If you live in toronto area, a 3 ton air conditioning unit should work well for a 1600 sf single, one story house with fairly good insulation.
For different area, this will need a experinenced HVAC person to provide the calculation.
In other words, you should trust your HVAC contractor.
Be careful, DON'T TRY TO BARGAIN WITH YOUR CONTRACTOR FOR A MUCH SMALLER UNIT THAN THEIR RECOMMENDATION. In addition, don't use the oversized unit even if you are rich and this could cause uncomfortable for your daily life.
Good luck for your ACU system.
For different area, this will need a experinenced HVAC person to provide the calculation.
In other words, you should trust your HVAC contractor.
Be careful, DON'T TRY TO BARGAIN WITH YOUR CONTRACTOR FOR A MUCH SMALLER UNIT THAN THEIR RECOMMENDATION. In addition, don't use the oversized unit even if you are rich and this could cause uncomfortable for your daily life.
Good luck for your ACU system.