I hate to be the bearer of bad news but designing and installing duct is probably the most critical of your ac. It is just something you can't explain over a forum.
Think about hiring a contractor or someone who knows how to install duct.

You missunderstood. I have done the loading calculations, sized the ducting, and purchased the registers. The Goodman system was purchased as a package. I'm going to be using R-19 insulated flexible ducting. I will not be doing wall stacks as this is a one story slab. I have done my homework. I was just asking for advice on the final connection to the air handler, as none of my info gives me a good look at that.

the best thing to do is go to a hvac shop that makes their own ducts and have them build you a duct system. most larger hvac shops have their own sheet metal bending shop. they can furnish everything you need.

OK. I see that no one who can answer wants to. Yes, I saw the two answers I got. Both were not answers. They just wanted me to "hire a professional". I have to wonder if they have a financial stake in that. I keep forgetting that not everyone in these forums is here to help. Some only wish to promote their interests.

You guys that answered may be or be friends with an HVAC professional but you must remember that no one becomes a professional until they study and learn by practice. I think it is unethical to practice on a system belonging to someone else. I am going to get my AC certification, and I will install my system. That is study and learning by practice. Who knows, I may become an HVAC service person part time.

You can rest assured that if I do, I will never give these kinds of answers to anyone. If I cannot give a workable answer, or refer to someone who can, I do not waste their time or mine with "you must get a professional". That answer is only correct after all others are exausted or it is demonstrated to be beyond thier ability.

Thank you guys for telling me nothing useful, nothing I did not already know. I will not expect anything more.

you ever consider that someone else may have traveled down the same road you are on and figured out the best way to get the job done? have a nice day oldsmartass.

Old,
I would suggest you order a Manual D book.
This book will guide you in duct design.
There is too many variables that your duct design may have to implement.
We are not psychics? I didn't even know your system was a package unit until your second post.

Your post is like saying
I am standing on a curve can you give me the specifics on how to get home? How many steps will it take? And what if a Volkswagen passes by, then what?
~You have no Idea where I'm standing or where my home is unless you are psychic.

I put a link so you can purchase the Manual D from amazon.
It will teach you the fundamentals on duct design.

Enjoy and have a nice day.

Here is a link that might be useful: Manual D

You need an EPA registration card to actually release the refrigerant in the condenser into the system after it is installed.

Putting ducts in an existing house is a nightmare.

It usually involves major wall demolition, and in multi story houses the loss of closet space to run the ducts from the first floor to the second.

Even the pros end up doing a lot of cutting and fitting to get things run.

Unico and SpacePak systems are marginally easier to install in older houses, but you still have to run the main plenum to supply the smaller take off hoses.

I stopped doing conventional duct work in existing houses about 15 years ago.
The extra cost of Unico equipment is more than made up by the savings in wall damage.

3.5 tons for 1000 sqft sounds more than just slightly oversized. In the DC metro area I cool/heat 3200 sqft with a 3.5 ton unit, and it cycles and does a fine job.

Charging the system and brazing in the line connections (the proper way) is likely going to be your greatest challenge. You have to be familiar with subcooling/superheat, line loss, etc. Plus as stated above you'd need a certification, which you may have already.

Proper procedures are hard to come by even by some HVAC installers that do this for a living (the ones that don't care enough or are just not educated enough). For you, having recently brought yourself up to speed with HVAC (and I commend you for trying to learn and working on your own home, I see no problem with that, provided you are careful and do things properly), probably going to be difficult.

BTW, I'm no professional myself. I'm not going to give you a hard time or anything, but I really agree with what others have said here. Maybe you know more than we think you do.

Ductwork being one of the most important parts of the system, I'd really try to get it designed and installed properly. The plenums you can attach the the supply and return air sides of the systems, sealed well. Then you'd have your trunk line run(s) (which I would use metal for), and to those you would connect your flex with the start collars, etc. Sizing it is key. Just ballparking it here, but you'd probably want at least 270 square inches of rectangular duct for the supply and return runs. IT IS DIFFERENT FOR EACH HOME THOUGH, DEPENDING ON STATIC CONDITIONS/REQUIREMENTS. That's why Manual D is important. My home has a 14x20 return rectangular duct, a 14x8 supply rectangular duct, and a 20x8 supply rectangular duct.

R-19 DUCT???
What??

"I am just not the 100% clear on the connection to the air handler I would like to be."

this is very vauge..do you mean

air handler..plenum..duct collars...ducts?

how to attach? is unit in closet, attic?

I don't get that you expected anyone to answer your
post with so little info..in what.... one day??

Many posters here are pros.This is one of the few fourms that cater to diy.

for pictures of installs..visit hvac-talk.com's wall of
shame (don't do those ) and wall of pride (try for those)
but don't ask for diy stuff there.

