While windows and siding are two very different parts of the house, not uncommonly homeowners will replace both at the same time. Both have a strong visual impact and are often considered when renovating the outside of a house. The window frame and the siding are also often made out of similar materials, and many companies provide materials for both projects, which can make accounting for the costs of both at the same time easier. However, costs can still vary widely for window and siding projects based on the details.
Windows
Replacing windows varies according to how much of the window is being replaced. Usually a replacement covers the window itself and the frame, which ranged from $300 to $700 in 2011 for an average window and up to $10,000 for replacing all windows, depending on the size of the home. However, large windows or windows located in difficult places may cost several thousand dollars for a single full replacement. If homeowners want to change the shape or size of the window through additional construction work, this can cost 50 to 100 percent extra to replace all windows in the house.
Siding
Siding tends to be less expensive than a full window replacement, mostly because the materials are simpler and easier to install. On average, in 2005 homeowners spent around $7,000 for siding replacement on the mid-range level. For high-end siding where materials were improved, costs rose to around $10,000. The eastern and western areas of the country tended to be more costly than the mid and southern areas.
Variance
Windows and siding have tremendous variance in costs, making exact prices difficult to determine. For instance, windows can come in one-, two- or three-layer versions with several options for gas mixtures between the panes and sealants along the edges. The most protective windows will cost much more than simple versions. Likewise, window frames and siding can be made of wood, fiberglass, vinyl and many composite materials. Vinyl tends to be the cheapest option at $1 to $2 per square foot of siding.
Payback
Payback refers to how much value the owner creates through a window and siding replacement project or how much the market value of the home goes up because of adding new windows and siding materials. For a typical windows project, expected payback is 80 percent, which means that 80 percent of the cost -- again, around $10,000 -- will be added to the home's immediate value. For siding, the numbers are slightly higher at 83 percent.