I have found a great air conditioning unit called "Frigidaire " it is excellent for any room to a certain size
But I'm looking for centralized system for my home
Okay that's great, any other requirements before I start my search? 
yeah I'm looking for low energy consumption system good for Canadian weather both work well in summer and winter off course in low budget
Okay I have found an air conditioning unit that is 13 Seer Goodman system - the best features appear to indicate reduced noise from airflow & better efficiency due to the refrigerant (R-410A)
but SEER value is very low its not low consumption systemm I thin SEER value should around 20 then it will good for me
Based on those requirements I think I have found a model with upto SEER of 22 and is meant to be one of the most efficient systems  
of which brand can you share some details ?
XV20i TruComfort is the one I am looking at, it has variable speed settings and is highly recommended for residential cooling
Ohh at last.Its cost effective to. I really appreciate your effort thank you