If you have a small room and do not have much in your budget for big addition, than consider adding bay window. Adding a bay window, or a oriel, increases the amount of natural light in any room, improves the view to the outside, and adds usable space, whether it's shelf space or floor space. A bay window can also add architectural interest to the house's exterior with its three-dimensional shape and interesting lines. If you plan to sell the house it will also add value.

You can buy prefabricated bay windows in new or use in 30-degree, 45-degree, and 90-degree bays. You can also create your own bay by building angled walls and framing for double-hung or casement windows combined with fixed units.

Each bay type comes in hundreds of standard and custom sizes to fit any opening. Standard sizes typically range in width from 3 feet 6 inches to 10 feet 6 inches, and in height from 3 feet to 6 feet 6 in.

Most windows are made of wood or vinyl. Exterior finish options include primed wood, extruded vinyl and wood clad in low-maintenance aluminum or vinyl. Primed-wood windows are economical, but they must be painted and periodically scraped and repainted to prevent rot. Vinyl windows are also affordable and maintenance-free, but their frames include vinyl on interior surfaces — a look not everyone likes. Clad windows usually cost more, but offer a low-maintenance vinyl or aluminum exterior and a handsome all-wood interior.

Most bays come with insulated glazing-two panes separated by an air space. If you want higher energy efficiency, order the window with argon gas between the panes, or opt for low-e glazing that admits solar heat in winter and reflects it in summer. Homes in cold climates might benefit from triple glazing (three panes, two air spaces), which provides 15 to 25 percent higher energy efficiency than standard insulated glazing.

Budget it out before you make the final decision. I have seen home owner start the project but never finish because of low budget. If you know how to do it yourself that is a bonus but I recommend hire a good contractor. This way you just tell them what you want and they will get it done for you.