HVAC Options - Packaged Unit?

I call upon the great hive mind of Grassroots Motorsports to help me solve an issue that I am facing. The natural gas furnace finally died in my house after 27 years of service. Due to the dead furnace's location in my crawlspace and limited access the HVAC technician recommends I consider replacing my AC and furnace systems with an exterior packaged unit. My current AC system (Weather King) is 11 years old and sees a lot of action during the summer since I live in Atlanta.

Does anyone have experience with a packaged HVAC system and how do they compare to a normal central air and furnace system? The HVAC guy is capable of replacing the crawl space furnace, but I can tell he really doesn't want to, as the crawl space access is limited to only 24” tall in some areas and he believes that maintenance and access will be an ongoing issue. Also how long can one typically expect their AC unit to last before replacement is required? Thanks everyone.

I live near Charlotte nc, so similar climate. 

Our last packaged unit lasted 13 years beforelightning took it out.

Extreme cold (for us, 20 degrees and below) the electric emergency heat strips come on. The all in ones just dont handle it well, and require assistance. It also doesn't have the same "heat" feeling coming out of the vents that gas does. It heats the house well, but a bare foot by the vent makes me think its not working. 

Ac? Fantastic. 

In reply to Dusterbd13 :

You have a heat pump system. There are versions available with gas furnace, sometimes called a 'gaspack'. You can also get duel fuel versions that have both a heat pump and gas furnace in one unit.

There isn't any operational difference between a packaged unit and a system with separate components. It's just that the blower fan and condenser are combined into a single package. 

It should save some money on installation, and perhaps maintenance. 

If you already have a gas furnace, then you have the gas lines.  Install a package unit with a gas pack, NOT electric heat strips. 

BTW, a gas pack IS a furnace. It's just stuck inside the package unit. 

Heat strips are more like electric baseboards stuck inside the ducts because the heat pump can't keep up. 

How much ductwork change will be required to relocate the unit?

I agree the package unit should be gas heat as well. Extending the gas line to the new location will add some cost, but I would argue less than the electrical changes required to power an electric furnace. Assuming your electrical service is even large enough to power an electric heater.

In my 25 years of experience with commercial package units (I work as an architectural engineer/designer), living outside tends to shorten the life.  Conversely, I've seen inside units that still function fine (if not always most efficiently) for decades longer than I've been alive (47 yrs).

Ductwork installed outside should be insulated, which isn't as cheap and can be a PITA to take care of. Especially if the unit is located on grade.

Without seeing a floor plan of your house and the layout of the existing ductwork and other services, it's a bit hard to make a solid recommendation, but I tend to lean towards replacing the existing unit, although I do agree with your contractor maintenance access will continue to be a problem.

A package unit will have to sit outside, and your existing ductwork will have to be extended to the package unit. 

You'll need a new hole in the crawlspace wall for this duct.. and power and gas lines need to come to it. Make sure it's a gas fired package unit, because Hotlanta actually needs heat a lot more than you think.

If cost is the same to do all that versus replacing the existing furnace.. I'd consider it an equal. More convenient for future maintenance.