How do we find the angle and composition of the sun rays falling on a house in each season?
This is taught while preparing maps: for summer, the rainy season and winter, the particular angle at which the rays strike and their composition are worked out, so that openings and walls can be planned for the maximum benefit without demolition.
Related questions
Does it matter in which direction silver, iron or other metals are placed underground?
No. Direction rules for metals apply above the ground, where the cosmic energy of the planet's location acts, not underground. If they applied underground, silver would be found only in the North-West, gold only in the East and iron only in the West. Iron rods are laid through the whole slab anyway, so cutting a zone with an iron strip means nothing; learn vastu with logic and science.
Why do even small children argue with their parents nowadays?
Every house used to have ventilators at the top of the walls, which balanced the air element. They have been brought down into the windows, and since the ventilator location changed even a ten-year-old child argues back. Keep the air element balanced with proper doors, windows, top ventilation and cross-ventilation.
A North window has its shutter kept closed. Can the shutter be removed and a jali (mesh) fitted?
Yes. The North results then start coming, though not fully; you get as much as is open. Through a window only air comes in, whereas people come in through the door.
About 11 or 12 of the 45 devtas are asuras. Whose energy should be increased and whose kept low to stay balanced?
This was to be explained in detail later, as there is a big confusion about it. Asura devtas are also needed: the day there are no asuras in your house, your work will not run, so the aim is balance, not removing them.
Are the water supply lines coming into the house counted as water bodies?
No. Water lines reach every zone anyway through washrooms and taps, and lines inside the ground do not have much effect. Only dirty water lines matter, which is why they should run clockwise.
Can all the doors and windows of the house be made of steel?
Yes, if Saturn is exalted in your chart. The same thing that harms one person can benefit another.