R-Value: The Key to Permanent Savings
The best way to save energy on cooling and heating is to attack the source of the problem: **thermal transfer**. The R-Value is a measure of thermal resistance—the higher the R-Value, the less heat passes through the walls and roof.
This calculator works by comparing your current heat loss rate ($U_{\text{Current}} = 1/R_{\text{Current}}$) to your target rate. By upgrading your insulation, you create a permanent reduction in your cooling/heating load, which translates to a smaller AC unit requirement and massive long-term electricity savings.
FAQ
What does this insulation ROI calculator estimate?
It estimates annual cost reduction and simple payback based on your current vs target R-value, your annual heating/cooling cost, and your installation cost.
Why is only part of my HVAC bill affected?
Not all HVAC energy is envelope-related. The tool assumes a portion of the bill is driven by wall/roof heat transfer, while the rest comes from internal gains, ventilation, appliances, and occupant behavior.
What should I use for annual heating/cooling cost?
Use your last 12 months of utility bills if possible. If you only have total electricity cost, use a reasonable estimate of the HVAC share for your climate and building type.
Is this result audit-grade?
This is a screening estimate. For a detailed design or rebate application, use an energy model or an audit with measured U-values, infiltration, and HVAC performance.