Window Replacement Lifecycle Calculator

Windows save energy when replaced. This calculator sizes.

Window count

Cost per window

Energy savings per window

Useful life years

Financing rate %

Payback years

8.9

NPV over life

$61,702

Total replacement cost

$204,000

How the math works

Total cost = windows × per-window. Payback = cost / annual savings. NPV = discounted 25-yr savings.

240 × $850 = $204k. Savings $22.8k/yr. Payback 8.9 years. NPV at 7% over 25 years: $61k. Positive NPV confirms replacement economically sound beyond comfort benefits.

How to Use

Enter window count.
Enter cost per window.
Enter annual energy savings per window.
Enter useful life years.
Enter financing rate %.
Read payback and NPV.

Frequently Asked Questions

Cost ranges?

Standard vinyl replacement: $400-900 per window. Commercial grade: $800-1,800. Historic/custom: $2k-5k+. Installation 30-50% of cost. Whole-building projects: scale discounts 15-25%.

Energy savings?

Single-pane → double-pane: 20-40% window heat loss reduction. Double → triple: another 15-25%. Actual dollar savings: $50-200/window/year depending on climate, heating/cooling costs, usage. Best ROI in extreme climates (heating/cooling dominant).

Other benefits?

Noise reduction (urban). Tenant comfort (satisfaction → retention). Sound transmission class (STC) improvement. Curb appeal. Historic or cosmetic upgrade. Beyond pure energy savings, these soft factors often justify replacement economics.

How do insurance carriers view this?

Insurance carriers underwrite per-peril and often stack deductibles — named storm, wind, hail, flood, and standard can all apply separately on a single event. Confirm with your broker which deductibles actually apply to your policy and stress-test liquidity against the highest applicable deductible. Endorsements and riders can modify base terms; read declarations carefully and keep a written summary on file for claim time.