"If I cannot give a workable answer, or refer to someone who can, I do not waste their time or mine with "you must get a professional". That answer is only correct after all others are exausted or it is demonstrated to be beyond thier ability."

the reason that the answer is hire a pro is because it will
take someone who can actually SEE your home to answer these questions with any degree of acuracy. any hvac company that
comes in after a botched diy job will charge you more. This is justified because first they have to figure out the mess that you gave up on..then they have to re-do what you messed up. there is a pita charge on these jobs, although it is not listed as so on the invoice.

if you would like to back up and start again..you may
get some answers. you will have to supply details and not just attitude. good luck with that.

btw hvac classes will teach you what you will need to know
for install and service,
and hopefully info on load calcs (although I had to attend extra classes for calcs) because
3 tons for 1400 sq ft tells me something is wrong with your inputs.

I've seen many detailed posts for diy here. most are
civil, some are funny, and almost all are helpful. the folks here are doing this on their own time, so response time is not the same as if you were paying someone for their time and expertiese.

Best of luck with your project.

I have no clue what your money situation is but I can vouch for having a duct system reworked/resealed because of an idiot installer that wasn't a diy'er, he 'HAD' a business.

If it is not built correctly and sealed correctly every bit of money saved doing it yourself will go to your utilities probably in the first two years.

Here is a tip... I had my ductwork inspected and paid for the brainwork of someone who had the knowledge and experience to correct the problems. I spent probably 3x as long fixing the system I had than I could have spent just doing it from scratch.

Every bit of information given out here is to help each person asking for help to manage to save on utility bills in the long term and have the best comfort available for the buck.

I work for a utility... not in any way affiliated with a hvac company or person... so don't bother to even think it.

The answer you want to hear is... jump right in... and you will save money... but every dollar saved will jump right back out and take a few friends with it... over the long term. Getting the feathers ruffled in here will just possibly cost you more money in good free information available and less headaches trying to DIY.

Hello all,

First I appologize for sounding off. I was having a really bad day and should have stayed off the computer.

I am not disrespecting anyone. I did consult with a design group on line before I purchased my unit and for this location in California, based on the degree day charts, a 3 ton unit is required for the 1400 sq.ft. of the intended addition. They also assisted me with zone design and return size and path. So I have been to professionals.

I know of the EPA requirement, as I have studied HVAC earlier and during this process. With my income reduced because I had to retire from a City job 12/30/2009. They were going to cut my pay and lay off people with low seniority. Those people are still raising families. Mine is grown and gone, mostly. So my money situation is short.

Another reason I want to DIY this system is I will need a part time job to provide health care coverage for myself and my wife when my savings run out two years from now and five years before we both qualify for medicare. This is not just a fix my house thing, but posible training.

I have priced the equipment and it would be a wash with having someone do it for me, but I will need some job soon anyway.

I found the answer to my question. All I wanted to know was how to turminate the flexible ducting to the air handler. It is done with a plate or plenum that has one or more circular holes into which an adapter is inserted, the tabs crimped over, and the whole unit sealed with aluminum duct tape. I worded the answer for either output or return connections, just in case the answer sounds wrong to you.

Thank you all for your help. I am sorry if I upset anyone. We are all here for the same thing---information. I just need to remember to count to 1000 before typing.

I hope my appology is accepted, and I hope I spelled all this correctly as my spell checker just died.

Thank you all.

not a problem..we all have those kind of days.

you can purchase a tool that attaches to your drill
to cut the holes in the plenum at any hvac supply house
and maybe even at box stores. there is an adjustment
for different size cuts/holes.
it takes a while to get the hang of the angle you
will need to cut the openings, and you have to
be careful not to get it into a bind and break the
bit.
once you cut the openings insert duct collar.
some have tabs that you bend into the plenum,
others attach differently. Using a short self tapping
metal screw will hold the collar in place while you
secure it. Use mastic (hardcast brand is what I use)
also available at hvac supply..this is a bucket of
sealant that you apply with a small paint brush.
mastic seal the duct collar to the plenum. seal
all gaps,
mastic will seal for years, unlike duct & foil tapes.
it is easier to seal with mastic when you finish
installing the duct collars than after attaching the
flex. duct leakage is a major issue and any time you
spend sealing is well worth the savings you will
have monthly. do yourself a favor and forget about
the foil tape. it fails in attic temps in a short
time period. mastic is much much better.
hardcast makes a foil faced mastic tape also
but it is pricey (approx $30 per roll) paint on
mastic is just as good when well applied.

as you progress we can talk more about other leakage
areas and how to seal them. and how to strap your ducts.

keep us apprised of your progress and we will try
to help you through your process.

where are you located?
Oh and is it R-8 ducts and not R-19?
I've never seen/heard of R-19 for ducts.

Have a good weekend.

best of luck,

ps countrybomo..I didn't realize that you worked for
a utility company!

Thanks for the tip on the mastic. I agree, that stuff seals better as I have used it in industrial (cool) air systems. I believe my inspector is going to want aluminum tape as I saw that sealing method on the building department information, what there was. I am going to use both to satisfy them and get a good seal. I will just cover the mastic with the tape to pass the inspection.

