Chapter 5 Exercises: Windows and Doors

These exercises are designed to be performed in your own home. Most require only your eyes, a notepad, and basic tools. A few require a trip to a hardware store or showroom.

Exercise 5-1: Window Inventory and Condition Survey

Walk through your home and create a complete inventory of every window and exterior door.

For each window, record: - Location (which room, which wall direction — north, south, east, west) - Type (double-hung, casement, awning, fixed, sliding, other) - Estimated age or approximate decade of installation - Frame material (aluminum, vinyl, wood, fiberglass, or composite) - Number of panes visible (single, double, triple) - Condition: rate each of the following 1–5 (1=poor, 5=excellent): - Glass condition (clear/fogged/cracked) - Frame condition (intact/cracked/deformed/rotted) - Hardware (latches/cranks function smoothly) - Weatherstripping visible condition - Exterior caulk condition

For each exterior door, record: - Location and type (entry, patio/sliding, garage man door) - Core type if known (solid vs. hollow) - Weatherstripping condition (perimeter and bottom) - Threshold seal condition - Deadbolt and latch alignment (does the door latch fully without lifting the handle?)

This inventory becomes your master reference document for all future window and door maintenance decisions.

Exercise 5-2: The Fogged Glass Inspection

Systematically check every IGU in your home for seal failure.

  1. On a cool morning (outdoor temperature below 50°F), examine each window from the inside. Look directly at the glass pane — do you see haziness, cloudiness, or streaks inside the glass (between the panes, not on the surfaces)?
  2. Come back and check again in the afternoon on a sunny day. The thermal cycling between morning cool and afternoon warm can make fog appear, then clear, in an early-stage seal failure. Panes that fog and clear are in early seal failure; those with permanent haze are in late-stage failure.
  3. Check the edges of each pane for mineral deposits — white or gray staining in a band around the glass perimeter near the spacer bar. This indicates past condensation and is a sign of seal degradation.

Record: How many windows have fogged or hazing glass? Locate the fogged windows on a floor plan sketch.

Follow-up: Get at least two quotes for IGU replacement only (not full window replacement) for the fogged units. Compare to the cost of full window replacement quotes if you get those too.

Exercise 5-3: The Business Card Weatherstripping Test

On a day with moderate wind, or indoors with the HVAC fan running, perform this test on every exterior door.

Procedure: Close each door fully and latch it. Insert a standard business card (or playing card) between the door and the door stop (the strip of wood the door closes against) at the following locations: - Top of door - Middle of hinge side - Middle of latch side - Bottom of each side

The card should be held firmly when you try to pull it out — if it slides out easily, the weatherstripping has failed at that location.

Additionally: Examine the door bottom. With the door closed, can you see light under the door at any point? Does the door sweep contact the floor across the full width?

Record your findings. Note which doors fail at which locations. Calculate the material cost to replace weatherstripping and door sweeps for each failing door (typically $25–$50 per door for a full perimeter kit).

Exercise 5-4: Find and Read an NFRC Label

Visit a window showroom (Home Depot, Lowe's, or an independent window dealer) and find a window with an NFRC label.

  1. Read the four values on the label: U-Factor, Solar Heat Gain Coefficient, Visible Transmittance, and Air Leakage (if shown).
  2. Calculate the approximate R-value from the U-factor (R = 1/U).
  3. Look up your climate zone and the recommended U-factor for your region (ENERGY STAR's climate zone map is a good reference).
  4. Does this window meet the ENERGY STAR requirement for your climate?
  5. If the showroom has multiple windows displayed, compare the NFRC numbers across at least three products at different price points. How much does performance improve with price?

Bring your notes home. Compare to the age and estimated performance of windows in your own home.

Exercise 5-5: Draft Detection Around Window Frames

On a cold, windy day (or with the HVAC fan running and the house slightly depressurized by closing return registers):

  1. Hold the back of your hand close to the edge of each window — not near the glass, but along the interior trim where the window frame meets the wall.
  2. Check specifically: the vertical trim at each side, the horizontal trim at top and bottom.
  3. Note any locations where you feel noticeably cooler air against your hand.

What you're detecting: Air bypassing through the wall cavity around the window rough opening — coming in behind the trim, not through the window itself.

If you find leakage here: Remove a small section of interior trim carefully (it can be reinstalled). Examine the gap between the window frame and the rough opening framing. Is it filled with foam? With nothing? With old crumbled material? Photograph what you find.

Remediation cost estimate: Low-expansion spray foam to fill the rough opening gap costs $10–$15 per can. A full perimeter interior trim removal, seal, and reinstall is a half-day DIY project.

Exercise 5-6: Evaluate the Window Replacement Payback in Your Home

Using your inventory from Exercise 5-1 and the framework from section 5.5:

Step 1: Look up the estimated U-factor for your existing windows based on their age, frame type, and pane count. Use these approximate values: - Pre-1975 single-pane aluminum: U-1.3 - 1975–1990 double-pane aluminum, no thermal break: U-0.70 - 1975–1990 double-pane aluminum with thermal break: U-0.55 - 1990–2000 double-pane vinyl or wood: U-0.45 - Current standard double-pane low-e vinyl: U-0.30

Step 2: Estimate your total window area (rough: count windows, estimate average size of 3 ft x 4 ft = 12 sq ft per window).

Step 3: Calculate estimated annual heating energy loss through windows: - Heat loss (BTU/hr) = Window area (sq ft) × U-factor × Temperature difference (typical winter design delta T for your climate, approximately 50–70°F in Climate Zone 5) - Convert to annual heating cost using local heating degree days and fuel cost per BTU

(This calculation is simplified; an online energy estimator like the DOE's Home Energy Saver tool can do it more accurately.)

