It looks like you have 4 different size operating windows on the front. The only two that are the same are the ones flanking the picture window in the living room.
Putting grids in them will only emphasize the issue as they will be different patterns and spacing.
Ron

We have a ranch (altho living in Tx, calling my little home a "ranch" seems kinda silly. When we say "ranch", we're talking a house on a hundreds of acres and livestock and farm equipment(g) I don't think one acre and two Labs make a ranch LOL) Anyway, we redid our windows two years ago. We used a local, independent (not a big box store) contractor that installed Simonton Reflections 5500 series, double hung, Low E2 windows. I'm very VERY pleased with them. Bids from Sears and Home Depot, supposedly using virtually the same window, were twice as high.
Nine windows and installation was about $3400. Don't know where they stand now, but at the time they were rated #1 by JD Powers for customer satisfaction. I took this picture yesterday of the sprinkler system being installed, but it shows the front of the house. We used grids on the front but not the sides or back. The 4x4 picture window has no grids but the side windows next to it do. Hope this helps.
Monica

I'm in Texas so the majority of our extreme weather is heat, but, we can have very cold temps too. I used to keep my windows covered during the hot months with drapes and blinds to keep the heat out. Now, I can let the light in without worrying about the heat and cold :) It's amazing to put my hand right up to the window and not feel the transfer of heat or cold. Here's a better picture of the picture window. I think the grids make the windows look better from the front but didn't feel I needed to put them on the sides or back.

Ron, If I understood you correctly it wouldn't look right due to the windows not being the same size because the grids wouldn't be the same for each window. This makes sense, thank you! I'm glad I came on here to ask!
Monica, thank you for taking the time to post your pics, you really do have a nice home and your windows look the same size. I'm going to go without the grids because of the point Ron made above (and I'm glad he did mention it to me) :)

I don't have any pics at the moment but I'd like to comment on the Simonton windows. We just did an addition and will be replacing all the windows in the rest of the house this summer. I'm quite pleased with the Simonton windows. One of the really nice features is that they can build them to the size you need and the price is super reasonable. We didn't have any stock size openings and just gave our rough opening measurements. I worked with our local store and they let me play with sizes, styles and grids on their computer program so that I could visualize the windows before I ordered them.

I don't need to purchase boxes so why is that link posted here?

mileaday I looked at the Simonton website and really like the windows. I especially like the bow window to replace the picture window. Thanks for the tip, I really appreciate it!

Look carefully at the bow or bay window before you decide. I ordered one for my kitchen window so that I'd have a nice large area for my african violets. Because of the sizing and the amount of vinyl vs. the amount of glass, I hated it. I felt like I wouldn't have been able to see anything in my backyard. The dealer would have taken it back with a 50% restocking fee but luckily I was able to find a spot for it in another room. It looks wonderful where it is now but the proportion just didn't work for the kitchen. Your window looks much larger than what I used so you are probably ok. The women at Simonton are very helpful and can give you exact measurements on how much glass you will lose to vinyl and they can send you samples of vinyl colors or glass if you need them. I originally wanted casements but because of some of the windows opening into walkways, we ended up using all sliders. I also didn't want a large horizontal band in the middle that you get with a double hung.