Typically ones makes an offer contingent on a inspection with repairs not to exceed some dollar amount. Why would anyone pay for an inspection before their offer is accepted?

I don't think you understood my question. I'm saying that you as a home buyer should check out the A/C unit before you make an offer on a home. You can tell if it is noisy or leaking water. They should also catch this in the home inspection too.

Most home inspectors don't know what to look for when inspecting a furnace or air conditioner. They either miss things, or report problems that are not real. If you want real peace of mind you should hire an HVAC contractor to inspect the system and the duct work.

You guys are missing his point. He want to know what to look before even offer to buy. Here is a couple of things you can do, only take 3 minutes, you can do this when you go see the house. Go to the condenser while the AC is on, hand touch the 2 copper pipes, if the small one feels a little warm and the large one feels ice cold, then most probably, the AC is OK.

All that tells you is the AC is providing some amount of cool air in the home. Basically is saying the AC is operational but gives no indication of the condition of the system and if it has fundamental problems.

You can't turn on the AC is your looking at houses in the winter. In addition most people look at houses with their realtor when the homeowner is not home. It is unlikely the realtor is going to let you turn on the AC without the homeowner present.

If it were me I would do a visual inpsection to estimate the age of the AC. If it is realtively new, I would review the quality of the installation and inspect any visual duct work. If the AC is running I would walk around the house to see if there is an even temperature distribution in all rooms.

Geez, some of you might be overgeneralizing just a little. Some inspectors know a lot about AC and some don't. All that I have seen, check the return and all the supplies and record that temps. If the difference does not look good, they report it and may investigate further or advise to have an AC specialist look at it.

Whenever I've looked at a house with an agent, the AC is running, often before I arrive.

I like the above post. I would want to know the average supply temp and the return temp, get the difference, and note outside temp. I want to know about the returns, where they are located, and how return air s filtered. I want to know complete specs on the system including condenser, furnace or air handler. Age,size and brand of system. Service history if you can get it.if you are not HVAC proficient, then pay to get a thorough inspection by a reputable dealer. Of course, you will pay for this cost.

IMO

These are great tips and not something I thought about. Checking the temperature in each room. That would tell me if the unit was working properly. If it was cooler in 1 room and it was central air then there was a problem. I can't imagine the realtor not allowing you to turn on the A/C when looking at a home.

In my area(Texas), during the Summer, even Fall or Spring, the seller will have to turn on the system to please the buyer, Some realtor won't even show house if the house has no AC, or not on.