiler and rads I did that, aluminum foil and masonite. I never tested it, so I can't say about effectiveness. I do recall how pleasant it was to sit on a warm radiator, for a few moments, anyway.
  • mvickers
    mvickers Member Posts: 30
    Not aesthetically pleasing, so if it matters, what does the keeper of the kave say?  Small, slim line, 12vdc vehicle fans behind the radiators on low speed
  • mvickers
    mvickers Member Posts: 30
    That is, the foil's not aesthetically pleasing, the fans attached to the radiators would essentially disappear 
  • JanitorJim
    JanitorJim Member Posts: 1
    I believe I read one time about a reflective paint that can be tinted to match any color. Would painting this on the walls behind radiators accomplish the desired radiation directing effect? For that matter maybe using this paint on all exterior walls would be a good idea for energy retention? 
  • Stuart Rogers
    Stuart Rogers Member Posts: 49
    The panels definitely work, and pay for themselves quickly. I recommend them without hesitation.

    I spearheaded the installation of reflective panels in my building in 2011. (Four-storey brick, 25-unit co-op in Toronto, built 1925; Weil McLean 1280 steam boiler with outdoor reset, Powerflame modulating burner.) I attach the report I prepared for our Board (ASAI = Amsterdam Square Apartments Inc.), which was accepted and acted upon. The Novitherm panels are designed specifically for radiators, and are shaped to increase convective airflow in addition to directly reflecting IR frequencies. (The airflow improvement is only an advantage if there is no cabinet over the rad, of course.)

    Thermograms taken a few years before for a different purpose showed heat penetration through the exterior walls where rads were located almost as brightly as what was being lost through 90-year-old single pane non-weatherstripped steel windows. (Don't have "after" shots to compare, unfortunately.)

    We were able to apply for an energy-saver grant from our gas supplier, and the estimate of annual gas savings was about equal to the fuel burned in April of that year (7900 cubic metres). At the time, we were paying CDN$0.33/cu. m., so the panels paid for themselves in under two years.

    (These photos are in the report but duplicated here for tl;dr )
    The panels for the test were on the wall behind only the top half of the rad.
    Test Rad Before:

    Test Rad After (note additional heat reflected from the supply pipe, which is hidden by the photo legend):

    and just 'cause I'm proud of our home with its new windows and cornice :smiley:

  • random12345
    random12345 Member Posts: 469
    @Stuart Rogers I believe I spoke with someone at Novitherm who said these were not suitable for steam radiators, hot water only. Plastic may not be able to withstand the higher temps.