Thanks pros for all the great things I have learned reading others' posts. I think I know the answer but I need to ask my question. I am replacing an 18 year old home system and all the R22 based system's dealers recommend that I should reuse my lineset. The current leading "finalist" would be installing an American Standard Allegiance 15 4Ton condenser with new coil and furnace. It uses R22 and the current lineset is 22' long and is a 7/8" 3/8". I mentioned to him that a 1 1/8" 3/8" set is recommended by the mfg. He said that because the line is so short, it will not make a noticeable difference. He said there would only be a 408 BTU loss and it would not be worth the replacement cost (which I won't post but it sure seemed high). I'm not sure about his calculation or how much importance I should give it. The lineset travels through an easily accessed basement.
Is his argument reasonable, or should I follow my instincts and replace the line? Thanks.