Wednesday, February 4, 2015

Replacement Windows for Improved Energy Efficiency

Replacement Windows for Improved Energy Efficiency: A Walk-Through Case Study

I'm not a building inspector, but as a former building contractor and a widely published home-improvement writer, I'm often asked by friends and acquaintances to assess their homes and suggest the best ways to address whatever issues there might be. My friend Tony—a person driven chiefly by a desire to responsibly fulfill his duties as a family man—recently presented me with an interesting case.
Tony and his wife, Karen, had been given stewardship of a 1950s rambler in an upscale suburb of Washington, D.C., that belongs to her 85-year-old father. It's modest by any measure except for its value—$450,000 to $500,000 in today's market—and in need of some TLC. The father is alive and well but living elsewhere. He doesn't need to recover equity or earn income from the house—it'll one day be part of his legacy to his daughter and grandkids—but he doesn't want the headaches of caring for it, either. That falls to Tony, and he's asked me what he needs to do to preserve the value of the house.
For the time being, Tony is letting one of his daughters—a recent university graduate—live in the house with friends until she gets a footing in her career (and with a B.A. in Cultural Anthropology, it’s anyone’s guess as to how long that will take).  The young woman had mentioned more than once during this unusually cold D.C. winter that the house is chilly.
Tony's focus is on the windows. Most of them are horizontal sliders. The living room also features two sliding-glass doors—a kind of glass wall that overlooks a rustic backyard. Should he replace any or all of them?
During my walk-through, I encountered 12 single-glazed, aluminum-frame horizontal sliders of 1970s vintage—not the best from a comfort or energy standpoint, but their factory finish is still in pretty good shape, and they're fitted with screens and storm sashes. The exterior caulking around the frames is fairly worn out and cracking.
On my way inside, I noticed that the soffit panels at the eaves have all been taken off. I saw that the underside of the sheathing is water-stained. I'll bet there was leaking from ice damming (thick ridges of ice along the eaves), and it’s ruined the soffits. Tony's already had a new asphalt shingle roof put on.  I hope they flashed the eaves against leakage caused by ice dams.

Looking at the windows from inside, I found some evidence of moisture infiltration around the jambs and sills. Was the source the damaged caulk?  Inadequate flashing in the original installation?  Leaks from ice dams?
Better windows are available these days. In our market, it would probably cost him about $1,000 apiece to replace the sliders with vinyl low-E, gas-filled units. There's also a big combination unit with fixed glass and double-hungs on the front of the house; replacement would cost about $2,000. But would replacement windows—properly installed—actually improve comfort, and preserve or add value to the house?
While mulling that over, I went into the living room to look at the sliding glass patio doors. They’re much newer than the other windows, as they have aluminum frames and insulating glass. They’re in great shape, but the sheer size of the glazed area explains why the house is so chilly in winter.

And there’s another issue:  the living room is above a walk-out basement, so the door sills sit about 9 feet above the grade of the stone patio below, which is a code violation. Tony would never be able to sell or rent out the house without addressing that problem.

The Remodeling Magazine’s 2015 Cost vs. Value Report states that the return on resale for vinyl replacement windows in the South Atlantic region area is about 60%.
My advice to Tony is this:
  • It wouldn't make much sense to replace the horizontal sliding windows throughout the house. While they're old and only single-glazed, they're fitted with storm sashes, so their energy performance is roughly comparable to double-paned glazing. I have concerns about the evidence of moisture infiltration around the windows, but my guess is that the new roof may have corrected the problem. I would, however, renew the exterior caulking, and fill and paint the interior finished openings, as well as keep an eye on them to see whether evidence of moisture intrusion returns.
  • It wouldn't make any sense to replace the sliding glass doors in the living room with new ones of comparable size. It would cost about $5,000 to upgrade them with doors with gas-filled glazing, and that would improve the energy performance from R-2 to R-4, but it would result in only a very small improvement in comfort, and probably no reduction in energy costs.  Plus, he'd still have the code issue to deal with.
However, there are a number of ways to address the code issue:
    • To simply remove the violation, install approved guardrails at least 48 inches high, and align them with the sliding door sills.
    • To remove the violation and improve comfort, take out the sliding glass patio doors and redesign the wall by reconstructing it with better insulation and smaller windows.
    • To remove the violation and add value to the house, add a deck off the living room.
The Cost vs. Value Report says that in the Washington, D.C., area, a deck addition returns almost 96% of its cost at resale.

Inspecting Aluminum Wiring

Inspecting Aluminum Wiring



Between approximately 1965 and 1973, single-strand aluminum wiring was sometimes substituted for copper branch-circuit wiring in residential electrical systemsAluminum and copper wiring, with each metal clearly identifiable by its color due to the sudden escalating price of copper. After a decade of use by homeowners and electricians, inherent weaknesses were discovered in the metal that lead to its disuse as a branch wiring material. Although properly maintained aluminum wiring is acceptable, aluminum will generally become defective faster than copper due to certain qualities inherent in the metal. Neglected connections in outlets, switches and light fixtures containing aluminum wiring become increasingly dangerous over time. Poor connections cause wiring to overheat, creating a potential fire hazard. In addition, the presence of single-strand aluminum wiring may void a home’s insurance policies. Inspectors may instruct their clients to talk with their insurance agents about whether the presence of aluminum wiring in their home is a problem that requires changes to their policy language.


