D. J. MCBRIDE says...

I believe the radiant paint is a Sherwin Williams product. And, I
believe it is available as an interior wall paint, in colors for those
rooms that catch a lot of sun on their exterior walls. I've heard it
opined that if you are not going to condition the space then insulation
is not the way to go. But, maybe that's just for high humidity locales
like Houston.
I'm also not a fan of blown-in cellulose insulation. I'd be afraid
it will break down as the years go by, make dust. Not to mention the
chemicals it's likely treated with.

Thanks. I'll look at Sherwin Williams products.