How a Simple Radiometer Proves Our Heat Control Glass Is Different
See visual proof of how New Generation Glass blocks solar heat for comfortable conservatories year-round. Watch our tunnel of heat demonstration that makes the invisible, visible.
What Does the Radiometer Test Prove?
Our “tunnel of heat” demonstration uses a 150-year-old scientific instrument to make invisible heat transfer visible. When exposed to the same heat source, a radiometer behind standard glass spins wildly (showing high heat transfer), while behind our New Generation Glass it barely moves. This visual proof demonstrates that NGG blocks up to 86% of solar heat energy, preventing your glass room from becoming an oven in summer while keeping warmth in during winter.
The Radiometer: A Clear Measure of Heat Transfer
To understand our demonstration, you first need to know about the radiometer. Invented in 1873 by British physicist Sir William Crookes, this clever device—also called a light mill—makes the invisible force of heat transfer visible.
Inside a sealed glass bulb, four lightweight vanes are balanced on a spindle. One side of each vane is black (to absorb heat) and the other is silver (to reflect it). When exposed to thermal energy, the air molecules inside the bulb move more vigorously near the warmer black sides, creating a force that causes the vanes to spin.
The key takeaway: The faster the radiometer spins, the more heat is passing through. It’s a direct, visual measurement of thermal energy transfer, not a parlour trick.
💡 Did You Know? The Science Behind the Spin
The radiometer works on the principle of thermal transpiration. When light or heat hits the black side of the vanes, they warm up, heating the air molecules nearby. These faster-moving molecules exert more force than those near the cooler silver side, creating a pressure difference that makes the vanes spin. It’s not directly from photon pressure (as Crookes initially thought) but from residual gas effects in the partially evacuated bulb.
The “Tunnel of Heat” Demonstration: Side-by-Side Proof
Our demonstration is elegantly simple and impossible to argue with:
Two Panels, One Source
We place a panel of standard conservatory glass and a panel of our New Generation Glass (NGG) side-by-side in our demonstration rig. Behind each glass panel, we position identical radiometers.
Identical Conditions
A powerful heat lamp—simulating intense British summer sunlight—is turned on. The same amount of thermal energy shines equally on both glass panels, creating controlled, repeatable test conditions.
The Reveal
Within seconds, the results are clear and dramatic:
- Behind the standard glass, the radiometer spins wildly. This shows a massive amount of infrared heat energy passing straight through, which would translate to an uncomfortable, overheated room in your home.
- Behind our New Generation Glass, the radiometer barely moves. The vanes may twitch slightly but lack the energy to spin. This demonstrates that the vast majority of the radiant heat is being blocked, reflected, or managed before it can enter your space.
💡 Why This Demonstration Matters to You
You shouldn’t have to be a materials scientist to trust your home improvement. This test removes technical jargon and complex sales pitches. It provides tangible, visual proof that our glass fundamentally performs differently—and vastly better—than ordinary conservatory glass. It’s the peace of mind that comes from seeing the science for yourself, not just hearing claims about “premium glass” or “advanced technology.”
The Science Behind the Stillness: What Makes NGG Different
The radiometer’s slow spin is the result of multiple advanced technologies engineered into a single pane of our New Generation Glass.
| Feature | What It Is | The Benefit to You |
|---|---|---|
| Solar Control Coating | A microscopically thin, invisible metallic layer applied to the glass using magnetron sputtering technology. | Reflects up to 86% of solar heat energy, preventing summer overheating and keeping the space usable year-round without excessive air conditioning. |
| Warm-Edge Spacer Bars | The critical seal around the edge of the glass unit is made from thermally broken materials like stainless steel or composite polymers. | Eliminates cold bridges, reduces condensation risk, and dramatically improves the insulating U-value of the whole unit. |
| Argon Gas Fill | An inert, dense gas sealed between the panes of glass instead of ordinary dry air. | Superior insulation compared to dry air, slowing heat transfer and improving both thermal and acoustic performance. |
| U-Value < 1.0 W/m²K | A measure of heat loss; lower is better. A value under 1.0 is exceptional for glazing (standard double glazing is typically 1.6+). | Keeps warmth in during winter, slashing energy bills and making your extension a cosy, draft-free living space even in cold weather. |
| Self-Cleaning & UV Guard | An external photocatalytic coating that breaks down organic dirt, plus an internal layer that blocks 99% of UV rays. | Minimises maintenance and protects your furniture, rugs, and artwork from fading and sun damage. |
Summer Comfort
Spaces stay up to 10-15°C cooler than with standard glass, eliminating the “greenhouse effect.”
Winter Warmth
Superior insulation keeps heat inside, reducing heating costs and cold spots.
Energy Saving
Reduced need for air conditioning in summer and heating in winter lowers energy bills.
Furniture Protection
Blocks 99% of UV rays that fade fabrics, wood, and artwork over time.
Easy Maintenance
Self-cleaning coating breaks down organic dirt, reducing cleaning frequency.
Noise Reduction
Improved acoustic insulation creates a quieter, more peaceful living space.
Beyond the Demo: Engineered for the British Climate
New Generation Glass wasn’t designed in a vacuum. It was created specifically to solve the unique challenges of the British climate and the common problems of traditional glass rooms.
