Wondering if anyone has any opinions on Farley 7000 casement windows vs. Okna 700 casement windows. The estimates I have are reasonably equivalent, as is the numerical performance. Edge to Farley for a lower SHGC with low-e 366, slight edge to Okna for U-Value.
Not sure about your window brands but I would think $55 for the upgrade may not be a bad idea. If they last 40 or 50 years, that, $1 or $1.50 per year per window not bad for the extra r-value, windows are the worst place for loosing heat.
Where are you located? The low shgc may actually be detrimental if you are not in a hot climate as passive solar heating is desirable in colder areas. You should also look at the structural ratings, namely air infiltration and design pressure. I'm not familiar with Farley, but okna/HiMark is one of the top performers on the market today .