So, the bulk of my electric bill every month in the summer time comes from running the air conditioner. In fact my bill doubles... Almost triples because of the AC. I've been thinking about putting the AC system on solar power. What information do I need to get about my AC system in order to purchase the correct solar power setup. I'm seeing 400 Watt systems but the description says it will only work smaller devices and such. Where do I find this information?
Solar Power for Air Condition System
- Thread starter CameraMan
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growler
Senior Member
- Location
- Atlanta,GA
I would think that you may want to get an energy audit to see if you can save on power by other means before jumping to solar power.
Making sure that insulation and windows are engery efficient. Maybe even a better and more efficient AC system.
The cost of solar power is not going to be cheap.
Making sure that insulation and windows are engery efficient. Maybe even a better and more efficient AC system.
The cost of solar power is not going to be cheap.
K8MHZ
Senior Member
- Occupation
- Electrician
Agreed. In fact, the above was part of a class I took at our local college on solar systems. AC systems are far more efficient now than ever. Even a 10 year old system will be more of an energy hog than a brand new one. A 30 year old system is a huge energy hog.
- Occupation
- Licensed Electrician
Power bills are not a good reason to buy a solar system. You can't make make your own power from the sun cheaper than you can buy it from the utility.
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
Start here:
https://www.gasolar.org/
https://www.georgiapower.com/about-energy/energy-sources/solar/home.cshtml
Don't think about just powering your air conditioner with solar. Think about gathering free solar energy, converting it to electricity, using what you can use and selling the excess for a profit.
A 400-watt system is not going to make a big difference. Your air conditioner probably consumes 4000 watts. But even a small system will save you some money; every watt that you generate locally is a watt that you don't need to buy from the power company.
You will need (among other things) a "grid-tie inverter" and professional installation. This is not a do-it-yourself job.
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Reducing how much cooling you house requires will also help, might not require much investment and can be a D-I-Y job. Shading the windows, ventilating the attic and installing radiant barriers can significantly reduce your energy consumption.
https://www.gasolar.org/
https://www.georgiapower.com/about-energy/energy-sources/solar/home.cshtml
Don't think about just powering your air conditioner with solar. Think about gathering free solar energy, converting it to electricity, using what you can use and selling the excess for a profit.
A 400-watt system is not going to make a big difference. Your air conditioner probably consumes 4000 watts. But even a small system will save you some money; every watt that you generate locally is a watt that you don't need to buy from the power company.
You will need (among other things) a "grid-tie inverter" and professional installation. This is not a do-it-yourself job.
- - -
Reducing how much cooling you house requires will also help, might not require much investment and can be a D-I-Y job. Shading the windows, ventilating the attic and installing radiant barriers can significantly reduce your energy consumption.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
The truth of that statement is going to vary widely across the US, depending on utility rates. I bet in much of California it is not true.
Cheers, Wayne
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
This sweeping generalization is highly dependent on local conditions, including tariffs and taxes. It is already false in many locations and will become more so in the future. The price of solar energy is falling; the price of utility-supplied energy is rising and once the solar hardware is installed, you don't get a monthly bill for solar energy.
K8MHZ
Senior Member
- Occupation
- Electrician
Correct, but it is a misconception that once solar is installed, it's free forever.
The panels have to be kept clean for maximum output. That means the owner has to keep them clean, or pay someone to do it. On occasion, a panel or some part of the system may get damaged and have to be replaced. The electronic parts, like the inverters, don't last forever and at some point will fail and have to be replaced.
If the panels are mounted on a roof, that presents multiple spots for leaks. Roofing doesn't last forever, and at some point will need to be replaced. The panels will have to come down for that, and that won't be cheap.
For the average Joe, what happens when a 25 year old solar system just stops working. Who will he call, and how much will it cost to get it fixed? That one call will probably wipe out 25 years of ROI.
If batteries are added to the mix, that raised the cost even higher.
I love solar technology, and think that it is going to be more and more relied upon, but it's not the golden egg just quite yet.
