a/c coil sizing

[ampulman]

I have read in this forum about the practice of mating an a/c unit with a higher rated coil, with the statement that an overage of a half ton was acceptable.

As part of a total heating-a/c system replacement (Infinity 96), it was proposed that an a/c unit (3-ton) be mated with a coil of 4-ton rating, which would result in greater efficiency. Is there a point (+1-ton) where it is no longer efficient to do so?

I had laboriously put together a long post (over an hour) which was lost while changing screens to login. If this one goes through, I can follow up with the rest of the post.

In an unrelated question, could you comment on set back practices. I currently set back 11 degrees at bedtime (7+ hours). At what point during the day does it make sense, or not make sense to set back for a period of say 1 - 4 hours, of up to 5 degrees?

Thanks in advance.

Ampulman

[seatonheating]

I'll broach on it a little. Others will get more descriptive.

1st thing to do: Have them perform a Manual J heat loss analysis.

2: Zoning the bedrooms separate from the rest of the house is actually a good idea.

3: NEVER set-back more than 6 degrees in my opinion. Makes the furnace/AC work too hard to get back to setpoint otherwise.