Often times when you shoot a home the sky isn't ideal for capturing a dramatic exterior view of the home. In this particular case, the sky was hazy and flat, without any color or contrast to speak of. This type of sky actually works quite well for a sky replacement.
I figured that I would try and use a sunset sky for this so I had the homeowners turn on their exterior lights, (even thought it was 9:30 in the morning), so I could more accurately capture a twilight setting in the final image.
By having a library of skies you can match a sky to the lighting conditions of the original image so that the final result looks realistic. In this case, I decided to use a sunset sky since the lighting was muted and somewhat resembled early evening lighting. By also increasing the contrast of the image and darkening certain areas I was able to make it match much better with the sunset sky.
I was also fortunate that the orientation of the home also matched with the location of the setting sun in the sky.
Here's the final image. It's a much more attractive view of the home and provides prospective home buyers with a very serene image of their future home!