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 - Calculate Daily Power Used:
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. But if you
do not have all your power bills, then simply use last month's one.
Then divide your monthly usage by 30 (the average number of days in a month, to get your daily power used.
- So for example: If you have a monthly power consumption of 800 kWh, then your daily amount is 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 auto parts mould 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)
- Continuing from our example: Our solar panel watt needs equal:
13.4 kWh / 5.5hrs x 1.25 = 3.045 kW or 3045 Watts per day.
This means we need solar panels with the capacity to produce at least 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.
- In our example: It will cost us at the most 3045 x 4.85 = $14,768
to install solar panels to halve our power bill. And that's before
wiring, charge controllers, batteries, inverters, and electrician costs.
4 - Offset Tax Credits And Rebates:
Before we jump the gun and think it will cost us at least $14,768
for 3045 Watts of solar panel watt power, we need to take tax
incentives and rebates in account.
With the new renewable energy tax credits going into effect from
January 1, 2009, and state-side rebates from states such as New York,
Connecticut, New Jersey or California, our solar installation costs
will be much lower than expected.
- 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).
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 good news
is, anyone can learn to find cheap solar cells and make their own solar
panel watt power.