Energy +
Comfort
Calculator
Your Choice of Windows Matters
The Energy + Comfort Calculator is an app designed to guide users through the process of selecting windows that meet energy efficiency standards, save on heating and cooling, and help maintain a comfortable home in all seasons.
Innovated by
cardinal
Features of this Application
By using this application, users can evaluate the best-performing windows based on these three criteria:
Code Compliance
Comparison
The application allows users to compare windows based on ENERGY STAR® 7 or IECC 2021 code compliance standards, ensuring that they meet regulatory requirements and provide optimal performance for various climate zones.
Heating and Cooling
Savings Calculator
The application will calculate heating and cooling savings percentages based on the climate conditions and energy costs in a chosen location. Each product is compared to a 2-pane window with clear glass.
Thermal Comfort
Calculator
This feature examines the thermal comfort of occupants during winter nights and summer days, taking into account responsive factors such as distance from windows and interior and exterior shading. Users can input window specifications to determine how well they meet occupant comfort requirements in their specific home circumstances.
How to Use this Application
How to Use this Application
How to Use this Application
How to Use this Application
Step 1
Select your location of interest,
Use a US zip code or city. If your city does not appear in the list, use the closest relevant city in your area. If you enter a zip code, the app will convert it to its corresponding city.
Step 2
Choose between ENERGY STAR or IECC 2021 code compliance standards.
ENERGY STAR is a joint program between the Department of Energy and the Environmental Protection Agency designed to help consumers, businesses, and industry save money and protect the environment through the adoption of energy-efficient products and practices. The IECC 2021 is the latest published International Energy Conservation Code. Many local regulatory bodies observe the IECC 2021 code but your individual code requirements may vary.
Step 3
Compare heating and cooling savings percentages
For each configuration that meets the chosen code compliance standard. Optionally, you may view products that are non-compliant, that is, that they will not meet the given code requirements.
Step 4
Evaluate thermal comfort during winter nights and summer days
You may choose between LoĒ coating types, insulating glass configurations and the window size.
How to Use this Application
Step 1
Select your location of interest,
Use a US zip code or city. If your city does not appear in the list, use the closest relevant city in your area. If you enter a zip code, the app will convert it to its corresponding city.
Step 2
Choose between ENERGY STAR or IECC 2021 code compliance standards.
ENERGY STAR is a joint program between the Department of Energy and the Environmental Protection Agency designed to help consumers, businesses, and industry save money and protect the environment through the adoption of energy-efficient products and practices. The IECC 2021 is the latest published International Energy Conservation Code. Many local regulatory bodies observe the IECC 2021 code but your individual code requirements may vary.
Step 3
Compare heating and cooling savings percentages
For each configuration that meets the chosen code compliance standard. Optionally, you may view products that are non-compliant, that is, that they will not meet the given code requirements.
Step 4
Evaluate thermal comfort during winter nights and summer days
You may choose between LoĒ coating types, insulating glass configurations and the window size.
Recommendations
When shopping for windows, our recommendation is to choose code-compliant products that maximize heating and cooling savings and maintain optimal comfort levels throughout the year.
When working with a window manufacturer, you might use this information to help guide your product choices. You may consider additional factors such as cost, aesthetics, and other personal preferences when making a final decision.
Future Updates
The application will be updated periodically to reflect changes in building codes, energy efficiency standards, and glass product updates. Users are encouraged to check for updates regularly to ensure they have the most accurate information available.
Common Questions and
Answers
What are the fixed window configuration variables?
We chose the following general values for all window configurations: a thermally efficient window frame, argon gas fill, 3mm glass panes, optimum gap width, low air leakage.
What are high solar gain, medium solar gain, and low solar gain products?
We divide our LoĒ™ coatings into three basic categories, based on Solar Heat Gain Coefficient (SHGC), which is the fraction of incident solar radiation that enters a building as heat. The LoĒ coatings in these categories share enough similar thermal and solar performance characteristics to predict their performance in any climate and comfort setting.
| High Solar Gain (HSLE) | Medium Solar Gain (MSLE) | Low Solar Gain (LSLE) |
|---|---|---|
|
≥ 0.60
SHGC |
0.31-0.59
SHGC |
≤ 0.30
SHGC |
|
LoĒ-180 |
LoĒ²-272 LoĒ²-270 |
LoĒ³-366 Quad LoĒ-452+* LoĒ³-340* LoĒ²-240* |
Note
* Some low solar gain LoĒ coatings not available due to higher minimum SHGC requirements specified by the ENERGY STAR 7 program in the Northern zone.
