The Building Envelope

Your building’s “shell” or envelope is made up of windows, outside doors, walls, foundation, floor, roof, and skylights. The envelope is the barrier between the carefully controlled, temperate indoor environment you maintain inside your building and the fluctuating outdoor environment. By allowing or blocking certain amounts of light, fresh air, heat, cooling and humidity, the envelope functions like a selective filter to make the indoor environment more comfortable. If the envelope works well as a barrier and as a filter, you will use less energy in your lighting and HVAC systems to control the light, temperature, humidity, and fresh air levels.

The Truth about Windows

Windows are the weakest part of the building envelope and account for heat gain in the summer and heat loss in the winter. The transfer of heat inside (heat gain) through the windows in the summer raise’s cooling costs and the transfer of heat outside (heat loss) through the windows in the winter raises heating costs. In reality windows are thermal holes. Single pane clear windows are 20 times less energy efficient than the wall area they replace and double pane Low-E windows  are 10 times less energy efficient than the wall area they replace. What that means is that an average building (home/office) can lose more than 30% of its heat or air conditioning energy through its windows. And while the amount heat loss or heat gain through windows depends on whether the windows are single pane glass, clear double pane, Low-E coated, or gas filled, the fact is if you have windows you have heat gain and or heat loss every day of every year.

Typical Window Performance in the Summer

In summer windows provide desirable daylight and a view, but also allow infiltration, unwanted glare, heat gain, plus damaging UV rays to enter buildings. The damaging results include increased greenhouse effect, increasing interior temperatures, and cooling costs, decreasing comfort, and productivity in work environments, not to mention the UV damage to furniture, carpets, etc.

 

Typical Window Performance in the Winter

While windows allow daylight and solar gain which we want in the winter they also allow the sun’s damaging UV rays to enter through the windows. Additionally, heat escapes through the windows at night and daily through windows when it is colder outside than inside. There is also heat loss due to exfiltration (air leakage).

 

The Solution

We are offering a unique product range that effectively addresses the energy inefficiency problem of heat transfer through windows, and subsequently offers the ability to reduce utility consumption.

Inflector See-Through Radiant Heat Barrier Insulators are the 1st line of defence against the transfer of heat in and out of buildings through windows.

These one way heat transfer reversible insulating panels are an engineered solution which addresses more than just the reflectance of solar heat gain. The Window Insulating material used in these panels has been designed to address all deficiencies of the building envelope pertaining to windows (or glass wall/ skylight/ glass walls/ doors) by effectively giving you beneficial control over reflectivity, emissivity, absorption, radiant heat gain, solar heat gain, privacy, infiltration, condensation, heat loss in the winter, as well as being a passive solar collector, absorbing sunlight and radiating free heat into building.

The reversible window insulating material puts three useful properties to work for you: reflectivity, emissivity, and absorption. The key is the product’s design. The reflective silver side (aluminum side) was chosen for two reasons;

1st to reflect solar heat gain back out through the window;

2nd and most importantly aluminium has a low emissivity of between 0.03 and 0.05. This means that only 3% to 5% of radiant heat is emitted through the aluminium; reflecting the heat in the direction the aluminum side is facing;

3rd absorption, the reverse side (black side) of the patented system is a passive solar collecting one way heat transfer material absorbing the suns rays and radiating heat into the building thus reducing the amount of heat the heating system is required to generate.

In fact our Window Insulators address all of the seasonal changes throughout the year keeping the heat in the building during the winter, while keeping the heat from entering the building during the summer.

The Cost Saving Objective

Even with a very good envelope, a building will still loose heat in cold weather and gain it when it is hot outside. Your basic cost-saving objective is to minimize the cost to correct these loses and gains. In the book “The Energy Efficiency Guide for Businesses, Industry, Government and Institutions” Third Edition on their segment titled “Envelope”, the objectives to minimize energy costs caused by unwanted heat loss and unwanted heat are clearly stated.

These objectives are to: stop infiltration, reduce heat transfer, control humidity, and control sunlight.

Stop Infiltration:

Prevent the leaking in of outside air, and likewise prevent the leaking out of inside air you have paid to heat or cool, through openings such as cracks in walls around windows, and where doors don’t fit or close properly.

