View Full Version : New House - Several Issues - Advice Needed
06-13-2007, 07:28 AM
We purchased a 3500 square foot two story new construction house last July. It is located in North Dallas and has two Goodman 13 Seer R22 AC systems. The downstairs unit is 5 tons and the upstairs unit is 2 tons. The house was energy-star rated and does have a radiant barrier on the roof decking.
The upstairs was always hot prior to move in and the unit seemed to run continuously with a minimal drop in air temp from the vents. The builder had it checked several times and assured me it was due to the builders coming in/out and not blinds on the windows, etc.
Here we are the following summer with high utility bills - and it is only now just beginning to get hot. The upstairs system seems to run almost 100% of the day time to maintain 78 degrees. The unit is able to cool down to 75 or during the night with no problem - after the sun goes down. There is a central return air duct in the hallway near the thermostat that registers 78.5 degree air going into it. The air coming out of the vents varies between an 8 - 12 degree temp drop depending on the location of the vent from the condenser/fan in the attic.
The HVAC company has been out twice this week. They state the Freon level is correct and it is cooling, so they don't know what to do.
I am pushing back through the builder and AC company. I also plan to contact Goodman directly and let them know what is happening.
There is either something wrong with the upstairs system, or the unit is just undersized. I believe the upstairs area totals about 1200 square feet. The downstairs system is 5 tons and is able to maintain reasonable temperature while cycling on/off during the day. It also registers between a 16 and 19 degree temp drop.
I appreciate any help and or comments.
06-13-2007, 09:09 AM
Any of you Dallasians out there able to help him?
06-13-2007, 09:36 AM
If you have been calling the same HVAC Co. out you may want to switch to another. I'd be looking at proper sizing, proper duct sizing, possible return air infiltration. If you have just one central return (not ideal) are the doors shut and possibly reducing airflow? As many on this site will advise "Proper installation is the key"
Lot of competent people in your area, most are very busy right now as well. Be prepared to compensate the company but with a good company that takes their time you will only have to pay once and have lower energy bills also.
As an example of what is possible, I owned a 2700 sq.ft. home in northern Collin Co. Had two builder grade Lennox heat pumps with crappy typical builder grade installation. Before I was even unpacked I was ripping that junk out, installed properly sized ducts, added returns and installed new variable speed high efficiency equipment. Also added some attic insulation. During the five years I lived there my electric bill was never over $156 verified by all my receipts. (Neighbor's bills were in the $500-$700 range)
My point is excellence will pay off for you even when you are paying much more than the lowballer charges. Don't expect the guy with the "Service call only $29.95 which includes 1# of freon" to get the job done.
06-13-2007, 09:41 AM
If the problem with your upstairs system is a sizing or capacity issue, I'm not sure what Goodman could do about it other than state it's an installer issue. 1200 square feet for two tons upstairs adjacent to attic space...and if there are more than just a few windows upstairs...it might be a bit on the light side. But I'm not one to size by square feet. You could ask the builder if a heat load calculation was performed for the second floor, but I don't know how far that will get you. You can run one yourself by downloading HVAC-Calc and carefully entering in the required information.
With that said, if there isn't anything outright wrong with the refrigeration side of the system (going by what your a/c guys said...who knows if they're interpreting their data correctly, since gauging correct refrigerant charge is an ongoing challenge in my industry), and let's say for the discussion that it is fine, then the focus is shifted toward either a sizing issue or factors about the installation that are robbing capacity from what the refrigeration system is producing. One of the main capacity robbers are restrictive ductwork - very common in new homes like yours that use flex duct - especially if it's flung everywhere like spaghetti and not stretched tight. But, if the ductwork was overly restrictive I think you'd be complaining of the system icing up frequently, or rooms with weak air flow.
Duct leakage is another big capacity robber. Since your ducts are likely in the attic, where it is hotter than blue blazes, if they are not sealed well you are losing capacity. Return duct leaks in an attic are very bad in that they draw into the return air stream that super hot attic air, loading down your cooling coil with excess heat. Supply duct leaks rob your house of cooler air, sending it into the attic. The air handler itself being located in the hot attic will undergo heat gain, also knocking down capacity a little.
