A feng shui mirror facing a window isn't necessarily bad, but it can be. Depending on the location, it might not be as auspicious as you think. If you have a large mirror facing a window, consider whether this is a good or bad placement. Here are some reasons why. You might want to change the location of a mirror if you're experiencing a bad or good feng shui effect.
A good mirror can improve your views of the outdoors. It's also good luck to place a mirror near a weak area in your bagua map. To improve this area, place a mirror with its back toward the weak area. It will reflect and expand energy, and can be very beneficial if you're dealing with a bad or oppressive energy. A feng shui mirrored placed on a south wall will extinguish the negative energy in that area and bring about disaster.
If you're trying to feng shui your home, a mirror facing a window can help. It can amplify positive energy and attract money. However, the chi flow through the mirror should be open and flowing, so you don't want it facing your front door. A feng shui mirror facing a window is a great way to visually enlarge a small foyer and welcome chi.
Another reason to place a feng shui mirror facing a window is to reflect the energy. Using a mirror in a foyer can help enlarge the foyer and welcome energy into the home. It can also serve as a welcoming space, especially for visitors. A feng shui mirror should not face the front door because it can block the flow of chi. The front door is a common place for a feng shui mirror to occur, so the reflected energy will converge there.
Mirrors should be positioned at the entrance. If it faces a window, it will increase the flow of chi into your home. A mirror facing a door will send negative chi out of a home. In addition, a mirror facing a window is good feng shui for a foyer. A crowded hallway will feel cramped and will be a poor feng shui for a mirror.
More information about the ideal mirror placements can be found here: Feng Shui Mirror Placement for Good Luck.