What are the 2 pane and 3 pane insulating glass configurations?
We use three common IG configurations which are defined by the number of glass panes, the number of coatings, and the coating types involved. The primary coating is defined by the LoĒ Coating Category. For 2 Panes with 1 LoĒ + i89, the LoĒ-i89 room-side coating is included for enhanced thermal performance. For 3 Panes with 2 LoĒ, a primary coating is used along with a LoĒ-180 secondary coating.
| 2 Pane with 1 LoĒ | 2 Pane with 1 LoĒ + i89 | 3 Pane with 2 LoĒ |
|---|---|---|
 |
 |
 |
How was the energy calculation data developed?
Cardinal’s Energy and Comfort Calculator uses data from the open-source EnergyPlus™ program from the U.S. Department of Energy (DoE). EnergyPlus is a whole-building energy simulation program that engineers, architects, and researchers use to model energy consumption for heating, cooling, and ventilation. Weather data from all climate zones and local energy prices for both gas and electric were also used.
How was the comfort analysis data developed?
Window comfort analysis is derived using ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy protocols (www.ashrae.org) and NFRC sponsored research “Window Performance for Human Thermal Comfort, February 2006”.
How do you define comfort?
Thermal comfort for an occupant in the context of windows can be defined as the state of mind that expresses satisfaction with the surrounding environment’s temperature conditions. It is a condition where the occupant does not feel too cold or too hot. In this application, variables that influence comfort include the following:
The most important metric is U-factor, which measures how much interior heat is lost through the window. The lower the U-factor, the lower the heat loss, and the more likely the user will feel comfortable when close to the window. With higher performance LoĒ coatings and possibly more glass panes, an occupant can drastically reduce U-factor and maintain a comfortable space.
The most important measurement is Solar Heat Gain Coefficient (SHGC), which defines the percentage of solar radiation passing through a window. The lower the SHGC, the less heat passes through, thus lowering the risk of the room overheating due to excessive heat gain. If there is too much solar heat, a type of shade (interior or exterior) will be needed to maintain a comfortable space, but at the cost of visibility and views.
Disclaimer
It’s important to note that occupant comfort is an individual preference. What may be comfortable to one person can be uncomfortable to another. With that in mind, the Comfort Analysis view takes into consideration the most commonly predicted comfort outcomes, with the majority of users’ needs in mind.
Can this application take into account any size of house?
Generally, yes. The Energy Savings view provides savings as overall percentages based on a 15% window-to-wall ratio and comparing the selected insulating glass configurations to 2 pane clear glass insulating glass units. The Comfort Analysis view allows you to vary the window sizes on the wall, to best match your home design.
However, note that actual results can vary. The estimated energy savings provided are based on general assumptions and average conditions. Actual savings may vary based on specific home characteristics, such as the home’s architectural design, construction materials, insulation levels, condition and efficiency of HVAC systems, and personal energy usage preferences. We advise consulting with a professional to assess potential savings specific to your home environment.
How can this be used when shopping for windows?
The Energy + Comfort Calculator helps both professional users and consumers make better buying decisions.
By being familiar with terms and technologies such as insulating glass and LoĒ coatings, users can shorten the learning phase. Understanding these concepts allows them to immediately engage in more meaningful conversations with window and door vendors or contractors about which products meet their needs.
With a clear understanding of what each technology offers, consumers can quickly narrow down their options based on specific performance criteria. This can expedite the process of obtaining quotes, clarifying product specifics, and making final arrangements for purchase and installation.
Knowledge of how different window technologies are rated (like by ENERGY STAR® program and the IECC energy code) allows consumers to quickly identify which products may meet the required standards for energy efficiency without needing to analyze more detailed technical data.
This familiarity simplifies the window and door buying decisions, and empowers users to make the best decisions for their energy savings and comfort requirements.
