Start with how the window opens
| Type | How it works | Space to consider |
|---|---|---|
| Picture or fixed | The glazing does not open. | Provide ventilation and any required escape opening elsewhere. |
| Single hung | The lower sash moves vertically; the upper sash stays fixed. | Reach to the lock and the actual clear opening. |
| Double hung | Both sashes move vertically. | Operating effort, reach and any cleaning features. |
| Sliding | One or more sashes move horizontally. | Usable opening width when the sash is parked. |
| Casement | The sash is hinged at a side. | Clearance for the open sash and access to the operator. |
| Awning | The sash is hinged at the top and opens outward. | Projection over paths, patios or nearby windows. |
Pella’s window guide explains these operating styles. Compare the complete unit’s performance as well as its movement; a type name does not establish an energy rating.
Reference: Pella window types and operation.
Materials: the first three choices
1. Metal windows. Aluminum and steel can create a slim-framed appearance. Ask about the frame construction, thermal breaks, coating and suitability for the exposure. Metal alone does not establish storm resistance or thermal performance.
2. Wood windows. Wood offers a visible grain and a range of finish choices. Some units combine a wood interior with exterior cladding. Compare care requirements and the assembled window’s ratings rather than assuming every wood frame performs alike.
3. Vinyl windows. Vinyl is used in many residential window systems. Compare the actual profile, reinforcement, finish options and warranty. A vinyl frame is not automatically maintenance-free or ENERGY STAR certified.
Everyday styles: picture through sliding
4. Picture windows. Fixed glazing frames a view without an operating sash. Compare picture window designs when the opening does not need to provide ventilation.
5. Casement windows. Side-hinged sashes commonly swing outward. Check the handle position, screen arrangement and exterior clearance. The casement window guide explains this operation in more detail.
6. Garden windows. A projecting glazed enclosure creates a small display area, often for plants. Check support, drainage, condensation and the plant’s light needs. A garden window is not automatically a greenhouse with controlled conditions.
7. Single-hung windows. One moving lower sash suits a familiar vertical layout. Check the clear opening and cleaning method rather than assuming the sash tilts.
8. Double-hung windows. Both sashes move. Some models also tilt for cleaning, but that feature should be confirmed on the selected unit.
9. Sliding windows. Horizontal movement can suit a wide opening. A two-panel slider does not usually provide the full frame width as an open passage because the panels overlap.
Privacy, projection and entry details
10. Glass block windows. Patterned blocks can obscure a view while passing light. Privacy depends on the pattern and lighting. Confirm ventilation and access needs; a decorative glass-block assembly is not automatically a security-rated window.
11. Bay windows. A group of windows projects from the wall, often with a wider center section and angled sides. Plan the supporting construction, roof or head detail and any interior seat as part of the assembly.
12. Bow windows. Several joined sections form a gentler curve than a typical bay. The curve can be made with a series of flat window units; it does not require curved glass. Review the size and support requirements early.
13. Sidelights. Narrow glazed units sit beside a door. Choose the glass and width alongside the entry, and confirm any safety-glazing and privacy requirements.
14. Transom windows. A transom sits above a door or another window. It may be fixed or operable, depending on the design. Explore doors with transom windows for entry and interior planning ideas.
Top, bottom and roof openings
15. Hopper windows. A hopper is hinged at the bottom and typically opens inward. Check the room-side clearance and whether the handle is reachable. It differs from a top-hinged awning window.
16. Skylights. Roof glazing brings light from above and may be fixed or operable. Match the unit and flashing to the roof. Do not assume an ordinary skylight provides an approved emergency escape route.
17. Storm windows. These are secondary units added inside or outside an existing primary window. They can support an energy upgrade, but “storm window” does not mean hurricane-impact protection. Look for the specific tested rating if impact resistance is required.
Reference: ENERGY STAR explanation of storm windows.
18. Arched windows. An arched top describes the shape, not how the window operates. Confirm whether the unit is fixed, operable or a combination, and plan the surrounding trim.
19. Awning windows. Top hinges allow the bottom edge to swing outward. The sash may shelter part of the opening in light rain, but it is not a promise to keep out wind-driven water. Follow the operating guidance for weather conditions.
Larger assemblies and special requirements
20. Window walls. A broad glazed wall can combine fixed and opening sections. Structure, joints, glare, solar heat and access for cleaning need a coordinated design. A residential wall of windows and a commercial window-wall system may use different construction.
21. Egress windows. “Egress” describes a required escape or rescue function rather than one style. A suitable casement, sliding or hung unit may serve that role only if the actual opening and installation meet the applicable requirements. Have the project team confirm the required clear opening, sill height and access.
22. Custom windows. Custom dimensions or shapes can solve a specific design need. Start with the opening, operating function and required performance, then compare Rustica window options. Custom size does not remove installation or performance requirements.
Compare performance without guessing from the frame
| Measure | What it describes | How to use it |
|---|---|---|
| U-factor | Heat transfer through the unit. | A lower value indicates less heat transfer under the rating conditions. |
| Solar heat gain coefficient (SHGC) | How much solar heat passes through. | Choose for the climate, orientation and shading plan. |
| Visible transmittance (VT) | How much visible light passes through. | Compare daylight along with glare and privacy needs. |
| Air leakage | Air movement through the closed assembly under test conditions. | Compare rated values and the installation requirements. |
NFRC provides independent energy-performance certification for window products. ENERGY STAR qualification also depends on the product and applicable climate-zone criteria. Neither a dark frame nor a particular opening style proves certification.
Reference: NFRC residential product certification.
Reference: ENERGY STAR guidance for windows, doors and skylights.
Bring these details to the window consultation
- Room use, orientation and desired daylight or privacy.
- Opening dimensions and whether the wall is changing.
- Ventilation, escape, accessibility and safety-glazing needs.
- The clear space on both sides of an opening sash.
- Frame finish, glass pattern and maintenance preferences.
- Required performance documentation for the exact configuration.
For sizing terms, use the window size planning guide. Keep shopping and measurement decisions together so a beautiful window also suits the opening.
Planning a client project?
Preparing a window and door schedule for a client? Record the required performance and operation for every opening. Rustica’s contractor discount program explains professional eligibility and how to apply.
