What's new
By:
Filters

Home AC efficiency

Kyle

Kyle

Formerly known as Kyle_T
Joined
May 24, 2020
Member Number
1339
Messages
602
Loc
Fort Worth TEXAS USA
So we have a decent sized hvac system but it struggles to cool. And barely blows air. I know that airflow isn’t the end all be all and the air is decently cool but can someone point me in the direction to make sure it’s setup as efficient as possible? We get a 6* rise in inside temp during the day at the the most at and it takes a long time to cool
back to what it’s set at. Runs 100% of the time until late at night.
unit is a Goodman 1200cfm heater blower unit with a 3(?) ton cooler. It’s modular. Filter is clean. RoomTemps vary wildly during the day and closing vents and stuff makes it worse. Some rooms will be several degrees below the set temperature and some well above. The unit is about a year and a half old. House has it when we bought. House has updated windows and like 3 feet of blown in insulation. I have basic home HVAC experiment so I’m not a noob. Electrical and the Freon is no issue. Basically what can I do to make this better. I can move ducts and stuff if needed. Old house so likely bad placement.
 
Pull the cover to the evap and make sure the inlet and outlet are about the same temp.
also make sure the fins are clean.

I just went through this. For 2 year old unit it would run 24 hours a day and not keep up. The AC company was not charging it all the way.

My uses 410 freon. The pressures are crazy high on the low side and throws off most techs but that is normal.

My vent temps went from 8-9 degrees below ambient to 17 below ambient.
The system maybe runs 15 minutes any hour now on even the hottest days and keeps up just fine
 
take a temp gun and walk around shooting temps of everything and see what is your major heat load. i have a a friends house that takes a beating because of the unshaded west wall. sounds like you may want to crawl up in the attic and shoot shit and see if you have a bad duct leak. it was a hot bitch yesterday, and today is no better. if you can borrow a flir or rent one i bet you could find your problem quick.
 
As mentioned above, check and clean all fins if necessary. Does the ductwork need insulated? Where's the air handler located? The split coil unit that heats/cools the upstairs of our house was starting to struggle on really hot days. I added a layer of insulation to the air handler in the attic and installed an attic fan to control the attic temps a little better. It works much better now.
 
It’s a Goodman. You are fucked from the minute it’s installed. Goodman units are fucking garbage! Installers that recommend Goodman units are fucking idiots!
 
For central Texas /Austin we design (manual j/load calculations) for 74 degree indoor on a 100 degree outdoor. 26 degree split. So When it is 104, indoor temps may reach 78. I imagine Dallas uses Design temperatures close to that. When it is a near and over 100 out do not expect your unit to shut off. If it was shutting off throughout the day with the temperatures like what we’ve been having, then it more than likely would be oversized. Also, I’m assuming all your ductwork is in the attic, so the rooms further away from the indoor unit could see slightly higher temperatures since they have longer runs within the hot attic. To maximize system efficiency check for air leaks at the ductwork connections at the indoor unit, and also look for large gaps between your supply register boots and the drywall. 10% duct leakage used to not be uncommon, and by better sealing those up you can get that cooler lost air back to inside the thermal envelope. Gross generalization, but in this area a Typical Batt/blown house with average amount of glazing usually ends up between 650/750 sq. Ft. Per ton.
 
Bamajeeper said:
It’s a Goodman. You are fucked from the minute it’s installed. Goodman units are fucking garbage! Installers that recommend Goodman units are fucking idiots!
Click to expand...

That or fucking schister theives
 
Consider some easy insulation upgrades or blinds on the sunny side(s)?
 
Bamajeeper said:
It’s a Goodman. You are fucked from the minute it’s installed. Goodman units are fucking garbage! Installers that recommend Goodman units are fucking idiots!
Click to expand...

Only people that lack knowledge have this opinion. It is cheaper budget equipment and is built from nearly identical parts as anything else. They don't claim to sell top tier Cadillac systems. They fucked up mainly by selling direct to GCs and homeowners. Fucked up installs yield fucked up results.

As for the OP- sq footage? Insulation? Duct location and insulation quality? How are the returns (how big and where?) What's your split before and after the evap coil? What's the split from the furthest return grill to the furthest supply register? You saying it has very low airflow is a good indication that the coil is frozen/freezing or there isn't enough return.
 
