Ductwork with R8 insulation better for attic?

[jimj]

The problem with power attic ventilators is that they can cause large infiltration issues in the home, pulling your cooled air from the home into the attic only to be replaced with hot and humid outside sir ( infiltration).

[jimj]

As Mark has said 800 cfm is about the most you want in your climate. If your having any humidity issues 350 might be better.

[energy_rater_La]

going from R-6 to R-8 isn't going to save you much.
large labor cost to replace flex or re-wrap hard pipe ducting.

I'd suspect there is another issue, or several issues.
I'm not going to search out your other postings as it is difficult
to back & forth between older & current threads.
Instead lets get some specific information in this thread to make
it easier for all of us!

how long have you been in the home?
prior to system change out & duct sealing was second floor
temps even? was second floor ever comfortable since you've lived there?
is the 2 ton unit for the upstairs only? what approx sq ft is upstairs?

does the second floor share walls with the attic of the house?
are these walls insulated? if so, is it batt insulation?
is there easy access to attic space & would you be
comfortable taking some pictures for us?

pics of walls of shared walls from attic side..pic of bathroom
walls shared with attic, from attic side.
if batts have been used, in the bathroom make sure that in tub/shower
area that there is actually sheetrock behind the batts & not just the
backside of the tub/shower unit.

these will help us to better address your problems.
and disconnect the pav, those things cause problems by
pulling conditioned air out of house into attic. that is how
they keep attics cooler. what type of attic venting do you have
aside from pav? soffit & ridge vents? gable end vents? or just soffit
& pav?

best of luck.

[545GAlady]

Thanks for the input!

We have been in the home since 2003 (one year after the house was built). No, there was no difference in temperatures upstairs before and after the sealing of the ducts. The upstairs has only been comfortable when the temperatures were less than 90*F outside. The upstairs is 1400 sq. ft. The old Lennox A/C was also a 2 ton. The system short cycles a lot (runs for about 5-10 minutes the majority of the time, unless it's very hot outside). Yes, the 2 ton only serves the upstairs. We have a total of 8 supplies (three 8 inch, two 6 inch, and three 4 inch supplies) and 5 returns (four 8 inch and one 10 inch on the return side).

My daughter's room has high ceilings. The attic space is above the 2nd floor with a pull-down ladder for attic access. I'll take some pics tomorrow when I get a chance.

[energy_rater_La]

are there walls of the second floor that are shared with the attic space??
and it has never been comfortable upstairs when outdoor temps are higher than
90 degrees...correct?

think of this. if it is 90 degrees outside, it is 120-130 degrees in the attic.
if the walls of the rooms on second floor are shared with attic space then
the R-13-R-15 in the walls isn't stopping the heat transfer into the living space
from the attic.
this would make perfect sense that at above 90 degrees outside that upstairs
would be hotter...because of extreme temp on other side of these shared walls.

is there an easy access at first floor to attic space around second floor?
it is the second floor walls on the attic side that interest me.

you state you can't afford more attic insulation...but asked about replacing
R-6 to R-8 ducts...do you really think insulation costs would be more than
repalcing ductwork??

best of luck.

[545GAlady]

are there walls of the second floor that are shared with the attic space??
and it has never been comfortable upstairs when outdoor temps are higher than
90 degrees...correct?

think of this. if it is 90 degrees outside, it is 120-130 degrees in the attic.
if the walls of the rooms on second floor are shared with attic space then
the R-13-R-15 in the walls isn't stopping the heat transfer into the living space
from the attic.
this would make perfect sense that at above 90 degrees outside that upstairs
would be hotter...because of extreme temp on other side of these shared walls.

is there an easy access at first floor to attic space around second floor?
it is the second floor walls on the attic side that interest me.

you state you can't afford more attic insulation...but asked about replacing
R-6 to R-8 ducts...do you really think insulation costs would be more than
repalcing ductwork??

best of luck.

