Top motors can cost considerably more, but reliability, performance and efficiency can be much better and worth it in the long run. Low KV motors running on lower voltage (fewer cells) with large propellers are the most efficient and provide the longest flight times. Selecting the best motor, propeller, battery set will enable you to build a copter with a usable 30 minute flight time including a camera.
Cost Factors. Replacing a window costs an average of $300 to $700 per window. This assumes that the replacement window is going into an existing and structurally sound frame on a ground floor. Replacing windows in a typical three-bedroom, single-story home with ten windows can cost from $3,000 to $7,000.This cost can easily double for a two-story home.In the case that a window frame must be replaced, it is called a new construction window. A new construction window can increase the cost of replacement by as much as 50% to 100%, raising the average cost to anywhere from $5,000 to $40,000.n the case that a window frame must be replaced, it is called a new construction window. A new construction window can increase the cost of replacement by as much as 50% to 100%, raising the average cost to anywhere from $5,000 to $40,000.
1 Windows/Stairs.  Cost to Replace a Window Sill. Find the average cost to replace a window sill yourself compared with the labor and material cost of hiring a carpenter. Use your ZIP Code to adjust the cost to where you live so you can decide to do it yourself or hire a pro to do the job. Learn what to consider and the steps involved. carpenter or window replacement contractor will charge $127 to install a 4-foot-wide sill, assuming no repair work is required on the window and wall (that will cost more).