Summary

Up to 30% of a building’s heating load is lost through windows, making them one of the biggest causes of heat loss in the winter. While many window coverings for energy efficiency claim to improve insulation,, their real performance under normal circumstances can differ greatly.

This study, carried out by Smart Blinds Shop, evaluates how well six different kinds of window coverings retain heat. A conventional double-pane glass window with normal installation gaps was employed for the testing, which was conducted in a realistic winter setting with external temperatures ranging from 1 to 4°C. We calculated the energy cost savings that resulted from each covering’s ability to keep the space warm after the heat was turned off. The maximum insulation values were obtained by double-cell honeycomb blinds, which were followed by single-cell honeycomb. Any window treatment can assist prevent heat loss and lower heating expenses, as evidenced by the fact that all coverings performed better than an unprotected window.

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1. Introduction

1.1 Purpose and Scope

 

• • Purpose: To assess and compare the real-world insulation performance of six common window coverings in winter conditions.

• Scope: The study focuses on household rooms maintained at 25°C, then allowed to cool to 20°C once heating is turned off. Outdoor temperatures ranged between 1°C and 4°C, representative of many temperate climates.

1.2 Background

Although double-pane windows are better at reducing heat transfer than single-pane windows, they still permit a significant amount of heat loss in cold weather. A less expensive option than replacing all of the windows is to add insulating window coverings. However, the design, substance, and sealing of the items vary greatly. This study offers insights to assist building managers and homeowners in making well-informed, economical decisions by examining test findings under consistent conditions.

 

2. Methodology

2.1 Testing Environment

All tests were carried out in a 13 ft × 12 ft × 8 ft (1,248 ft³) room with:

 

• • Window: A double-pane glass window, sized at 5 ft × 4 ft (1.86 m²).

• • Heating System: A 3,000W electric baseboard heater (10,236 BTU/hr).

• • Outdoor Conditions: Temperatures ranged from about 1°C to 4°C over two weeks in February.

• • Installation Gaps: Each set of blinds had a 1 cm gap around the edges, reflecting imperfect real-world installations.

The room was sealed (door closed, vents blocked) to avoid interference from adjacent spaces or drafts.

   

2.2 Blinds Tested and Specifications

We compared six popular window treatments against an uncovered, double-pane window (the baseline):

 

1. 1. Double-Cell Honeycomb (19 mm air cells, polyester-coated)

1. 1. Single-Cell Honeycomb (14 mm air cells, uncoated)

1. 1. Blackout Roller Shade (PVC backing, 0% openness)

1. 1. Light-Filtering Roller Shade (1% openness, fibreglass weave)

1. 1. PVC Vertical Blinds (89 mm vanes, thin plastic)

1. 1. Faux Wood Venetian Blinds (50 mm slats, polymer composite)

 

2.3 Testing Protocol

 

1. 1. Preheating Phase
      

       

      • • Heated the room to 25°C using the baseboard heater.
      • • Maintained temperature for 30 minutes before powering off the heater.

1. 1. Cooling Phase
      

       

      • • Measured the time for the room to cool from 25°C to 20°C, using temperature sensors with 1-minute intervals.
      • • Recorded the rate of temperature drop (°C/hour).

1. 1. Control (Baseline) Test
      

       

      • • Repeated the procedure with no blinds installed to gauge the difference each covering makes.

1. 1. Repetitions and Averaging
      

       

      • • Each blind type was tested twice; results were averaged to minimize variations from day-to-day weather changes.

 

2.4 Data Analysis

 

• • Heat Retention: Examined the degree to which each style of blind impeded cooling in comparison to the uncovered (baseline) window.

• • Energy savings: Calculated using a common usage scenario, such as a 1000W heater that runs seven days a week at $0.16/kWh for six months.

 

3. Results and Analysis

 

3.1 Heat Retention Performance

Blind Type	Time to Cool (25°C–20°C)	Heat Loss Rate (°C/hr)	Efficiency vs. No Blinds
Double-Cell Honeycomb	3.7 hours	1.35 °C/hr	311% improvement
Single-Cell Honeycomb	3.1 hours	1.61 °C/hr	244%
Blackout Roller Shade	2.4 hours	2.08 °C/hr	167%
PVC Vertical Blinds	1.9 hours	2.63 °C/hr	111%
Faux Wood Venetian	1.7 hours	2.94 °C/hr	89%
Light-Filtering Roller Shade	1.5 hours	3.33 °C/hr	67%
No Blinds (Baseline)	0.9 hours	5.56 °C/hr	0% (baseline)

 

2.4 Data Analysis

 

• • Heat Retention: Compared how much each blind type slowed down the cooling process relative to the uncovered (baseline) window.

