New 2 ton Carrier basic. 13 seer. Previously used Filtrete 1500 filters. I wanted to have Aprilaire hepa installed but could not due to clearance issues.
My return can accept either a one inch or 4 inch filter. Given the same Merv rating is 4 inch any better?
On another forum I was advised to have airflow and static pressure tests done to determine optimal filter. Not in the budget. Is this really necessary or just the best way to go? In a like manner I was advised to have all kinds of calculations done for heat load etc before install. I replaced 2 ton with 2 ton and all is well. Just how important are these calculations as opposed to the "rule of thumb"method based off geographic location and square footage?
Secondly regarding extended warranty. I have one year labor and 10 years parts. If I want to extend the labor portion it is $900 for an additional 9 years or $500 for additional 4 years. Does this sound like its in the ballpark. It's only $10 a month but must be paid in full up front. Good insurance??
4 inch one is better because, it has more area, so it can increase the air speed/vol. unless your want it slow down, then use 1 inch.
Forget about those calculation, as soon as your unit cools your home effectively, you are OK, those calculation are all theory, depends on who is doing it, most time it is not accurate. Warranty ? I never bought those, in the last 9 years, I had one repair (cost me $400), my brother have had several repairs, cost him $3000+. so it is up to you...