hi this is my first time on . but i have been browsing for months. i have a house about 90 yrs. old . i have but new windows and doors gutted the walls and but in insulation.i would now like to have central air installed. my furnace is about 4 yrs. old and this past fall i had a repairman replace an ignighter and he told me the furnace was fine. the house is about 1600 ft. what else can i do to assure no loss of heat or ac. and also what size unit would i need and maybe aballprk figure on how much it would cost for everything with labor. oh also have low-e argon fill windows. thanks for all the tips i gotten already.

I live in an apartment and my landlord is a jerk and keeps having the maintenance guys attempt to fix my A/C and well...they arent cutting it. I need help! I cant go and hire a guy either. First of all, the A/C is constantly running and it stays at 75 degreees and really never cools completely, and most of all it is humid and musty. the interior unit is brand new, as far as the compressor outside, I dont know what could be wrong. I would like to know what to say might be the cause to my landlord so I can convince hm etoo hire the proper people to fix it. I live in southe Louisiana and this is really killing my electric bill.