casement to double hungs/loss of glass area estimate

[petras52]

in previous post, I mentioned switching from wood casement to vinyl double hungs, (insert only, using existing frame).house is vinyl sided and window casements are aluminum wrapped..I am concerned about the loss of glass area with this type of install especially on the smallest casement windows we have, 2 in tandem, measure 22wx30h each at the sashes and 18.5x26 actual glass area..I'm looking to buy softlite ls dh windows..would a loss of approx 1" glass area on all sides be a good guess with this type of install? thanks

[Windows on Washington]

Probably a bit more than 1" extra. If you are figuring that you are losing 3.5" or 1.75" off of each side, you probably need to add about 1.75" to each side for total loss on the Soft-Lite LS.

Maximum glass would be had by ripping out the center post and putting in a 2-Lite slider.