A retrotted space-heating system is being considered for a small ofce building. The system can be purchased and installed for $110,000. The market value of the system will be $8,000 at the end of six years, and additional annual operating and maintenance expenses are negligible. What is the minimum annual electrical power savings (in kWh) required to make this project economically acceptable? The MARR = 15% per year and electricity costs $0.10 per kWh