With our current economic melt down and energy prices fluctuating daily, many of us are thinking of installing solar panel power to contribute to our homes’ energy needs, and reduce our power bills.
But how much solar panel watt power do we need to say halve our power bills? And how much will that power cost us to install?
Here is a four step process that you can follow to answer these two vital questions:
1 – What Is Your Daily Power Consumption?
To do this, get your last 12 monthly power bills and calculate your average kilowatt hour (kWh) usage per month. The reason we use 12 is because our power consumption fluctuates with the seasons. The calculation would be to add up the power used over the past 12 months and divide it by 12. But if you do not have all your power bills, then simply use last month’s one.
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.
- Now if you want to only halve your power bill then you need to produce 26.7 / 2 = 13.4 kWh of solar panel watt power per day.
2 – Calculate Total Solar Panel Watt Needs
To do this, you first need to determine how many usable hours of sunlight your area receives per day. This is where a solar insolation map comes in handy – you can view one from our original article on our website.
Once you know your daily sunlight hours, go back to your daily kilowatt hours needed and divide it by the daily sunlight hours, then multiply it by a factor of 1.25 (takes into account energy losses from the solar panel watt wiring, battery , and inverter)
- 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
Now you you need to calculate how much these solar panels will cost you. At the moment $4.85 per Watt is the highest average cost in the United States.
- Continuing with the same example, the cost of the solar panels will be 3045 x 4.85 = $14,768. This is only to reduce our power bill by 50%, and it is before the costs of charge controllers, inverters, batteries, and electricians.
4 – Offset Tax Credits And Rebates
Before thinking that your solar power investment is going to be $14,768 to only halve your power bill, you need to subtract any tax rebates and subsidies on offer.
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.
Since there are many factors that go into calculating your solar panel watt costs, please only use our steps as a rough estimate. Some things were impossible for us to take into account, such as special offers by solar installation companies, where they offer you discounts on the full installation (including charge controller, inverter, battery, grid-tie electrician costs, etc).
But, from our example it would cost a Californian about $7089 to invest in solar panels that can reduce his electricity bill by only 50%. We, on the other hand, know how to source cheaper and even free solar cells, and build our own solar panels, which makes the cost MUCH lower. If you are a DIY fanatic then it would save you a lot of money if your bought a solar power guide that show you how build your own solar panels.