🇬🇧 Designed for British Weather
The UK’s climate presents unique challenges: relatively mild but damp winters, unpredictable summers with occasional heatwaves, and frequent overcast conditions. Our glass is engineered specifically for these conditions:
- Variable Season Performance: Works efficiently whether it’s 30°C in July or -2°C in January
- Humidity Control: Warm-edge technology reduces condensation that plagues many conservatories
- Low-Light Efficiency: Maintains thermal performance even on cloudy days when solar gain is minimal
- Durability: Withstands British weather extremes without degradation of performance
Year-Round Comfort: It’s a true all-season performer. By rejecting solar heat gain in summer and retaining interior heat in winter, it creates a stable, comfortable environment regardless of the weather outside. No more avoiding your conservatory on sunny days or needing separate heating and cooling systems.
Energy Efficiency as Standard: Exceptional thermal performance isn’t an optional upgrade—it’s built-in. This translates to lower running costs for heating or cooling your new space and a reduced carbon footprint for your home.
Protection for Your Home: The combination of UV protection and the strength of modern laminated or toughened glass variants means your investment is protected, and so is everything inside it.
What Homeowners Say About Comfort
“Our old conservatory was unusable in summer—like a greenhouse. With Room Outside’s New Generation Glass, we actually use the space year-round. The demonstration with the spinning device convinced us it wasn’t just marketing. The difference is night and day, and we’ve recommended you to all our neighbours.”
“We were sceptical until we saw the heat test. Our glass room faces south-west and gets full afternoon sun, but it’s never uncomfortably hot. The difference from our neighbour’s traditional conservatory is incredible. We use the room every day now, regardless of the weather outside.”
“The best investment we made. Not only is it comfortable, but our energy bills haven’t increased despite adding a whole new room. The UV protection means our furniture won’t fade either. We love how bright and clear the glass is – no tint or colour distortion at all.”
Sources and References
Crookes, William (1873). “On Attraction and Repulsion Resulting from Radiation”; Royal Society of London; Glass and Glazing Federation: Technical Standards for Thermal Performance; Building Research Establishment: UK Climate Data for Building Design; Room Outside Laboratory: Comparative Thermal Testing Data 2020-2024.
Frequently Asked Questions
Is the radiometer demonstration just a sales gimmick?
No, it’s a legitimate scientific demonstration of the principle of radiative heat transfer. The radiometer is a sensitive instrument that reacts directly to infrared radiation (heat). The dramatic difference in spin rate is direct, quantitative proof of our glass’s superior solar control properties. It’s the same principle used in scientific laboratories to measure thermal energy transfer.
Does the excellent heat control mean the glass looks different or tinted?
No. The advanced solar control and low-emissivity coatings are almost completely invisible to the naked eye. Your views will remain stunningly clear, bright, and neutral, without the green or blue tinge associated with older, inferior coated glasses. The coatings are applied at a microscopic level during manufacturing and don’t affect visibility or colour perception.
Is New Generation Glass only for conservatories?
While it is the perfect solution for conservatories and orangeries, its benefits apply to any glass extension. Our premium glass rooms, frameless glass boxes, and large structural glazing projects all utilise this technology as standard to ensure unparalleled comfort and performance. Anywhere you have extensive glazing facing the sun, this glass will improve comfort and energy efficiency.
Can I see this demonstration for myself?
Yes. We regularly perform this live demonstration during our design consultations at our showroom. You can also watch our official “tunnel of heat” video on our website or YouTube channel to see the striking difference for yourself before we even visit. Many homeowners find the visual proof more convincing than any technical specification sheet.
How does it work in winter to keep heat in?
New Generation Glass uses low-emissivity (Low-E) coatings that reflect interior heat back into the room while still allowing visible light to pass through. Combined with argon gas filling and warm-edge spacers, this creates a thermal barrier that significantly reduces heat loss. The U-value of less than 1.0 W/m²K means it’s more insulating than many solid walls in older homes.
Is the self-cleaning feature effective in the UK climate?
Yes. The self-cleaning coating is photocatalytic and hydrophilic, meaning it uses UV light (even on cloudy days) to break down organic dirt, and causes water to sheet evenly across the surface, carrying away debris. While it won’t eliminate cleaning entirely, it significantly reduces frequency and makes what cleaning is needed much easier—particularly helpful for hard-to-reach glass roofs.
What about security and safety?
New Generation Glass is available in toughened or laminated safety glass variants as standard. Toughened glass is heat-treated to be 5x stronger than ordinary glass and breaks into small, relatively harmless pieces. Laminated glass features a protective interlayer that holds the glass together if broken, providing additional security and safety benefits.
How long do the coatings last?
The coatings are applied during the float glass manufacturing process and are permanently bonded to the glass at a molecular level. They are located inside the sealed glass unit (between the panes) where they’re protected from weather, cleaning, and physical contact. They will last the lifetime of the glass unit itself—typically 20+ years—without degradation of performance.
Questions about our heat control glass? Call our technical team on 01243 538999 or send us a message
See the Proof for Yourself
Don’t just take our word for it—watch our tunnel of heat demonstration and see the dramatic difference between ordinary glass and New Generation Glass. Book a consultation to experience this live demonstration and learn how comfortable your glass extension can be year-round.
Room Outside: Experts in comfortable, energy-efficient glass extensions since 1973.
Serving Kent, Surrey, Sussex, Hampshire, London and across the South East.
