Unacceptable Heating?

I live in one of the 'luxury' apartments around downtown. When it gets down to -10 the water based baseboard radiators can only keep the apartment at ~17 degrees. It does have floor to ceiling windows, but I feel like the heating system should be able to keep a temp of at least 20. Am I unreasonable in thinking this? Maintenance attempts at fixing have been largely unsuccessful and I would like to avoid just adding electric heaters.