Disclosure: I operate AirCost Tools. Some pages contain clearly identified Amazon.es affiliate links that may earn commission on qualifying purchases. This post links to the free tool, not directly to a retailer.

I am testing a small calculator site as a potential evergreen affiliate asset. It is a working project, not a proven passive-income method or an income promise. The ongoing work includes checking calculation accuracy, maintaining useful guides and finding relevant distribution.

The useful task is comparing a household appliance’s purchase cost with its electricity use. One important distinction in the dryer calculator is keeping a machine already owned versus buying a replacement: the old purchase price is a sunk cost, while the replacement has to recover its full new price. Comparing two new machines instead uses their price difference.

A fictional example: 3 versus 1 kWh/cycle, four cycles/week, 52 weeks/year and EUR0.25/kWh gives EUR104/year in electricity difference.…