Facts and Figures

  • On April, 28, 1974, two people were killed in a house fire in Hampton Bays, New York. Fire officials determined that the fire was caused by a faulty aluminum wire connection at an outlet.
  • According to the Consumer Product Safety Commission (CPSC), "Homes wired with aluminum wire manufactured before 1972 ['old technology' aluminum wire] are 55 times more likely to have one or more connections reach "Fire Hazard Conditions" than is a home wired with copper."

Aluminum as a Metal

Aluminum possesses certain qualities that, compared with copper, make it an undesirable material as an electrical conductor. These qualities all lead to loose connections, where fire hazards become likely. These qualities are as follows:

  • higher electrical resistance. Aluminum has a high resistance to electrical current flow, which means that, given the same amperage, aluminum conductors must be of a larger diameter than would be required by copper conductors.
  • less ductile. Aluminum will fatigue and break down more readily when subjected to bending and other forms of abuse than copper, which is more ductile. Fatigue will cause the wire to break down internally and will increasingly resist electrical current, leading to a buildup of excessive heat.
  • galvanic corrosion.  In the presence of moisture, aluminum will undergo galvanic corrosion when it comes into contact with certain dissimilar metals.
  • oxidation. Exposure to oxygen in the air causes deterioration to the outer surface of the wire. This process is called oxidation. Aluminum wire is more easily oxidized than copper wire, and the compound formed by this process – aluminum oxide – is less conductive than copper oxide. As time passes, oxidation can deteriorate connections and present a fire hazard.  
  • greater malleability. Aluminum is soft and malleable, meaning it is highly sensitive to compression. After a screw has been over-tightened on aluminum wiring, for instance, the wire will continue to deform or “flow” even after the tightening has ceased. This deformation will create a loose connection and increase electrical resistance in that location.
  • greater thermal expansion and contraction. Even more than copper, aluminum expands and contracts with changes in temperature. Over time, this process will cause connections between the wire and the device to degrade. For this reason, aluminum wires should never be inserted into the “stab,” “bayonet” or “push-in” type terminations found on the back of many light switches and outlets.
  • excessive vibration. Electrical current vibrates as it passes through wiring. This vibration is more extreme in aluminum than it is in copper, and, as time passes, it can cause connections to loosen.

Identifying Aluminum Wiring

  • Aluminum wires are the color of aluminum and are easily discernible from copper and other metals.
  • Since the early 1970s, wiring-device binding terminals for use with aluminum wire have been marked CO/ALR, which stands for “copper/aluminum revised."
  • Look for the word "aluminum" or the initials "AL" on the plastic wire jacket. Where wiring is visible, such as in the attic or electrical panel, inspectors can look for printed or embossed letters on the plastic wire jacket. Aluminum wire may have the word "aluminum," or a specific brand name, such as "Kaiser Aluminum," marked on the wire jacket. Where labels are hard to read, a light can be shined along the length of the wire.
  • When was the house built? Homes built or expanded between 1965 and 1973 are more likely to have aluminum wiring than houses built before or after those years.

Options for Correction

Aluminum wiring should be evaluated by a qualified electrician who is experienced in evaluating and correcting aluminum wiring problems. Not all licensed electricians are properly trained to deal with defective aluminum wiring. The CPSC recommends the following two methods for correction for aluminum wiring:

  • Rewire the home with copper wire. While this is the most effective method, rewiring is expensive and impractical, in most cases.
  • Use copalum crimps. The crimp connector repair consists of attaching a piece of copper wire to the existing aluminum wire branch circuit with a specially designed metal sleeve and powered crimping tool. This special connector can be properly installed only with the matching AMP tool. An insulating sleeve is placed around the crimp connector to complete the repair. Although effective, they are expensive (typically around $50 per outlet, switch or light fixture).

Although not recommended by the CPSC as methods of permanent repair for defective aluminum wiring, the following methods may be considered:

  • application of anti-oxidant paste. This method can be used for wires that are multi-stranded or wires that are too large to be effectively crimped.
  • pigtailing. This method involves attaching a short piece of copper wire to the aluminum wire with a twist-on connector. the copper wire is connected to the switch, wall outlet or other termination device. This method is only effective if the connections between the aluminum wires and the copper pigtails are extremely reliable. Pigtailing with some types of connectors, even though Underwriters Laboratories might presently list them for the application, can lead to increasing the hazard. Also, beware that pigtailing will increase the number of connections, all of which must be maintained. Aluminum Wiring Repair (AWR), Inc., of Aurora, Colorado, advises that pigtailing can be useful as a temporary repair or in isolated applications, such as the installation of a ceiling fan.
  • CO/ALR connections. According to the CPSC, these devices cannot be used for all parts of the wiring system, such as ceiling-mounted light fixtures or permanently wired appliances and, as such, CO/ALR connections cannot constitute a complete repair. Also, according to AWR, these connections often loosen over time.
  • alumiconn. Although AWR believes this method may be an effective temporary fix, they are wary that it has little history, and that they are larger than copper crimps and are often incorrectly applied. 
  • Replace certain failure-prone types of devices and connections with others that are more compatible with aluminum wire.
  • Remove the ignitable materials from the vicinity of the connections.

In summary, aluminum wiring can be a fire hazard due to inherent qualities of the metal. Inspectors should be capable of identifying this type of wiring.