Post on 15-Aug-2020
transcript
Knowing Your Home:
Windows 101
Presented by: Fred Cortright
Use, Insist On
Lead Safe Practices
Multiple Functions• Passive Light Source
• Passive Ventilation
• Passive Heat Gain (in Cold Weather)
• Prevent Air Infiltration
• Prevent Water Infiltration
• Prevent/Reduce Dust Infiltration
• Prevent Pest Infiltration
• Reduce Noise Infiltration
• Reduce Ultraviolet Light Infiltration
• Security
• Egress
Multiple Improvement
Options• Window Rehabilitation
• Exterior Storm Windows
• Interior Storm Windows
• Sash Modification
• Insert Replacement Windows
• Complete Window Replacement
Options Involve…
• Competing Claims
• Competing Qualities
• Confusing Terminology
• Why Should My SHGC be High, My U Low, and
My Low-e Southern?
Okay, Smart Guy,
What’s the Best, the “Right”
Choice?
The Right Choice is
Situation Specific
The“Right” Answer
Addresses Specific:
• Desired Outcomes (Prioritized)
• Existing Structural Realities
• Available Resources
• Money, Time & Energy, Planetary
Desired Outcomes re:• Energy Performance Goals
• Environmental Performance Goals
• Cost
• General Performance Goals
• Aesthetic Goals
• Disruption to Occupants
• Durability / Maintenance …
Structural Realities
• Condition of House (Sealed? Insulated?)
• Condition of Frames and Sashes
• In Sunlight or Shade?
• Climate
Available Resources
• Your Money
• Your Time & Energy
• The Planet’s Air, Water, Sand, Aluminum, Landfill
Space…
… and Energy
Sources
Saving “Energy”:
A Brief History
UPGRADE TO ENERGY STAR
Calculating Environmental
Costs (vs. Energy Savings)
• Operating Energy
• Embodied Energy
• Life Cycle of Materials
• Taken Together = “Carbon Footprint” (Say What?)
• Calculating co2e
Rule of Thumb:
co2e Calculations Favor
Preservation Over Replacement
Complete Window
Replacement
• Involves:
• Removing (then Replacing) Casing & Trim
• Removing Old Window and Frame
• Reconfiguration of Rough Opening
• Changes as Needed for Proper Installation
Complete Window
Replacement• Pros
• Potentially Very High Performance
• Opportunity to Change Window Size, Location
• Integration with Enclosure Retrofit
• Low Maintenance
• Cons
• Affects Interior and Exterior Appearance
• Not Reversible
• Significant Disruption to Occupants
• Durability Concerns, Depending on Option Chosen
Complete Window
Replacement
• Relative Cost: Most Expensive Option
• Relative Performance: Moderate to State-of-the-Art,
Depending on Option Chosen
• Relative Environmental Costs/Impact: High to
Extremely High
Insert Replacement
Windows
• Involves:
• Removal of Old Sashes
• Reconfiguration of Window Frame
• Should Include Partial Rehab of Existing Frame
Insert Replacement
Windows• Pros
• Improves Air Infiltration, Conductance, Solar Gain Performance
• Reduces Potential for Interior Condensation
• Low Maintenance
• Little Disruption of Occupants
• Cons
• Affects Interior and Exterior Appearance
• Not Reversible
• Vision Area Reduced
• Low Durability
• At Low End, Mechanical Issues
Insert Replacement
Windows
• Cost: Moderate to High, Depending on Options
Chosen ($270 to $800 per Window)
• Performance: Moderate to High, Depending on
Options Chosen
• Relative Environmental Costs/Impact: High
Interior Barriers
• Done in Conjunction with Window Rehabilitation
• Removable and Permanent Options
• Involves:
• Precise Sizing
• Following Recommended Installation Practices
Interior Barriers• Pros
• Reversible
• Maintains Exterior Appearance
• Improves Air Infiltration, Conductance Performance
• Low Maintenance
