For 1600 sq.ft. on one level (which means 1600 sq.ft. +/- roof area) I'd probably grab the 25k and be done - one installation, one breaker.

Other than a single 25k you may toy with possibly using two smaller units in a phased approach, the first being an 18k. Ultimately this will give better air distribution for so much area on one level. So you get an 18k and see how it goes then add a 10k elsewhere if needed. But this, of course, costs more than a single 25k and will have higher total power demand.

I read about a lot of the 25's being quite loud - probably because they're throwing the air harder and further for the greater room size - but it seems I read how loud my Samsung was and I'm amazed at how quiet it is... So read up on the noise levels if it's an issue. I doubt the store has the ability to plug in a 230v unit for you to check out.

I agree w/ Matt, look at the features.

Most of the bigger units (I think 12k and up) use a slide in chassis - so you can mount the chassis and then put the unit into it. I built a subframe tied directly to my wall framing to carry the 100+ pound window unit instead of putting that load on the twin window unit. Doing this also eliminates vibration since I thoroughly fastened (screwed) the chassis to this subframe instead of just resting the unit in a winow opening.

Energy star usually means the fan and compressor shut down when the unit reaches temperature. The non-energy star units run the fan all the time and only the compressor cycles on and off. The fan probably doesn't consume very much power, but it adds up and it's just quieter without the fan running. Mine shuts down about 9pm and doesn't resume till around 9 am.

The samsung has a 'dry' setting which is basically using it as a dehumidifier - I don't bother with this because you can't use it and the energy star feature at the same time. And I've got a dehumidifier down on the first floor (which unfortunately contributes to heat load...)

The Frigidaire likely has all the same specs in a comparable unit except my Samsung does NOT reset after a power failure.

With a 5 year warranty it's worth $350 for the benefits even if I replace it every 5 years...

Chaser