All VEKA windows we sell come with Saint-Gobain PLANITHERM triple glazing as standard. But prospective buyers often ask us: is triple glazing really necessary, or is double glazing good enough? The answer depends on where you live. This article runs the numbers by US climate zone so you can make an informed decision.
In This Article
1. How Triple Glazing Works
A triple-glazed unit contains three panes of glass separated by two insulating cavities filled with argon or krypton gas. The gas cavities slow conductive heat transfer. Low-emissivity (low-E) coatings on the glass surfaces reflect infrared radiation — keeping heat inside in winter and outside in summer.
VEKA's standard triple glazing uses Saint-Gobain PLANITHERM glass with a silver-based low-E coating on surface 2 (inner face of the outer pane) and surface 5 (inner face of the inner pane). The outer cavity is filled with 90% argon, the inner with krypton — the denser gas provides better insulation in the thinner inner gap.
The result is a center-of-glass U-value (Ug) of approximately 0.5 W/m²K — compared to 1.0–1.2 W/m²K for standard double glazing and 2.8 W/m²K for single glazing.
2. Triple vs. Double: The Performance Gap
Beyond energy, triple glazing delivers two other significant benefits that double glazing cannot match:
- No condensation on the inner pane: The inner glass surface of a triple-glazed unit stays warm enough (above dew point) in virtually all US climates. Interior window condensation — a common problem with double-glazed and standard US windows — is eliminated.
- Superior acoustic insulation: Triple glazing reduces outdoor noise by approximately 40–45 dB vs. 28–32 dB for standard double glazing. For homes near roads, airports, or urban environments, this is transformative.
3. The Cost Difference
Triple glazing adds approximately 15–25% to the glass unit cost compared to an equivalent double-glazed unit. In the context of the full window (including frame, hardware, delivery), the real-world uplift for a complete VEKA window is closer to 8–15%. For a 20-window home, this typically represents an additional $2,000–$5,000 on the total project cost.
This is the number to weigh against the energy savings below.
4. Payback by US Climate Zone
We've calculated the energy cost savings of triple vs. double glazing across four representative US markets, assuming a 20-window home and current electricity/gas rates:
Annual Energy Savings: Triple vs. Double Glazing — 20 Window Home
| Location | Annual Savings | Payback (est.) | Verdict |
|---|---|---|---|
| Connecticut | $380/yr | 6–8 years | ✅ Strongly recommend |
| Colorado (Denver) | $290/yr | 8–10 years | ✅ Recommend |
| Texas (Dallas) | $160/yr | 15–20 years | ⚡ Marginal |
| California (Los Angeles) | $90/yr | 20–30 years | 💬 Consider noise benefits |
For cold and mixed climates (roughly IECC Climate Zones 4–7), triple glazing pays back in well under 15 years — and provides comfort, noise, and condensation benefits throughout that entire period. For warm climates (Zones 2–3), the energy payback is slower, but the noise reduction and condensation elimination often justify the upgrade anyway.
Note: for California homeowners, our triple glazing with low-SHGC solar control coating also significantly reduces summer cooling loads — which can shift the payback calculation favorably even in mild climates.
5. Why We Use Saint-Gobain PLANITHERM
Not all triple glazing is equal. We specify Saint-Gobain PLANITHERM glass across all VEKA systems for three reasons:
- Proven low-E technology: PLANITHERM's pyrolytic silver coating has been in production for over 30 years with documented performance consistency. The coating is baked into the glass surface (hard coat), not applied afterward — making it more durable than soft-coat alternatives.
- Solar control variants: PLANITHERM TOTAL+ and PLANITHERM XN provide different combinations of thermal insulation and solar control for different orientations and climates. We specify the right variant for your project.
- Light transmission: PLANITHERM triple glazing transmits approximately 72% of visible light — more than adequate for comfortable daylighting without the slight darkness that cheaper triple glazing can create.
6. The Verdict
For any US home in Climate Zones 4 and above (Connecticut, Massachusetts, Colorado, New York, New Jersey, Washington State, and northward), triple glazing is not a luxury — it's the correct specification. The payback is clear, the comfort benefit is immediate, and the acoustic improvement is significant.
For warmer climates, the payback from energy savings alone may be slow — but the elimination of condensation and the noise reduction often tip the decision in favor of triple glazing anyway.
Since all our VEKA uPVC systems and Schüco aluminum systems come standard with Saint-Gobain PLANITHERM triple glazing, the upgrade cost is already included in every quote we provide. You get triple-glazed performance without paying a separate premium.
