So the 20+ old years furnace finally died on me this winter and I enjoyed a crash course in HVAC systems – Heating, Ventilation and Cooling systems to newbies such as myself. It was quite interesting reading while the temperature hovered around the freezing mark, I didn't have to worry about my computer overheating.

If you have a standard furnace in your home then you are using an ancient technology of generating heat by changing the composition of an element, wood or gas and forcing it to release the energy stored. A heat pump uses a heat exchange system which allows it to provide 2 to 4 times as much energy as they use. If, like me, this is where you start going 'Huh? ! ?' let's see if I can explain. That's the test of whether you really know a subject, can you explain it to someone else?

Freon, yep that nasty gas that is contributing to the depletion of the ozone layer, is one of the better elements for absorbing differences in temperature which is why it's used so much. This element is put into a closed system where there are two areas with compression coils and a condenser, one inside the building and one outside. When it's cold outside and the heat pump is moving heat from the outside air to the inside of your home, the element is in liquid form in the outside coils. The liquid obtains, or extracts, the heat from the outside air and evaporates into a gas. This gas is pumped into the house to the indoor coils where the heat is released into your ventilation system and the element condenses into liquid form again, the liquid is moved back to the outside coils and the process starts all over again.

Still saying 'Huh? ! ?', I was too at this point. But think of it this way, you know how ice works. Water releases heat as the temperature falls. When the temperature is low enough the element changes form into ice. If you take the ice cubes out of the tray and pour liquid over them the ice starts to melt and the temperature of the liquid drops as the ice changes its state. If you continue to apply heat to water it will absorb it until it starts to boil and evaporates away as a gas until it condenses down again either on a window or your glasses or as precipitation.

Ta-Dah! You now know how a heat pump works. Because the elements used in the heat pump system are much more sensitive to temperatures than we are, it can absorb heat when we think it's 'freezing'.

And thanks to the ingenuity of some really smart engineers, heat pumps can be used until the temperature is around the freeze mark. This saves you money and helps to eliminate adding to the global warming issue by burning more fossil fuels. And in the summer, there's a reverse switch on the heat pump to allow it to do the same process only then it's pulling the heat out of your house and releasing it into the outside air, which is what your current air conditioner is already doing just as a one-way street. The heat pump runs both ways.

Yep, it was more expensive up-front to put a furnace (back-up heat system) and a heat pump in but in the long run, in the Midwest, it will pay off big time in energy conservation.