Coil Dimension question - should it match my current or future furnace width?

[flat.tire]

I have a 19 year old Carrier furnace and AC.
The AC has failed - tech says low coolant.

Rather than pay for him to hunt down and repair the leak on a 19 year old unit I have decided to replace it with a Carrier 24APA530A31

I have some questions concerning the new indoor coil.

My current furnace (also 19 years old but still working) is the Carrier Infinity 58SXB80. It is 17 inches wide.

I will likely replace it with a new Carrier Infinity when it eventually fails. I'm hoping to get another 5 years out of it.

My Carrier dealer says the furnaces in the current Carrier line with 80,000 BTUs are typically 21 inches wide. Hard to say what the "typical" width will be when my furnace is evantually replaced

If I put a new 17 inch coil on my current 17 inch furnace, what do I do when I replace the furnace with a 21 inch wide unit? Can I put the 17 inch coil on a 21 inch furnace? what are the pros and cons?

Can I put a 21 coil on my current 17 inch furnace? This would likely "future proof" it. What are the pros and cons to this approach?

Should I put a 17 inch coil on my 17 inch furnace now and change it out for a 21inch coil (or whater the appropriate size is at that time) when I eventually replace the furnace. What are the pros and cons?

Thanks in advance

Mike

[skippedover]

There are many, many coils available in various Btu capacities, widths and heights. If you can find one that fits your unit now, I'd not worry about the future at this point. It's easy to replace the indoor coil when the furnace is changed in a few years if necessary. Also, it's not a big deal to install a transition, if absolutely necessary, to accommodate the 21-inch furnace and a 17-inch coil. Mind you, that's not ideal for external static pressure purposes but it's not uncommon either.

[D-Allen]

If there is room to install a nice transition fitting between the existing furnace and coil, go for the 21 wide. If not you might consider changing it all now. Later prices will rise.

[jdaley]

Most spec sheets I have looked at show that wider coils have less pressure drop (a good thing). If it's practical, I would get the wider coil now.

[hvacvegas]

I have a 19 year old Carrier furnace and AC.
The AC has failed - tech says low coolant.

Rather than pay for him to hunt down and repair the leak on a 19 year old unit I have decided to replace it with a Carrier 24APA530A31

I have some questions concerning the new indoor coil.

My current furnace (also 19 years old but still working) is the Carrier Infinity 58SXB80. It is 17 inches wide.

I will likely replace it with a new Carrier Infinity when it eventually fails. I'm hoping to get another 5 years out of it.

My Carrier dealer says the furnaces in the current Carrier line with 80,000 BTUs are typically 21 inches wide. Hard to say what the "typical" width will be when my furnace is evantually replaced

If I put a new 17 inch coil on my current 17 inch furnace, what do I do when I replace the furnace with a 21 inch wide unit? Can I put the 17 inch coil on a 21 inch furnace? what are the pros and cons?

Can I put a 21 coil on my current 17 inch furnace? This would likely "future proof" it. What are the pros and cons to this approach?
Yes, you can. Should you? Depends on if it's a cased coil or not. Be prepared for it to look goofy, with a overhang.
Should I put a 17 inch coil on my 17 inch furnace now and change it out for a 21inch coil (or whater the appropriate size is at that time) when I eventually replace the furnace. What are the pros and cons?
The pros, are not much. The cons, are you have to pay to have your contractor reinstall a new coil, which hopefully matches your outdoor unit when the time comes.
Thanks in advance

Mike

Mike, I would tell your contractor to get you a coil that is a correct match. I wouldn't worry to much about if the coil is 17" wide, or 21" wide.

I would say at 19 years old, you'll probably be getting a new furnace before another product line comes out.

For looks, I would get a cased coil that matches a new furnace. That way when you get a new furnace, It looks clean.

Another point to mention, is why don't you change the furnace?
Your missing out on variable speed, on demand dehumidification, staging, high efficiency air conditioner.

That furnace is really holding back your options.