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Electrical / AC planning questions

BigDanSBigDanS Posts: 820 Officer
Our home has one 5 ton A/C unit and it is really too small for our 3400 sq ft. I want to add a two or three ton package unit to cool the north side of the house and split the house cooling to two units instead of one large. The existing unit would cool the bedrooms, and the new unit the living areas.

The electric meter is on the north end of the house, and feeds the electrical panels that are located on the south end of the house, about 80 feet away, which are in the same room as the air handler for our split 5 ton unit.

I want to split the existing A/C trunk in the ceiling that runs the same 80 feet of the electric supply and cool the living room, dining room , kitchen and family rooms with the new unit ( about 1400 sq ft ). To do this I need electric supply to the package unit. Design wise I would use a side by side, run the return and output duct up the north wall and into the attic via the gable end of the roof, cut a return in the ceiling and duct the output into the existing trunk.

I have a couple of questions:

1. Is possible and or practical to split power off the meter and create an outdoor electrical sub panel that would feed the package unit? They would be within 10 feet of each other. The alternative would be to run an approximate 100 ft conduit from the existing panel back to where the package unit would be set.

2. What size would you use for a 1400 sq ft area? It has minimal exposure, good insulation but the doors and windows are leaky. I am guessing 3 ton.

3. If you were going to install a unit like this, what would you install in this situation?

4. Would I need two permits? An electrical and mechanical? Would the duct work be construction and require a third?

5. Finally, would any of you have a ballpark figure for this type of work?

I am budgeting and planning for this fall.

Thank you in advance.

D
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Replies

  • BigDanSBigDanS Posts: 820 Officer
    Hey .. knock knock.. AC guys!??!?
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  • GA FinGA Fin Posts: 8,945 Admiral
    BigDanS wrote: »
    I have a couple of questions:

    1. Is possible and or practical to split power off the meter and create an outdoor electrical sub panel that would feed the package unit? They would be within 10 feet of each other. The alternative would be to run an approximate 100 ft conduit from the existing panel back to where the package unit would be set.

    2. What size would you use for a 1400 sq ft area? It has minimal exposure, good insulation but the doors and windows are leaky. I am guessing 3 ton.

    3. If you were going to install a unit like this, what would you install in this situation?

    4. Would I need two permits? An electrical and mechanical? Would the duct work be construction and require a third?

    5. Finally, would any of you have a ballpark figure for this type of work?

    I am budgeting and planning for this fall.

    Thank you in advance.

    D
    1. Yes. That is a sub panel. 2. 2.5 ton if you mitigate the air infiltration. 3. Heat pump. 4. HVAC & Electrical. 5. $4,200 for a 2.5 ton. Note: I'm a builder not an HVAC contractor. My answers are what I would do in Athens, GA.
    Straight white male living a life of privilege and proud of it.


    "The greatest pleasure is to vanquish your enemies and chase them before you, to rob them of their wealth and see those dear to them bathed in tears, to ride their horses and clasp to your bosom their wives and daughters."
  • BigDanSBigDanS Posts: 820 Officer
    GA Fin wrote: »
    1. Yes. That is a sub panel. 2. 2.5 ton if you mitigate the air infiltration. 3. Heat pump. 4. HVAC & Electrical. 5. $4,200 for a 2.5 ton. Note: I'm a builder not an HVAC contractor. My answers are what I would do in Athens, GA.

    Thank you! So I should budget about $4500 - $5000. That actually seems reasonable.

    D
    CAMTEQ Computers - Networks - Service - Sales
    We do it all for business and home
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    Save $125 on your first service call
  • GA FinGA Fin Posts: 8,945 Admiral
    BigDanS wrote: »
    Thank you! So I should budget about $4500 - $5000. That actually seems reasonable.

    D

    Keep in mind, those are prices I pay. The average guy on the street usually gets Rheemed(see what I did there?).
    Straight white male living a life of privilege and proud of it.


    "The greatest pleasure is to vanquish your enemies and chase them before you, to rob them of their wealth and see those dear to them bathed in tears, to ride their horses and clasp to your bosom their wives and daughters."
  • BigDanSBigDanS Posts: 820 Officer
    GA Fin wrote: »
    Keep in mind, those are prices I pay. The average guy on the street usually gets Rheemed(see what I did there?).

    Apparently better than getting Traned!

    D
    CAMTEQ Computers - Networks - Service - Sales
    We do it all for business and home
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    Save $125 on your first service call
  • AC ManAC Man Posts: 7,436 Admiral
    I think the reason you are not getting many replies is there are way to many unknowns. First of all, why would you want to use a package unit? They are relegated to mobile homes when it comes to residential. Second, you just can't tap into the ducts that feed the bedrooms, they were designed to work with the whole system. Chances are, it will need to be re sized and replaced. You are saying the living area is 1400 ft, I assume you mean the other way around. How old is the house? How old is the A/C?, Is it not keeping up,or is the electric bill to high? A mini split or two may also be the answer as well. Can you IM me your address? I can punch it up on the property appraiser and give you a better answer.

