The Rice Cooker Replacement Decision
A family of four is replacing a broken rice cooker. They cook rice twice a day and often leave it on keep-warm for 5 hours so a grandparent can eat late. They have a HK$700 budget and a small kitchen. Three models are available. Model A: 1.8 L, 800 W cooking power, 35 W keep-warm, HK$399, one-year warranty, basic keep-warm. Model B: 1.0 L, 500 W cooking power, 35 W keep-warm, HK$659, two-year warranty, fuzzy logic and keep-warm. Model C: 1.8 L, 1200 W cooking power, 55 W keep-warm, HK$299, one-year warranty, keep-warm, no steam vent filter. Electricity costs HK$1.3 per kWh. The family usually cooks 3 cups of raw rice per meal.
1. Compare the models using a five-year life-cycle cost estimate and discuss the capacity issue.
Read the worked answer
Assume each batch cooks for 30 minutes at rated power, twice daily, and keep-warm runs 5 hours a day. Model A: cooking 0.8 kW × 0.5 h × 2 = 0.8 kWh; keep-warm 0.035 kW × 5 = 0.175 kWh; total 0.975 kWh/day, about 356 kWh/year, HK$463/year, HK$2,315 over five years, plus HK$399 purchase = HK$2,714. Model B: 0.5 × 0.5 × 2 = 0.5 kWh; keep-warm 0.175; total 0.675 kWh/day, about 246 kWh/year, HK$320/year, HK$1,600 over five years, plus HK$659 = HK$2,259. Model C: 1.2 × 0.5 × 2 = 1.2 kWh; keep-warm 0.275; total 1.475 kWh/day, about 538 kWh/year, HK$700/year, HK$3,500 over five years, plus HK$299 = HK$3,799. Model B has the lowest estimated total cost, but 1.0 L may be too small for 3 cups of raw rice, especially with late keep-warm. Capacity must be checked against the inner-pot markings before price decides.
2. Recommend one model with justification, acknowledging uncertainty.
Read the worked answer
Recommend Model A unless the family can confirm that 3 cups of raw rice fits Model B comfortably. Model A has the 1.8 L capacity the family needs, uses less energy than Model C, and costs less to buy than Model B. Its estimated five-year cost is about HK$455 more than Model B, but it avoids the risk of an undersized pot and has a simpler control system for the grandparent. Model B is the best choice only if the capacity is sufficient: it has the lowest life-cycle cost and a two-year warranty. Model C is the cheapest to buy but the most expensive to run, has no steam vent filter, and its higher keep-warm power matters because the family keeps rice warm for 5 hours daily. The judgement should be based on fit for daily use, not purchase price alone.
3. Explain one responsible-living principle that this decision illustrates.
Read the worked answer
The decision illustrates life-cycle costing rather than purchase-price thinking. A cheap appliance can cost more over five years through electricity, while a more efficient or better-sized model may be better value. The family should compare purchase price, running cost, warranty, capacity and repairability. This is also a needs-versus-wants judgement: a 1.0 L cooker may be a want for a small kitchen, but it is a need to cook 3 cups of rice for four people and hold it safely for a late meal. Responsible consumption means buying the capacity that fits, avoiding unnecessary features, and disposing of the old cooker through a proper recycling channel rather than general waste. The principle is to use resources, money and energy to meet the household's actual needs with the least long-term waste.