Quote Originally Posted by R1976 View Post
frank,

Why do you say it was over sized?

I have found that all split ac systems bring the temp down to 21/22 degrees in about half an hour. Being an inverter unit, this is not really an issue anyway. I think 5 - 6 kW is good for a south facing conservatory of 20-30 square meters.

Regards
Imagine that your unit was not an inverter.

You switch it on in a high internal temp and it brings it down to set point in 30 mins then switches off.

The temp then rises a couple of degrees and it switches back on.

now it only has a couple of degrees to handle, it will take a matter of minutes. So it is on and off continuously. Not good for the compressor. System is over sized.

With an oversized inverter system, the unit will back off as it approaches set point, and therefore spends the majority of its time at low hertz, part load. Not good for energy efficiency, oil return due to low gas velocities, and air flow velocities (the indoor fan backs off as well. )

When an inverter system spends most of its time in low hertz, part load, it's a sign that it is oversized.

Guessing what size system to use instead of doing the heat gain calculations is not the right way to do it.