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Discussion Starter #1
Just got my electric bill and figure if I have to pay this much $$$ I think my a/c should at least cool the house so I have questions.
My place is not real big, about 1540 sq ft w/ a 3 ton central unit. The air coming out of the vents is cold, right now 62 degrees but it is 79 degrees in the house. I try to keep the thermostat at no lower than 76. I have sprayed extra cellulose insulation in the attic, ( currently as deep as the boards 8") added ridge vents and it's still the same. I did notice ( or at least I think I did ) that when I switched to a programable thermostat is feels more humid in the house yet this thing will be running at 3 am when it is 74 degerees at night. It never seems to shut off when outside temps reaches the 90's.
I am using a IR thermometer and the wall right next to the unit is at one spot 87 degrees, inside the adjoining closet 92 degrees on the near wall, a little ways down the wall it is 82 degrees. Ceiling temps vary throughout the house from 76 deg to 82 deg.
The unit ( a/c /heater) extends from it's own "closet" up into the attic and it is open around the unit in the attic so it makes sence the heat is radiating down inot the ceiling and walls in that area. Can or should that open area be closed off to block the heat ? Wouldn't that stop any venting of gas leakage ? Deer Park Tx.. Cool place, just hot... Oh yeah, the thermostat is in a bad spot, on the back side of the wall where the oven is but the oven does not get used much, and it is directly in front of the unit's closet and intake.
 

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How old is the unit? Have you cleaned the condensor coils lately? Also would not hurt to clean the coils on the outside unit and is the outside unit in a place where it gets plenty of air. If it surrounded by a fence and some shurbs that will not help. The thermostat should be close to your return air and you should change those filters once a month at least. I use to live in Deer Park. Call Adams A/C. Ron is very fare and honest. He is in Deer Park. My family has used him for 20 plus yrs. Russell
 

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What about the ducts? What year was the home built?? If it was in the late 70's to late 80's you may have "grey flex" which falls apart. Also your temp split is off a little ...should have about a 20 degree split. How old is the system...is it matched...are the ducts sealed with mastic and mechanical straps. Basically there are lots of variables to consider and if your t-stat is near the "hot closet" it needs to be moved. The top of the closet being open is ok but you should have combustion air pipes installed for proper venting. I am on my way to dinner but email me and I can give you some info. WWW.ATEXSERVICE.COM for my background. I am in Austin but will be glad to give long distance advice.
 

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Discussion Starter #4
a/c

Thanks guys. OK to answer the basic questions from your replies. The house was built in 85, the a/c is new ( 2.5 years ) all ducting was changed then also and I did see tie straps on the ducting high in the closet, I'm assuming it it that way throughout. The unit is clear of shrubs and visually clean. When the stove is not in use, as in now, the area where the thermostat is placed is not hot.
The air flow out of the registers does not seem to be enough to me but the a/c guy that installed it said he checked it ( I had one really hot room when we bought the place, he came in and changed the ducting for $ 40 to correct that ). In switching from heat to cool, the fan is definetely on the higher setting for cool.
Condenser coil, on the inside ? How the H. would you do that ?
 

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Make sure your thermostat is on an insulated wall.

Stick an oven thermometer in the return side of the unit and one in the supply side just pasy the coils. The difference in readings should exceed at least 16-17 degrees. Anything less and you could have a number of issues. That is a good starting point.

Your air should be coming out of the grills cooler than 62 degrees if you want to cool your home.
 

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There are many reasons why you can't get colder than 79 degrees.

Using a digital thermometer take these readings...

Starting in the attic: Delta-T for an attic is 20 degrees MAX. above the outdoor temp. If your higher than 20 degrees you need more ventlation ...Whirlley Bird/s Power Vent/s.

What kind of meetering devise do you have?? Cap Tube... Flowrater... TXV.

