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  1. #1
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31

    If this were your new retail store what changes would you make?

    Hello everyone. I am a long time lurker and decided I would join the site. I am interested in learning as much as I can about the proper methods of HVAC equipment installation and maintenance.

    I am builded a pawn shop in my area in NW Louisiana. I have gotten 3 quotes for installation of a HVAC unit that I already own. I am not satisfied with the quotes that I am receiving in terms of price, nor installation materials and methods. For example, I do not want to run supplies with flex, and the installers that have been out everyone runs flex on the majority of jobs.

    I went also to a sheet metal shop and they wanted a tons of money to provide and install a supply plenum, return plenum, and 5 supplies in the showroom. They didn't even quote on putting supplies and returns in the offices and bathrooms.

    I have a Rheem 5 ton heat pump with 10kW of electric heat. I do not have natural gas at my location, only electricity. The unit may not be ideal, but I already own it and I do not have the budget to purchase anything else this summer. If I can install this unit and make it through the summer then I may have the funds to add to or upgrade next year.

    I have some drawings of the building.

    Questions: how would you position the unit?
    I am thinking of hanging it with all-thread and uni-strut.

    How would you run supply lines?
    I am thinking 8" + 10" + 10" + 10" + 10" + 8" sidewall supplies on the main wall of the showroom.
    I am thinking 16" return at the peak on the wall in the showroom.
    I am thinking 8" supply and 10" return in office #1.
    I am thinking 8" supply and 10" return in office #2
    I am thinking 5" and 6" supplies in the bathrooms.
    I am thinking 10" return in the hallway.
    This would all be rigid fittings, connectors and KD pipe, and all fittings and joints covered with duct mastic (pookie, duct butter) and insulated.

    Not sure on what kind of insulation. I understand it needs to be insulation design to insulate ductwork but I am not sure what brand or R-value. Assuming I should go with R-8.


    Notes: Windows face South and are shaded by the 5 foot overhang.










    Note: the windows face South and in the summer they are mostly shaded by the 5 foot overhang. They are Low-e double pane and have solar tinting on both surfaces. They are in aluminum frames.

    Shots up in the attic where I would like to place the HVAC equipment.

    Another view. If I place the HVAC unit perpendicular to the showroom wall (as shown) I would have up to 80" to divide between the supply and return plenums.

    This is the wall were I would like to place the 8", 10", 10", 10", 10", 8" supplies and 16" return.

    I appreciate anyone who offers helpful suggestions and constructive criticism.

    Thank you for your time.

    jonblack

  2. #2
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    I wanted to add this photo to give you an idea of the window exposure.



    This photo was taken about 9:40 am back in May. During the latter part of the day the windows are fully shaded by the overhang.

    jonblack

  3. #3
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    I can offer a few comments. How much insulation on the ducts depends on the surrounding space. Are the ducts going to be in conditioned space or unconditioned? Conditioned space you can get away with lower R value because the dewpoint is lower and it is less likely to sweat. Return in a conditioned area does not need to be insulated. If it passes thru unconditioned space it should be.

    Perform a load calc or have one done and determine how near the 5 tons is to capacity you need. Whatever duckwork you put in should be put in in such a way that you can increase the capacity if needed without scrapping what you put in now for the five ton unit. Consider springing for a smaller separate unit for the office space to help you meet the proper load now (need that load calc). This can be an energy saver in that you don't have to run a five ton unit when only the office area is being used before or after store hours if working early/late in the office.

    FWIW, If you are running ducts to ceiling registers or diffusers in a dropped ceiling, consider using insulated flex for the last 5 feet or so. It makes installation a lot easier and doesn't really cheapen the quality of the job. It also makes it easier to make changes later should the need arise.

    Also, you should properly insulate the partition wall between the interior conditioned and interior unconditioned spaces.

  4. #4
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,296
    If you aren't getting a suspended ceiling, consider spiral duct. I think that would look the nicest. Whatever you do for duct-work/registers, you will want some of the air blowing on those windows, so keep that in mind also.

  5. #5
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    There is not going to be a suspended ceiling. You can see the ceiling panels in one of the photos. I am not going to run ductwork overhead, I will be using wall registers and ceiling registers.

    The space where the HVAC equipment and ductwork will be installed is over the offices. I would not consider this space conditioned space even though it is within the insulated envelope of the building, as I am not planning an air drop in the attic.

    I need to double check but I believe IBC calls for R-8 on the ductwork in an unconditioned space.

    Thanks guys
    jonblack

  6. #6
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Quote Originally Posted by jonblack View Post
    There is not going to be a suspended ceiling. You can see the ceiling panels in one of the photos. I am not going to run ductwork overhead, I will be using wall registers and ceiling registers.

    The space where the HVAC equipment and ductwork will be installed is over the offices. I would not consider this space conditioned space even though it is within the insulated envelope of the building, as I am not planning an air drop in the attic.

    I need to double check but I believe IBC calls for R-8 on the ductwork in an unconditioned space.

    Thanks guys
    jonblack
    Look online for the local codes and the year of the codes being followed. There are often little changes that occur from year to year that can bite you should the inspector decide to hold you to the year that has been adopted.

    I agree that you should consider the space unconditioned. Any extra insulation used won't hurt, except first cost wise.

    Nice looking building by-the-way.