This is what gets me about the "Energy Start" rating. Does a house get this just because a bunch of appliances and products that carry an "Energy Star" label go into it? Or are there higher standards for the construction of the house, such as upgraded windows, radiant barrier (which you mentioned), thicker insulation, better sealing of the structure to reduce infiltration, etc? Is there someone who verifies if all these items are installed correctly and functioning correctly before the Energy Star label is applied? Probably not. The Energy Star to me seems more like a sales technique than an actual standard that is sought for and enforced. Compare it to Austin Energy in Austin, Texas, which has a program offering generous rebates for energy efficient rated construction, but the requirements to obtain that rating are pretty stringent. IOW there is follow-up to see if any energy efficient efforts are actually installed and functioning according to their design. Any efforts like that for Energy Star rated homes?
06-13-2007, 09:48 AM
I understand completley what you are saying about the install and quality componets. I would love to have the type of systems you mentioned put in, but i would be replacing equipment that is less than one year old - at my cost.
If I thought I could update the equipment/install with a break-even in cost of less than 5 years, I would be very inclined to do this...
I spoke with Goodman this morning and they would like the HVAC company to come out and do a manual heat/loss calculation. She said if the company won't do it, then they will contact them and arrange for a rep to be on site with the company to do the job.
I will attempt to work with the builder/HVAC company and Goodman to resolve this. If within several weeks we don't have a resolution, I plan to hire an independent company to come out and access the situation. I feel I would have the best chance in recouping my costs by giving them a chance first. I'll look here for recomendations of an HVAC company when the time comes.
06-13-2007, 09:56 AM
The Energy Star program does include at least two inspections -prior to sheetrock and prior to closing. I believe they actually seal the house and "preassure test" it. However, all houses built in Frisco currently have this seal... I don't know how much a difference it makes.
I do have concerns about the ductwork. The return air duct comes up from the floor and makes a 90+ degree turn into the system. The HVAC company said this was fine as it was for return air and the system could "suck" the minimal amout of air it needed easly through an even smaller diamater duct. The tech also performed a check on the ducts to verify they were not leaking or sucking in attic air. I don't think he spent more than 5 minutes on this however.
The entire house does have flex duct thrown about everywhere. It is a very sloppy job. Short of ripping it all out and redoing it, I don't know what to do about it.
06-13-2007, 10:20 AM
If I thought I could update the equipment/install with a break-even in cost of less than 5 years, I would be very inclined to do this...JS
Very difficult to break even in this time period if extensive re-work would be required.
The "Cadillac" model of calculations would be a Manual J for heat load, Manual S for equipment sizing and a Manual D for duct design. Your contractor should be able to perform all these calcs for you.
Hope you have a good resolution with the HVAC Co. and Goodman.
06-13-2007, 10:20 AM
Have reputable dealer do complete capacity check using flow hood, sling psychometer, with accurate measurements with digital thermometer, & you will find your problem. Unfortunately, most dealers cannot do this!
I grew up in Dallas and am familiar with currently popular housing styles there. I am concerned there might be a large open space which communicates between 1st and 2nd floors, and wonder if the Manual J model knows how to deal with this adequately. You've probably seen a grand two-story front door entrance, perhaps there is a grand space just inside? Version 7 from Hvac-Calc does not seem to address this, in my homeowner opinion.
Just curious, is the 2nd floor considerably smaller than the 1st floor? Having the 1st floor 5-ton AC cycle during these fairly hot days, seems to me to indicate an excess of capacity. When the Manual J is done, I wonder if it will indicate 3T upstairs, 4T down would be a better fit... if indeed 500 sqft/ton is the correct sizing overall. My 1989 house near Houston is sized right somewhat smaller, Manual J would say 700 sqft/ton if I had quality modern windows.
I'm just speculating here, it's intended to be harmless and casual talk while waiting for a pro to do a valid Manual J model. I hope you get a really top-notch professional to identify the source of the problem, and prescribe a solution.
06-13-2007, 12:45 PM
The upstairs contains three bedrooms, one gameroom, and two bathroom. The entry downstairs is two stories, but this is not a huge "grand" entrance you mentioned.
I have thought a 4T and 3T Might be better suited, but I haven't done any calculations. I started to last night, but I didn't have the volumes of infomation required at the time.
The downstairs unit does seem to cool the area well and probably runs 20 minutes and cycles off for about 15 minutes. This continues throughout the day when it is 95 degrees outside and 77 or 78 inside. It will still cycle on/off when the indoor temp is 74 or 75, though not as much.
