Adding another unit

[ZackN]

I know there are a ton of variables in a question like this, but I am curious as to your past experiences. When you are faced with a unit that is too small for your home, what is the most cost effective option (typically). Adding an additional small unit? Or replacing the system entirely with a larger one.

In our hypothetical scenario, the existing unit is 6 years old.

[second opinion]

I know there are a ton of variables in a question like this, but I am curious as to your past experiences. When you are faced with a unit that is too small for your home, what is the most cost effective option (typically). Adding an additional small unit? Or replacing the system entirely with a larger one.

In our hypothetical scenario, the existing unit is 6 years old.

Depending on the layout of the home a second unit would be my choice, being in a hot climate if one unit went down you would still have cooling

[ZackN]

Single story, 2000 sq. ft. 2 windows on the east facing wall, 2 on the west facing wall. Built 2006.

It seems like just installing an additional small unit would be much cheaper than just upgrading to a bigger system, but I'm concerned about the electric bill. Would having a second unit reduce the load enough to counter balance the added energy draw of using two AC units?

[fliks]

If not all the space is used you could use one until you need the other. It is always going to be cheaper with a smaller unit. Also the electric may be actually less cause it won't be running all the time which is your current problem.

[ZackN]

If not all the space is used you could use one until you need the other. It is always going to be cheaper with a smaller unit. Also the electric may be actually less cause it won't be running all the time which is your current problem.

Yeah, in this Texas heat, I'm lucky if I can get my central AC unit to stay below 80 and it hasn't shut off in 4 days.

You guys have any experience with just the portable AC units that you can roll around your house? My main concern with all of this is energy consumption. I want to be as efficient in both energy and cost as I can be.