Are the ducts original or been replaced? If it's older its likely not big enough.

I've seen many flex ducts and boxes broken or ripped open as well as completely missing insulation in some areas running electrical in attics. I've seen insulation companies blow 3 feet of insulation only within sight from the attic accesses and not actually insulate the whole house. I've seen hvac companies "replace all the ducts" and just replace whats within sight of the attic accsses too.

I would go up there at 6am with a good flashlight and dust mask to see whats actually up there.
 
I’ll try to answer some questions
yes ducts are soft insulated
Attic is not in cooled space, and doesn’t feel like there is a loose hose
air isn’t noticeable warmer the further from the unit but the velocity is and rooms are.
Insulation in walls is whatever was put in 1968 ceiling has massive layer of blown in where I can see. Roof
line is really low on certain parts and I can’t get to
it without a mask goggles and jumpsuit. Has eve and peak vents but no fan for venting.
2250sqft single story. I’ll get the actual tonnage tonight from the condenser.
we try to keep it as 67-69 but it creeps up to 76 during the day and nearly 80 in some rooms. Our bedroom is facing west with little shade until evening and it’s the worst offender. I’ll get a gun and shoot different areas and see what I get.

sounds like it might be under sized?
 
So nubicon will have us believe that a hundi and a caddilac are the same?!
​​​​​​SOUNDS like b.s.!
now fukt up installs aside, no way the difference in cost between a Coleman\edit, goodman, edit\home cheapo unit and a say a Carrier's 3 ton unit is the housing!

Give some credit to good,fast,CHEAP (pick 2) there hombre'

And yes
I am a retired b. General!
 
Last edited:
3 ton unit on 2300sq ft is definitely undersized and expecting 68-69 deg interior temps with 100+ outside temps in an older home with unknown insulation in the walls plus any other air leaks isn't going to happen.

Whats rule of thumb, like 25deg below ambient for this thype of heat?
 
Clb said:
So nubicon will have us believe that a hundi and a caddilac are the same?!
​​​​​​SOUNDS like b.s.!
now fukt up installs aside, no way the difference in cost between a Coleman\edit, goodman, edit\home cheapo unit and a say a Carrier's 3 ton unit is the housing!

Give some credit to good,fast,CHEAP (pick 2) there hombre'

And yes
I am a retired b. General!
Click to expand...

Hes not wrong, Copeland makes the compressors, Mars the contractors, who the fuck knows on wire, limit switches and copper fin tubes. You are a dolt if you think otherwise.:shaking:
 
45acp said:
If you really have a 3 ton on 2300ft, you're going to need a new unit. Everything new. I'm sorry dude, but nothing less will even help.
Click to expand...

Or maybe a second unit and zone some shit?

a couple mini splits?

Lighten the load on the little guy:laughing:
 
Kyle said:
I’ll try to answer some questions
yes ducts are soft insulated
Attic is not in cooled space, and doesn’t feel like there is a loose hose
air isn’t noticeable warmer the further from the unit but the velocity is and rooms are.
Insulation in walls is whatever was put in 1968 ceiling has massive layer of blown in where I can see. Roof
line is really low on certain parts and I can’t get to
it without a mask goggles and jumpsuit. Has eve and peak vents but no fan for venting.
2250sqft single story. I’ll get the actual tonnage tonight from the condenser.
we try to keep it as 67-69 but it creeps up to 76 during the day and nearly 80 in some rooms. Our bedroom is facing west with little shade until evening and it’s the worst offender. I’ll get a gun and shoot different areas and see what I get.

sounds like it might be under sized?
Click to expand...

You didn't answer return air question.


We are 3 ton in 2500 sq ft plus another 900 sq ft of basement, so 3400 sq ft conditioned space, 9 foot ceilings...has absolutely no problem keeping the house at temp, running maybe 25% of the time, even when 100f+ outside. I'd spend money on insulation before I'd spend money on a bigger unit.
 
SomeGuy said:
You didn't answer return air question.


