when should you replace your old central a/c unit?

JEDI

Lifer
Sep 25, 2001
29,391
2,738
126
my old central ac unit is all rusted outside. seer ratingis an 8. fed law now has a min seer=13 for new units.

and the bottom fins are damanged due to lawnmower strikes.

when should u replace an old outside compressor/ac unit?
 

ggnl

Diamond Member
Jul 2, 2004
5,095
1
0
does your ac still do an adequate job cooling the house?

if you have to run it constantly on hot days then you might want to think about replacing.
 

Vette73

Lifer
Jul 5, 2000
21,503
9
0
Most wait until it stops working, but that may not be the best.


Ask yourself this.

How long do you plan to stay there?

How much will you save over that time frame with a new 13+ seer unit?

Do you have enough to replace the FULL system and get the tax credit?

and so forth.


but if it is as bad as you say then your seer rating may be half what it was when it was new, let alone the age of duict work, air handler, etc...
 

BUTCH1

Lifer
Jul 15, 2000
20,433
1,769
126
Sooner, that seer rating of 8 might even be lower because of the rusted condition of the condensing coils. More than likely it will fail during the peak time of usage in summer as well. A lot of the cost will be defrayed by the power savings the new unit will offer.
 

rivan

Diamond Member
Jul 8, 2003
9,677
3
81
Are you trying to save the planet or your wallet?

Save the planet = replace now.

Save your wallet = replace when it dies. Higher efficiency units will save you some, but the cost of replacement will take quite some time to make up. How long depends on many personal factors - the cost/model of replacement, number of cooling days per year, home efficiency, just how bad your current one is. It's not as if going from 8-->13 will use 40% less electricity.

We replaced our main unit year before last when it died, went from a non-SEER rated unit (installers guessed it at about a 6) to a SEER 16 and we saw perhaps 15-20% lower impact from AC use on the electric bill (not 20% lower total bill). Hard numbers are difficult as we also switched from electric to gas dryer.
 

SarcasticDwarf

Diamond Member
Jun 8, 2001
9,574
2
76
Originally posted by: BUTCH1
Sooner, that seer rating of 8 might even be lower because of the rusted condition of the condensing coils. More than likely it will fail during the peak time of usage in summer as well. A lot of the cost will be defrayed by the power savings the new unit will offer.

True, but I would also wait until the winter when you should be able to get a better deal on one. Also talk to the installers beforehand about doing something to either raise, move, or otherwise protect the outside unit from damage.
 

BoomerD

No Lifer
Feb 26, 2006
66,404
14,798
146
Pay an HVAC company to come out and do a "tune-up."

Have them evaluate the efficiency of the system and explain and compare the costs vs. savings of both options.

The better companies here charge $59 to $99 for the service...and most will check and recharge the system if it needs it.

(recharging may mean a leak somewhere though...added cost IF it's repairable)
 

Yreka

Diamond Member
Jul 6, 2005
4,084
0
76
Originally posted by: BoomerD
Pay an HVAC company to come out and do a "tune-up."

The better companies here charge $59 to $99 for the service...and most will check and recharge the system if it needs it.

Got any you would recommend locally ?
 

BUTCH1

Lifer
Jul 15, 2000
20,433
1,769
126
Originally posted by: SarcasticDwarf
Originally posted by: BUTCH1
Sooner, that seer rating of 8 might even be lower because of the rusted condition of the condensing coils. More than likely it will fail during the peak time of usage in summer as well. A lot of the cost will be defrayed by the power savings the new unit will offer.

True, but I would also wait until the winter when you should be able to get a better deal on one. Also talk to the installers beforehand about doing something to either raise, move, or otherwise protect the outside unit from damage.

