How do I find the incremental savings of buying the valves?

Howell Corporation produces an executive jet for which it currently manufactures a fuel valve; the cost of the valve is indicated below: Cost per Unit Variable costs Direct material $900 Direct labor 600 Variable overhead 300 Fixed costs Depreciation of equipment 500 Depreciation of building 250 Supervisory salaries 300 The company has an offer from Duvall Valves to produce the part for $2,000 per unit and supply 1,000 valves (the number needed in the coming year). If the company accepts this offer and shuts down production of valves, production workers and supervisors will be reassigned to other areas. The equipment cannot be used elsewhere in the company, and it has no market value. However, the space occupied by the production of the valve can be used by another production group that is currently leasing space for $55,000 per year. How do I find the incremental savings of buying the valves? (The answer is stated in a perunit format and is a positive number)