What's the wet bulb and Dry bulb temp. entering and leaving the evaporator coil...( take wet bulb temp. by weting the tip and than taking the temp. ) Dry bulb should be between 16- 19 degree Delta-T..

What's the temp. of the liquid line outside ( leaving the condenser ) and inside ( entering the evaporator ) Should be no more than 4 degrees differance ( normaly 2 degrees )

What's the temp. of the suction line outside ( entering the condenser ) and inside ( leaving the evaporator ) Should be no more than 4 degrees differance ( normaly 2 degrees )

What's the outdoor coil entering temp./ leaving temp. should be at least ( 20 degrees differance )

We really need ( high and low ) pressure readings.

Do you have shade trees on the East / South / and West sides of the house?

What kind of doors do you have? Do they leak air?

What SEER Rating is your unit? Or the Model number...

What's the amp draw?

What kind of windows do you have?... How many and what size face East / South and West?

Do you have wood floors by the return air grill?

Do you have long hair Cats or Dogs that shead?

After you answer all these questions we may still come to the same conclusion: that is you need a 3.5 ton system, but without answering all of the above we are just guessing.

BE SMART!

BE SAFE !!

LET'S GO FISHING !!!

MB
 

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Reese, I feel for you bro. I am in the same exact boat! I think some of my problem is the fan. I was in the appliance business and I used to have to clean squirell cages in order to get enough air flow to make up contact swiches on some of my equipment. Only problem is I can't figure out how to get the darn thing out without using a Saws-all! I think the air is cool enough but I'm just not getting enough out to do the job. When I visit my parents house you can hear the air coming out and their unit actually cyles on and off throughout the day! I know several nights and early mornings when I have shut the thing off just to give it a break. Good Luck.
 

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I'm not sure but a 3 ton unit sounds a bit big for a 1540 sq ft house. My understanding of ac units (admittedly pretty small) is one that is too large will cool it but won't effectively take out the humidity. It's the humidity that makes homes feel uncomfortable inside. A lot of mold problems came from houses having too big an ac unit b/c the units would cool the house but wouldn't dispatch the moisture inside. Just a thought is all.
 

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Having run 1000's of loads for all over Texas I can assure you that 3 tons is enough. I imagine there are possibly several possible problems..... 1. wrong metering orifice in coil 2. improper charge 3. t-stat on hot wall . Another potential problem is some evaps with a txv are shipped without the bulb connected and they will cool but not well and humidity will be high....seen lots of dummy's miss that one. Also is the blower a variable speed or standard blower...if it's a v/s it may not be set properly.
 

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Does anyone have any leads on someone who checks/installs ductwork. I think I have covered everything else: ventilation, coil cleaning etc. Anything to lower the electric bill. Friendswood are.

TIA steve
 

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Thanks for all the info, fellas. Seems I'm doing ok over here with my unit set on 74 or 75 full time.

Sometimes I get a little uncomfortable but I'm pretty sure I just need to seal the extra return air vent I cut better to eliminate the slight humidity discomfort I sometimes feel.

I aint all that handy with a saw zaw but good thing Mama got me a corless set for Daddy's day.

Time to get busy.
 

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you should pm mont or call him, his number is in his user profile. He owns an large AC company as well as this site.
 

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Anything to lower the electric bill.

You can spend 1000's on this topic.....and wind up back outside.

We ask 2 questions:

1) What's your base electric bill ( that's the lowest power bill you've paid in the past 8 months ) the KW number on that bill will show the load of everything but the condenser and indoor blower.

2) What's your latest electric bill ( the high bill that's taking away all your extra fishing money when the A/C is running ) subtract the base bill from the higher A/C bill ( High bill - Base bill = Cost of A/C ) this will show you about what it cost to run your A/C.

Get an AMP reading from the condenser.

Get an AMP reading from the indoor blower.

We've been keeping AMP draw readings on new 14 SEER equipment and have seen real good results.