I appreciate the info, thanks. There is only one wall that shares with the attic, and that is the upper part of one of the walls in my daughter's room since the room has high ceilings. The upstairs does sometimes feel comfortable when its above 90*F. Mostly not. We had our attic insulation evaluated several times and everyone said there's enough. There's no other access point to the attic other than the pull-down ladder which is in the upstairs hallway.

For adding more insulation, what I'm really saying is that we can't afford it at this very moment. However, it's something to think about in the near future.

[545GAlady]

We had a tech come out the other day and he lowered the blower speed for the system. It now runs around 675 cfm for the first 7 minutes then ramps up to 824 cfm after that. Is this proper?

[jimj]

Yup. That will work

[motoguy128]

We had a tech come out the other day and he lowered the blower speed for the system. It now runs around 675 cfm for the first 7 minutes then ramps up to 824 cfm after that. Is this proper?

That will help. Even better is a thermostat that measures humidity and tells the unit to slow the blower in demand. IMO, this should be standard on ALL installation in all but hot dry climates.

[545GAlady]

Thanks for the info guys. I just felt the air temperature and it's still not very cold. I went outside to look at the A/C and I find several holes in the condenser coil. There's also a very high pitched noise coming from the A/C as well. What could be wrong? Should I start another thread for this next issue? I'll have to call a service tech back out.

[energy_rater_La]

keep it all in one thread makes it easier to see where we
have been rather than searching out different threads.


best of luck.

[545GAlady]

Ok thanks! We believe it was vandalism that caused the holes. All of the refrigerant leaked out and now the unit won't turn on (except the blower). Our HVAC company is coming out on Tuesday next week to look at the system and might quote us on a condenser coil replacement or a whole new A/C unit. It's a shame to have this happen on a 1 year old unit.

[545GAlady]

Since the unit won't turn on at all now, do you think the compressor burned out because of running when there's no refrigerant or is there a low pressure cut off switch that's preventing the unit to run? A tech is coming out in a few days and I have the system completely off now.

[jtrammel]

Since the unit won't turn on at all now, do you think the compressor burned out because of running when there's no refrigerant or is there a low pressure cut off switch that's preventing the unit to run? A tech is coming out in a few days and I have the system completely off now.

Hopefully it has a low pressure switch that shuts down the unit in a lp situation. Is it bullet holes? I'd like to see a pic.

[545GAlady]

Hopefully it has a low pressure switch that shuts down the unit in a lp situation. Is it bullet holes? I'd like to see a pic.

I'm hoping it does too. The whole outdoor unit isn't turning on at all. Only the blower in the furnace turns on. There is 0 refrigerant in the whole system. It looks more like someone stuck a screw driver in several locations on the coil. I'll upload a picture when I get a chance.

[RyanHughes]

Can you post the model number of the condenser as well? I think you mentioned once it was a Goodman/Amana SSX14, and if so then it has high and low pressure switches. Bigger concern is that system has been opened up to the atmosphere (moisture) for a prolonged period. Proper repair procedure is critical as far as evacuation and replacing the filter drier.

[545GAlady]

The hole in the second picture is where we think the refrigerant leaked out. When I went outside yesterday I heard a loud hissing noise coming from the unit.

[energy_rater_La]

are you sure it wasn't shot up with a gun?

sorry to see this has happened, hopefully it
can be repaired/replaced at little cost to you..

best of luck.

[545GAlady]

are you sure it wasn't shot up with a gun?

sorry to see this has happened, hopefully it
can be repaired/replaced at little cost to you..

best of luck.

Well I'm not completely sure. Not all the holes are big. Some are extremely tiny. Our area of town see very little crimes.

It's alright I guess. Our other two units weren't touched at all. My husband will file a police report. Hopefully insurance can do something about it. Doesn't a low pressure switch shut the unit off when its on or can it not start the unit up if there's very little or no refrigerant?

[energy_rater_La]

I wouldn't take any chances. I'd turn it off at the shut off on the wall behind it.

my little town is pretty much crime free too...but lots of gunshot holes in
stop signs!