We are 3 ton in 2500 sq ft plus another 900 sq ft of basement, so 3400 sq ft conditioned space, 9 foot ceilings...has absolutely no problem keeping the house at temp, running maybe 25% of the time, even when 100f+ outside. I'd spend money on insulation before I'd spend money on a bigger unit.
Click to expand...
Either you live up north, or you live way out west, or you're mistaken, or you're flat out fucking lying and the truth is not in you.

3 tons on 2500ft, w/900ft basement in Fort Worth is the equivalent of a box fan. This is assuming the attic is r100 and walls are r75 and there's tons of old growth shade trees on the east, west, and south side of the house. 3 ton is a goddam single wide unit in Fort Worth.
 
SomeGuy said:
You didn't answer return air question.


We are 3 ton in 2500 sq ft plus another 900 sq ft of basement, so 3400 sq ft conditioned space, 9 foot ceilings...has absolutely no problem keeping the house at temp, running maybe 25% of the time, even when 100f+ outside. I'd spend money on insulation before I'd spend money on a bigger unit.
Click to expand...


Dont you live in Canadia? Do you also have a Honda Civic that runs 12's with just a cold air intake and lowering springs?
 
We have a 2 ton on 1850'. Runs a lot, but it's still cheaper operate than the R22 one it replaced. It's a Goodman, 4 years and no complaints yet.
 
45acp said:
Either you live up north, or you live way out west, or you're mistaken, or you're flat out fucking lying and the truth is not in you.

3 tons on 2500ft, w/900ft basement in Fort Worth is the equivalent of a box fan. This is assuming the attic is r100 and walls are r75 and there's tons of old growth shade trees on the east, west, and south side of the house. 3 ton is a goddam single wide unit in Fort Worth.
Click to expand...

In Canada yes, but we do get 100 degree days every now and then (not continuous like you guys down there though). Yes a 3 ton AC unit, Tempstar (Carrier), with a variable speed modulating furnace pushing it around...yes that square footage...front facing south without any shade....R22 walls, R60 attic, very well sealed duct work, no ducts in the attic, new build ~5 years ago, so properly sealed, all brick exterior.

HillbillyDeluxe said:
Dont you live in Canadia? Do you also have a Honda Civic that runs 12's with just a cold air intake and lowering springs?
Click to expand...

Have never owned a Civic, wrong person.
 
It’s a 3 ton. 1200cfm max air handler. Today with no one coming or going temps were 108 outside and inside was 70 when I got home at the thermostat near the return. Our bedroom was significantly warmer and the kids rooms cooler (one exterior wall vs our bedroom has 3). So it barely does it with no doors opening all day. I came in and out a few times and it went to 71. I’m sure the kids going in and out it can’t keep up.
like I said it was in the House when we bought it last year and inspector said it was sized appropriately. But alas here we are. Lots of good info to make a plan.
 
SomeGuy said:
In Canada yes, but we do get 100 degree days every now and then (not continuous like you guys down there though). Yes a 3 ton AC unit, Tempstar (Carrier), with a variable speed modulating furnace pushing it around...yes that square footage...front facing south without any shade....R22 walls, R60 attic, very well sealed duct work, no ducts in the attic, new build ~5 years ago, so properly sealed, all brick exterior.



Have never owned a Civic, wrong person.
Click to expand...



You comparing temps in moose country to Texas is just like a ricer spouting off HP per liter bs.

Its almost 10pm here and its currently 90deg.
 
Kyle said:
It’s a 3 ton. 1200cfm max air handler. Today with no one coming or going temps were 108 outside and inside was 70 when I got home at the thermostat near the return. Our bedroom was significantly warmer and the kids rooms cooler (one exterior wall vs our bedroom has 3). So it barely does it with no doors opening all day. I came in and out a few times and it went to 71. I’m sure the kids going in and out it can’t keep up.
like I said it was in the House when we bought it last year and inspector said it was sized appropriately. But alas here we are. Lots of good info to make a plan.
Click to expand...


Im pretty impressed that it held a 38 deg difference during this heat. We keep ours at 78 when at home in the day and it runs friggin all the time with the kitchen feeling like the oven is cranked on in the middle of the day.
​​​​​
 
You must log in or register to reply here.
Top Back Refresh