For example:

4 Ton ( 9 SEER Trane ) running 25.5 AMP'S Replaced with Lennox 4 Ton ( 14 SEER ) now running 13.5 AMP'S

2.5 Ton ( old Day & Night 8 SEER maybe ) running 17.3 AMP'S Replaced with Carrier 2.5 Ton ( 14 SEER ) now running 9 AMP'S

5 Ton ( 12 SEER Carrier ) running 19.7 AMP'S Replaced with Carrier 5 Ton ( 14 SEER ) now running 15 AMP'S

Note: these are condenser / coil replacments only.

Your indoor blower motor can pull about 5-9+ AMP's. Varible Speed blower motors run alot lower than that. Larry ( the head traner at Carrer Houston ) was showing me last week in the lab an AMP reading on an 80,000 Varible Speed Furnace and it was 2 AMP'S on high speed. I have a 5 ton in my attic that I'll check to see what it does and post that number.

The point I'm trying to make is this:

During the summer ( and in Houston it seems like it's year round ) your A/C condenser / blower motor are going to increase your electric bill when they run. You can spend 1000's on attic insulation, new windows, and doors, power vents, Radient Barrier, setback t'stat's, and will still have High AMP equipment running up the bill.

If you want to lower your " Electric Bill " Start outside with the high load equipment. This will produce a lower AMP draw that you can see using an ampmeater before and after the equipment is installed, and no one can BS this.

BE SMART!

BE SAFE !!


LET'S GO FISHING !!!

MB
 

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this past feb i needed to up grade my elect service as i did that i had a friend pull the cooling coil from inside the house and clean them (yuk!!) they were really clogged
by doing these two things i cut my bill in half
my house was build it 62 and is poorly insulated so that will be the next project

henry
 

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Higher SEER and LESS AMPS

I am a regestered energy auditor meaning I can tell you exactly what in your home is not efficient...from blower door/flow hood testing of ducts to load calcs and inspections for infiltration (where plumbing pipes come through the wall ect). And yes the first thing to do is make sure you have a matched system that is installed PROPERLY...to many "techs" cannot even charge a system the right way...and use a TXV metering device! As for insulation, solar screens, attic ventilation(not powered vents)...they are money well spent because once you pay for them they do nothing but save you money and never cost a dime to own down the road. As where your a/c system costs money to operate...and a poorly insulated home needs more a/c to cool it....and a home with leaking ducts has to run more and is not healthy. It is a WHOLE HOUSE approach......or look at it this way, you wouldnt put 3 new tires on your truck cause one of them still looked good would you, sure it will go down the road but how will it affect mileage ,handling ect?? As for how much the system uses take the SEER rating here is THE formula..... Capacity (Btuh)/SEER X Cooling Load Hrs/2200 X Elec. Rate = Annual Cost of Operation...so say you have a 3 ton, 36(kbtuh) divided by the seer times the cooling load hours (2200 for houston) times the rate (.095 is avg for the area) and you have thie annual cooling cost. Here is a link to some very helpful info for efficiency from our program here in Austin http://www.austinenergy.com/Energy%20Efficiency/Tools%20and%20Tips/index.htm . And remember...it aint too smart to put a $50 saddle on a $2 pony!! You can run your old inefficient equipment and throw money at the utility company every month then still have to get a new one or you can replace it and do some other stuff(solar screens,insulation) and start making money back...usually a new system pays for itself in 5 years. Make sure you seal the space between the sheetrock if you cut in a new return in the wall...otherwise you are just sucking hot air from the wall cavity...and ultimately the attic in most cases...they drill holes for electrical wires in top plates and air comes through them!! Just replacing equipment in a home over 15 years old is a good move...BUT if you do not adress the passive means(duct sealing w/mastic,insulation,solar screens) of conservation you are screwing yourself!! Call Mont and I am sure he can hook you up. Do not trust just anyone to your a/c work...today's more efficient products are more advanced and sadly our industry is full of guys who do not know their stuff..there are "parts changers and there are "Technicians" !!

