Our toilet area is 3 x 5 with a pocket door (that is never used). There is a fully functioning window in there.. 28 x 48ish and we open it all the time. When we remodel, we are losing the door, 1/2 of a wall, and installing a new window exactly the same size. There is another window in the master bath, they both face east. We LOVE the natural light and when the master windows are open too (those face west), the breeze is heavenly. It helps that we have a nice view and privacy isn't really an issue. The entire room would be a lot darker without it... couldn't really imagine not having that window! I REALLY couldn't imagine having a closed room with no window.

I have windows like that as well. We painted the inside of the window the same color as the trim. I'm not saying that's the way it has to be or should be, it's just the way that looked best to us. That area does get dirty also so using the same gloss makes it easier to clean. As far as the closet goes, if you don't want to paint them, don't. The only problem with that is when the doors are open it doesn't look very nice because the paint is obviously old and a lot more tired looking. If it were me, I'd bite the bullet and paint them. In some of our closets, we used the same color as the main walls and in others, we used contrasting color, it's really up to what you prefer.

So fade is caused ultraviolet, visible and infrared (heat) wavelengths. The fading rule of thumb is 40% is caused by UV, 25% by Visible, 25% by IR. 10% is considered miscellaneous, or even oxidation. In practice, the visible and ir are both heat, as uv has 3% of the heat, visible has 44% and ir has 53% of the heat we deal with. So visible and ir light together have 97% of the heat. The uv light has an opposite electrical value to that which bonds man made materials together, and when they meet, it is a short circuit, and cancellation. This is why uv is referred to as a burning ray. The heat buildup is different as it excites atoms until bits fly off and structure changes. Things shrink for example. Also oxidation comes into play with increased heat. So how to implement this into design? The situation can be described as a heat source near the clothes. This is important because as a window warms, it will re-radiate that heat toward the colder area, that being the room temperature closet. The low-e glas glass has two layers of glass with the low-e layer to the exterior in warm climates and to the interior in cold climates, depending on whether the climate design is trying to retard heat gain or heat losses. The key is that the coated piece of glass will grow very warm as it does its job, and in this situation it would be better if the inside piece of glass was not 20 to 30 degrees warmer than it is now. Additionally UV light can be controlled, but this needs to be a separate specification and does not come naturally with all the coatings available. Window films are offered with many options, enough to confuse a person, but the same idea applies. A low E film will offer a lower effective surface temp than a solar film as both grow warm as they stop energy, the low E type film is going to stay effectively closer to the current glass temp as a result rather than lowering the inside glass temp the way a designed glass can with its dual layer design. However energy will have been rejected so film is a viable option. They inherently stop UV, Visible, and many have suprising IR light control. A few films have a insulation value referred to as the U factor. This number is the reduction of heat from one side to the other. These numbers around .60 are effectively the same insulation as the dual pane commonly has by design and would further serve the design of lowering the surface temperature inside the room.

Keep playing with drawing til something makes sense. I tried to sketch something out, let's see if I can attach it. Did you want to add a tub, or just a bigger shower? If windows can be added to the left wall, it would really add more possibilities! I made the bigger closet skinny so the window light still comes in. This loses the hall closets so it may need more work. I am not a big fan of the hall between the closets, it was my attempt to keep the window. Either of the closets where the master was could be removed to be a sitting area or a desk area. Obviously I am not a professional. I just like looking at and thinking about floor plans. I am sure others will jump in to improve my sketch by criticizing it lol. I left the toilet and one sink in place. I think the shower could use the same drain and it would not be too bad to extend the pipes to make it bigger, and add the second sink. The entry point is a bit crowded but I was having trouble adding a second sink if I made the bathroom door by the closets.