AC Assistance Requested for 1500 sq ft Shop

13 years ago

Brand new member, but have used the excellent advice on gardenweb for many home projects for a number of years and am hoping for some advice on putting AC in my home workshop.

Its been getting over 100 degrees quite often where I live and its making working in the shop pretty uncomfortable.

Im looking for some recommendations for AC to cool it down.

Shop is 1500 sq ft.(30x50x12) Insulated pretty well. 8x 3x3 Dual pane windows, insulated double garage door, walls and ceiling. I was thinking of going with a regular home unit with a basic air handler that I can hang from the ceiling or a wall and just have a single large vent right off the air handler.

I need to keep the cost down and at this point donÂt want to deal with ducting if I can get away with it. Id like to get the temp to mid 70's if I want when its 100f outside. I donÂt need heat at this time since I have a pellet stove that works great for that.

Ive run a few of those online sizing tools and its says I need about ~3 ton unit for my sq ft. I will only be running it a couple times a week depending on when I get time out there. Is sizing critical, or will the online tools give me a good enough range? Ive read it should not be oversized or the system wonÂt control humidity. Does a 3 ton unit sound right?

This place sells kits for the DIY and I can get something in that size complete with AC only air handler for $1500-2K. This place sells kits from Ruud, Fedders and Goodman brands.

http://www.acdirect.com/air_conditio...ditioners_.php

Are any of these brands good?

Suggestions on size and a reliable manufacture would be greatly appreciated. I donÂt need fancy features, just a reliable unit thatÂs value priced. Its just a shop.

I have a friend that is an HVAC pro that will help me install it. Any suggestions on where to buy the unit would be appreciated as well.

David

Sort by:Oldest

Comments (6)

fluffybunnysui
13 years ago
We've been installing lots of package units on garages down here. That keeps all the a/c - heating equipment outside. The only thing inside would be your supply vents, maybe a small trunk line, return air and thermostat.

Hope this helps
creek_side
13 years ago
I agree, buy a package unit. Get a Ruud from AC Direct. They are good to work with. Ruud is just Rheem with a different name, slight change in color, and a one character difference in the part number. Rheem/Ruud makes very good equipment at a reasonable price. I've never had a problem with any of mine.

I'm not sure about needing 3 tons for a 1,500 sf shop, though. Did you use HVAC-Calc. It gives pretty good results, but I don't think it is optimized for something like a shop building.

HEED is superior, in my opinion, but it is harder to use. It requires more complex data entry than HVAC-Calc.

HEED is priced right. It's free!

