Home
Back
Energy Efficiency Formula:
| From: | To: |
Window energy efficiency measures how effectively a window prevents heat transfer. It's calculated by comparing heat loss through the window to the total heat energy, expressed as a percentage where higher values indicate better insulation performance.
The calculator uses the energy efficiency formula:
Where:
Explanation: This formula calculates the proportion of heat energy that is retained rather than lost through the window, providing an efficiency percentage.
Details: Calculating window energy efficiency is essential for evaluating insulation performance, estimating energy costs, making informed purchasing decisions, and improving home energy conservation.
Tips: Enter heat loss and total values in BTU units. Both values must be positive numbers, and heat loss cannot exceed the total value for a valid calculation.
Q1: What is considered a good energy efficiency percentage for windows?
A: Generally, efficiency above 70% is good, with modern energy-efficient windows often achieving 80-90% efficiency ratings.
Q2: How does window energy efficiency impact heating costs?
A: Higher efficiency windows reduce heat loss, leading to lower energy consumption and reduced heating costs during colder months.
Q3: What factors affect window energy efficiency?
A: Glass type, number of panes, gas fills, frame materials, and installation quality all significantly impact window energy efficiency.
Q4: Can this calculation be used for commercial buildings?
A: Yes, the same efficiency calculation applies to both residential and commercial windows, though commercial applications may have different performance requirements.
Q5: How often should window efficiency be evaluated?
A: Efficiency should be assessed when purchasing new windows, after significant renovations, or if you notice drafts, condensation, or increased energy bills.