![Smart Glass IGU + Low-E · How Much Can You Really Cut Your AC Bill? Up to 55-70% vs Clear Glass [2026]](/assets/uploads/portfolio/charoensuk-animal-clinic-glass-house/smart-film-charoensuk-animal-clinic-glass-house-full-opaque-privacy-mode.jpg)
Heat Blocking Tier · Summary Table
InHouse grades heat blocking across 5 tiers — each cuts your AC bill by a different amount:
| Structure | Heat blocked | AC saving | °C reduction | Price/sqm |
|---|---|---|---|---|
| Standard clear glass | 0% | 0% | 0 | ~2,500 |
| Smart Film Outdoor PDLC (Aquaris™) | 40-55% | 25-40% | 4-7 °C | 9,500-12,000 |
| Smart Glass Tempered Laminated | 50-65% | 35-50% | 6-9 °C | 14,500-22,500 |
| Smart Glass IGU (no Low-E) | 65-75% | 45-55% | 8-11 °C | 19,500-22,500 |
| Smart Glass IGU + Low-E | 75-88% | 55-70% | 10-13 °C | 19,500-22,500 |
Figures from InHouse sample-room testing · real-world results depend on orientation · glass area · wall and roof insulation · AC system.
What Low-E Is · How It Works
Low-E (Low Emissivity) = a nanometre-thin metallic coating (usually Silver Oxide) applied to the second glass surface inside the IGU cavity · it does the following:
- · Reflects infrared (IR) radiation · solar heat is ~50% of total energy — Low-E reflects it back outside
- · Lets visible light pass through — the glass stays transparent at 70-80% VLT (not dark)
- · Blocks 99.99% of UV · reducing fading of furniture, curtains and wood floors
- · Lowers the U-value · thermal conductivity drops from ~5.8 W/m²K (clear glass) to ~1.4-1.8 W/m²K
An easy way to picture it: standard clear glass is like a thin T-shirt — sunlight passes straight through · Low-E is like a jacket that blocks heat while staying transparent.
Real Case · West-Facing CEO Meeting Room
Take a tower office in the Sathorn district: a 25 sqm CEO meeting room with an 18 sqm glass wall facing west. It originally used clear glass plus heat-blocking film, but even with 4 AC units running it stayed hot, costing about 7,500 THB/month for this room alone.
After switching to Smart Glass IGU + Low-E:
Before (clear glass + film)
7,500
THB/month
After IGU+Low-E
2,400
THB/month
Saving
68%
~61,000 THB/year
Replacing 18 sqm of glass at 22,500 THB/sqm ≈ 405,000 THB, paying back in ~6-7 years while the glass lasts 15+ years at base and gains a +50% boost (Smart Glass + Aquaris™/Lucida™), for cumulative savings of roughly 1,000,000 THB over its service life.
Payback Calculation · by Building Size
| Building type | Total glass (sqm) | IGU+Low-E cost | Saving/year | Payback |
|---|---|---|---|---|
| 2-storey detached house, west-facing | 20 | ~450,000 THB | ~75,000 THB | 6.0 yrs |
| 100 sqm office suite | 30 | ~675,000 THB | ~150,000 THB | 4.5 yrs |
| 5-storey building facade | 200 | ~4,500,000 THB | ~900,000 THB | 5.0 yrs |
| 30-room hotel | 180 | ~4,050,000 THB | ~720,000 THB | 5.6 yrs |
Electricity reference 4.2 THB/unit · AC on 10 hrs/day · 26 days/month · counts only the reduction in AC electricity · excludes cooling towers and major systems.
Compared to "Heat-Blocking Film" Applied Over Glass
Clients often ask: why not apply heat-blocking window film (ceramic/carbon film) instead?
