If you're dealing with rooms that do not have southward-facing windows or you can't install new windows, you might consider budgeting for tubular skylights. These are vertical tubes with a dome on top that go through the roof and attic space in order to focus outdoor sunlight into a specific room directly below. These are much more cost effective than traditional skylights because they don't involve major construction for installation and they don't let in ultraviolet rays like traditional skylights, so your furniture and carpets won't fade. Tubular skylights are designed to bring more natural light into single-storey homes or the top floor of a multi-storey home, and not into floors that have rooms above them. However, you can find some tubular skylights that have "elbows" that will allow you to fit them around obstacles.