In addition, paint features such as mold and mildew resistance are important cost factors. Many mold-inhibiting bathroom paints, for instance, cost substantially more than ordinary latex-acrylic paint—sometimes close to twice the cost. Also, paints that come with warranties from the manufacturer may be more expensive depending on the length of the warranty. (A two-year warranty is standard.)
Painting exterior windows depend on the size of the window and the number of panes. To calculate the price for windows larger than 15 sq. ft., add 1’ to each side of the window and then multiply width x length. Add two sq. ft. for each window pane for painting the mullions, muntins, and sash and then multiply your total sq. ft. by $84/100 sq. ft. So a 4’ x 4’ window with 4 panes will come to a total of 44 sq. ft. x $84/100 sq. ft. = $37.
Some siding on older homes might need so much repair that it is more cost-effective to replace the siding rather than repair it all and then paint over it. Expect to pay between $1,550 and $3,050 for the removal and disposal of old siding and $4,000 to $14,000 for new siding and installation. Expect to pay more if the wood underneath is wet and rotten and needs structural repair work.
For walls, measure the linear feet of wall space (measuring along the baseboards) for the areas to be painted (using a tape measure, laser, or both). Then multiply this by the ceiling height (usually it is 7.5 or 8). If there are 2 story areas, measure them separately, and multiply them by double the regular wall height. Then multiply the total number by 2 (for 2 coats).

Specialty painting, like murals and trompe l’oeil, costs $40 to $50 per hour. Paint might range between $75 to $90. The professional’s skill and experience are also determining factors. While a freelance artist might charge $25 to $30 an hour, a very skilled professional might charge $80 or more. Some might also charge $60 or more for a consultation.

Painters will agree that you should always aim to paint in the part of the year when it’s least likely to rain, has low humidity, and when the temperatures are above 50 F. Rain can wash wet latex paint off a wall, and temps that are too low can affect the way the paint sticks to the walls. Some painters will add additives to the paint if working in very high temperatures to slow down the drying time.
Most of a projects price is the cost of labor at $25 to $75 per hour. However, most contractors bid out based on the entire project which includes all work hours. Hourly rates are only useful if your pro asks to do the job as “time and materials.” However, be wary of this pricing structure, it usually shows the contractor is uncertain how long the project will take.