Hello, I assume that you dont have a basement or you would know the difference in temp. it has as compared to the upper levels of the house.The dirt surrounding an underground room is going to be cooler than above ground. The radiation from the sun will also be blocked by the layers of soil. If you've ever dug a hole, the ground a few inches from the surface is moist and cooler. This surrounds a room, it will be cooler. On the contrary in the winter, these layers will act as insulation and keep it warmer than the outside. I wouldn't say it would be cold/hot but it would be more comfortable without airconditioning or heat throughout the year.

this depends on airflow, ventilation, elevation, how deep underground, above or below sea level, air pressure, how much sunlight, what part of the world you are in. Remember heat always rises, so generally speaking yes it will be colder below ground but now if you had 5 people with you and there was no way the body heat could escape due to the insulation or whatever then it will be hotter than above ground. it all really depends.

http://igg.me/p/97591?a=578745

Not necessarily.

IF more than a few feet underground, and properly constructed and ventilated, they tend to stay about the same temperature year-round; and they are quite livable.

The temperature range depends in part on where they are built.

On the contrary, it may be hot due to no circulation of air ...

Heat comes from the sun and caves are always cold because their walls are thick enough to block the radiation. I had been through an underground tunnel and it was damn hot but thats because the air was congested.

I am wondering, is it cold if a house was built underground?