New Addition questions

[wraunch]

Guys,
I'm a newbie here so give me a little leash on my request. I know enough to be dangerous about HVAC. I am currently in the process of working on finishing out my 2nd floor attic which is adjacent to my game room which is finished and separated by an insulated exterior door. I currently have an 8 yr old 1.5 ton Trane electric heat pump servicing roughly 750 finished sq ft upstairs. My addition will add approx 8-900 sq ft upstairs. Obviously my current setup will not service that. I have had a trane contractor come out and quote me a 3 ton, 13,15 and 18 seer option. I just had a different contractor out this morning that essentially eyeballed it and said I think we'll need to add one return and we can do a 3 ton to cover it, he recommended a 13 or 15 Seer American Standard unit. I would love to do a gas furnace option if possible but I'm on LP for now and hope that natural gas will make it out to me in the near future. I am in NC and we do have quite a few weeks every summer with 100 degree and 60-80 percent humidity days. That current 1.5 ton would let it get up to 78 or 80 on really hot days as it just can't keep up.

I guess what I need help with is how do I know the differences in these various brands and types of units? Also, if I am doing a dedicated theater for most of this space I am finishing and I plan on also having an equipment room that will get very hot and a separate bedroom, will one return cut it? I would think I would need at least two to move enough air. The tech this morning said oh well we'll just do one bigger one in the theater. I didn't really like that answer.

Looking for help, glad I found this place!

CW

[Cli-Max Indoor Air]

Ductless.

Sent from my XT907 using Tapatalk 2

[wraunch]

Huh? Care to elaborate?

[wraunch]

I assume you're referring to a mini split. I don't want to go that route. I need to keep the noise from this unit down and I don't want to see the unit in the room. Also, I don't think my HOA would be ok with a mini.

[tipsrfine]

How you finish out that attic will play a big part in how & what you will need to heat/cool it. Do you have any knowledge in Building Science to air you in finishing that attic?

[BaldLoonie]

LOAD CALC!!!!!

Anyone who doesn't do that, dispose of properly. A room by room calc will tell total capacity needed and CFM per room. Only way to do it. No eyeballing!

If they cut corners designing your system, what corners will they cut putting it in?

[mechanical'al]

one big return in your theater will make for alot of background noise though sorround sound systems are loud are'nt they???

[mechanical'al]

by the way your gas furnace starting as propane to change it to nat. gas is a fairly simple kit any qualified tech. can do

[dan sw fl]

1600 square feet /// finished properly can be handled by a 2 ton.

R-15 walls
R-30 ceiling
Floor to conditioned Space?

Window size in each direction ...?
Small TOTAL Area of /windows means 2 ton HP is likely O.K.

CFM per room needs to be addressed in Significantly MORE DETAIL.

[wraunch]

This space will all be above conditioned space. There will be two 30" windows in the space. 2 ton seems to be small. What would you consider properly finishing it? I agree one return will probably not be enough and I don't want to hear the return or the registers when the system is running at full blast. I plan on doing at least r15 in the walls abd r35 in the ceiling as that is code in NC now.

[dan sw fl]

This space will all be above conditioned space. There will be two 30" windows in the space. 2 ton seems to be small.
What would you consider properly finishing it?
I agree one return will probably not be enough and I don't want to hear the return or the registers when the system is running at full blast.

I plan on doing at least r15 in the walls and R35 in the ceiling as that is code in NC now.

Properly finished = Exceeds Code and Well Sealed ( low infiltration)

So 25 square feet =total window area with 12.5 facing East and 12.5 Facing West.

IS that at 5,600 foot elevation or 12 feet? Town would be appropriate reply.
Design temps
Summer 93'F
Winter 16'F ?

74'F / 72'F Inside Summer/ Winter

[wraunch]

Raleigh, NC. Summer temps probably average 95, low in winters around 30. I would prefer 74 summer/ 72 winter.

[dan sw fl]

Manual J 8th edition, Abridged

19,700 ---------- Heating
13,800 BTU/HR Sensible Cooling

based on post #11 info

[jtrammel]

Looks like 1.5 ton heat pump with 5kw auxiliary heat will do just fine

[wraunch]

I don't speak HVAC, what would that equate to from a tonnage standpoint?

[wraunch]

I have a 1.5 ton now and it can't keep my existing 750 sq ft cool when it's 95 outside. Roughly 400 sq ft of that is over an unconditioned garage.

[hkempf]

if they dont do a manual j keep looking for good contractor

[dan sw fl]

hkempf - u are running the risk of getting booted by continuing to reply in the AOP Forum.

See Rules for "registering" in this particular forum.

[dan sw fl]

I have a 1.5 ton now and it can't keep my existing 750 sq ft cool when it's 95 outside.
Roughly 400 sq ft of that is over an unconditioned garage.

Is that an equipment performance issue or a question of whether the area thermal envelope needs improvement?

[wraunch]

I believe it's an equipment issue.