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How Much Does it Cost to Replace Bay Windows?

Bay windows can offer a panoramic landscape that is not found in other types of windows. These windows are designed to jut outward from the walls of a building, creating a bay within a room. Modern bay windows may include a large variety of choices, including built-in seating as well as slide-out windows. They may also match the historical or decorating style of the home. Examples include bays with craftsman style transoms or windows that slide open at various points for ventilation. Garden bay windows include a structure that offers a greenhouse style surface for growing plants. See all their costs below.

The Costs

  • Average minimum costs: $1,200

  • Average maximum costs: $3,000

The costs associated with bay window installation depend on the installation and window type. Fiberglass and more weather-resistant finishes increase the price to approximately $2,500 for a basic window installation. Labor charges range from $1,000 to $3,000, depending on the complexity of the structure and the existing home's framing and studs. Older homes may require additional framing costs to beef up the load-bearing structure of the bay. 

A determination on costs will often rely on measurements of the bay itself to the structure of the home. Measuring is a fairly simple task that can save costs in the long run. The opening of the bay can be determined by measuring the rough opening from the header to the sill plate. A guide can be provided as a sample from a bay window manufacturer to determine the distance between seam joints.



A fiberglass bay is the most durable of all materials used. Fiberglass is a strong material for extreme weather changes and UV light. It is resistant to cracking and bowing as well as air penetration. Fiberglass is a slightly more expensive product, but the upfront costs are mitigated over time with reduced maintenance expense. Fiberglass also has a lower carbon footprint and can combine the aesthetics of other materials for a complete look. 


A clad window is simply a window with a basic wooden structure with an outer skin of aluminum or vinyl. This reduces costs while adding durability. Clad construction will typically have similar maintenance as a vinyl bay window. The additional maintenance of wood will be associated with the interior portion of the bay window. This is why it's important to determine the species of wood to match interior portions of the home. The clad vinyl will be encased as individual window components instead of an entire structure. This means that the wood bay structure will be the frame distinct from the windows themselves. This allows for some customization of window sizing and the quality of window glass.


Vinyl bay windows are practically maintenance free. They function in a similar fashion to clad and fiberglass windows. The difference usually exists in price and style. Vinyl bay windows provide an economical structure that is resistant to temperature and weather fluctuations. Maintenance for these materials may include pressure washing and bleaching from time to time. The difference between vinyl and clad-vinyl is that the entire bay structure may be considered a single piece and less of a load-bearing structure.


A wood bay window will typically have a wood framed interior with a clad style exterior for extra strength and weather-proofing. Wooden bay windows have a more traditional look on the interior side of the bay. The wood framing of the window may match the bench seating or storage of the bay construction. The wood grain choices can be used as part of a very classical appearance in the home. The maintenance requirements are higher and may require extra protection to resist fading or cracking. The wood will need to be stained and varnished for extra protection. Species such as cedar and other redwood grades are used for a long-lasting base in construction. Additional protection may include siding sheathing.

Bay Window Roofing 

Bay windows that are more substantial may require extra flashing and roofing materials. Timber frame construction with a copper or metal roof are the most durable. Traditional stick framing and shingles are also available to match the style of the roof of the main home's structure. It should also be noted that costs can fluctuate between the types of flashing in the roof and roof structure. Architectural shingles can cost around $40 per square foot while metal roofing can be compared to a tile or cedar style mission roof, which can cost between $60 to $70 per square foot. The roof of the bay window is both a part of the bay structure and the home. These materials will need to be considered for matching the home profile. 

Advantages and Disadvantages

Bay windows offer a distinct advantage over other windows. The extruded profile can allow for presentation and additional seating in a room. It also has the potential to raise the value of a home and add a classical touch to living rooms and formal areas. Bay windows also provide a level of ventilation and light not found in traditional double-hung windows. The overall size allows natural light to pour into a room. A good perspective on space is the additional increase of 3 feet in length of additional storage and seating. There are also many styles that can be achieved with the combination of other window sets. Historical and modern components can be blended to increase the functionality of the window.

The advantage of additional light can also be a disadvantage in terms of energy efficiency. This requires careful placement of a bay window for solar gain in climates that have more extreme temperatures in summer and winter. Energy-efficient thermal glass can raise the cost as well as reduce choice in particular styles. Adding a bay window can also cause structural concerns in existing homes. The bay window may be considered a load bearing structure and require extensive structural expertise, depending on the loads of the home. Careful planning will also need to take into consideration the layout of the home.

Last updated on Aug 8, 2014

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