Yes, you were right on the R number. It's 6 or 8 for ducts. The 19 was the attic insulation I was also pricing to insulate the box I will build around the heater and plenum in the attic. I just mixed the numbers.

Thanks again. Installation begins in 3 days (company showed up). After that's complete I have to install a hydroponic/aeroponic system in the 10'X20' greenhouse my wife had me buy. Who said you stop working when you retire? You just change bosses!!! That project is also a first for me, but that's the way I like it. I always try to do things well as a matter of pride but it keeps me sharp to do new things. Between the two it makes me take longer then my "boss" likes, but it's what I must do. That is also how and why I learned computer programming and networking and that has served me well. Wish me luck.

I second or third the mastic. I had holes at connections that I could insert fingers and spent 30-40 bucks on tape and it let go in less than three months. I attacked with mastic and a chip brush and it is still sealed over a year later.

The less attic and basement you are trying to unintentionally condition the more money will stay in your pocket.

I would also recommend checking to see if your utility has home energy auditor or whatever the term is. I have had my house done which was built in 2006 and it was saddening to see the thermal imaging pictures. I also learned that I had like less than half of my return air going through the registers and the rest was being sucked out of the attic,basement and other voids in the wall pockets.

Take your time and bend an ear in here if you need to. Keep us posted on the progress and learnings.

Yes, the mastic stuff is the bomb! I had used it on a chlorine leak scrubber system some years ago. The trick is to buy or mix to just the right consistency and then you are basically painting a plastic seal or your chosen thickness. I too think the aluminum duct tap is expensive, but it is approved, gives a good smooth interior, and when used over the mastic I will bet it stays in place giving the best of both.

We used IR to check our electrical connections in the plant. 480 volts at 100 amps generates measurable heat when the connecting screws are loose and that uses power. So, though I have not had the energy audit I have purchased an IR gun (got it cheap!) and am finding lots of unexpected holes. I was also surprised to find the walls did not show the heat level I expected. It turns out that the previous owner did some exterior wall insulation. A 1950's house here in California had next to none.

This means that my AC unit is oversized, not having that loss to compensate for. It will still work out. I will have to fine tune for efficiency now, but if I ever build the extra conditioned floor and attic space it will be about right. The furnace is still oversized, but that is why I went for the two stage.

It just hit me that what most of you guys are talking hard duct as it is normal. That stuff is better done by a professional unless you have all the equipment and can afford to practice (waste cost). But then you would, if you did your research, nearly a professional. I am doing Flexible ducting now because it's easy and my final configuration will not be fixed. My attic space and roof may be changing in the future if I can find the money. At that time I will be doing hard duct, wall stacks, and the like. That is major and will probably be contracted. Right now I want to spend as little as possible to get my system working. I have a wall heater and window air, so the efficiency increase could be as large as 50%. Just replacing my water heater with a tank-less last December gave me about a 15% reduction in gas usage and I think we are using more because it doesn't run out in the shower anymore. If the HVAC works as well I may save over $100 per month this summer on AC and an unknown amount next winter on heat.

Hey, I just looked back at this and my other posts and realized that they are WAY long. I apologize. I am more used to writing memos, letters, and manuals. Give me time. I will get used to shorter posts.

hvac mastic is premixed.
I was refering to flex duct not hard pipe.
more leakage areas to seal in hard pipe before it
is insulated.
and don't worry better too_much info than
not enough.

best of luck

Energy: I don't speak much about it because usually in most conversations it doesn't matter. I think it is interesting how the times have shifted from pushing all electric to some pushing and only offering rebates for dual fuel setups or geothermal. Some of the rebates are substantial... and some have zero interest plans or very minute interest.

and we could have quite a discussion about this!!

geo is a great system, but you have only to look
at the posts that start out geo and end up heat pump.
cost here for geo are very high, although in other
states it is more affordable. (I hear)

I've been doing some diagnostic work for a local utility.
mostly high bill complaints..the common theme to all these
homes are all a/c with electric strip heat. combine the high winter operating cost of elec strip and the unusually
cold winter we have had..the result is utility bills over
$500 per month.
If we could shift the focus from larger hvac units to fixing
the house problems and then properly sizing the hvac..it would be a win-win for everyone. Lower utility cost and better, healthier homes, and hvac companies would sell smaller units ..but more efficient units..same $$ just better spent.

here in La we have a couple of rebate programs through the
dept of natural resouces..only one pushes whole house/house as a system. as always with goverment..there is the program I work with for whole house improvement..and another that
rebates for appliance replacement. participation in one
prohibits participation in the other...

I hear that many of the utility companies are getting
audit programs started within the company. NJ for instance
has quite a program! Locally there are utilities offering
$1000 for heat pumps on new construction,
I think that the stimulis money is funding quite a bit of this.

sorry OP didn't mean to hijack your thread.