Real estate investors are familiar with yield calculations and NPV analysis, but frequently overlook that a Smart Longevity system is an Energy Asset generating a positive cash flow stream across its operational life. Calculating the NPV of energy investment produces clearer decision-making than examining payback period alone.
Case study: A Bangkok home with a current electricity bill of THB 4,000 per month (THB 48,000 per year), a 3% annual electricity tariff escalation rate, and a 5% discount rate.
Scenario 1 — IoT Energy Management only: THB 80,000 investment (hub, sensors, smart plugs). Energy saving of 20% = THB 9,600 per year. 25-year NPV: THB 135,000. ROI: 169%.
Scenario 2 — IoT plus 5kW Solar: THB 320,000 additional investment. Production of 20–22 kWh per day. Combined saving of 60–70%. 25-year NPV: THB 480,000. ROI: 150%.
Scenario 3 — IoT plus Solar plus 10kWh Battery: THB 580,000 total. Self-consumption rate of 85–90%. 25-year NPV: THB 620,000. ROI: 107%.
Key observation: adding battery storage increases NPV but reduces ROI, because battery cost per kWh is still significant. Battery storage is justified for homes that experience frequent power outages or require high resilience, but for pure ROI maximisation, IoT plus Solar without battery delivers a higher return. As lithium battery prices continue declining globally — following the trajectory of solar panel costs — the ROI of battery storage will improve. The NPV rises further with electricity tariff increases above 3%, current bills above THB 4,000 per month, and participation in EGAT Demand Response programmes that pay homeowners for load curtailment.