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Central air vs 5 window units. Cost advantage?

Posted on 8/6/23 at 2:21 pm
Posted by The Cool No 9
70816
Member since Jan 2014
11019 posts
Posted on 8/6/23 at 2:21 pm
HVAC experts feel free to reply....So my central ac shite the bed. Switch it on by dropping the temp as usual I hear a faint click but the system doesnt switch on as it used to. Side question: can this possibly be resolved by resetting the breaker by the condenser unit? Haven't tried.

We have five window units which serve as a backup that work relatively well were not sweating our junk off anyway.. My question is should we notice any substantial drop in kwh used to save on the bill? My thought was yes since central hvac is the top power consumer in any household from what I understand and since that's not running.. Well you see where this is headed.

Ill hang up and listen. Thanks in advance.

ETA dont know the exact sq footage its just your average four bedroom house in the sherwood forest area
This post was edited on 8/6/23 at 2:23 pm
Posted by MikeBRLA
Baton Rouge
Member since Jun 2005
17130 posts
Posted on 8/6/23 at 2:35 pm to
quote:

My question is should we notice any substantial drop in kwh used


If you have Entergy, the app will tell you your daily usage. Check it out and this will answer your question about power usage
Posted by Tigerpaw123
Louisiana
Member since Mar 2007
17764 posts
Posted on 8/6/23 at 2:55 pm to
Sounds like it may just be a capacitor or contactor, both are really easy to change

If all of your window units add up to the tonnage of your central AC then you will use more electricity to achieve same coolness, as a central AC is more efficient than a comparable window unit

Have you been using the window units in addition to your central all along?

5 window units in a house, guess there is no HOA?
This post was edited on 8/6/23 at 2:56 pm
Posted by Zappas Stache
Utility Muffin Research Kitchen
Member since Apr 2009
42422 posts
Posted on 8/6/23 at 3:36 pm to
If you turn the window units off in the rooms you are not in, then they can save you money.
Posted by bee Rye
New orleans
Member since Jan 2006
34390 posts
Posted on 8/6/23 at 5:02 pm to
quote:

So my central ac shite the bed. Switch it on by dropping the temp as usual I hear a faint click but the system doesnt switch on as it used to


Sounds like your capacitor. $20 part and 30 minutes
Posted by armsdealer
Member since Feb 2016
12277 posts
Posted on 8/6/23 at 5:06 pm to
We ran 3 120v window units for several weeks during peak summer a couple years ago during covid and it kept our house cool and the usage was WAY down from the 5 ton unit. Parts shortage, took weeks to get whatever board or controller they needed... 2200sft but only about 1500sft was being cooled by the window units.
Posted by Nawlens Gator
louisiana
Member since Sep 2005
5946 posts
Posted on 8/6/23 at 5:11 pm to

Tigerpaw123 is correct. The Kw-Hr consumed per ton of refrigeration is higher for window units than central A/C systems.



Posted by jmarto1
Houma, LA/ Las Vegas, NV
Member since Mar 2008
38010 posts
Posted on 8/6/23 at 7:36 pm to
quote:

Sounds like your capacitor. $20 part and 30 minutes


A couple of these sitting around from Amazon is a life saver
Posted by The Cool No 9
70816
Member since Jan 2014
11019 posts
Posted on 8/6/23 at 9:15 pm to
^ Im all about it if thats what it is.

Yeah def no HOA poking around here where im at..

Well we havent ran the central in quite a while I dont know if its the fan speed or what but there is like no air blowing out of half the ducts in the house I think the ducts need to be cleaned but I just havent had the money to pay for something that isnt going to fix it. Other half of the house the ducts blow air fine.

This place is like the bermuda triangle of hvac. The western sun just bakes the front of the house with its lack of shade weve gone from window units to central and back over the last 30 years and still cant seem to find a sensible efficient situation. The other half of the house is an addition that was built on and the air does fine there.
This post was edited on 8/6/23 at 9:17 pm
Posted by FOBW
N.O.
Member since Sep 2016
429 posts
Posted on 8/6/23 at 9:45 pm to
But, no duct loss or other system design inefficiencies.
Posted by bapple
Capital City
Member since Oct 2010
12194 posts
Posted on 8/6/23 at 10:05 pm to
quote:

Switch it on by dropping the temp as usual I hear a faint click


You're probably hearing the 24V relay in the thermostat trying to turn on the 24V coil at the compressor outside. As another has said, if you're capacitor is bad, it's a simple swap.

