The windows are newer? Have you seen what the privacy is like yet? Low-e will provide a measure of reflectivity that is usually adequate for non bed/bath windows.

Not sure if window film is the answer unless it has a pattern of some sort that is aesthetically appropriate and has enough obscured or opaque areas where it is needed. I think a reflective film would be sometimes appropriate for commercial applications.

For those reading:

Houses should respond to their site. Part of that is window location, size, function and treatment that should be determined during the design process. Windows provide little thermal insulation but do offer natural light, natural ventilation, views out, and views in. It appears in this design the views in were not considered during the design process.

Funny you refer to your parents by numbers and not names.

(humor)

Window film will most likely void the warranty of any new windows. Read the fine print. Buyer beware.

"how do we keep the home private and also temperature-controlled for cold winters and humid summers?"

This should all have been addressed while designing and building the home.

For shades, I would look at slim-profile cellular shades with bottom-up/top-down feature. I like Hunter Douglass and have used them in several homes. These are the extras that people forget to budget for when building. I spent around $20K on my HD blinds for the house, not including the HD Vertiglides for 3 large sliders which were around $12K. You can get light filtering, opaque and room darkening fabrics depending on the room and privacy needed.

Mirror window film looks amazing on til tok. In reality your house looks ridiculous but private by day but at night when the lights are on inside the mirror effect moves to the interior so you can’t see out but everyone can see in easily. Hard no. We have regular tinting on our historic single pane west facing windows and the tinting does make it harder to see in.

Window film can be a bit tricky to understand for me, but Chispa is absolutely right about cellular shades—they’re excellent for both privacy and insulation. Their honeycomb structure traps air, providing a buffer against cold in winter and helping keep the home cooler in humid summers. They’re a great choice for both energy efficiency and comfort.

I use motorized solar shades for this type of issue I use 10% and the darker the color the better the view which IMO is imporatnt . I dislike window film since I open my shades all day on a cloudy day to get as much natural light as possible . Thos eshades give you good daytime privacy and I mix them with drapes on the windows where privacy is an issue and IMO that is in few spaces , usually privacy issues are more in your head than reality. I do not think shades , window film or blinds really do much for controlling cold but mine sure do control heat form the sun I would never do anything that looks like mirror

The first thing I would do is figure out where you actually need the privacy. I did this in my home. My house sits higher than the road, so I had a friend inside walking around while I was outside on the road looking in - day time and then at night. Good thing - I realized that all people would see was my head and the ceiling of that space so I saved a ton of money thinking I had to cover 6 large windows. I did do blinds on the bedroom windows .

The idea of mechanical blinds might be really nice so your parents don't have to open and close them manually - if that helps them.

Good luck