Ask the Woodchucks: Basic heat transfer

Heating and cooling your house is basic heat transfer. In the summer, you are collecting the heat in your house with the air conditioning evaporator located in your furnace. The heat is then pumped outside with the air conditioner refrigerant and dumped into the outside air through the condenser. In the winter, your house is heated by burning natural gas inside a heat exchanger in your furnace. The furnace fan draws the air from your house and passes it over the heat exchanger where it is heated and circulated back into the house through the ductwork and the air registers. The furnace is either full on until the set temperature is reached or full off.

Modern high efficiency furnaces no longer work like that. They have variable heating levels and variable fan speeds, but most Sun City homes still have the older full on or full off furnaces. Setting the thermostat five degrees above the temperature you would like does not make it get warm quicker than setting the temperature to where you want it to be. Residents who change the thermostat settings in the Prairie Lodge should reread this paragraph. To warm up or cool down a room, move the thermostat just a small

amount. When the furnace and air conditioner are off, heat transfer is still in effect. When it is 80° inside and 75° outside, it feels good to open the windows and cool down the house. When the outside temperature gets to 82° and there is a nice breeze blowing, it still feels cool. This is because the air blowing over your skin is evaporating moisture cooling your skin, but it actually is heating your house from 80° toward 82°. Whenever the outside temperature is above the inside temperature, the house will stay cooler with the windows closed. Ceiling fans work in a similar manner. In the summer they blow down on the occupants of a room and the air passing over their skin evaporates moisture cooling the skin. When you leave the room you are no longer cooled by the fan’s breeze. The room is not being cooled by the fan; in fact it is actually being heated. The motor on the fan gives off a small amount of heat

that adds heat to the room. Now that you know the basic heat transfer of a ceiling fan, you should turn it off when no one is in the room.

In the winter, ceiling fans still have a function. You should be sure to reverse the direction so that instead of

blowing down on the room’s occupants air is blown up toward the ceiling. This action forces the warm air that drifts up and accumulates near the ceiling to wash across the ceiling and down the walls. As the air in the room is mixed to a uniform temperature, you will actually feel warmer.

When you understand it, heat transfer can be your friend. It will make you feel more comfortable in your house and save you money on heating and cooling.

Reader comment on sillcock

I just finished fixing my sillcock and the packing nut turns clockwise to tighten not counter-clockwise as the article states. Counter-clockwise loosens it!

Woodchucks, I have never seen a packing nut that turns clockwise to tighten, but be forewarned that apparently there are some.

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