I vaguely remember someone on MN said they look cheap and ugly. But DH is really keen to push it ahead for reasons below:
1 Blocking light: We've tried all sorts reasonably priced options to block light out in summer time for DS1's bedroom which is in the loft. It's very wide with three panel windows. All attempts failed. Currently, I'm using baby portable blackout curtain to cover up the part near his bed every evening.
2 Improve insulation: DS1's bedroom is the coldest one in winter, as it's in the loft. The thermostat for our centre heating is in his room to keep it above 16C in winter days. But since the insulation is not brilliant, often downstairs bedrooms could be overheating in the coldest days.
3 Reduce indoor awkward fixtures/fittings: Same morning light problem for DS2's bedroom which is on the 1st floor. Currently it uses a blackout roller blind plus a very wide ugly IKEA blackout curtain to catch the light leaked from the sides/top.
We used to live in France and those external shutter blinds are rather common and effective to keep heat/cold/light out.
If people really don't like the look of them, would it affect the property resale value, given that we only install them at the rear for two upstairs bedrooms?
Picture attached.