Yolonda,

The four coatings that you mention all come from Cardinal Glass. Cardinal supplies the majority of LowE coatings to the residential window companies, but they aren't the only LowE supplier to that market.

Your primary concern is visible light transmittance, and while LoE-180 does have the best highest visible light transmittance of any of the coatings that you mentioned. You also noted that LoE-180 has 80% visible light transmittance - technically it's really 79% for a dual pane with 3mm glass - which is about the most VLT as you will get with any coating (dual pane without any coating is 82%).

LoE-180 has high visible transmittance because it's a HIGH solar heat gain coating - meaning that it lets the sun's heat through your windows and it keeps that heat inside. LoE-180 is a great choice if you live in Minnesota, or Maine, or North Dakota, but it's a very bad idea if you live in Houston, or anywhere where cooling is more important than heating.

LoE-180 has a single layer of silver in the coating stack. The number of layers of silver in the coating stack is directly related to how much direct solar heat is blocked by the coating, so a coating with two silver layers (270 and 272) block more solar heat than 180 and are known as moderate solar heat gain coatings, while coatings with three or more layers of silver in the coating are considered to be low solar heat gain coatings. There are also dark-tinted two layer and three layer LowE coatings that are intended for places with serious solar heat gain. Obviously these coatings have very low visible light transmittance, so not what you want.

Windows will have a VT rating for the entire window, not just the glass. Window VT will be and can be much lower than glass-only VT because it includes not just the glass, but the sash and frame plus any grills or anything else in the window that blocks visible light.

In Houston you want the lowest Solar Heat Gain Coefficient that you can find, but you also want the highest visible light transmittance that you can find. Unfortunately, physics is not on your side. Higher VT also means higher SHGC just as lower SHGC means lower visible light.

If code allows the higher SHGC, your best compromise among the coatings you mentioned would be LoE²-272. LoE²-272 is a neutral gray color so less noticeable than any of the triple silver layer products. It's pretty much the standard for people in moderate climate zones.

Look into Anlin in Socal, they make a very nice window.

Installer depends where you live.

I would strongly consider fiberglass windows such as those from Marvin and Milgard. If you're replacing single- or double-hung windows, consider casement (and awning) windows as these are the most energy efficient. Take care to understand glass options, particularly for west-facing windows where noon-to-sundown sunlight can easily overheat a room. Chosen carefully, energy-efficient windows can help reduce heating and air conditioning costs where electricity prices are high.