No
.. it’s very effective in keeping the heat in, otherwise, the ceiling will absorb heat and it will emit out into the cold atmosphere…

Yes, I use at least 2 layers, with a 1″ airspace between
them…I build high end custom homes, and the biggest often incorporate 5 foil barriers in flat roofs… radiant foil is low emissive, that means that it doesn’t emit heat off the cool side of the membrane, if it isn’t in contact with a solid material…It DOES NOT “REFLECT” HEAT BACK IN TO THE ATMOSPHERE.
So, the most efficient way to really make a 95-97 percent radiant barrier, is 3 layers with a 1″ air space on both sides of the center layer. It’s a lot of extra work, so that’s why you don’t see it done on most construction projects…

A radiant barrier works the same winter or summer. Take a foil blanket & sit by a fire. The hot side is hot the away side is cool. It reflects the heat back on either side.

Those zones can still take advantage of radiant barrier. The thing to keep in mind is that it’s giving you cost savings during the time of year you run your AC, so some parts of the country see greater benefits than others.