• Little Disruption of Occupants
• Cons
• Alters Interior Appearance
• Potential Interstitial Condensation (Durability Concern)
• Requires Seasonal Installation and Removal
• Potential to Impact Egress
Interior Barriers
• Relative Cost (Removable): Low
• Relative Cost (Permanent): Low to Moderate,
Depending on Option Chosen
• Relative Performance: Low to Moderate,Depending
on Option Chosen and Quality of Installation
• Relative Environmental Impact: Low to Moderate,
Depending on Option Chosen
Exterior Storm Windows
• Involves:
• Done in Conjunction with Window Rehabilitation
• May Require Slight Modifications to Frame
• Moderately Precise Sizing
• Ladder/Scaffolding Work
Exterior Storm Windows• Pros
• Improves Air Infiltration, Conductance, Solar Gain Performance
• Maintains Interior Appearance
• Reversible
• Reduces Potential for Interior Condensation
• Low Impact on Occupants
• Cons
• Changes Exterior Appearance
• Potential Interstitial Condensation (Moderate Durability Concern)
Exterior Storm Windows
• Cost: Low to Moderate Depending on Options
Chosen
• Performance: Moderate to High, Depending on
Options Chosen
• Relative Environmental Impact: Moderate
Window Rehabilitation• Involves:
• Range of Activities Depending on Window Condition and
Desired Outcomes
• Relative Cost: Low to Moderate, Depending on
Needs/Choices
• Relative Performance: Low
• Relative Environmental Impact: Lowest
Sash
Modifications/Replacement• Involves:
• Should be Done in Conjunction with Window Frame Rehabilitation
• Replacing Sash-Weight System, allowing retrofit of Weight
Pockets
• Workmanship Sensitive: Tight Tolerances
• Possible Modifications Include:
• Improved Pane Configuration
• Adding Gaskets and Other Gap Fillers
Sash
Modifications/Replacement• Pros
• Improves Air Infiltration, Conductance Performance
• Maintains/Can Match Interior and Exterior Appearance
• Reduces Potential for Interior Condensation
• Durability
• Cons
• Relatively High Maintenance
Other Rehab Actions• Remove sashes by removing stops and parting bead
• Clean frame and sashes
• Reglaze Panes as Needed
• Caulk and Seal Frame Corners and Joints
• [Optional] Cut Grooves in Sashes for Gaskets
• V-Groove at Jambs and Meeting Rails
• Bubble at Head and Sill
• [Optional] Replace Weight System with Spring System
• Seal and Insulate Weight Pockets
• Prime and Paint Frame and Sashes
• [Install Gaskets]
• Reinstall, Testing and Making Adjustments as You Go
Also Consider …
• Honeycomb blinds
• Heavy Curtains That Overlap Trim
• Your Behaviors
Find Your Sweet Spot:
The (Right) Answer Where
All the Lines Cross
The Sweet Spot
(Generally Speaking)• First Put $1000 into Sealing and Insulation
• You Get Equal (or Better Energy) Savings with Low Environmental Impact
• Rehab Existing Windows to Reduce Leakage
• Use Honeycomb Blinds and Lined Curtains
• Install Low U-Value Exterior Storms (.35 or lower)
• .6 (or Better) SHGC on South Side
• Why? Combines:
• Low Environmental Impact
• Low Cost
• High-Moderate Energy Savings
A Few Terms• SHGC (Solar Heat Gain Coefficient): Measures Solar Heat Flow
(Radiation)
• Recommended: .42 and higher; .6 or higher on south side
• U-value: Measures Non-Solar Heat Flow (Conduction over Time)
• Recommended: .35 or Lower
• Gas-Filled: Argon or Krypton, to Increase Resistance to Heat Flow
• Low-e (Low Emissivity): Glaze that Reflects Long Wavelength Radiation, Allows Short Wavelength Radiation (Sunlight) to Pass Through
• Cost +10-15%; Reduces Energy Loss 30-50%
• Available as DIY Film
Fred Cortright
fred@oneloom.net