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Patrick Presti
Sunrad Recessed Radiator Help

Hi Guys,

I recently purchased a 1953 cape on Long Island. For heating, it has a relatively new gas fired hot water boiler with Sunrad recessed radiators mounted underneath the windows on the exterior walls. I noticed there is no insulation behind the radiators (just the sheathing).

I am wondering when I renovate the house, if it would be worth it for me to take the existing recessed radiators and mount them on the interior walls.

I would appreciate anyone's thoughts.



Re: Sunrad Recessed Radiator Help

The best location for any source of heat is the outside walls. The way they were installed is with a reflective paper placed behind the radiator.


Re: Sunrad Recessed Radiator Help


Radiators are designed to be mounted directly under a window on exterior walls for specific reasons; the most important reason is that in winter weather, a wall of cold air is present coming in from any large glass object like a window due to the relatively low R-value of the glass; with the hot radiator placed directly below & in front of the window, it actually creates a convective current of heated air that is forced out into the room & circulates throughout the room, as the cold air from the colder floor & glass mixes with the hot air from the radiator---it's like an invisible fan that circulates warm air throughout the room to keep the room comfortable; these air currents can be seen if you hold thin strips of cut-up newspaper over the rads while they are heating the room, and notice the movement of the paper strips.

You say there is only the sheathing behind the rad, but installers are supposed to install a REFLECTIVE metal panel behind each radiator so that the infared portion of the radiator's heat waves (radiators emit both convective & radiant heat waves) is reflected back into the room, and is not lost by escape thru the exterior wall---it's what makes radiators so effective in heating rooms in winter; run your hand along the wall sheathing behind the radiator when the rads are heating to make sure the walls do not feel cold to the touch---if they feel cold, have a hydronic heating technician come over the house to make sure the insulation & reflective sheets are in place behind each radiator---have these components installed if either or both are missing.

Patrick Presti
Re: Sunrad Recessed Radiator Help

I just have a hard time believing that a reflective metal planel would be equilivant to an R13 insulation.

If you have a house that is insulated with the best products and new energy effieicent windows, it would kill me having these 2'x3' recessed radiators in exterior walls with just a reflective metal panel behind it.

I can't run my hand behind the wall sheating of the raditaor because the radiator is in direct contact with the sheathing of the wall.



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