    The price GA said is correct for equipment and electric, but there may be way more to it than just the equipment and electric. Trust me, you don't want a package unit.
  • JoshWJoshW Posts: 523 Officer
    I am a home builder but I sometimes build homes with 1 ton per 1200 sqft. My advice is to put the money into fixing your building envelope. Improve your insulation (spray foam perhaps) and tighten up your windows and doors. Add a SolarBan LOW-E coating on the west and south facing glass to reduce your Solar Heat Gain Coefficient. You may find that these things solve all of your issues. I have not built a home with 1 ton per 700 sqft in almost 15 years. Adding more air to your house would be like adding a bigger engine to a car with no tires and expecting it to go faster, in my opinion.
  • AC ManAC Man Posts: 7,436 Admiral
    Hey Josh, I assume you build houses in Sarasota from your sig. I don't know what your building, but the average house today is 600 ft per ton, years ago it was 500 ft per ton. 95% of the change outs we do have 500 ft per ton. Oh, and I get plenty of calls with people in 2000 sq ft houses that have a three ton in their new home that the contractor installed and it wont go below 77 degrees on a 98 degree day.
  • S.S.TupperwareS.S.Tupperware Posts: 1,056 Officer
    Griz, where is the flir? can ya help him out? When I do IR inspections, a lot can be done to help with the solar gain...
  • coldaircoldair Posts: 11,490 AG
    Pictures of house are not loading
    169304.GIF
  • JoshWJoshW Posts: 523 Officer
    AC Man wrote: »
    Hey Josh, I assume you build houses in Sarasota from your sig. I don't know what your building, but the average house today is 600 ft per ton, years ago it was 500 ft per ton. 95% of the change outs we do have 500 ft per ton. Oh, and I get plenty of calls with people in 2000 sq ft houses that have a three ton in their new home that the contractor installed and it wont go below 77 degrees on a 98 degree day.

    Fair enough. Rest assured, mine are not among them. I am recognized annually by Dr. Sam Rashkin, the head of the DOE, for advancing efficiencies in construction and design. My point was, if you go beyond the requirements of the code with your envelope, 1 ton/700 sqft can be more than enough. Still, I would work with an HVAC design consultant and run a load calc to be certain.
  • AC ManAC Man Posts: 7,436 Admiral
    Not saying it isn't possible, It is. Just saying it isn't typical.
  • S.S.TupperwareS.S.Tupperware Posts: 1,056 Officer
    It isn't typical because of the up front costs...
  • BigDanSBigDanS Posts: 820 Officer
    First, thank you all for your responses.

    1. Package unit - we need to go with a package unit because on the north end of the house there is no place to put an air handler. I would prefer a split, but we are limited.

    2. Insulation vs. splitting the house - We are fortunate to have some mahogany windows and doors that look great but are just not air tight and there are 36 linear feet of them in French doors and 20 linear feet x six feet in windows.. Replacing them would be a $20,000. The attic is very well insulated.

    3. Splitting the A/C trunk - The A/C trunk is very large and runs the center of the house. It would be ideal to reduct. but tearing out the old duct would be easily 1500 of work and debris. Splitting the trunk and tying new supply in from the opposite side would be the simplest way.

    4. Square footage - Total under A/C is about 3250 today. I would split the house into 1400 sq ft / 1850 sq ft, with the 1850 sq ft being the sleeping side with the existing 5 ton unit. It is a variable speed American Standard and is about 9 years old. I might point a duct into the 600 sq ft of garage off the 5 ton unit that can be cut off for the summer time work I do in there.

    I know it would be ideal to start over. However the package unit plan would be about $5000.00 and provide a second unit in case the primary fails. Re-ducting could add $2500, and replacing the existing unit would be another $3500, taking a $5000 project to $11,000.

    D
    CAMTEQ Computers - Networks - Service - Sales
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  • Procraft1750Procraft1750 Posts: 46 Deckhand
    seems to me like you need to get heat calc done and look into Mini Splits.
  • BigDanSBigDanS Posts: 820 Officer
    I have looked into mini splits. A four zone mini split is about the cost of a 2.5 ton AC installed, and I think the mini split vents are ugly.

    D
    CAMTEQ Computers - Networks - Service - Sales
    We do it all for business and home
    http://www.camteq.net
    Save $125 on your first service call
  • Procraft1750Procraft1750 Posts: 46 Deckhand
    Yeah there are many different manufacturers out there for Mini Splits for different looks for the different air handlers, you will have better control of your system and comfort and a little less cost to run a zoned mini split system than a package unit. There are many variables that come in to designing the best system for a space even many options when it comes to tailoring a system to a person or family and the needs they have vs anyone else. if you had the space you could mount a mini split air handler in an attic as well and duct it out like a normal split system as well. They sometimes can take up a little less space than a normal Air Handler. What area are you located in? If you are in Central Fl I could send someone out to take a look at things and give you options.
  • BigDanSBigDanS Posts: 820 Officer
    Yeah there are many different manufacturers out there for Mini Splits for different looks for the different air handlers, you will have better control of your system and comfort and a little less cost to run a zoned mini split system than a package unit. There are many variables that come in to designing the best system for a space even many options when it comes to tailoring a system to a person or family and the needs they have vs anyone else. if you had the space you could mount a mini split air handler in an attic as well and duct it out like a normal split system as well. They sometimes can take up a little less space than a normal Air Handler. What area are you located in? If you are in Central Fl I could send someone out to take a look at things and give you options.

    South Miami / Pinecrest.

    D
    CAMTEQ Computers - Networks - Service - Sales
    We do it all for business and home
    http://www.camteq.net
    Save $125 on your first service call
  • jad1097jad1097 Posts: 9,611 Admiral
    AC Man wrote: »
    First of all, why would you want to use a package unit? They are relegated to mobile homes when it comes to residential. .

    Since when?
  • DarcyDarcy Posts: 1,711 Captain
    JoshW wrote: »
    Add a SolarBan LOW-E coating on the west and south facing glass
    Just what I was thinking of doing at my house, and was looking for advice. Tx
    Sorry, didn't mean to steal your thread.
    "No i'm NOT Darcizzle!":blowkiss


    https://captainsforcleanwater.org
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