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My AC outdoor unit gets direct sunlight (no shading whatsoever) from morning to noon. Temperature normally soars up to 40 degree Celsius (I am from India). I have two questions:

  1. Is this bad for the AC's refrigerant, does it lose efficiency over time?

  2. Does an AC compressor located in full sun work harder than one located in the shade?

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Direct sunshine heats up the enclosure of the air conditioner to much higher levels than ambient temperatures, greenhouse effect.

Also the UV Rays will break up plastic and paint and rubber molecules in such component as washers, hoses, brackets and clips.

The compressor must work much longer to cool off the room because it has to deal with a much higher initial temperature in the housing.

This causes extra wear and tear, higher utility bills, loss of refrigerant liquid more rapidly.

It is very helpful to choose the window or location of the unit judiciously, where you get mostly shade from trees or have minded the angle of sun in the afternoons and have a wall or other part of building blocking it, when the daily temperatures are at their peak.

It is advisable to cover the unit in a nice bamboo or similar indigeneus shade lake a small cabinet with enough room around the air condition to allow free ventilation.

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    $\begingroup$ It is not much higher temperature in the housing as it has a high volume fan. The air in the unit is cleared in the first second of the fan coming on. Cover the unit could actually reduce effectiveness if the cover interferes with air flow. $\endgroup$ – paparazzo Jun 6 '18 at 20:35
  • $\begingroup$ @paparazzo , I edited my answer to clarify I meant something like a cabinet. I worked for years in arid, desert areas of middle east building public projects in temperatures of 140+ and we learned by trial and error how to optimize our window air conditions. $\endgroup$ – kamran Jun 6 '18 at 22:32
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Direct sunlight increases power usage and wear of the unit.

The cooling efficiency depends directly on temperature gradient - difference between temperature of the coolant and ambient air pushed through it. With direct sunlight the chassis heats up, the protective mesh on the fan heats up, surrounding walls and floors heat up from sunlight, the air passes, it also heats up from these, entering the radiator at significantly higher temperature than had the unit been shaded. Also, the radiator and coolant heat up through conduction from chassis, requiring more cooling.

And that means less heat is drawn from the coolant, the coolant returns warmer to the indoor unit, the AC will need to work longer before it reaches the temperature set on the thermostat, and in consequence it will use up more electricity.

Additionally, the extra workload put on the device results in faster wear and shorter lifetime.

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  • $\begingroup$ is it bad for the AC's refrigerant? $\endgroup$ – Paran Bharali Jun 6 '18 at 12:28
  • $\begingroup$ @ParanBharali: I don't know for sure (never bothered to learn what exactly freon was replaced with), but if its properties are similar, then I doubt it. $\endgroup$ – SF. Jun 6 '18 at 12:35
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An AC uses a large volume of air for cooling. Air in the shade is the same temperature as air in the sun. Yes sun will heat the outside of the unit but it will have a small effect on the cooling air.

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  • $\begingroup$ It is much higher, in fact that's is exactly how the sun heaters create hot water, by circulating cold water in pipe network exposed to sun. $\endgroup$ – kamran Jun 6 '18 at 22:35
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    $\begingroup$ @kamran You are comparing a solar water heater to an AC with a fan? That is not even apples to oranges. $\endgroup$ – paparazzo Jun 6 '18 at 22:48
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In this type, the rated power is determined in such a way that the outdoor unit is not in any way protected by shadows or shields; That is, the outer plate casing essentially casts a shadow on the condenser, i.e. the heat sink. If the system is completely enclosed, ie well-installed and well-fitted, it will not leak for many decades. This, of course, depends on the quality of the copper tube used, the quality of the flange on the tubes. Of course, it increases the lifetime of the climate if it is in a place where it is more protected. Generally speaking, if the outdoor unit is in a sheltered place, it will dust sooner. With a hand-held sprayer, it is advisable to wash more frequently with clean water from the lamellae of the outdoor unit. This keeps the factory performance. If you are in shade and in a sheltered place, less energy is invested in the operation, but of course this is very small overall. Regular cleaning is more important. I noticed that the pipes running outdoors do not have any protection. In Europe, it is standard that these pipes should be routed in an outdoor plastic air channel, because their outdoor insulation will eventually dissipate from the sun's UV radiation. If this happens, it is advisable to put in a new tube. Furthermore, the pipe is more aesthetic when running in a plastic channel. Be careful to drop the pipeline at all points towards the outdoor unit. Many people forget, but the refrigerants in them are no longer as perfectly blended as the banned ozone damaging R22. (Mixing of oil and refrigerant). For this reason, not every point of the system is lubricated (low oil consumption) or even an oil plug may develop. Therefore, they are instructed by thermal engineering engineers to make the piping slightly sloping (ie not a rough slope). Of course there is also a horizontal section if there is no other solution. However, very little climb in the tube is forbidden, especially for inverters with low power. If you pay attention to this, you will be in good friendship with this device for long years. Durable, high quality device. The indoor unit, however, often needs to be cleaned with a fungicidal composition, such as alcohol-containing hospital and solarium disinfectants. Use of chlorine-containing agents is strictly prohibited! Especially, the blower of the indoor unit needs to be cleaned with this alcoholic substance, because in this type of black fungus is highly prone to settling.Greetings from Hungary.

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  • $\begingroup$ Helló :-) Please consider registering the site, you are writing good things. $\endgroup$ – peterh Jun 28 '19 at 21:46
  • $\begingroup$ Also, please use paragraphs. A wall of text is too easy to ignore. $\endgroup$ – Ray Butterworth Jun 29 '19 at 0:29
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The possible air flow restriction caused by a shade or awning will more than offset the advantage of slightly cooler air ( provided by shade) entering the compressor/condenser. I see nothing on my outdoor unit that could be exposed to solar UV except paint. My previous unit ( 15 years old) showed no damage from UV except a decal with a name that was somewhat curled on an edge.I had my new unit installed a little further from the house to avoid the roof/eave over hang which gave some shade but at a cost of some interference with the upward hot air flow from the unit. Update : Just had a new unit put in and I checked the installation instructions ( American Standard unit , in the US) : There is no mention of shading the unit. However, it does say that there must not be anything above it for at least 5 ft. so that air flow is not impaired.

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