Reduce Heat Transfer:

Minimize the transfer of heat through materials in the building envelope by conduction and convection. Heat always flows from a warmer environment to a colder one. All materials conduct heat, but some, such metal or a single pane of window glass, conduct it faster than a substance such as fibreglass, which is a poor conductor and therefore a good insulator.“R” value is a measure of resistance to heat flow; the higher the “R” value number, the higher the resistance. There are various ways you can increase the “R” value of your roof, walls, floor, and windows, to reduce the transfer of heat from one side to the other.·

Control Humidity:

Control the movement of water vapour in and out to achieve appropriate humidity levels. For health, comfort, and protection of materials such as wood, relative humidity should range between 30-60%. Vapour barriers and ventilation can prevent condensation and associated rot and mildew problems.

Control Sunlight:

By letting in the sun’s light and heat or blocking them out when not wanted, you can reduce levels of artificial light, heating, ventilating, and air conditioning loads.

Options of Heat Loss or Gain through windows

Windows provide sunlight but result in inward heat transfer in the summer and outward heat transfer in the winter, cause air inflitration letting outside heat to enter the building in the summer and inside heat to go out in the winter, and also result in changes in humidity level inside the building.

Windows are insulated to achieve four objectives. These  objectives are to control sunlight (CS), reduce heat transfer (RHT), stop infiltration (SI), and control humidity (CH). Here is a comparison of the performance of the different types of Window Insulation options available to date:

Option

CS

RHT

SI

CH

COMMENTS

Blinds, Shutters, Shades, & Curtains

Y

N

N

N

Makes more shade but reduces natural light. No real payback.

Window Film

Y

N

N

N

Darker tints make people feel cooler, but can attract heat. Ruin the outside view. No payback.

Solar Screens

Y

N

N

N

Not much benefit for cost with limited life span. Limited payback.

Double Pane & Triple Pane Glass

N

Y

Y

Y

This is a double or triple bad insulator. Minimal payback.

Wisteria’s Insulator

Y

Y

Y

Y

The engineered solution, with Window Insulators the most comfort enhancement, two to four year guaranteed payback , long lifespan, & UV protection, 7 year warranty.

 

Energy loss through glazing (windows) is the largest and most variable loss in buildings and has major  implications on energy consumption and peak heating and  cooling loads. - 2009 Buildings Industry Data Book

Windows are considered responsible for more than 50% of a building's heat loss by the industry Standard 90 developed by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHARE).

Insulated Windows - Summer Benefits and Value

In the summer, our Window Insulators are positioned so that the silver side faces out and reflects 72% of radiant heat back out through the window (reducing the greenhouse effect in buildings). It also reflects 65% of solar gain back out through the window (reducing overheating in buildings); and reflects 92 % of damaging UV rays back out through the windows (reducing fading & sun damage); controls glare (especially for computers & televisions); provides daytime privacy (one way vision); provide cool day lighting with a view; reduces the load, wear, & maintenance on HVAC units. It reduces cooling requirements which reduces energy consumption, saving you money.

Insulated Windows - Winter Benefits and Value

In colder climates in the winter, our Window Insulators are reversed so that the shining side (aluminium) is facing inward, reflecting the thermal heat back into the building reducing heat loss through the windows. For windows that have direct exposure to the sun the black side of our Window Insulators faces outward and acts as a passive solar collector absorbing the suns rays and radiating the heat inward. As an example, a 4 X 4 window in direct sunlight can produce 2096 BTU’s of heat per hour, which is equivalent to a 600 watt electric heater. Meanwhile the damaging UV rays are reflected back outside. Here our Window Insulators reduce the load, wear, & maintenance on HVAC units. It reduces heating requirements, which reduces your heating costs, and saves you money.

Summary

Reducing heat gain through the windows in the summer reduces energy consumption for cooling and reducing heat loss through the windows in the winter reduces energy consumption for heating.

Energy inefficiency with windows should be a concern to everyone. The fact is utility costs are going to keep rising; it should be our top priority now to start reducing the consumption of utilities.

The cleanest, greenest, cheapest, and most efficient energy is the energy you save!

Stop thinking. Act now!