In terms of costs, a higher score entails a greater cost,since cost
factors have negative implications . The oil-fired boiler (OB) scored
the highest at 6.33, followed by the coal-fired boiler (CB,5.79), and
the electricity heater (EH,5.29). The geothermal heat pump(GH)
and the aero-thermal heat pump (AH) earned a higher score on
Initial investment cost (C1), but scored low on Fuel cost (C2) and
Environmental cost (C4). These technologies posted low overall
scores for costs.