• • Energy Savings: Modeled on a typical usage scenario (e.g., a 1000W heater running 7 hours/day at $0.16/kWh for 6 months).

 

3. Results and Analysis

 

3.1 Heat Retention Performance

Blind Type	Time to Cool (25°C–20°C)	Heat Loss Rate (°C/hr)	Efficiency vs. No Blinds
Double-Cell Honeycomb	3.7 hours	1.35 °C/hr	311% improvement
Single-Cell Honeycomb	3.1 hours	1.61 °C/hr	244%
Blackout Roller Shade	2.4 hours	2.08 °C/hr	167%
PVC Vertical Blinds	1.9 hours	2.63 °C/hr	111%
Faux Wood Venetian	1.7 hours	2.94 °C/hr	89%
Light-Filtering Roller Shade	1.5 hours	3.33 °C/hr	67%
No Blinds (Baseline)	0.9 hours	5.56 °C/hr	0% (baseline)

Key Takeaways

 

• • Compared to a plain double-pane window, Double-Cell Honeycomb increased the room’s warmth by more than three times.

• • Additionally successful was Single-Cell Honeycomb, which demonstrated the importance of trapped air layers in the blind construction.

• • Absence of light When compared to no blinds, roller shades greatly decreased heat loss; however, total efficiency was impacted by side gaps.

• • Light-filtering, Venetian, and vertical shades only offered modest insulating advantages.

 

3.2 Calculated Energy Savings

We used a model where a 1000W heater runs 7 hours/day at $0.16/kWh for a 30-day month:

 

• • Monthly Baseline (per standard window): $33.60

• • 6-Month Heating Season (per window): $201.60

 

3.2.1 Typical Home (30 Standard Windows)

 

• • Total Baseline: $6,048 (30 windows × $201.60 per window)

Blind Type	Savings %	Annual Savings (vs. $6,048)
Double-Cell Honeycomb	78.7%	$4,760
Single-Cell Honeycomb	71.6%	$4,327
Blackout Roller Shade	54.3%	$3,278
Light-Filtering Roller	33.3%	$2,012
PVC Vertical Blinds	11.1%	$670
Faux Wood Venetian	8.9%	$538

 

3.2.2 Condo (10 Large Windows, each 2.5× standard size)

 

• • Total Baseline: $5,040 per heating season

Blind Type	Savings %	Annual Savings (vs. $5,040)
Double-Cell Honeycomb	78.7%	$3,965
Single-Cell Honeycomb	71.6%	$3,610
Blackout Roller Shade	54.3%	$2,738
Light-Filtering Roller	33.3%	$1,678
PVC Vertical Blinds	11.1%	$559
Faux Wood Venetian	8.9%	$449

 

4. Discussion

 

1. 1. The Significance of Air Pockets: Because honeycomb constructions include built-in air layers, they function exceptionally well in terms of heat. This design method continuously performs better than thinner materials and slat-style blinds.

1. 1. Gaps in Installation: Large gaps around the edges reduce the effectiveness of even the strongest blinds. This problem can be resolved with extra side channels or careful installation.

1. 1. Performance versus Cost: Double-cell honeycomb blinds may cost more up front, but they may end up being a wise investment due to the long-term heating expense reductions.

1. 1. Lifestyle Factors: Users usually consider aspects like privacy, light filtering, and aesthetics in addition to energy efficiency. Blackout roller blinds, for example, might be perfect for bedrooms, but when fully dropped, they obscure daylight.

 

5. Conclusion

Real-world research conducted over a two-week winter period demonstrated that double-cell honeycomb blinds are the most effective method for minimizing heat loss through standard double-pane windows. Single-cell honeycomb designs demonstrated significant enhancements, with even the least insulating variants outperforming the absence of coverage. These findings emphasize the importance of selecting high-R-value window coverings and ensuring their appropriate installation.

 

6. Recommendations

 

1. 1. Pick out Honeycomb: Choose double- or single-cell honeycomb blinds for the best protection.

1. 1. Focus on Fit: Carefully measure and try to keep any edge gaps to a minimum. In case you can, use side openings or tapes to seal.

