Insulation and design...worth it?

The house we are slowly building is one which has passive solar design at its core. There has been an amazing amount of research and effort put into the selection of materials, the location of the house in respect to the surrounds and its passive solar design.
These extra bits sure add up $ along the way but I have kept to the original idea as much as possible while hoping all along that these extras will pay off in the long run.

Now that we can "lock up" our project it has been very interesting to see how the house is performing during the recent run of hot days during the heatwave of 2013.

One recent day at 3 pm I was unloading materials on the deck and had to eventually give up. I could no longer handle the steel I was unloading. It got me thinking "how hot is it on this deck?".
  
I went and found a thermometer and took a series of measurements;

1. On the deck in the sunlight (where I was working...actual decking board temperature! [48C]).

2. On the deck under some shade..actual air temperature [38C].

3. Inside the house only a few meters from the first temperature [23C].

 
The house had been closed up all day and still doesn't have all the ceiling insulation or any window dressings.
 
The temperature range shown below is a result of material selection, sighting, and passive solar design [23-48C].

I think seeing these numbers has confirmed that we are on the right track, even if it is slower then just taking the cheap path and banging a standard house up. It is always comforting to see the proof!

Painting

We are nearing the end of painting the interior. There are little spots of paint all over the both of us, over the kids and on the floor! How does paint give such great coverage on everything except the walls and ceilings on which you are trying to cover?
The DW has really taken to the task and is doing a stellar job.
The heat that we are experiencing has made the painting job very unpleasant.
I can't believe the cost of paint now. The cost adds up so quickly and the recommended number of coats on the can must be considered very optimistic. We have had to apply more coats then recommended to get a good result.
Photos to follow soon.