We are looking at replacing all of our sliding glass doors (4) with 1 door being a whole wall of window due to the sun and sounds of downtown Los Cabos, Mexico. We were told that a thicker (@ 11mm) window with an added darker tint to replace the much thinner pane that exists with foam sprayed into the track would suffice instead of 2 panes of thinner glass that is used for double pane windows... Does this make sense or are we being hoodwinked into an inferior job? Please help.

Double pane with Argon gas between the two panes would be a better choice over a single pane.

Sealed Glass units are the best! Two pane or with an Invisible third pain witch will reduce solar heat gain and uv effects even further. You want a window that will allow for little solar heat gain for your windows to operate efficiantly year round. If you live in a cold climate and do not use air conditioning then you what widows that allow for solar heat gain. Foam filled vinyl extrusion is a sale gimic for the price it only gives you decimals or R value increase. The air in non foam filled vinyl extrusions provides alomost the same R vale so do not waste you money on the Foam filled extrusions.

Go with double pane, argon filled, Low-E. You will never regret it. I install windows and would never put in a single pane. In fact, it is not approved in GA to install single pane windows.