  7. #7
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    Quote Originally Posted by vangoghsear View Post
    Nice looking building by-the-way.
    Thank you for the compliment. I will definitely look into the IBC code and double check with my inspector to see what he expects before I have the duct work insulated. He may want to see that all the connections are fastened and sealed properly anyway. Even if the code allows R-6 I may go ahead and check the price of R-8. I would like to make sure this is done "right" without hitting the point of diminishing returns.

    jonblack

  8. #8
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    " If this were your new retail store what changes would you make? "

    The very first thing I would do is find myself a qualified HVAC contractor with commercial building experience and get them onboard from the very beginning. They are the "friends" you need to make sure that everything is done to code and will make your new business a comfortable place to visit for your customers. It's hard to place a dollar figure on the return in investment you get from having a business where the comfort of your customers keeps them looking and spending money instead of walking in and their first thought is "let's hurry up and get out of here". That HVAC system is not there to spend your money, it's there to help you make money.

    Without a load calc that takes into account the commercial building code everything is guess work. If you haven't figured it out by now by reading all of the posts on this site, guess work and close enough for what I can afford costs on average twice as much as those jobs done right the first time.

    You have a very nice building there and it looks like you're sparing nothing to make it look just as nice inside. Spend the extra it takes to make it feel as nice as it looks.

    A thought. HVAC trades people talk to hundreds if not thousands of your potential customers every year. You're in the business of making deals............... Just an idea.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  9. #9
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,167
    One thing to consider: If you do not duct conditioned air to the front of the store... it will be warmer and more humid.

    My grandparents lived in Shreveport... I know the climate (we buried my Dad there last Summer).

    As FireControl said... a comfortable shop makes for happy customers. I would not skimp in this area.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  10. #10
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    Quote Originally Posted by firecontrol View Post
    Without a load calc that takes into account the commercial building code everything is guess work.
    I have a HVAC contractor working up a load calculation for me. So, we should have a better idea of the cooling/heating loads of each individual area.

    Quote Originally Posted by firecontrol View Post
    You have a very nice building there and it looks like you're sparing nothing to make it look just as nice inside. Spend the extra it takes to make it feel as nice as it looks.
    Thanks for the kind words, as well as the words of advice.

    jonblack

  11. #11
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    Quote Originally Posted by ga-hvac-tech View Post
    One thing to consider: If you do not duct conditioned air to the front of the store... it will be warmer and more humid.
    I am trying to budget for this building the best I can. To be honest, everything is costing much more than I can imagine. I am losing money by the bucket fulls by not being open yet. I am going to have to do what I can just to get the doors opened. I may have to "back up and punt" next spring, but I can't get there without getting the doors opened.

    The pawn shop business can be very profitable, and I do realize that part of the profit making potential is going to hinge on the ability to keep my customers cool and comfortable. The position I am finding myself in is a "rock and a hard place."

    I think that a reasonable and logical approach to conditioning the area by the windows is to add another heat pump, with the air handler mounted vertically, and run the duct work across the front of the store along the front wall. I think that will cover any potential issues with heat gain/loss associated with the windows. I already have a 5 ton unit, so once the load calculations come back we can see what we need in terms of additional BTUs of heating and cooling.

    Here is a photo looking at the front of the store. We are looking South in this photo. I would have to build a closet but there is space on the far left (east side of building) to put an air handler. I could set the HP right outside and it would be shaded in the heat of the day. Then I could run spiral duct across the front of the store. It would not be visible when walking in the store and would look pretty good when walking out of the store. I don't have the budget to do that just yet, but if it is uncomfortable near the windows I may have to do something like that next spring.



    Thanks again
    jonblack

  12. #12
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,167
    Quote Originally Posted by jonblack View Post
    I am trying to budget for this building the best I can. To be honest, everything is costing much more than I can imagine. I am losing money by the bucket fulls by not being open yet. I am going to have to do what I can just to get the doors opened. I may have to "back up and punt" next spring, but I can't get there without getting the doors opened.

    The pawn shop business can be very profitable, and I do realize that part of the profit making potential is going to hinge on the ability to keep my customers cool and comfortable. The position I am finding myself in is a "rock and a hard place."

    I think that a reasonable and logical approach to conditioning the area by the windows is to add another heat pump, with the air handler mounted vertically, and run the duct work across the front of the store along the front wall. I think that will cover any potential issues with heat gain/loss associated with the windows. I already have a 5 ton unit, so once the load calculations come back we can see what we need in terms of additional BTUs of heating and cooling.

    Here is a photo looking at the front of the store. We are looking South in this photo. I would have to build a closet but there is space on the far left (east side of building) to put an air handler. I could set the HP right outside and it would be shaded in the heat of the day. Then I could run spiral duct across the front of the store. It would not be visible when walking in the store and would look pretty good when walking out of the store. I don't have the budget to do that just yet, but if it is uncomfortable near the windows I may have to do something like that next spring.



    Thanks again
    jonblack
    Understand about construction costs being higher than budget... I left remodeling for HVAC 11 years ago.

    If you removed the ceiling fan in the middle... you could run one spiral down the middle with vents towards the sides, and a little extra ducting in the front. OTOH: The extra capacity of a second unit might be a good idea... management of capacity.

    Let us know how the load calc turns out and your HVAC guy suggests.

    I may be over to Shreveport in the fall... might look you up...
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  13. #13
    Join Date
    Jun 2013
    Location
    DeSoto Parish, Louisiana
    Posts
    31
    Putting spiral duct right down the middle sounds interesting. However, the fans sure are handy and I am afraid spiral duct might cost more than I expect. It would be good to know what the cost of spiral duct is, though. Do you have an online supplier you can recommend?

    I am located south of Shreveport, but if you are ever in the area definitely look me up.

    jonblack

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