Here is a link that might be useful: HEED
Related Discussions
Help Needed for Furnace/AC Purchase
Q
Comments (7)
Thank you so much for your responses! I am also concerned about the 3 ton size. Two contractors recommended 3 tons and 2 recommended 3. I thought maybe Lennox did not make this model in the 2.5 ton size. The Lennox contractor said he would come back and do a load calculation. Thank you for the better thermostat suggestion. Are you satisfied with coil choice? I thought I would also see how much more the 2 stage with variable speed motor would cost and would consider especially if you thought this would be an advisable upgrade. I also wonder if the furnace is on the large side like the ac. I only use gas for heating and have been paying c. $700 for the heating season. I donÂt think my home has good insulation properties so the heat pump may not be best option. I may add more to minimum insulation that is in the attic but have no plans to replace old windows. Again thank you for your feedback.
...See More
New a/c but doesn't perform like other a/c systems
Q
Comments (26)
So yesterday buddy comes over to look over things with the a/c system and I think we've got things nailed down properly now. The superheat for the given ambient temperature and heat loading from the indoor coil was way off (5F) vs. the 14-15F that it was supposed to be so he had to remove some of the refrigerant (I was quite surprised how little he had to remove to get the superheat up) and we even went as far as measuring the furnace's CFM flow rating using a differential manometer. I'm pushing roughly 1000CFM across a 2 ton coil so which is a tad bit on the high side but my colleauge says it's a margin of safety for the a/c to not freeze over as we have relatively little humidity in the air would means that on the cooler days we wouldn't be heat loading the coil enough which could lead to freeze up. I personally would like to try running my furnace on the lowest speed to get the 855 CFM but I'm not sure how that will affect the superheat. Presumably I would imagine that if a system is charged properly using the superheat method for fixed orifice systems that blower speed shouldn't dramatically impact the superheat values to the point where they're completely out of whack. I would guess that superheat would rise but isn't that sort of a given? I mean hotter days for example would increase loading so therefore superheat should rise no? For the record the pressure reading on the manometer with the furnace on medium low with a 3M 1500 series filter installed has a -0.44 in wg static pressure difference. With no filter the static pressure diff changes to -0.55. Humidity was still somewhat of an issue yesterday night when it was raining but it was quite cool outside. I had to drop the tstat to 21C to force start the a/c on but after just 20 minutes the house was nice and dry and less stuffy. Just for the sake of my understanding does TXV technically do any better or worse job of temperature/humidity control over a fixed orifice system IF both systems were installed properly and charged to near perfection? I have a friend that is looking to install a/c and his contractor insists on having TXV and says that fixed orifice is evil and should never be used. I find that rather extreme to make a claim like that. I've tried to do my own research online and although it's a given that TXV is the way to go I think it has a lot to do with the fact that it will better protect the compressor from liquid flooding + it's more forgiving for techs that do an incorrect charge on the system - critical charge isn't nearly as important on a TXV system vs. fixed orifice. Thanks,
...See More
bryant furnace/AC replcmt and contractors-please help!
Q
Comments (5)
squids I will offer my opinions.First Bryant is very solid equipment. It appears you have been quoted both the 80% eff and 95% Evolution furnaces. Great equipment. You do want the Evolution controller-no substitute please. For your area/climate, I see nothing wrong with the 80% eff furnaces(315AAV)-as long as they are paired with appropriate heat pump/evap coil. If you do not pair with heat pump, then go with 95% eff furnace(355CAV). As far as condenser line, stay with Preferrred 15 series, AC and HP "H" model. either way, you do want to take advantage of Fed Govt Tax Credit. 80% eff Evolution Furnace with qualifying HP 3107587 Active Systems PREFERRED 15 PURON HP BRYANT HEATING AND COOLING SYSTEMS 265ANH036-A CNPV*4217A** 315(A,J)AV048090 35000 12.50 15.00 35400 8.50 21400 3496618 Active Systems PREFERRED 16 PURON HP BRYANT HEATING AND COOLING SYSTEMS 266ANA036-A CNPV*4821A**+UI 315(A,J)AV048090 34600 12.60 15.50 37000 9.10 22200 95% Evolution Furnace with Preferred AC condenser 1390145 Active Systems PREFERRED 15 PURON AC BRYANT HEATING AND COOLING SYSTEMS 165ANA036-B CNPV*4821A** 355(A,C)AV042080 35400 12.90 15.00 3485032 Active Systems PREFERRED 17 PURON AC BRYANT HEATING AND COOLING SYSTEMS 167ANA036-A CNPV*4821A**+UI 355(A,C)AV060080 36800 13.00 16.50 IMO Good Luck!
...See More
Assistance Needed on Replacement Heat Pumps
Q
Comments (17)
I could be wrong, but I thought I watched at least one project where the local historical society had to approve some exterior work. I can't say even for those projects if replicating historical windows was involved, so you may be right. I do remember one episode where the old windows were taken out and painstakingly rebuilt. They were probably tighter, but still a single pane of glass. I would think you could make a reasonable copy of an old double hung window with a double pane of glass. One big problem is as the house settles the frame becomes crooked and the window can't close properly. It is probably not such a big problem in Florida, but it is for the cold winters of New England.
...See More
djborden
Original Author
13 years ago
Thanks... appreciate the replies! I'll look into the package units.

How far apart does the retun and output need to be? My only concern with one of those units, is figuring out how to run the ducting without taking up too much space.

Cool deal on Ruud... thats one option for me.
Could I get a few more suggestions for other brands that are good quality and reasonably priced? Again, the goal is reliability, but I have no interest in fancy features.

I got the 3 Ton figure from a few online sizing guides. They were not very specific though. I will check out the software suggested above!
hvacgene
13 years ago
For shop use and what you explained as to the efficiency, sounds like a 2.5 Ton. If it was for your house I wouldn't guess. As Far as a Duct system for (plenum) supply, picture a "T" on top of the Air handler hanging Vertically! Get a roll of Foil Tape and a sheet of 1" duct Board 4'x 10'. Make Two rectangular boxes the same diameter as the opening at the top of the Air handler. Put two registers (two way) on either side of the top of the T. Don't worry about the return if you are hanging it on the wall. just filter it! And yes, under size in a humid area is better! You want to get as many air exchanges as you can per hour to ring out the moisture.
hvacgene
13 years ago
Problem with a package unit is you need to run the supply and return thru the wall. This can be a big penetration in your wall. You also need a dog house to protect the duct work from the elements. It also takes up more real estate With a split you have to do refrigerant lines and a condensate line but, a smaller hole in the wall
creek_side
13 years ago
The package unit does not require a federal refrigerant license for installation. A split system will, unless it comes with precharged lines and quick couplers. Either may require a permit and a licensed electrician per local rules.

The package system manufacturer will not honor the warranty unless a licensed installer checks the installation.

However the savings in price between buying your own package unit and installing it yourself instead of buying it from a local dealer will be more than enough to buy a whole new system.

AC Assistance Requested for 1500 sq ft Shop

Comments (6)

fluffybunnysui

creek_side

Related Discussions

djborden
Original Author

hvacgene

hvacgene

creek_side

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

AC Assistance Requested for 1500 sq ft Shop

Comments (6)

fluffybunnysui

creek_side

Related Discussions

djbordenOriginal Author

hvacgene

hvacgene

creek_side

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

djborden
Original Author