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THE FEUTEX TOOLKIT

Building Retrofit Lifecycle Savings

Estimate annual energy savings and undiscounted lifecycle surplus after retrofit cost.

Property workspace● Runs in your browser
01 Your input
02 Your result
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FormulaAnnual saving = v.baseline_energy*v.reduction/100*v.energy_price+v.maintenance_saving ; Lifecycle surplus = (v.baseline_energy*v.reduction/100*v.energy_price+v.maintenance_saving)*v.years-v.installation
Sources and model references

Worked example

Inputs

Baseline energy
100000 energy/year
Reduction
20 %
Energy price
0.2 currency/energy
Maintenance saving
500 currency/year
Installation
20000 currency
Years
10 years

Expected results

Annual saving
4500 currency/year
Lifecycle surplus
25000 currency

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter your own assumptions using a consistent currency and period.
  2. Review the scenario outputs and compare alternative inputs.
  3. Check the stated model limits before using the result in an operating plan.

Try this example

{
  "baseline_energy": 100000,
  "reduction": 20,
  "energy_price": 0.2,
  "maintenance_saving": 500,
  "installation": 20000,
  "years": 10
}

Accuracy and scope

Undiscounted constant-price scenario, not an engineering forecast. Does not include degradation, energy-price change, taxes or replacement cycles.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.