Solar gain

 

It’s not that we can’t just block out the sun.  We have everything we need.  We have an external sun shade that snaps across the windshield of the bus and the adjacent windows on both sides.

 

 

The sunscreen diffuse the light and cuts way down on the solar gain.  If that’s not enough, we just close the drapes.

 

They have a white backing and reflect the light right back out.  We can close them all the way across.

 

We have air-conditioning.

 

The question I was asking about the sunshades; it was just about whether black interior sunshades would make it hotter or cooler inside compared to just letting the sun shine in onto the lighter colored fabric of the interior.  I thought maybe we could determine the best configuration theoretically.  The results were inconclusive.

 

I decided to experiment:

 

I put the black sun visors down.  In the morning sun the outside air temperature was 85 degrees.  I measured the air temperature in the windshield.  105 degrees.  I measured the surface temperature of the black sun visors.  118 degrees.  I measured the surface temperature of the tan dashboard leather.  118 degrees.  The black sun visor wasn’t any hotter than the lighter colored dashboard!  That’s not what I expected.

 

So, given that the black sun visors only heat up at the same rate as the upholstery inside the bus, it probably doesn’t make much difference whether I put them down or leave them up.  I’ll say maybe it makes sense to cut the sun off with the sun visors and keep that heat up by the windshield instead of letting the sun shine all the way in the coach onto the floor and heat up the front room.  (Unless of course I just close the drapes and block the sun out entirely.)