It takes an adult about 2.5 years to reach max size and without brumation it will take about 18 months.
It will be very difficult. seeing as you live in NYC. to allow them to have anything but a semibrumtion---you can't place them outdoors because the weather is too severe. If you leave them in their cage and let the household temps naturally drop without helping--you will need to do this in a step by step fashion and if you have never done anything like this it could be dangerous.
Also, being I'm sure your heat will fluctuate depending on whether your home or not this will ensure the need for a basking site somewhere within the cage which will also bring up the ambient temps. Without a basking site you run the risk of the animal looking for a needed
UVB source with heat (like the sun) because of some digestive need unexpectidly and not finding it. This will cause and has caused death among some tegus.
It's much better to allow them to do as they will and provide them with what they would have outdoors.
If you plan on letting them out EACH DAY without fail----you can get by with a 6 x3 x2 cage. If you feel you can't always be there to allow them to roam--then replace the 6 with an 8.
Males will get a bit larger as a rule---but my female is bigger then her counterpart.
You can see pics of my setup and tegus in this forum (TEGUS)..the forum is fairly new so all the info is very accessible
There are also many photos in my yahoo group.
