AC not keeping up - tech says its ok - any ideas?

I'm having trouble with the air conditioner in the house I just moved into. I know its hard to diagnose anything over the 'net but I am out of ideas and am looking for things to check on.
The house was built in '85, its 1450 sq ft, split level design. I am in the midwest. The livingroom and dining room are together under a vaulted ceiling. I've been in the attic and it looks like there is at least 12" of newer fiberglass insulation up there. The AC unit looks fairly new (5 yrs?) and is a 2.5 ton.
The symtoms are: its hot! I had an AC guy come out because the house was 80 degrees at the thermostat, which is located in a hallway between the living room/dining room and the bedrooms. He checked the freeon level, put a new filter in, and cleaned the condenser coils. He said when its 100+ degrees out, its reasonable to only get down to 80. My last house, a 1960 ranch, had no problem cooling in any conditions, but ok.
Today its 84 degrees out, and its 75 in the house. A 9 degree drop! Seems ridiculous to me. Also since the tech has been out I had the strongest tint available installed on all the windows in the living room and dining room.
He said he was getting a -21 degree drop between in the in/out air at the evaporator, which he said was normal. I've checked the air coming out of the vents and its around 56-59 degrees. It feels like there is plenty of air flow out of the vents. Half of the vents in the basement are closed to push more air to the upper levels.
If you have any ideas I'd appriciate it. My AC pretty much runs constantly during the day, all the way until 11 or 12 at night. I'm not looking forward to getting my first electric bill.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds like you are fucked.
Better buy some stock in the electric company.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Cleaned outdoor coils... how? Hope he used chemicals and a water hose.
Twenty degrees is a good temp drop over the evaporator. But is the fan in the furnace at top speed?
What's the humidity like, there? High humidity takes a lot of power to dry the air.
The one time I saw this kind of problem, the folks were smokers. It was a 90 degree humid day, and every time they would step out to smoke, they would hold the door open for several seconds. And let the heat and humidity in.
Try opening ALL the vents, and see if that helps. Makes me wonder if you've restricted the air flow.
Also wondering if there is enough return air ducting?
Please let us know how things work out.
--

Christopher A. Young
You can\'t shout down a troll.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Stormin Mormon wrote:

With a garden hose.

I'm not sure. I'd probably have to open up the unit and see what wires from the motor are hooked up. Its pretty noisy when the system kicks on, I'm pretty sure its on the highest speed.

Its been very humid lately.

No smokers here. And the doors have not been opened much in the last few days.
I went over a talked with my neighbor today, and his house was 79 when mine was 75. He said thats just about all they do around here, and that these open floor plan houses run pretty warm.

Return ducting could be an issue, I don't see a whole lot of it. We sleep with the bedroom door open, and when I open that door I can feel a ton of air flowing out of the cracked door. - I just went and looked and only found two returns on the upper levels of the house. One in the hallway between all the bedrooms and main bath, and one in the living room. Cheap construction I guess. My last home had returns in just about every room.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

hose.
With a garden hose. CY: I've used a garden hose. Had good results with a pressure washer, but that's a skill to be learned. Som eof the coil cleaing chemicals sure help loosen the dirt.

fan
I'm not sure. I'd probably have to open up the unit and see what wires from the motor are hooked up. Its pretty noisy when the system kicks on, I'm pretty sure its on the highest speed. CY: A slower speed can give you a higher temp drop. But that doesn't mean you are moving heat.

to
Its been very humid lately.

the
No smokers here. And the doors have not been opened much in the last few days.
I went over a talked with my neighbor today, and his house was 79 when mine was 75. He said thats just about all they do around here, and that these open floor plan houses run pretty warm. CY: Hmm. Maybe needs better window shades, or more air flow. Or some more cooling, like a window unit upstairs.