Numerous calls have been placed to the HVAC company by myself, the warranty person for the homebuilder, and I believe by Goodman.
I don't believe a manual J calc was ever done on the house, but they designed the system based on generic floorplans the builder supplies. Whatever model "X" house built gets the same system...
06-13-2007, 03:42 PM
Any dealer recommendations for Frisco/Plano/North Dallas that are also autorized Goodmand dealers?
I have just met w/ our Electric company regarding excess electrical usage. He made a number of suggestion, but said the HVAC systems were a complete mess. Specifically, both units are leaking cold air into the attic in several places. The ductwork is sloppy and bent too tight, a thermostatis located in a bad location downstairs, etc.
I am still working with our HVAC company, but am leaning towards having another company come in and fix everything. I'll then attempt to get our builder and the original HVAC company to repay my repairs.
The HVAC person also said the systems might be out of balance - needing a 4T down and 3T up. He said an actual calculation would be needed to tell for sure. I mention this becuase somebody else also stated this down below.
8 to 12 degree drop upstairs system and 16 to 19 downstairs,the difference in drop is not do to an undersized system.
06-13-2007, 05:50 PM
dash, why is the difference in drop not due to an undersized system? I am not suggesting otherwise, I am just trying to figure out why.
If the air flow and refrigeration system are correct,you'd have more then an 8-12° drop thru the coil,even if the system was too small for the space.
Too small would not have any infulence on the drop,just the indoor temperature and run time.
Are your temps ,in and out at the equipment or the supply and return grilles?If at the grilles ,it could be return duct leakage pulling in attic air ,really kills capacity when the sun is shinging.
06-13-2007, 06:39 PM
That makes sense. I am awaiting the visit of yet another "experienced senior" tech tonight. Hopefully he will find something. It is encouraging that the 2 ton system might be sufficient. I really don't want to fight with them on replacing it. I'll update later tonight with the results of the visit.
06-13-2007, 10:56 PM
Do you have the Energy Star report? If so, it will identify the amount of duct leakage, which would help understand the problem. A two ton unit does not have much room for margin if it is leaking, which is highly likely.
06-16-2007, 09:08 AM
I don't have the energy star report, but I could try and get a copy of it. I know Frisco won't pass a final inspection with a failed report though...
The HVAC company is supposed to come out today and replace the 2 Ton upstairs unit w/ a 2.5 Ton. They discovered on their plans that our house is supposed to have the 2.5 Ton unit. They plan to address the other areas once the replacement unit is up and running.
I am hopeful this will make a difference, but I'm not sure at this point.
06-16-2007, 09:49 AM
Are they changing the whole system or just the condenser?
06-16-2007, 10:05 AM
They are changing the outside unit, which is the condensor and compressor??? There is a gas furnace/fan and coils in the attic. My understanding is they will stay the same. I was already told the unit in the attic was a bit oversized for the 2T outdoor unit. They reduced the fan speed to compensate. I really don't think these guys know what they are doing.
I asked the lady on the phone about having someone perform an actual heat/loss calculation on the whole house and making decisions from there. She was going to check into that and get back with me...
We are having some rainy cooler weather for the next few days. I probably won't know much until we get into the high 90s next week.
06-16-2007, 10:40 AM
when they show ask if they will be using a vacuum pump or changing the piston on the evaporator coil to match the new size condenser.
06-16-2007, 08:48 PM
They did use a pump on and they did change the piston on the coil. The new 2.5 ton is in and it is working now, but we'll see once the heat returns next week.
Have to wonder what the duct static is now,with a larger system.
06-17-2007, 12:32 PM
They told me the attic stuff was 2.5 tons - and the new compressor is 2.5 tons. They should have installed a 2.5 ton unit per their own plans, but put in a 2 ton for some reason. The part in the attic (coil & furnace & fan) was correctly put in(at least per their plans), initially.
Would a 2 ton unit outside and 2.5 ton setup upstairs make the system inefficient? The new unit cooled the upstairs from 79 down to 73 in 2 - 3 hours time. There was about a 20 degree drop from the return to the outlet vents. This is all much better than before, and I really think there was something else wrong they may have "inadvertently" fixed during the swap.
However, it was overcast and rainy outdoors with outside temps in the upper 70s. The tech is coming back next week during a hot afternoon day to go over things again.
