Seriously, you'll retain heat better with a dark, matte finish on your dome, and you'll blind me less often. In any case, you might also want to reconsider your choice of moons, as yours seems a bit deep into the radiation belts. Out here we orbit much more slowly, peacefully, and we're far from the radiation.

No, they won't. There's a reason a perfect radiator is known as a "black body". Emissivity (a coefficient that describes the degree to which an object radiates, compared to a black body) is the exact inverse of reflectivity. That's why space blankets are shiny.

Of course, dark objects also absorb more heat, so depending on how much radiation you're getting from the sun, a black roof might result in a warmer home. But it won't be because it's retaining heat.