Real estate owners have multiple motivations for sustainable renovation: 1. Value. The value of the portfolio is declining. 2. Indoor climate. Complaints about comfort and poor lighting. 3. Costs. The operating costs are increased by increasing (i) energy prices and (ii) maintenance. 4. Sustainability. Tenants ask for a better energy label.

The most common measures to: (i) increase value , (ii) improve the comfort, (iii) control costs, and (iv) the energy upgrade are: Wall insulation, external wall insulation, roof insulation, HE glass, energy efficient lighting, Heat Pump, Solar, PV panels