Compare the Same Cooking Task Over the Same Period
Purchase price is paid at the start. Fuel or electricity, maintenance and replacement arrive at different times. Compare alternatives against the same useful task and period before treating the cheaper device as the cheaper service. First read needs, devices and service.
A Transparent Fictional Comparison
Two unnamed options are assumed to provide the same household cooking task for 24 months. All amounts are invented currency units, with no inflation, interest, financing charges, resale value or residual value. The exercise assumes monthly costs remain constant, fuel is available and both devices are technically suitable. Those assumptions require real evidence before a purchase.
| Cost for 24 Months | Option A | Option B |
|---|---|---|
| Device at the start | 30 | 90 |
| Fuel or electricity per month | 12 | 7 |
| Fuel or electricity for 24 months | 288 | 168 |
| Planned maintenance, total | 12 | 24 |
| One assumed replacement during the period | 30 | 0 |
| Total modeled cash cost | 360 | 282 |
For A: 30 + (12 × 24) + 12 + 30 = 360. For B: 90 + (7 × 24) + 24 = 282. Under these assumptions, B costs 78 less over the modeled period while requiring 60 more at the start. Its average modeled monthly cost is 11.75, versus 15.00 for A. These averages do not describe the actual payment schedule.
Test What Can Reverse the Result
If B's monthly energy charge is 11 instead of 7, its total becomes 90 + 264 + 24 = 378, exceeding A by 18. Holding the other assumptions fixed, B matches A when its monthly charge is 10.25: (360 - 90 - 24) ÷ 24. This is a sensitivity boundary for the exercise, not a forecast.
If A needs no replacement, its cost falls to 330. If B needs one additional 90-unit replacement, B's original scenario rises to 372. A decision should therefore investigate expected life and repair support instead of hiding replacement risk in an optimistic total.
Affordability and Reliability Remain Separate
A household may be unable to pay 90 today even when a long-run estimate favors B. Credit would change the comparison and require its actual terms. An unavailable fuel can also invalidate the equal-service assumption. A cheap option that leaves meals uncooked is not delivering the assumed task; do not divide its lower expenditure by an imagined full service.
The exercise's useful output is a conditional statement: "B has the lower modeled cost if equal service, the 7-unit energy cost and no replacement hold; initial affordability and local supply remain unresolved." Attach dated price information, payment timing, maintenance responsibility and uncertainty rather than a universal ranking.
Ask a qualified specialist to verify suitability, safety and supply requirements using the energy question brief. This calculation does not approve any real device, financing arrangement or purchase.
Sources and Scope
WFP's May 2022 report, printed pages 15 and 20, places affordability within supply and upkeep conditions. UNHCR's January 2024 Rwanda case, page 2, illustrates context-specific equipment-cost questions. Sources consulted October 29, 2026. All prices, lives, replacement assumptions and calculations above are original fiction.