Windows

 

Windows are one of the major character-defining features on most buildings. The architectural details were carefully designed and relate directly to a building’s architectural style and construction period. Therefore, there is a wide variation of window designs and materials used; every part of the window contributes to its distinctive physical character.

Windows add light to the interior of a building, provide ventilation, allow emergency egress, and are a visual link to the outside. The demands of modern energy efficiency and security standards, along with marketing campaigns from window manufacturers, have led some owners of older buildings to consider replacement windows. The following information will help owners better evaluate the value embedded in existing historic windows, the actual need for replacement windows, and what to look for when repair or replacement is being considered.

 

Table of Contents:

1. What do I do with my old windows?
2. All about window repair
   • Levels of repair
   • Condition Assessment 
   • Retrofitting
   • What about lead?
   • Before and after
3. Repair vs. Replacement
   • Comparison and identification of details lost
4. Replacement Windows
   • Sash
   • Pocket
   • Full Frame
5. Window Replacement Application

Types of Windows:

 

Awning: A window that is hinged at the top and tilts outward.

Bay: A bay window is constructed of three windows: the center window is typically larger and placed flat, while the other two are set at a 30- or 40- degree angle. This type of window protrudes from the side of a building.

Box Bay: A window constructed with three wall that extend/protrude from the wall of the house. Multiple windows will be placed on the wall parallel to the house. The side walls are set at 90 degree angles and may, or may not, include windows. 

Bow: Four or more windows that are set within a curved, rounded wall that extends from the wall of the house. 

Casement: A window that is relatively narrow (taller than wide) and opens on hinges that are fixed to one of the vertical frames. 

Cottage: A window that has two moveable sashes, one on top of the other. The upper sash is smaller/shorter than the lower sash. An alternative, yet seldom used, style is when the lower sash is shorter than the upper sash. 

Double-hung:  A window with two sashes of the same dimensions, each movable vertically. The upper sash ca have a curved or straight top. Double-hung is the most common window used in residential construction. 

Fixed/Picture: The term "fixed" or "picture" generally relates to the size of a non-operable window. Fixed windows can be all shapes and sizes, but a picture window is a large window that is a focal point on a wall. Picture windows became popular in the mid-20th century and can have operating windows on either side. 

Hopper: Similar to an awning window, but hinges are located at the bottom of the window and tilts inward. 

Jalouise: A window made of narrow, horizontal glass louvers, or slats, that rotate outward when cranked open, and close flat against each other when closed. 

Oriel: A window that protrudes/extends from the main wall of a building but does not reach the ground. It is supported by corbels, brackets, or another type of small support. 

Transom: A small window that is located above a window or door. Transoms can be operable, with hinges at the top like an awning window, or be fixed. 

 

What can I do with my old Windows?

Many property owners have some (or many) windows that don’t work, are drafty, and look bad. It is common to think that the only, or at least the best way, to fix window problems is to remove the old windows and install new “highly efficient” replacement windows. 
Replacement window companies are very successful in touting their products as the best choice for consumers, and that bad looking, leaky, difficult to operate, old windows can’t be repaired. What property owners need to know is that the best choice for affordable, energy efficient windows is to keep the original windows, repair them and have storm windows installed. With this work, the old windows will likely be as energy efficient, be better for the environment, and last longer than new replacement windows. Shown below are some examples of wood and steel windows that have been repaired. 

Five Reasons to Keep your old, original windows

1). Replacement windows are not always better than old, historic windows.​​​​​​

• Old windows on most houses in Detroit have been in place since the house was constructed and can be over 100 years old. These windows are made from individual parts which means they can be repaired, allowing the owner to only spend money on the parts of the window that need to be fixed. Properly repaired and maintained original windows will last longer and continue to work better than replacement windows. Double-hung windows that have had their sash cords removed are hard to open and close. The repair of this feature only involves a few items that can be purchased. 
• A replacement window is made as a unit so there aren’t individual pieces that can be repaired (except for replacing broken glass). Therefore, if any part of a window frame breaks, an entirely new window will need to be installed, and will possibly need to be purchased by the property owner, due to the fine print of a warranty.
  • Normal weathering of window frames is often not covered.
  • One warranty only covers the possibility of vision obstruction should seals fail.
  • Another warranty only covers the replacement of a window with the exact model match - if a newer version of the window is being produced, the warranty is void.
  • Some warranties come with multiple time frames, such as 10 years for the frame, 20 years for the glass, yet the manufacturers typically advertise their windows as having a 20-year warranty. 
• Repair your windows. Look for window repair companies as well as carpenters, as they regularly work with wood and likely repair windows and doors (but may not advertise as a window company). You may also consider repairing the windows yourself. There are YouTube tutorials, websites, and blog posts that offer step by step guidance that show and explain how to repair wood and steel windows. 

2). Make a true environmentally conscious choice.

Almost all replacement window companies market their products as environmentally friendly and energy efficient. However, it is historic buildings that should be marked by the phrase “the greenest building is the one already built”.