1. 1. Think about automation: Automated motorized blinds that are set to open and close at sunrise and sunset or that are linked to temperature sensors can greatly improve total efficiency.

1. 1. Mix up your treatments: Putting blinds on top of curtains can help keep heat in and make a room look better in places where both warmth and looks are important.

1. 1. Look at regional rebates: In some places, changes that save energy, like blinds that keep out drafts, may be eligible for rebates or tax breaks.

 

7. Additional Observations and Future Work

 

• • Summer Performance: Although winter heat loss is the main focus of this analysis, summer heat gain can also be reduced by the same covers, increasing year-round comfort and reducing cooling expenses.

• Advanced Window Options: For optimal results, especially in regions with high temperatures, combine energy-efficient coverings with dual-pane or triple-pane windows.

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8. Appendix: Detailed Assumptions and Calculations

This appendix explains the study’s main presumptions and demonstrates how the principal computations were carried out.

 

8.1 Heat Retention Measurement

 

• • Temperature Range Chosen (25°C to 20°C):
    These bounds were selected to align with typical indoor comfort settings. The time required to drop 5°C, once the heat source was turned off, served as a straightforward indicator of heat retention.

• • Double-Pane Glass Baseline:
    We assumed a standard, mid-grade double-pane glass window commonly found in 1990s-era homes. R-value data for double-pane windows typically falls between R-2 and R-3, depending on coatings and gas fills.

 

8.2 Baseline Energy Cost Assumptions

 

1. 1. Heater Size: 1000 W (1 kW), chosen for simplicity in per-window calculations.

1. 1. Daily Usage: 7 hours/day of operation.

1. 1. Electricity Rate: $0.16 per kWh.

1. 1. Monthly Consumption (per window): Power (kW) x Time (hours/day) x 30 days
      = 1 kW x 7 h/day x 30 days
      = 210 kWh/month.Then, converting kWh to cost: 210 kWh/month x $0.16/kWh = $33.60/month (per window).

1. 1. Heating Season Length: 6 months per year. Thus, the total cost per window per season is: $33.60 x 6 = $201.60/window per season.

 

8.3 Typical Home and Condo Scenarios

Typical Home:

 

• • Number of Windows: 30 standard windows.

• • Annual Baseline Heating Cost: 30 windows x $201.60/window = $6,048/season.

Condo with Large Windows:

 

• • Number of Windows: 10 large windows, each 2.5 times the area of a standard window.

• • Monthly Cost per Large Window: $33.60 x 2.5 = $84.00.

• • Seasonal Cost per Large Window (6 months): $84.00 x 6 = $504.00.

• • Total Baseline (10 large windows): 10 windows x $504.00/window = $5,040/season.

 

8.4 Savings Percentages

Savings percentages reflect how each blind type reduces heat transfer relative to the uncovered (baseline) window. They combine measured cooling times and lab-derived R-values, translating into estimates of reduced heater operation. The general formula for annual savings is:

Annual Savings = (Baseline Cost) x (Savings %)

For a typical home with 30 windows, the baseline cost is $6,048 per season. For each blind type (for example, double-cell honeycomb at 78.7% savings), we multiply 78.7% (0.787) by $6,048 to estimate total savings:

$6,048 x 0.787 ≈ $4,760

The same logic applies to the condo scenario, where the baseline cost is $5,040 for its 10 large windows. Savings percentages therefore provide a quick way to calculate how much each blind type can reduce overall heating expenses.

 

8.5 Limitations of Calculations

 

• • Outdoor Temperature Range (1°C to 4°C):
    Our results are representative of mild to moderate winter conditions, and savings may scale differently in areas with more severe cold.

• • Assumed Heating Hours:
    We used a simplified model of 7 hours/day. Actual daily operation can vary based on thermostat settings, occupant behavior, and local climate.

• Single-Room Simulation:
  Results focus on heat loss through one window in one room. Real dwellings can have heat transfer through walls, infiltration around doors, and more complex heating systems (e.g., furnaces, heat pumps).

Prepared by

Smart Blinds Shop (Luminex Smart Blinds Inc.) Research Group

Disclaimer: The data and results in this study are provided for general guidance on energy-efficiency measures only. Smart Blinds Shop (Luminex Smart Blinds Inc.) is not liable for any damages resulting from the use or interpretation of this study’s findings.