My system is about 3 years old. It has been working fine since it was installed 3 years ago. Last week I received a special for a tune-up on my Air conditioner, so I decided to get it tune-up since I never had it done before. Unfortunately, the news that the tech gave me was a shock. The tech is a nice and honest man, but before I spend this much cash. I want to ask the expert opinions.
Here is my duct design based on his drawing. My current system is a carrier 4 ton A/C in the attic. He said it is suppose to push 1600CFM total. This is his drawing
1 7" = 150CFM x 2 = 300 CFM
3 6" = 100CFM x 3 = 300 CFM
2 8" = 210 CFM x3 = 630 CFM
2 5" = 60CFM x 2= 120 CFM
He said that my ductwork is way undersized my for current system and I will have alot of problems with the furnace and A/C if the ductwork is not size properly. I went up there with him and the ductwork is what he said it is, he also show me how he calculated with his duct calculator. It makes sense to me with his drawing, but my question is my furnace a/c worked fine and never had any problem before, and is it really neccessary to spend the money?