In variable climates, the system may include a reversing valve that switches from heating in winter to cooling in summer. By reversing the flow of refrigerant, the heat pump refrigeration cycle is changed from cooling to heating or vice versa. This allows a facility to be heated and cooled by a single piece of equipment by the same means, and with the same hardware.

1) Change your filter. The simplest and most effective way to keep your AC running smoothly is changing your filter once a month. By regularly changing your filter, you reduce a lot of the burden on your system. A dirty or clogged filter makes your air conditioner work much harder than does a clean filter. Changing your filters regularly is easy on your budget and easy on your system as well. It will lower your utility bill and extend the life of your AC. 
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