Thinking about going to a grid tie solar panel sytem for a new home...how many watts would we need?

A really nice article by someone who has "been there, done that" can be found here: http://www.hollowtop.com/cls_html/solar_power.htm

The number of watts you need will depend on your expectations as well as the actual load drawn by appliances and lighting in hour home. The number of solar panels you will need depends on location and whether you choose a fixed-angle installation (optimized for only one day of the year!) or a sun-tracking installation (expensive!). Consult with experts in solar panel sales and installation before plunking down any cash.

In general, the only way that solar panels are economically justifiable today is if you purchase with OPM... other people's money. Most states and the national government offer "incentives" in the form of rebates, tax credits, or outright cash if you install solar electric panels. In the article cited, these rebates virtually payed for the entire cost of the solar panels... $4.66 per watt paid minus $4.50 per watt in rebates.

For the size home you are considering, my "gut" feeling is you need at least 2000 watts capacity, and twice that amount would allow you to sell power back to the grid most of the time that the sun shines... all at taxpayer expense. What a deal!

There are too many variables to give you an answer. A better question might be, "If you have an all electric home, what is your annual kWh electric usage, roughly how many square feet is the house, and where do you live?"

This will give you a rough estimate of how much you might use. The orientation of your house, the slope of the roof, and your ideal of acceptable temperatures will have effects on the size of your system.

If you leave space for maintenance (primarily roof leak prevention) there might not be enough room on the roof.

Take a look at http://www.angelfire.com/ca2/roderick/solar/photov... for some detailed info

My six kW system averages about 20 kWh per day in northern California

Average electricity usage in the US is about 1kW per house.

Area is not a factor, except in calculating heating or AC usage.

But peak loads can be a lot higher, and are dependent on climate and time of year, and on your individual preferences. For example, in the deep south (US) you will need AC, which can use a lot of power.

energy you get from a solar array depend on amount of sun you get which depends on climate and on your location.

So there are a lot of unknowns you have to work with. As a start, look at your present consumption, by looking at your power bills, year round.

Count on probably a solar array three times your average usage, so you have some left to sell to the power company for times when the sun doesn't shine.

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that sounds like a big house. i believe the average consumption of power in US is 9,300 kWh a year.

you'll obviously need more, if you build a house from ground up, that is designed to save electricity and powered by photovoltaic cells, then that may be possible. but if you try to power an existing house on solar cell, that might not be an economical alternative.

generally, 1,400 W is a typical output of solar cell powered house.(not really sure bout the figures there, they're estimates)

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