On average, the ROI of a solar system where I live is 50 years. How much of that system will have lived that long? 50 years is just the break even point, now the trick is to keep a 50 year old system running with no costs to get any real payback.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
170611-1418 EDT
Don't forget about personal property tax. In my town a solar installation adds to the value of a home (not really, but the city thinks so). Thus, assessed valuation goes up, and your taxes go up. This is an ongoing cost that is about equal to what you would pay the utility for the energy. Thus, a net loss because you had to buy and have to maintain the equipment.
If solar or wind is to be encouraged, then a state law needs to be passed to exempt these installations from taxation.
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Don't forget about personal property tax. In my town a solar installation adds to the value of a home (not really, but the city thinks so). Thus, assessed valuation goes up, and your taxes go up. This is an ongoing cost that is about equal to what you would pay the utility for the energy. Thus, a net loss because you had to buy and have to maintain the equipment.
If solar or wind is to be encouraged, then a state law needs to be passed to exempt these installations from taxation.
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ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
You don't get solar to power anything in particular; you get it to offset your overall utility bill. A 400W PV system won't do much to help you, especially if it's one of those silly, NEC non-compliant, possibly illegal "systems" that plug into an electrical outlet. Those things don't work and could possibly start a fire. Most residential PV systems are at least ten times that size, anyway.
Deal only with reputable solar contractors.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Not a true statement.
- Occupation
- Licensed Electrician
I stand by it.
growler
Senior Member
- Location
- Atlanta,GA
Think of it like this. If his power bill is high because of an old inefficient system or leaking duct work then going solar is not going to solve the problem. His AC system will still have to be replaced sooner or later ( normally that's sooner).
To get the most bang for your buck you need to know where you stand right now.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The statement I am willing to stand by is this:
In most areas of the country you can generate kW of solar PV and convert it to kW of grid-equivalent AC for less than the highest tier rate for power from POCO. As long as you have a grid tie inverter with net metering you can take advantage of this to meet most or all of your net energy need from PV at less than the cost of grid power alone. This currently depends strongly on having net metering available and less strongly on having a high POCO rate and tax and utility rebates on the installed price of the system.
If, on the other hand, you are trying to use PV instead of a grid connection and rely on battery storage to deliver the power when you need it and at the rate you need it instead of being tied to solar production hours you cannot do that in the US for less than $.50/kWh, and that makes it a bad deal except maybe in Hawaii.
One other consideration for Hawaii is that they are restricting new grid interactive installations because of their destabilizing effect on the power network. If you are committed to go solar there you may have to look at a storage system even if it is not currently economically viable.
GerryB
Senior Member
- Location
- woodbridge, ct. USA
I don't know about MI., but our POCO,s here will not let you make more than you use. They are not buying anything back, if that is what you meant by "making a profit".
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Well, Renewable Energy World says that the average cost of PV in the US in 2017 is about $3/Watt. A 10kW system will cost you about $30k, but the ITC will pay for 30% of that, so if there are no other incentives available your out of pocket would be $21k. In my area, PVWatts calculates the production to be about 15,100kW/year from a well placed 10kW PV system. Over the 20 year expected life of a system that's 302,000kWh. Electricity is cheap around here at about $0.11 per kWh, but even at that rate, that's $33,200, or over $12,000 to the good, and that's assuming that the price of electricity won't go up during that time.
And there are places where electrical power is much more expensive than it is here.
K8MHZ
Senior Member
- Occupation
- Electrician
I know Consumers Energy in Michigan won't. Solar systems that are to be grid tied need to be sized small enough so that the net metering over a year won't cause a deficit.
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
'Tis true; Michigan's not the optimum climate for solar electricity, either meteorologically or politically. But the original question was about Georgia.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
It's a little different in most places where this is true; it's not that they restrict the size of your PV system or forbid you to export energy, it's just that they won't pay you for any production that exceeds your consumption.
K8MHZ
Senior Member
- Occupation
- Electrician
Here they do restrict the size. In order to get a permit to build a grid tie system, plans have to be submitted with load calcs that show the solar energy won't exceed the grid energy. IIRC, the solar must only provide 80% as averaged over a year. Part of the permit also states that if the system does produce more than the premises uses, the utility has the right to disconnect the solar system from the grid. If you don't allow them to do that, they have the right to pull your meter.
In the class I took we spent several hours going over the paperwork needed to get the POCO to allow a grid tied system. Lot's of paperwork.
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