MB said:
You can spend 1000's on this topic.....and wind up back outside.

We ask 2 questions:

1) What's your base electric bill ( that's the lowest power bill you've paid in the past 8 months ) the KW number on that bill will show the load of everything but the condenser and indoor blower.

2) What's your latest electric bill ( the high bill that's taking away all your extra fishing money when the A/C is running ) subtract the base bill from the higher A/C bill ( High bill - Base bill = Cost of A/C ) this will show you about what it cost to run your A/C.

Get an AMP reading from the condenser.

Get an AMP reading from the indoor blower.

We've been keeping AMP draw readings on new 14 SEER equipment and have seen real good results.

For example:

4 Ton ( 9 SEER Trane ) running 25.5 AMP'S Replaced with Lennox 4 Ton ( 14 SEER ) now running 13.5 AMP'S

2.5 Ton ( old Day & Night 8 SEER maybe ) running 17.3 AMP'S Replaced with Carrier 2.5 Ton ( 14 SEER ) now running 9 AMP'S

5 Ton ( 12 SEER Carrier ) running 19.7 AMP'S Replaced with Carrier 5 Ton ( 14 SEER ) now running 15 AMP'S

Note: these are condenser / coil replacments only.

Your indoor blower motor can pull about 5-9+ AMP's. Varible Speed blower motors run alot lower than that. Larry ( the head traner at Carrer Houston ) was showing me last week in the lab an AMP reading on an 80,000 Varible Speed Furnace and it was 2 AMP'S on high speed. I have a 5 ton in my attic that I'll check to see what it does and post that number.

The point I'm trying to make is this:

During the summer ( and in Houston it seems like it's year round ) your A/C condenser / blower motor are going to increase your electric bill when they run. You can spend 1000's on attic insulation, new windows, and doors, power vents, Radient Barrier, setback t'stat's, and will still have High AMP equipment running up the bill.

If you want to lower your " Electric Bill " Start outside with the high load equipment. This will produce a lower AMP draw that you can see using an ampmeater before and after the equipment is installed, and no one can BS this.

BE SMART!

BE SAFE !!

LET'S GO FISHING !!!

MB
 

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Clean the Evaperator coil (the one in the air-handler) To do it right it needs pulled out & washed. Also when your up & running make sure you have good "sweat back" on your suction line back at the condensing unit.
Go grab the larger insulated line on the outdoor unit. if its nots sweating & ice cold like grabbing cold beer you need freon.
 

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The proper method is superheat for fixed orifice and subcooling for txv. Accuracy is the key here. Doubt a 2.5 year old system has a dirty evap unless there are 20 cats in the house and no filter in the unit. As stated earlier...there are "techs" and there are "parts changers" who rely on guesswork.
 

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I have no cats in my house and my coils were plugged up after 4 years. I had to get up in there and clean them cause my unit would not work. I change my filters pretty regularly.
 

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Was your filter allowing air around it...lots of systems have poor means of holding a filter on all sides and it allows air to get around it...also some closet return cavities are poorly sealed. I am not saying it is impossible just that it is not as likely as the other scenarios, after 20 years I have learned that anything is possible and that most a/c guys out there today are little more than goons with tools.
Argo said:
I have no cats in my house and my coils were plugged up after 4 years. I had to get up in there and clean them cause my unit would not work. I change my filters pretty regularly.
 

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have learned that anything is possible and that most a/c guys out there today are little more than goons with tools.
I find that statement highly objectionable on my forums. I have been in the a/c business for 30+ years, and own half of the largest a/c company in the state. We spend thousands upon thousands of dollars for training, tools, equipment, and consultants every year. You may be a "registered" auditor, but I hold one of the first 10,000 licenses issued by the State of Texas for a/c work, and my dad holds one of the first 200. Your blatent generalizations tell me you really don't know as much as you think you do.

Monty Weeks
TACLA9976C
 
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