If you have an electric meter of some sort, it's simple to check the capacitor. Even if your meter can't read nano-farads, if it shows open contacts that mean the capacitor is likely bad. And if it can read nano-farads and doesn't match the rating on the body of the capacitor, it's bad.
Posted by tunechi
Member since Jun 2009
10545 posts
Posted on 8/6/23 at 11:24 pm to
quote:

Sounds like your capacitor. $20 part and 30 minutes A couple of these sitting around from Amazon is a life saver


How does a complete HVAC dumbass like myself figure out which capacitor I need to order to have on hand for my unit?
Posted by DMAN1968
Member since Apr 2019
12620 posts
Posted on 8/7/23 at 4:06 am to
quote:

How does a complete HVAC dumbass like myself figure out which capacitor I need to order to have on hand for my unit?

Take the cover off the outside unit...find the capacitor, hopefully you can see the numbers on it...take a picture with your phone...Amazon it.

Grab a contactor while you are at it.

YTube video on capacitor replacement
This post was edited on 8/7/23 at 4:08 am
Posted by jmarto1
Houma, LA/ Las Vegas, NV
Member since Mar 2008
38010 posts
Posted on 8/7/23 at 5:42 am to
Let me start by saying I am pretty dumb on these things, so it is that easy. I'll put it in terms my brother put for me. Big metal box that makes noise outside is where it is at. Small metal box on the wall that is connected to it is your disconnect, pull the black thingy out. You're not going to hurt it. I still turn off my thermostat for the hell of it. Big metal box has a panel with about 4 screws on it, take it off. You'll see a small, fat cylinder in there. Read the info on it and do an Amazon search.
This post was edited on 8/7/23 at 5:44 am
Posted by baldona
Florida
Member since Feb 2016
23425 posts
Posted on 8/7/23 at 6:23 am to
The capacitor that usually fails is on the outside unit, if the outside capacitor fails the blower still runs and will run normally you just don’t have cold air and you won’t hear the outside unit run.

OP’s issue sounds different. Window units are NOT as efficient OP.

Spare capacitors are not a bad idea, and honestly I’m not sure why Lowes or HD et all don’t sell them. They are $15-25. But, they don’t fail as often as people think and the capacitor has to match the unit and the fan. I’ve replaced fans before and the new fan requires a different sized capacitor. But outside units will last 10-15 years and yes there’s a good chance you have a cap failure once in that time span.

Posted by dragginass
Member since Jan 2013
3183 posts
Posted on 8/7/23 at 6:55 am to
quote:


Tigerpaw123 is correct. The Kw-Hr consumed per ton of refrigeration is higher for window units than central A/C systems.


I'm not qualified to run the calculations, but there are savings by eliminating losses to ductwork. Some duct systems being better than others obviously, but it's one of the reasons mini-splits are so efficient.
Posted by gumbo2176
Member since May 2018
19436 posts
Posted on 8/7/23 at 9:47 am to
Well, I can't speak for everybody's results, but I helped my brother-in-law install central air and heat and run metal ductwork in his house prior to Katrina.

It was a 4 ton unit that replaced 5 window units and 2 floor furnaces and a couple space heaters. Four A/C units ran on 220 and one on 110 for a small room and the floor furnaces and heaters were gas fueled.

His utility bill dropped by a full 1/3 over what he had been paying running those multiple appliances and his house was uniformly cooled and heated.
Posted by BilbeauTBaggins
probably stuck in traffic
Member since May 2021
7664 posts
Posted on 8/7/23 at 10:02 am to
quote:

Central air vs 5 window units. Cost advantage?

Tell me where you see an average home in the South running solely off of window units that is comfortable in both the rooms and wallets.

Posted by poochie
Houma, la
Member since Apr 2007
6765 posts
Posted on 8/7/23 at 10:03 am to
Posted by Wraytex
San Antonio - Gonzales
Member since Jun 2020
3499 posts
Posted on 8/7/23 at 11:11 am to
well since y'all went that way....


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