Warning... this is a long post, contains solar math that may assist you in getting the correct sized system for your home. For those that want the bottom line: Here it is... Just take your avg kwh off your electric bill and divide by 150.. this is a rule of thumb for sizing a solar install that will come close to a zero power bill.
But, if you want a better understanding, then continue down the page!
First, the homeowner should have a basic understanding of how their current electric bill works.
All electric bills are made up from watts, and we get billed in kilowatt hours.
A kilowatt hour is simply, 1000 watts of accumulated power usage for 1 hour.
A simple example would be a microwave oven.. An average microwave uses about 1,000 watts on high, so a microwave running for one hour would use 1 kilowatt hour of power.
Understanding Kilo Watt Hours
How about a dryer.. An average dryer on high heat (towels setting) can use about 3,000 watts..... so in an hour of running, a dryer could use 3 kwh..
In fact, many people can go around the home and see what is using the most power, and how long does is run. We have a worksheet for just this task!
Got an older pool pump? Old style pool pumps can avg about 2,000 watts, or 2 kwh per hour... But, pool pumps run about 6 hours a day, x 30 days a month. so 2 kwh x 6 hours a day = 12 kwh per day, x 30 days a month= 360 kwh per month.
A single speed pool pump can use a lot of kwh, now you know why.
Other items in the home that are ran a lot consume a lot of power too. Some DVRs and Game Systems actually use power whether on or off, and they are consuming power 24 hours a day, 30 days a month.
Two other items in most homes that have a big impact on the kwh are the AC & Hot Water heater. In other posts, we cover these items in detail, but together they can add up to over 50% of the total KWH consumption.
Ok... now you have got an idea of how we end up with an electric bill, and there may be cost effective ways to make your home more efficient. Why make your home more efficient? Because it pays to do so, if you do it right!
Your entire goal of going solar is to become more efficient. By making the home more efficient, the solar pv project can actually be smaller, and get you closer to a zero bill.
And like we say, becoming more efficient does not mean you have to live in a tent....Just make better decisions on how to reduce your kilowatt consumption...
OK, so now lets look at how solar reduces your electric bill.
Now that you have a basic understanding of how KWHs are formed, you can do the math to see what is your basic usage. If your bill shows say, 1,500 kwh per month, then that is 50 khw per day. ( 1500 kwh divided by 30 days)
So, to get a net zero bill, we would need a system that could average a production of 50 kwh per day.
Here is a worksheet to download that has this detailed math! It really is simple when you look at it this way!
Now to understand the simple basics of solar panels. First, all panels make DC power. Second, everything that plugs into the wall sockets in our home runs off of AC Power. So, the power from Solar Panels has to be inverted from DC to AC power. No problem, that science has been worked out for years!
Next, solar panels need to be installed in the sun. In Fl, we have about 5.5 usable hours of average sunlight a day. Some days more, some less. Some days it rains.. But an average of 5.5 hours a day for the whole years calendar is a good average to calculate.
Back to the math.........
Solar panels are based on watts, but they make DC watts. (remember inverting). So, if we have 4 250 watt panels, that would make a potential 1,000 DC watts. Simple?
Remember, 1,000 watts is a KW, so these same 4 panels in the bright sun for an hour could produce a kilo watt hour of power. On an average day, you will get about 5.5 usable hours, so that means those 4 panels could make ( at max) 5.5 kwh per day, x 30 days a month = 165kwh total MAX production at the panels output.
Solar does not work at night, so an understanding of Net Metering helps.
How Net Metering Works In Fla
Now, here is where some people mess up with the math... The DC output has to be inverted, travel thru wires, the meter, ect... the actual power that your home will get to use is not 165 kwh per month, more likely down to about 150 kwh per month.
Now, we see a lot of brochures that use very, very different numbers from this. But, this math we have shown is the very best you can expect on an annual average for Fl homes.
So, lets pull all of this together... for a bill that used 1,500 kilowatt hours, divided by 150 kwh per kw of power produced, equals a 10kw system to zero out the bill.
Now, we don't have to zero out the bill to be highly effective. In fact, if we can get between 70 to 50% of the bill we are pretty happy. We also should look at conservation in other area of the home to make up the difference.
WOW>>>>>>>>>>> That's a lot to consider... But, i promise you, we go thru this math with every single customer. Installing solar is a big project, so understanding the basics helps to project what a properly installed solar project will achieve.
In fact, if you go over this page a few times, you will have a better understanding of the basics of solar math than many of the people that might show up to show up try to sell solar.
In fact, if you would like to get a free online consultation, then click on the button below... If you fill in the form, we can send you back a custom solar report based on your house. If you like what you see, then you can go a step further and request a link for our screen share presentation, all from the comfort of your home.
This presentation should be about 15 minutes... long enough to answer your questions, and decide if you are ready to move to the next step, which is to have one of our techs come and do an onsite inspection of your home. This will allow us to finalize our bid, and to make sure that the roof, electrical and other components of your home are a good match to install solar.
Bottom line... we promise a respectful presentation, based on common sense facts. We will give you all the options, including several financing options.
In our experience, most homeowners can install their solar project for less than what they are currently spending on the power bill.
Thanks for taking the time to go thru this. We know that an informed customer will make a better decision, and we work hard to show you that 3Guys Solar is the company to entrust your solar project.