Hi Ivan: This is a topic I and others have spoken to in the past. You don't mention what hints you have tried, but at the expense of repeating what has been posted before, let me offer a couple of points.
Yes, you are correct, the condensation probably indicates you have a 'tight' house. But the the excess moisture can be from any number of sources: long hot showers without running an exhaust fan; lots of kitchen cooking again without exhaust; an overly active central furnace humidifier you may not be aware of, in-house exercise equipment that when used vigorously, leads to lots of sweating and breathing or, as is our case, a ventless gas log set.
Without running a dedicated dehumidifier, the only means I have found (short of opening windows and doors) is to run the fan only in the central furnace, provided you have an A/C evaporator in the furnace plenum. The hundreds of aluminum fins of the evaporator that the house air circulates through are usually cooler than the house air and will condense out the excess moisture, dripping it to a collection pan and then hose drain it into a floor drain or to a pump to be pumped to a sink or other drainage spot. We will get a considerable moisture build up on windows if we don't run our fan a couple of hours each evening.
It is possible you are getting moisture up through your basement. You can test this by taping a 2 foot square piece of plastic to the concrete floor and leaving it for 2 or 3 days and then taking it up. If the plastic has moisture condensed on the inside (surface facing the floor), you then have moisture rising up through the concrete.
I doubt the contractor/developer is responsible for excess moisture in the house, although it doesn't hurt to ask. Many local building codes now require heat exchangers in new construction that pump inside air through the exchanger which extracts most of the heat, then pumps the air outside, bringing in new and cooler air to replace it.