Disgraceful treatment by a property that presents itself as one of Cambridge's more upscale hotels. For the second night, I'd ask for at least half the room rate to be comped, or points for 75% of the cost (points are not convertible, after all).
If they refuse, initiate a chargeback or consider doing MCOL - I can't see this sorry excuse for a management team going to court to defend their attempt to make guests pay for renovations.