Window film (heat-blocking)
- · Blocks 25-50% of heat
- · Price 800-2,500 THB/sqm
- · Lifespan 5-10 years
- · No on-demand privacy
- · Not safety glass
Smart Glass IGU + Low-E
- · Blocks 75-88% of heat
- · Price 19,500-22,500 THB/sqm
- · Lifespan 22+ years (base 15+ years + Aquaris™/Lucida™ +50%)
- · On-demand privacy + 35-42 dB sound dampening
- · Tempered Laminated safety glass
Bottom line: window film is worth it for clients on a very tight budget · Smart Glass IGU+Low-E is the better value long term and delivers "multi-function" — heat blocking + privacy + sound dampening + safety — in a single pane of glass.
LEED · TREES · BCG Buildings
Smart Glass IGU + Low-E is a component that helps buildings meet these standards:
- · LEED (Leadership in Energy and Environmental Design) · the international Green Building standard · Silver/Gold/Platinum levels
- · TREES (Thai Rating of Energy and Environmental Sustainability) · the Thai standard from the Thai Green Building Institute
- · BCG Model · the government policy supporting the Bio-Circular-Green Economy
- · EEC (Energy Efficiency Certificate) · reduces a project's tax cost
InHouse sends an engineering team to help prepare the Energy Modeling documentation supporting your project's certificate application.
CO₂ Reduction · Environmental Impact
Saving AC electricity = less power generated = indirectly less CO₂:
- · 100 sqm office suite · saves ~35,000 kWh/year → cuts CO₂ by ~17 tonnes/year
- · 30-room hotel · saves ~170,000 kWh/year → cuts CO₂ by ~80 tonnes/year
- · Over the glass's lifetime (Smart Glass + Aquaris™/Lucida™ boost) · cumulative CO₂ reduction of 374-1,760 tonnes (depending on size)
Emission factor per EPPO 2025 · CO₂ ~0.5 kg/kWh.
Cases Where IGU + Low-E Isn't Necessary
In the interest of honesty · IGU + Low-E isn't worth it in some cases — for the following, standard Tempered Laminated is enough:
- · North/south-facing glass · little indirect sun · standard Tempered Laminated is enough
- · Glass under eaves / building overhangs · no direct sun · no need to invest in Low-E
- · Fully indoor areas · a meeting room with no exterior glass · Laminated handles privacy on its own
- · Frames that can't take the load · older frames can't bear an IGU's weight → choose Laminated instead
Frequently Asked Questions · Smart Glass IGU + Low-E
What's the difference between Single (One) and Double Silver Low-E?
Single Silver Low-E: one silver layer · lowers U-value to ~1.8 W/m²K · cheaper · Double Silver Low-E: two silver layers · lowers U-value to ~1.4 W/m²K · about 20% more expensive · used for jobs that need maximum savings.
Does Low-E make the glass dark?
Not very dark · Low-E is engineered to let 70-80% of visible light through · from inside the room you won't feel it cutting the light, because it's designed to block IR (heat) primarily · some shades may carry a faint blue/green tint that most people won't notice.
Will the Argon gas in the IGU cavity leak?
Industry standard: Argon leaks at < 1% per year · InHouse uses a 2-layer sealant (Primary PIB + Secondary Polysulfide) with an Edge Seal test before shipping · in the event of Seal Failure within warranty → the whole pane is replaced · surveyed effective Argon service life is 20+ years.
Can I get an Energy Modeling Report to submit for LEED?
Yes · InHouse works with your project's MEP Consultant to output Energy Modeling using certified U-value and SHGC test figures · we provide the Test Report documentation for the model you choose.
After installing IGU + Low-E, do I still need sun-blocking curtains?
It greatly reduces the need for curtains · IGU+Low-E blocks 75-88% of heat and cuts 99.99% of UV · many clients stop using curtains in meeting rooms and lobbies · in a bedroom you may still want curtains for total blackout, since Smart Glass in its opaque state isn't 100% blackout.
Calculate the AC Savings for Your Project
Send your plans and the last 6 months of electricity bills to the InHouse team — we'll calculate the ROI of IGU+Low-E with an Energy Modeling Report · free.
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