This house affects Archery Ranges and all Towers besides Monument to Aphrodite which has its own range scaling. Do not place them around any other building as the bonus will be wasted.
The range bonus is given as a percentage, so an Archimedes Tower that has 1000 range will gain 200 range from a 20% bonus. But a Greek Tower will only gain 90 range from a 20% bonus. To gain the maximum bonus put this house next to towers that have a high range.
Use this house on towers close to the centre of your base to give your towers a range that spans over more of your base rather than being able to reach further out into the clouds.