• Replacement windows are rated based on their energy performance during the “use” phase. This tactic purposely overlooks the larger environmental impact caused multiple manufacturing processes, transportation to deliver the windows, as well as the transportation to, and long-term disposal of, the existing windows to landfills.
• Property owners interested in eco-friendly windows need to consider the entire lifecycle of the product they are considering, which includes the long-term environmental impact of the product(s). the will be thrown away. As shown in the adjacent image, replacement windows, regardless of the frame material, are not a sustainable option. Beyond the materials needed for window frames (wood from trees and chemicals for vinyl), sand must be extracted for new glass. Sand is a limited natural resource - the increasing demand for sand has caused river pollution and flooding, while also shrinking aquifers and deepening droughts. 
• Repairing existing windows preserves “embodied energy” (the energy already expended to manufacture and deliver the existing windows), reduces consumption of resources and materials, creates less waste, and consumes less energy.
  • A 2002 study conducted by Lawrence Berkeley National Laboratory confirmed that installing a storm window over a historic window can achieve a similar thermal performance to that of a new low-E vinyl replacement window. https://eta-publications.lbl.gov/sites/default/files/lbnl-51453.pdf
• Modern replacement windows have a relatively short lifespan, compared to historic windows.
  • Old historic windows are 50-100+ years old, and when repaired and maintained can last at least another 100+ years.
  • As discussed on page one, replacement windows are made in a way that they cannot be repaired, forcing an owner to purchase a new window when one or more internal parts break or wear out. This leads to a continuous cycle of purchase, disposal and waste, which is the opposite of the marketing slogans that say replacement windows are “a low impact on the environment” and are “an environmentally friendly option”. 
• Retaining original windows can be essential in maintaining building integrity and character. Original windows are regularly identified as “character-defining features” and are often some of the most significant architectural features and visual parts of a house. As shown on pages five and six, window design, placement and arrangement communicate the character, style, and age of a building. 

3). Windows are not the primary cause of heat loss.

Windows, whether historic or new, are a source of heat loss but are not the first, second, or third, place to look at when you want to address retaining heat and lowering energy bills. 

The areas where air can leak within window openings are small and close to you, so you often directly feel these minor leaks. What you don’t see and can’t really feel are the larger surfaces and areas where most of the heat loss occurs.

Attic/Walls/Floors/Basement/Crawl Space

According to the US Department of Energy “Heat loss through the floor, ceiling, and walls in your home could be very large if the insulation levels are less than the recommended minimum. When your house was built, the builder likely installed the amount of insulation recommended at that time. Given today's energy prices (and future prices that will probably be higher), the level of insulation might be inadequate, especially if you have an older home.”  https://www.energy.gov/energysaver/do-it-yourself-home-energy-assessmen…;

The Environmental Protection Agency goes one step further, “If installed properly, the addition of insulation can reduce energy costs by as much as 50 percent in some cases and make your house more comfortable.”  https://archive.epa.gov/region5/sustainable/web/html/energyadvice.html

Attic - Heat rises and will naturally move up to the attic. Without adequate insulation, sealing, or vents, heat will escape through the roof and chimney.

Walls - These very large surfaces are in direct contact with the outside temperature. There may not be insulation, or insulation at an adequate level, inside the walls.

Floors/Basement/Crawlspace - Rising heat moves towards the attic and moves through uninsulated areas of the floor and foundation. 

Heating and Cooling Equipment; Lighting; Appliances; and Electronics

High heating bills may be caused by an outdated furnace, boiler and/or water heater that isn’t operating efficiently. Inspect heating and cooling equipment annually and change filters on forced-air furnaces regularly. Check duct work for leaks and insulate ducts and pipes. 

The Department of Energy states energy for lighting accounts for about 10% of your electric bill. The appliances and electronics you own (and how you use them) also affect your energy use and costs.

Windows and Doors

Many energy websites state only 10-15% of heat loss is through doors and windows. Caulking and weatherstripping are easy, effective ways to reduce air infiltration. Caulk is generally used for cracks and openings between stationary house components (i.e., around door and window frames). Weatherstripping seals components that move, such as doors and operable windows. 

Installing replacement windows to fix window leaks is only a temporary fix, as the new windows will also need to have caulking and weatherstripping replaced at some point. The energy/financial gain through new windows will be very small when compared against the cost to purchase and install new windows.  

Repairing old windows and installing storm windows will likely be cheaper and may offer similar energy savings as the new replacement windows. 

4). Take advantage of the previous owners' financial investment

• The density of the wood used in new replacement windows doesn't compare to the wood that was used 70-100+ years ago. In the 19th century and early 20th century, wood used for houses came from trees that were 100-200+ years old. Theses trees had grown slowly over a long period of time; this slow growth caused the rings of a tree to be very tight which created dense, strong, and stable lumber. Wood cut today is from new growth tree that were grown fast - the differences between old and new lumber is visible. Old wood window frames were made from wood that is no longer available; it is denser, and more rot- and wrap-resistant than wood grown today on tree farms. 
• Windows are character-defining features and an important part of every historic building’s original design. Original windows, which include the surrounding window trim, can identify the style of house and its age, due to the materials used, the window function, design details, and dimensions; they make your house stand out from the more generalized designs and dimensions used in new construction. Also, many older houses have unique windows that would be very expensive, and at times impossible, to replace.

5). Your house is unique and important.

 Historic houses are not mass-produced structures built by a developer within a short period of time. Historic houses in Detroit have individualized features that identify the architectural style, time of construction, and usually the use of the building. There is financial (in addition to the visible architectural) value in the materials and decorative elements on a building which can be very expensive (or sometimes not possible) to reproduce. Hang on to them, repair them, restore them. Keep your house looking unique and contributing to the city’s vibrant architectural history

In conclusion, please email Detroit Historic District Commission staff at [email protected] for assistance in identifying, and discussing, the windows on your house. Staff must receive clear exterior photographs of each side of the house, as well as close-ups of the individual window openings. Interior photos may be requested if windows are behind storms or difficult to see due to close placement of neighboring house. 

Please do not replace any windows within your house without having received the approval of the Detroit Historic District Commission. Thank you.

 

HDC Guidelines for Historic Wood Windows