Step 4: Calculate the savings if you replaced all windows with U-0.27 units.

Step 5: Get or estimate the replacement cost ($400–$800 per window installed, depending on size and type).

Step 6: Calculate simple payback. Does it exceed 20 years? This is common and is the conclusion the research consistently reaches.

Exercise 5-7: Inspect Your Garage Door Seals

  1. Close the garage door fully.
  2. Stand inside the garage and look along each side edge and the top edge — can you see daylight between the door and the stop seal?
  3. Examine the bottom seal: press it gently with your finger — is the rubber/vinyl bulb still soft and flexible, or has it hardened and compressed flat?
  4. Run your hand along the bottom seal with the door closed — can you feel cold air coming under the door?
  5. Look at the lower corners of the garage door panels: are there gaps where adjacent panels meet due to panel deformation?

Follow-up: Measure the length of each seal type (bottom seal, side seals, top seal). Calculate replacement cost (bottom seal kits: $25–$45; perimeter seal kits: $40–$60).

Exercise 5-8: Test and Adjust a Door Threshold

If you have an adjustable threshold on an exterior door (most thresholds installed since approximately 1995 are adjustable via screws), perform this adjustment check.

  1. Close the door and look at the gap between the door bottom and the threshold. Is the door sweep contacting the threshold seal fully across the entire width?
  2. Find the adjustment screws (usually 3–4 screws along the top face of the threshold). Turning these clockwise raises the threshold; counterclockwise lowers it.
  3. Adjust until the door sweep makes full contact but the door still opens and closes without excessive drag.
  4. Re-do the light test (hold a flashlight outside at night and check for any light visible under the door from inside).

Note: If the threshold vinyl bulb seal is cracked or completely flat, no amount of adjustment will fix it — replacement is needed.

Exercise 5-9: Research Interior Storm Window Options

For any room where noise, drafts, or cold glass are a concern, research the cost and effectiveness of interior storm windows.

  1. Measure the interior dimensions of the window opening (inside the stops — the frame dimension the interior storm would need to fit).
  2. Research at least three interior storm window products: - Indow Windows (custom-made, acrylic panel with compression edge) - Magnetite Window Systems - DIY rigid acrylic cut-to-size with magnetic tape
  3. Compare cost per window, estimated R-value improvement, estimated STC improvement, reversibility (can be removed seasonally), and installation method.
  4. Compare total cost of interior storms on your problem windows vs. full replacement cost for those same windows.

Most homeowners find that interior storms cost 20–30% of full window replacement and achieve 70–80% of the performance improvement.

Exercise 5-10: Inspect Window Flashing From the Exterior

On the exterior of your home, inspect the visible flashing details at window perimeters.

  1. Look at the top of each window (the head) where the siding meets the window frame. Is there a visible flashing piece or membrane? Does it lap over the siding below (correct) or is it tucked behind the siding (potentially incorrect)?
  2. At the sill (bottom), is there a drip edge or flashing that directs water outward, away from the wall? Or does water have a path to run behind the siding?
  3. Look for paint failure, staining, bubbling, or wood softness at the corners of any window — these indicate past or present water intrusion at the flashing.
  4. Check the caulk joint where the window frame meets the siding or trim on all four sides. Is it cracked, pulled away, or missing entirely?

Any location where water can enter behind the siding at the window perimeter is a potential rot site. Photograph any concerns and note them for repair.

Exercise 5-11: Window Hardware Lubrication and Adjustment

Perform basic maintenance on all operable windows.

Double-hung windows: 1. Raise both sashes to clean the track channels. 2. Apply a light coat of paste wax (like Johnson's Paste Wax) or silicone spray to the plastic track liners or wood tracks. This reduces friction and improves sealing. 3. Operate both sashes to their full travel and back. Note any binding, sticking, or sashes that won't stay up (indicating balance failure).

Casement windows: 1. Locate the crank mechanism housing (typically at the bottom of the window). 2. Apply white lithium grease or the manufacturer-recommended lubricant to the crank arm and the track the arm slides in. 3. Open and close the window fully. Does it close with even compression around the full perimeter? Any hinge-side gaps when closed indicate hinge or hardware adjustment is needed.

Sliding windows and patio doors: 1. Clean the track channel thoroughly — grit in the track causes wear on both the track and the rollers. 2. Lubricate the track with a dry lubricant (silicone spray or Teflon; avoid petroleum-based lubricants that attract dirt). 3. Locate the roller adjustment screws (typically at the base of the sliding panel) and adjust until the door runs smoothly and the latch engages without lifting.

Exercise 5-12: Create a Window and Door Maintenance Plan

Synthesize your findings from the preceding exercises into a three-year maintenance and improvement plan.

Organize your plan in three tiers:

Immediate (this season, under $200 total): - Weatherstripping replacements - Threshold seal replacements - Window caulk repairs - Garage door seal replacements

Near-term (within 12 months, $200–$1,000): - IGU replacements for fogged windows - Rough opening air sealing (any locations found in Exercise 5-5) - Any exterior flashing repairs (Exercise 5-10) - Hardware replacement for non-functional windows

Long-term (3–5 year horizon, evaluate cost-benefit annually): - Interior storm window additions - Full window replacement for any frames found to be structurally compromised - Garage door insulation upgrade (if applicable)

Include cost estimates for each item and the source of your estimates. This plan is more valuable than any window salesperson's pitch — it prioritizes actual, diagnosed problems over marketed solutions.