PV Gap

Grace Said:

About how much will getting your household to run fully on solar panels reduce your carbon footprint?

We Answered:

A great bang for the buck to reduce your home's carbon footprint is solar water heating. This uses the heat from the sun to heat your water, instead of electricity,oil, or gas. Water heating is as much as 30% of a home's energy usage. For about $8000 - 12000 installed, you can have the sun heat up to 75% of your water.

As for solar electricity, the debate about the embedded energy, or how many years it takes to balance how much carbon it takes to make and transport has long been proven to be just a few years. Since solar panels have a life expectancy of about 50 years, they more than pay for themselves, both financially and carbon-wise.

Before trying to power your house entirely with solar, it is much more cost effective to work on energy conservation first. For every $1 you spend conserving energy, that's $4 less you have to spend on solar. So after reducing your usage, you may be able to run the rest of your needs with about $50k of solar installed. This would be grid-tied, so you make extra power during the day to sell to the electric company, and buy it back at night when the sun is down.

Remember we are talking generalities, this varies greatly depending on where you live and how much power you use. I can do it for half that price at my house, I know many people for whom that would only do a fraction.

There are tax credits and rebates available to pay for 30% to 50% or more of the solar systems and energy efficiency, making it more affordable. Check them out at http://dsireusa.org/

Cathy Said:

Is it possible to connect solar panels to a household outlet?

We Answered:

You need an inverter. This requires professional installation. They do make self contained solar panels for RV use, that can run things like radios, small TV's, or charge batteries.

Rachel Said:

Does anyone know who one should contact to recieve the £900 (tax-free) grant for households with solar panels?

We Answered:

It isn't due to happen until April so you will probably need to wait till then to find out how to claim it.

Anne Said:

what materials would you use and how would you construct solar panels enough to run a household?

We Answered:

Silica based solar cells are not the kind of thing you whomp up in you basement.
Here are a couple ideas for solar systems you can build and install yourself.

Take a 4 x 8 sheet of 1/2 inch plywood. Frame sides with 2 x 4's. Screw tin cans in a staggered row (checker board) pattern inside frame. The more cans the more heat you get so place them nearly touching. Paint cans and entire assembly flat black. Cover top with glass, plexiglass (best) or heavy mill clear plastic (cheapest)Place on roof. Drill 3-4 inch holes in opposing sides. Run pipe or tubing into house. Attach to small low speed fan.
The black paint will absorb sunlight and heat. The air moving through box will carry heat into house. It's a cheap efficient way to help heat your home. You can vary size and shape of box to fit your roof. If you use more than one box, hook them up in series. More boxes mean more surface area means more heat.

To heat water. Take a steel tank. A car gas tank works well. It is galvanized so it won't rust, is cheap, and easily available at any auto salvage yard. But you will have to flush in throughly to remove gasoline odor. A steel 55 gallon drum is easier to work with but may cost more. Paint exterior of tank flat black. Weld/glue/clamp water pipes to tank. Place on ground in area that gets lots of sunlight. Attach water supply to tank and route discharge pipe to house or appliance. Black painted steel absorbs heat from sun light and heats water. In spring and fall you get warm to hot water. In summer you get scalding hot water and in winter you get cold to luke warm water.

Both of these solar powered systems are seasonal and their output varies according to location and climate, but they are very inexpensive and easy to build and provide FREE heat and/or hot water for many years with little or no maintainence.

Isaac Said:

How much would it cost to buy solar panels for my whole household electricity?

We Answered:

This is a common question, and not such an easy one to answer, as it depends on

1) Where you live (sunny locations, low latitude is better)

2) How much electricity you use (some houses use 10x what others do)

3) State, Federal rebates (federal is 30%, state varies)

And how long it takes to pay back, if ever, depends on the price of grid electricity in your area. Obviously, if you live in a place where electricity is 50 cents a kWh, the system will pay back quickly, vs. a place where electricity is 5 cents/kWh.

The system on our house cost $12,000 net (including tax, shipping, permits, rebates), and supplies basically 100% of our electric usage.

Josephine Said:

How many solar panels do i need to have enough energy for a household per day ?

We Answered:

last night I saw a solar panel for sale. It was $229. It produced 45 watts. To run an electric dryer, or hot water heater, it would require 100 for each. To run both at the same time, you are talking 200. My calculator says $229*200=$45800 as an initial investment. If you figure about $200 in electricity costs per month, you can have it paid off in $45800/12/200=19.1 years that it will be paid off, if you don't have a wind or hail storm. That does not cover inverter or batteries.