Return ducting could be an issue, I don't see a whole lot of it. We sleep with the bedroom door open, and when I open that door I can feel a ton of air flowing out of the cracked door. - I just went and looked and only found two returns on the upper levels of the house. One in the hallway between all the bedrooms and main bath, and one in the living room. Cheap construction I guess. My last home had returns in just about every room. CY: Very possible. Might be depending on people leaving doors open. I'm starting to think that poor return air is a serious problem in a lot of cases.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 22 Jul 2006 21:15:43 -0700, snipped-for-privacy@yahoo.com wrote:

Almost None of the 500 homes in my neighborhood have room returns. Only those that were added by a few homeowners after the fact.
The main 20x25 return is in the common area next to the furnace and all the interior doors have a large gap at the bottom for return air.
But my doors are seldom closed anyway so no big deal to me and in 22 years, I have no complaints about no returns.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
JimL wrote:

Bottom link provides some info concerning duct systems. - udarrell
--
Air Conditioning\'s Affordable Path to the "Human Comfort Zone Goal"
http://www.udarrell.com/udarrell-air-conditioning.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I would pay to have another company do a heat load of the house and see if it, the A/C the right size for your home.
If it is then have them check the duct work to see if it has been installed right.
--
Moe Jones
HVAC Service Technician
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Moe Jones wrote:

Seems like one of the few people on this site that have any idea of what they're saying. Heat load is required, however a rule of thumb (130-140 w/m2) can be applied. In domestic installs I've witnessed, the ducting is usually installed poorly, BUT, capacity is important. 1st things 1st. The unit needs to cater for the correct load. Either reduce the load or increase the unit size.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
PJ ;-) posted for all of us... I don't top post - see either inline or at bottom.

Huh? Ya got two? I have been reading this group for years and even I have picked up: rule of thumb = hack.
--
Tekkie

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tekkie wrote:

Read the first sentence of my post dated Tues, Jul 25 2006 4:18 pm in relation to Moe. Take the hint !! Prove my figures wrong !
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
PJ ;-) posted for all of us... I don't top post - see either inline or at bottom.

YOU are WRONG -- Tekkie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@yahoo.com wrote in
I've checked the air coming

Then the AC is doing it's job. It sounds like an airflow issue. Like someone said, could be a return air problem.
--
Respectfully, Bob

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I missed there area of the country you live in. If the system is designed for 90 out side temp and you have 104 outside. This will have a great difference in system operation. You gaining more heat than removing.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
its looks like your unit may be undersized a bit ...i would check with a local reputable ac dealeer with both sizing ac questions they will tell u accurately..altho not so cheaply..but you dont want cheap when it comes a a major purchase such as a new ac snipped-for-privacy@yahoo.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Pardon the obvious, but add 10 - 12 inches of insulation in the attic.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@yahoo.com wrote:

~135m2
~8.8kW Now, 8800/135 = 65w/m2. Normal design for domestic would be 130-140w/m2. You are way short on capacity. Your a/c will run continually on hot days and cost lots of energy.

He wasted your money. He didn't pick the unit is too small. Another professional ripping of the public.

It will be a killer. You need a bigger unit or zoning to reduce the load. Best of luck.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You just described my situation EXACTLY. Exactly the same kind of temperature swings, etc.
Outdoor unit is a TempStar 2.5 ton 12 seer.
Indoor unit is a Goodman GMP075-3 (only one notch up from the cheapest and least powerful unit they made).
I live in a condo which I learned are usually made from the absolute cheapest materials available to keep costs down.
I've had techs as well say the same thing, "it's running fine." Finally I was advised that the system just isn't powerful enough.
I'm having someone come out to spec me out a new ac/air handler that will do the fucking job.
snipped-for-privacy@yahoo.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Gibbel wrote:

You need to have the tech carryout a heat load. Anything less than 90w/m2 (for the specific zone being conditioned) and you have to start asking questions. Why is the capacity low. Could be VERY efficient house, doubt it, small unit costs less (read more profit for the cost).
I have seen people on this site bitchin' about unit performance and it happens they have something like 50w/m2. No bloody wonder it doesn't work. Put a two cylinder bike motor in an F350. It will perform like shit. You need correct capacity for the job.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Before you replace equipment, please try to find an AC service guy who knows how ot clean coils. I've seen several times that dirty coils behave like too little cooling. A cleaning may restore the cooling.
--

Christopher A. Young
You can\'t shout down a troll.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.