Where does the heat come from?

Here is a very perplexing question – if it is ZERO degrees outside and your Air Source Heat Pump is extracting heat from outside’s COLD air to heat your home…., how does that happen?  Today we are limiting our conversation to Ductless Mini-Split Heat Pumps.

Wouldn’t common sense tell you that cold outside air is not a great source of heat?  We were all kids once and mom would tell us “….shut the door, are you trying to heat all outdoors?”  So, how is it that today the same cold air is going to heat our home?

For starters let’s look at exactly what we are talking about, there are three component parts to every Ductless Heat Pump.  There is the outside compressor, the inside unit sometimes called The Head, and insulated pipes that connect the two major parts.  That is all there is.  But, how does it work?

  1. The Head is comprised of a Heat Exchanger, a fan, a check valve, and an expansion valve
  2. The insulated pipes are just that, insulated pipes that connect the inside Head to the outside Compressor.
  3. The outdoor part is comprised of the compressor, a reversing valve, another heat exchanger, and lastly a fan.

Between the Compressor and The Head, the system is filled with refrigerant,  As the refrigerant is compressed, in the outdoor compressor, it boils and changes to a hot gas.  The refrigerant boils at a very low temperature unlike water.  The hot gas is then passed to the evaporator where it loses its heat.  This is what happens in the winter, the refrigerant boils into a hot gas outside and is transferred to the inside of the house and it then provides heat for the home.  After heating your home it returns to a liquid and the cycle repeats itself over and over.

During the summer months the process is reversed so that cold air is transferred indoors, this is Air Conditioning.  Yes, a Heat Pump will heat your home in the winter and cool it in the summer.

Your window AC unit pumps cold air into the living room while outside it is expelling hot air.  This is the exact same principle as a Heat Pump.

Tomorrow, we will look deeper into the advantages and disadvantages of Heat Pumps.

What do you think up to this point?  Good idea?  Not-so-good idea?

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