They are also going to move the thermostat on the downstairs system to a more central location. It currently is in the hallway going to the laundry room and garage and cycles on often when somebody walks in or out of the garage.
I am hoping for a more efficient system and reasonable electric bills this summer.
06-17-2007, 01:03 PM
You tell me … … … ….. the upstairs coil is rated at 30,000 btu/h and the 2 ton is rated for 24000 btu/h.
These type problems I’ve seen over and over again. I worked for a company that installed 100’s of systems for a builder that did very large sub divisions. And I’ve seen it all and I had my hands full trying to fix all the crap systems they put in. worst company I ever worked for and I ended up there because my brother hung around with the service manager.
I’ve seen the girl that answers the phone and types letters in the office doing the heat load from the drawings. And the person who told her how to do it had no education whatsoever in the process. He knew just enough to be dangerous.
And the installers were all hacks who were subcontractors. They would show up at the loading dock in a beat up pick up with a few stolen tools.
They got just enough money to keep them in booze and drugs. When it was gone they would be back at the loading dock.
I’ve gone to brand new homes were they installed the p-trap sideways because they had no clue what it was for. Or even better they just bend the PVC because they were short of 90’s.
You got your hands full trying to get this mess straightened out. I have no doubt that everyone your dealing with is lying through their teeth just to get through it with out ending up in court.
What does the inside of your equipment look like? Is it full of sheet rock dust and construction debris?
06-17-2007, 01:15 PM
I'll assume the mis-match componets are a valid reason for the system running poorly...
I agree with the rest of your comments as well. It sucks, but what can I do? I will see this out even if it means I hire someone to replace the the whole system - and then take them to court to recoup my expenses.
At this point, I would be happy to get the system performing as good as the lower end equipment can perform. If we are still here, I'll replace it with quality componets when necessary.
06-17-2007, 01:24 PM
And the installers were all hacks who were subcontractors. They would show up at the loading dock in a beat up pick up with a few stolen tools.
Your location shows Boston - you sure its not the DFW metro area????:confused:
06-17-2007, 01:36 PM
06-17-2007, 01:50 PM
Sorry for the confusion, I was responding to the previous post. I always feel for the unsuspecting HO that assumes the company they've hire to install their expensive system gets installed by a bunch of subcontractor gorillas in a beat up 1970's pickup piled high with equipment, ductwork, tied down with baling twine and four guys in the cab. That post gave me a clear mental image of the subcontract crew driving down the Tollway to a job.
I've done a little service work in the Frisco area, inspectors there are usually pretty good about spotting obvious missteps but generally don't go into sizing or airflow issues. Best of luck on your new home - supposed to get hot this coming week. :)
06-24-2007, 03:52 PM
I wanted to post an update.
-They have replaced the upstairs 2 Ton w/ a 2.5 Ton unit. Per their own plans, this should have been installed originally.
-They have moved the downstairs thermostat to a central location so it no longer comes on when the garage door is opened.
-They have replaced the standard smaller coil with a "B" coil which is supposed to be more efficient.
-They have replaced the piston valves in both units with expansion valves - As they are supposed to be more efficient.
-There are now some additional air leaks where the ductwork attaches to the new coil. I have asked them to come back and fix that.
-The upstairs unit is working MUCH better, but it still won't cool adequately with a decent heat load. For example, the unit was set and maintaining 77 degrees all day yesterday, but it was still humid up there. Some friends of ours and all the kids were all upstairs in the gameroom and kids rooms and it was getting warmer. I turned the thermostat down to 76, but within 30 minutes, the air temp had increased to 78 even though the unit was still cooling. We then left to go eat and I set the temp down to 74. We returned two hours later and the upstairs was 74 and much less humid. The sun had also gone down while we were out.
We started out with an 8 degree temp drop and couldn't maintain 78 easily and now have an 18 degree temp drop. I feel there are some air leaks which need to be addressed, but it still seems like the unit needs to be a bit bigger to handle the load when we are using the upstairs. The gameroom will soon become a media room, so it is likely there will be times when we have 8 people up there, and I don't want to sweat through the movie!
Please post opinions on the work done and how to proceed from here.
06-24-2007, 04:02 PM
The air leaks need attention first.
There may be other air leaks in the attic, and they should check the duct for them.
If you didn't have the game room desinated as having 8 people on the plans,
plus a media center, then you might end up paying for a larger A/C to handle the load.
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