Insulation Behind Cast Iron Radiators?
My Zone 5 house is about 100 years old and is heated with hot water circulated through original cast iron radiators, which all have wooden covers. Almost all of them are under a window on a exterior wall. The walls are brick, ~1″ air gap, ~1″ Celotex or similar fiberboard attached to stud framing, then lath and plaster inside. Last heating season, I tried sliding Radflec reflective sheets behind the radiators https://www.radflek.com/what-is-radflek/ This produced a small, but noticeable improvement in how warm rooms felt. I’m guessing this simply because more of the infra-red energy was reflected inward.
There is about 3″ between the back of the radiator and the wall. I’m wondering if it would be worthwhile to cut a rectangle of Tuff-R polyiso (or similar), and then drop it in with the foil side next to the radiator.
Thanks in advance.
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