Maybe a better price during off-season but then he's stuck paying the extra $$ that his current unit will use during peak summer months. Here in FL you usually get 10-12 yrs. max out of one and they always seem to croak during a hot august afternoon. As for the lawnmower strikes I just stop a good '1 from mine and use the weed wacker to finish it to avoid damage.
 

mugs

Lifer
Apr 29, 2003
48,920
46
91
I'm not entirely clear on the math for calculating your savings with a higher SEER, but going from an 8 to anything above 13 should yield substantial savings unless you live in Canada or something. How much are your summer electric bills? We had a new SEER 16 A/C and high efficiency furnace installed last year for ~$5600. If the A/C was half of that, it probably wouldn't take more than a few years for it to pay for itself vs a SEER 8.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
get an estimate on replacement cost, the yearly savings and any rebates/tax incentives.

Work it out over how long you plan to stay.

Being you are dealing with an 8 seer, I am sure your comfort level will improve as well even if it's working decent.
 

mugs

Lifer
Apr 29, 2003
48,920
46
91
Originally posted by: alkemyst
get an estimate on replacement cost, the yearly savings and any rebates/tax incentives.

Work it out over how long you plan to stay.

Being you are dealing with an 8 seer, I am sure your comfort level will improve as well even if it's working decent.

Oh yeah, are high efficiency A/Cs one of the things that Obama will pay for 30% of this year?
 

BoomerD

No Lifer
Feb 26, 2006
66,404
14,798
146
Originally posted by: Yreka
Originally posted by: BoomerD
Pay an HVAC company to come out and do a "tune-up."

The better companies here charge $59 to $99 for the service...and most will check and recharge the system if it needs it.

Got any you would recommend locally ?

Sent ya a PM.
 

JEDI

Lifer
Sep 25, 2001
29,391
2,738
126
Originally posted by: Marlin1975
Most wait until it stops working, but that may not be the best.


Ask yourself this.

How long do you plan to stay there?

How much will you save over that time frame with a new 13+ seer unit?

Do you have enough to replace the FULL system and get the tax credit?

and so forth.


but if it is as bad as you say then your seer rating may be half what it was when it was new, let alone the age of duict work, air handler, etc...

tax credit? esplain pls
 

Vette73

Lifer
Jul 5, 2000
21,503
9
0
Originally posted by: JEDI
Originally posted by: Marlin1975
Most wait until it stops working, but that may not be the best.


Ask yourself this.

How long do you plan to stay there?

How much will you save over that time frame with a new 13+ seer unit?

Do you have enough to replace the FULL system and get the tax credit?

and so forth.


but if it is as bad as you say then your seer rating may be half what it was when it was new, let alone the age of duict work, air handler, etc...

tax credit? esplain pls


If you replace the whole system and its SEER rating is high enough then you can claim up to $1500 back.

http://www.energystar.gov/inde...ucts.pr_tax_credits#c3



 

magomago

Lifer
Sep 28, 2002
10,973
14
76
Originally posted by: Marlin1975
Originally posted by: JEDI
Originally posted by: Marlin1975
Most wait until it stops working, but that may not be the best.


Ask yourself this.

How long do you plan to stay there?

How much will you save over that time frame with a new 13+ seer unit?

Do you have enough to replace the FULL system and get the tax credit?

and so forth.


but if it is as bad as you say then your seer rating may be half what it was when it was new, let alone the age of duict work, air handler, etc...

tax credit? esplain pls


If you replace the whole system and its SEER rating is high enough then you can claim up to $1500 back.

http://www.energystar.gov/inde...ucts.pr_tax_credits#c3

Not to be offtopic, but did brandonb really say that in your sig? I've seen the other two, but not this one
 

JEDI

Lifer
Sep 25, 2001
29,391
2,738
126
Originally posted by: Marlin1975
Originally posted by: JEDI
Originally posted by: Marlin1975
Most wait until it stops working, but that may not be the best.


Ask yourself this.

How long do you plan to stay there?

How much will you save over that time frame with a new 13+ seer unit?

