Double glazed windows seem like they should be immune to issues like annoying condensation. However, compromised seals can allow moisture to penetrate the insulated glass unit, especially during humid seasons. Condensation then forms as temperatures fluctuate throughout the year. Managing this seasonal struggle requires diligent maintenance and prompt repair.

Summer Sizzle

Summer’s heat and humidity pushes condensation risk to the maximum. Hot outdoor air holds a high absolute humidity load which migrates through failed seals into cooler air-conditioned interiors. This condenses abundantly on inner pane surfaces. Heavy seasonal rains also raise local humidity levels.

Strategies to reduce summer condensation include:

• Running air conditioning to lower indoor vapour content.
• Increasing ventilation with outdoor air when humidity is lower.
• Checking for plumbing leaks or damp raising indoor moisture.
• Avoiding large temperature differentials between inside and outside.
• Confirming drainage holes are clear for moisture run-off.
• Identifying and repairing any failed edge seals promptly.

Autumn Haze

Lingering humidity along with cooler outdoor temperatures in fall sees high relative humidity levels. This permeates double glazing cavities through defective seals. Misting issues intensify as warm vapour-laden indoor air meets cold glazing surfaces.

Fall condensation prevention involves:

• Sealing draughty windows to minimise air leakage.
• Monitoring indoor humidity and ventilating appropriately.
• Preheating glazing with central heating to reduce temperature differentials.
• Ensuring low-E coatings are functioning to stabilise glass temperature.
• Repairing failed seals before winter arrives.

Winter Chill

Frigid outdoor temperatures in winter see vapour drive reversing as warm indoor air pushes outwards through imperfect seals. This hits cold outer panes and condenses. Running heaters to warm up glazing helps avoid this issue. However, rooms can still become humid from everyday activities.

Winter condensation reduction tips:

• Draught proofing windows to minimise air leakage.
• Ventilating with outdoor air on dry days.
• Using dehumidifiers to actively lower indoor vapour.
• Positioning glazing away from direct heat sources.
• Checking frame seals and repairing any deterioration.

Spring Showers

As rainy seasons increase local humidity combined with warmer spring temperatures, condensation likelihood rises. Vapour drive moves both ways across failed seals as outdoor and indoor moisture levels fluctuate. Ensuring seals are intact is paramount before the summer wet season.

Helpful springtime measures include:

• Inspecting frames and seals for damage during seasonal window cleaning.
• Repairing any cracked seals or gaps allowing vapour infiltration.
• Installing exterior storm windows as an additional weather barrier.
• Ventilating rooms on dry days to reduce residual winter humidity.

Troubleshooting Persistent Condensation Between Double Glazing Panes

If condensation keeps returning between your double-glazed window panes despite your best efforts, methodically troubleshoot the root causes:

Inspect Frames and Seals

Carefully run your fingers around window frames to feel for gaps and cracks that disrupt the air tight cavity. Look closely for any seal deterioration, missing sections, or damage. Probe with a thin object like a credit card to check for openings. Focus on the more vulnerable outer seals which weather external conditions. Have an expert assess if unsure.

Check Draught Proofing

Use a smoke pencil or incense stick to identify any draughts around windows that allow humid indoor air to penetrate into glazing cavities. Target areas include sash joints, sill joints and junctions between frames and walls. Apply silicone caulk, weatherstripping, brush seals or other draught exclusion products to remedy leakage points.

Assess Indoor Humidity

Measure indoor relative humidity using a hygrometer. Consistently high readings over 60%RH can drive moisture into sealed units. Identify and limit sources like cooking, bathing, and leakage. Improve ventilation and consider installing a dehumidifier to actively control indoor vapour levels.

Inspect Low-E Coatings

Low emissivity coatings on outer panes regulate heat flow and stabilise the temperature of the glazing cavity to minimise condensation potential. Verify if your double glazing has low-E applied. Inspect for signs of coating damage or wear which would reduce its effectiveness. Have it reapplied if necessary.

Check Age of Units

The seals around double-glazed units gradually degrade over time. Condensation affecting older units may simply indicate worn seals are due for replacement. Most will last 10-15 years, though periodic seal failure can start appearing after 8 years in some units. Plan proactive replacement of aged glazing.

Confirm Proper Use

Ensure windows are operated, ventilated, and cleaned according to manufacturer guidelines to minimise seal wear and prevent excessive humidity buildup indoors. Avoid maintaining large temperature differentials across the glazing. Report any mechanical damage immediately for repair.

Diagnosing the source of persistent condensation issues allows you to implement targeted solutions for durable results. Be systematic and address all potential contributing factors.

Materials Used in Double Glazed Window Frames

Double glazed windows are constructed using various frame materials that impact durability, insulation, cost, and condensation resistance:

• Wood – Traditional solid timber frames with good insulation properties if properly sealed against moisture. Requires extensive maintenance.
• Aluminum – Very lightweight but conducts heat readily. Thermal breaks needed to minimise condensation risk. Durable and low maintenance.
• Vinyl (PVC) – Budget option with moderate insulation levels. Can become brittle and discoloured over time. Good resistance to moisture.
• Composite – Blend thermally-broken aluminum exterior with an inner wood or PVC frame for optimal thermal performance.
• Fibreglass – Composite frames with an outer aluminum shell and inner compressed fibreglass core for high insulation. Expensive but very effective.
• Steel – Strong and secure but prone to thermal bridging issues without thermal breaks. Difficult to seal effectively.

Ideal frame materials for minimising condensation are composites with a thermally insulated core, along with fibreglass and well-sealed wood frames. Aluminum and steel frames require thermal barrier technology to reduce condensation risk. The frame composition impacts the lifespan of sealed glazing units.

Preventing Condensation When Installing New Double Glazing

Condensation resistance should be a priority when choosing new double-glazed windows. Specifications to maximise condensation prevention include:

• Butyl or polysulfide edge seals – More effective than silicone or rubber seals. Stainless steel spacers better than aluminium.
• Thermally broken frames – Limit heat transfer across frames to reduce surface condensation.
• Low-E coatings – Regulate glazing cavity temperatures and minimise humidity.
• Argon or krypton gas – Inert gas fills reduce convection and conductance within the sealed unit.
• Adequate glass-to-frame clearance – Allows humidity dissipation and prevents stresses on the seal.
• Snug fit – Eliminate potential air leakage paths around the perimeter.
• Precision manufacturing – Ensures airtight, long-lasting edge seals.

Insist on meticulous installation sealing all joints and gaps in frames and building interfaces. Draught proofing prevents humid interior air entering the glazing cavity. Careful product selection and installation is key to preventing inherent condensation risks in new double glazed windows.

Final words

With diligent maintenance and prompt repair of compromised seals, troublesome condensation can be contained year-round. Don’t resign yourself to eternal condensation issues – a proactive approach keeps double glazed windows clear through every season.