Question:  What would be the ideal humidity inside a Southern California home during the summer and cooling with central air conditioning?

Reply: Actually if you go below 50% RH you will feel quite dry, in fact too dry. The other consequence is that the static electricity in the home builds up as well at lower humidity levels, this can be a problem if you have carpet in your rooms
The advisable level is somewhere between 55 and 65%RH if you have the ability to control it, all the better.
A/C in dry climates tend to over dehumidify the air as the moisture in the air is condensed on the indoor evaporator coil and drained away….causing dry eyes etc and A/C in high humidity zones tend to add to the cooling capacity making you feel less comfortable.
Some people in dry climates have been known to put containers or bowls of water in their home to keep the dryness at a reasonable level.

Question: 

The air conditioner guy tells me that’s the brand he uses. I’ve never heard of them. Does anyone have any advice for me?

Reply:

Yes I know of them. I am not quite sure what you are asking but to hazard a guess I would say you are wondering if they are any good.
Not the best unit around at all, they are cheap and that’s all I can say about them.
For a reliable unit / brand try the following:
Daikin
Mitsubishi Electric
Carrier
There are many many more but the first 2 are who I recommend especially Daikin, for reliability.

Question:

I ive in a appartment and over the winter the maintance men put in a new central heat and air system…. a few weeks ago when i turned the air on the apartment filled with a haze that smelled like achemical. they later came out and said the A/C wasn’t hooked up and that they had fixed the problem. Now the air works but tis not cool, and I was wondering if all of the coolant could have leaked out ??? Thanks to anyone who can help!

Reply:

That is a most likely scenario, if the freon leaked at a fast rate it pushed some system oil out with it causing a haze not dissimilar to what you described.
Since the machine does not cool now then it is highly likely that it has dropped it’s gas charge.
Call the maintenance men and tell them your story, they should find the leak repair it and re charge the system.

Question:

I have a really small cabin that I use a portable air conditioner. It works good until the temps outside rise above 90 degrees. Anything in the 100′s, or 110, it can’ tkeep up. I live in a VERY dry climate with < 10% humidity. I was thinking of also getting a portable evaporative cooler and running them both at the same time. Do you think there would be any benefit? I would like to add some humidity to the air anyway..

Reply:

Without going into a lot of detail the short answer is no. Evaporative cooling and refrigerated cooling working in the same environment do not work. The 2 types of cooling do effectively cancel themselves out.
If you do have a humidity problem and wish to cool your cabin you should invest in a dedicated humidifier that supplies the required humidity and can also be regulated according to your settings.
Sounds also that you need to upgrade to an A/C unit that will do the job. My advice is to buy a unit that will perform better in high temperatures conditions, have a heat load calculation carried out on your premises, they are usually given free with a quote for a new unit.
FYI: The industrial computer rooms of the past have struggled with this conundrum for many years and found the only solution to be as I have stated above or installed A/C units that have built in humidification systems.
Hope this helps.

Reply:

Don’t even go there.
The consequences of attempting this are not worth it.
If you knew what the fines were for doing this I do not think you would contemplate trying this, never mind the danger.
Final note, you haven’t a hope in hell of getting it right anyway.
Sorry to sound fierce but I want to stress that you are asking the wrong question, you should be asking, who can I hire who is qualified to carry out this type of repair.