Do you have enough to replace the FULL system and get the tax credit?

and so forth.


but if it is as bad as you say then your seer rating may be half what it was when it was new, let alone the age of duict work, air handler, etc...

tax credit? esplain pls


If you replace the whole system and its SEER rating is high enough then you can claim up to $1500 back.

http://www.energystar.gov/inde...ucts.pr_tax_credits#c3

doh!
i replaced my furnace portion 3yrs ago when it broke in the middle of winter. the hvac guy came that day to replace it for ~$2500. eer=13 (my a/c compressor was still in decent shape back then.)

and it looks like i cant get any tax credit for just the a/c portion :(
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Originally posted by: JEDI
doh!
i replaced my furnace portion 3yrs ago when it broke in the middle of winter. the hvac guy came that day to replace it for ~$2500. eer=13 (my a/c compressor was still in decent shape back then.)

and it looks like i cant get any tax credit for just the a/c portion :(

you should, why not?
 

Drekce

Golden Member
Sep 29, 2000
1,398
0
76
I just replaced my entire system (original, house was built in 1991, there were no SEER ratings back then) with a 15 SEER heat pump for $5200. After the tax credit it will only be $3700. I live in Central Florida, and am expecting to save about $80/month on my electrical bill for about 6 months out of the year.

My old system was still cooling fine, but I wanted to get it out of there before it decided to die on me, likely in the middle of August.
 

dud

Diamond Member
Feb 18, 2001
7,635
73
91
Originally posted by: Drekce
I just replaced my entire system (original, house was built in 1991, there were no SEER ratings back then) with a 15 SEER heat pump for $5200. After the tax credit it will only be $3700. I live in Central Florida, and am expecting to save about $80/month on my electrical bill for about 6 months out of the year.

My old system was still cooling fine, but I wanted to get it out of there before it decided to die on me, likely in the middle of August.



I too live in Central Florida nd the price you paid (for such an efficient system) is hard to believe.

I've sent you a PM ...
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
I don't remember the details but in 1995 I replaced my a/c in S.Florida in my first house (I think built around 1986 or so). My bills averaged $300/month...after I swapped I was more comfortable and my highest bill was $175, average $100ish. It was ~2000 sq/ft
 

Chaotic42

Lifer
Jun 15, 2001
34,962
2,112
126
I replaced mine two months after I bought my house. It was 81F inside and my power bill was $330.

It was from 1979! :eek:
 

Born2bwire

Diamond Member
Oct 28, 2005
9,840
6
71
Originally posted by: Chaotic42
I replaced mine two months after I bought my house. It was 81F inside and my power bill was $330.

It was from 1979! :eek:

The worse part was that it was 79F outside at the time too right? ;)
 

Sea Moose

Diamond Member
May 12, 2009
6,933
7
76
Hey OP

I am a HVAC+R Mechanic.

As someone previously mentioned, you need to determine your short term and long term goals.

If you only plan on living where you are short term, then have somone come out and service your equipment.

When i service somones ducted system, I basically do the following (This is my basic domestic routine for a ducted system)

Wash Filters <-- this is very very important, you should ask the local HVAC guy how to do this, and wash regulary. I try to educate my clients and get them to clean as often as possible because the efficiency of the unit can depend on having clean filters.
Checker damper moters plus air flow
get into ceiling and check duct material and clean the drains out, check drain pans etc.
then outside i check the refrigerant pressures plus other things and wash the outdoor unit.


There really is no such thing as a "tune up". Air cons are a "sealed system" The major thing is to keep your air filter clean and replace once every couple of years. Depending on how often you use the unit. (replace yearly if you use it heaps)


If you decide to replace, you will have to replace both the indoor and outdoor units, as well as the interconnecting pipes. They may be seperated by copper pipe but you need to think of them as one machine.

If you find that you do need to replace than have the unit fitted on wall brackets about 300 to 400mm off the ground. That way you can clean underneith easily.


I would highly highly highly recommend getting a Daikin and having it fitted by the daikin dealer. I have worked on most brands and can give you an unbiased opinion on what to get and what to avoid.


If you get me some pictures of the damage on the outdoor unit, i can try and tell you if the rust is worth worrying about. PLus i can tell you a few basic things you can check to do a kinda self diagnosis. Shame i dont live round the corner, i would have a look at it for you.

I have not had experience with furnace systems (australia is too hot for furnaces, we basically live in one :p)

Any other questions, let me know