To close or open the blinds?

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Q. Before leaving the house on a summer day, I close the blinds (slants up) to deflect the sun, and with it, the summer heat. My husband maintains that it’s useless to do so on the north side of the house (and the south side, I imagine) as it doesn’t receive direct sunlight. Whether direct or indirect, doesn’t sunlight hitting a window create heat that is transferred to the interior of a room?

A. This is a hot topic! Heat transfers in three basic ways and, apparently, will also change the temperature and amount of inflation in footballs, especially during an important playoff game. And even though I’m not a highly paid football coach who clearly explained why football inflation fluctuates with temperature, I, too, can answer your heated question. Temperature is transferred by conduction in solids, convection in liquids, and radiation in gasses, which includes reflectance, through the air. Basically, two objects, such as molecules, transfer temperature when in contact, and warmer molecules are attracted to cooler molecules, so that as they continue bumping into one another, the warm molecules will transfer until they balance temperature with cooler molecules. Guess where the warmest place in a hockey arena is. If you guessed that it’s right at the surface of the ice, give yourself 10 points.

Depending on temperature, molecules will move faster or slower and the transference will also happen faster or slower. In summer, the indoor, air-conditioned temperature is cooler than outside, and sun-radiated air molecules in your house, bombarded by infrared rays from the sun, which are warmer. will warm your indoor air. The time it takes to warm your cooler air is mostly dependent on insulation, which slows down the speed of the transfer of warm to cool. On a cold day, the same will happen in reverse, meaning that cold outside air will cool your warm house at a rate dependent on wall and window insulation, or resistant infrared ray tinting as well. So the transference is based on the temperature conduction of the air as well as radiation from the sun.

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