I have a couple of questions about the radiators in my house starting with should they be painted with that silver paint to get maximum efficiency? What about regular latex paint? Do radiator covers block heat from coming into the room and last question, should foil be placed on the walls behind radiators?


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  1. With a cover on, the convective heat currents carried by the air, would just be directed out of the front grille and then could rise straight up anyways, so I do not understand how a cover would prevent that.
    Covers block the best part of the heat of a radiator, which is the radiated heat that does not dry the room and is more even and force it to give off it’s heat mainly by convection.
    Theoretically the paint color would affect radiation and the best color would then be matte black. Silver paint was used on rads that were oversized to acually DECREASE heat output. But, in real life it does not make much of a difference.
    Latex paint is harder to strip down the road if you wanted to restore your rads and their ornamental detail. Ideally, you should at least use an oil-based primer on cast iron. And no, high-heat paint is not necessary. Like cmu says, they do not get that hot, like stoves or barbecue grills.
    Has anyone ever heard of kids seriously burning themselves on a radiator without a cover? Especially hotwater rads? Or is that just one of those urban things that get passed on.

  2. Radiator covers don’t necessarily make a room colder. Properly designed, they actually redirect heat out into the room as opposed to it rising straight up (and in my case, out my leaky 100-yo windows). My house has been noticeably warmer since I had radiator covers installed.

  3. agree with the last, if the rads are perfect.

    can you cite your studies? because it seems to me that convection (70-80%) transfer cannot possibly be affected by type of paint. So the cited study’s conclusions make sense to me.

  4. CMU,

    I’ve read other studies that say that it does reduce the heat output of radiators if you paint them.

    I’ve had radiators that were painted with regular paint start peeling during heating season, so I always have my contractors used high heat spray paint when we paint them.

    Personally I think radiators look better unpainted anyways.

  5. Ironballs, please read the link from SS. It directly contradicts what you said. There is no insulative effect in painting radiators. And there’s no reason to use high-heat paint, they don’t get hot enough.

  6. Of course it’s better not to paint radiators if you want them to get as hot as possible.

    If you do paint them, use a high heat gloss spray paint if you want the the best finish.