With green living becoming more and more vital, many people are starting to install home solar power to supplement their power, and reduce their electric expenses.
But before you install a home solar power system, how many panel will you need in order to say reduce your utilities by half? And how much will you have to invest in the system?
Here is a four step process that you can follow to answer these two vital questions:
1 – What Is Your Daily Power Consumption?:
To work out how much power you use on an average daily basis, this is what you have to do: First go back and look at your past 12 months electricity bills. Then work out the average kilowatt hours (kWh) used per month. The reason we do this is because we use different amounts of power throughout the year. The calculation is month 1 + month 2 + month 3 etc… then divide that by 12. If you do not have all the statements, just use last month’s bill.
Now take your average kwH per month and divide that by 30 to get your average kWh per day.
- Here is an example: Lets say the power used last month was 800 kWh. Your average daily usage would be 800/30 = 26.7 kWh per day.
- So to reduce your electricity bill to half, 26.7/2 = 13.4 kWh of solar power per day is needed.
2 – Calculate The Total Wattage Of Solar Power Needed:
To work this out you are first going to look at an insolation map to see the average usable hours of sunlight your area receives each day. A map is available on our website.
Now take the average daily kWh calculation and divide that by the number of daily usable sunlight hours, then multiply that by 1.25 (to take into account the wasted energy from wiring, charge controllers. batteries, and inverters).
- From the previous example, if you live near California where the average daily usable hours of sunlight is 5.5 hrs, the solar wattage needed is:
13.4 kWh / 5.5hrs x 1.25 = 3.045 kW or 3045 Watts per day.
This indicates that our home solar power system must have the minimum capacity to produce 3045 Watts of power.
3 – Calculate Solar Panel Watt Costs:
This step will help you work out the cost of the solar panels needed to make 3045 Watts of power. At the moment the highest average cost for solar panels in the US is $4.85 per Watt.
- Following on from our example, the solar panels will cost 3045 x 4.85 = $14,768 to only halve our monthly power costs. This excludes the cost of wiring, charge controllers, batteries, inverters, and installation fees.
4 – Take Government Rebates and Credits Into Account:
Before you reckon you are going to have to fork out at least $14,768 for only 3045 Watt of solar panel power, you need to consider the effect of government subsidies and incentives.
2009′s Federal renewable energy tax credits came into effect from the beginning of the year, and coupled with the state-side incentives in places like Connecticut, California, New York and New Jersey, the cost of the solar power system will be much less.
- Let’s use our example: If we were from California we would receive tax rebates of about 20% of the cost, and a federal tax credit of 40% on the remainder. So after rebates and credits, our solar panels would cost us:
$14,768 – $14,768 x (20%) – $14,768 x (1 – 20%) x 40% = $7,089.
A word of warning: The formula outlined here will give a rough estimate of what you can expect to pay for your solar panel watt needs. Obviously the costs will differ with regard to special offers, the state you reside in and the contractor you use to install the system.
Anyway, from what you can see it would cost us around $7,089 to buy enough solar panels to halve our power bill. We, instead, either get our solar cells at cost or source them for free, and wire up our own solar panels, which obviously saved us a lot of money. The excellent news is, anyone can learn to find cheap solar cells and make their own solar panel watt power.
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