but is that per day, per hour or minute?How much watts does the average AC unit use?How much does an energy efficient lightbulb use?All in all let's hypothetically say we no longer use the electric company for our energy source, How many of these panels do you estimate it would take to supply our small home?
Some great answers 23 max watts is per hour I live in an area that has 5.5 average sun hours per the solar insolation data which would give me a base of 676 watts produced per day for one panel. That 23 watts is most likely STC or standard test conditions which is far from standard it is ideal 70 degrees Farenheit with a 000 set flash PTC or physical test conditions are not always on labels and are not always accurate because of varied conditions. Heat has a huge factor on PV production. The panels should be derated by for the following reason ampacity correction or line loss Temperature correction PTC correction Inverter loss these corrections account for about 5 % on standard panels Our 676 watts per day has been dropped to 574 watts per day per panel Lets start with the light bulb. a standard 60 watt bulb uses 60 watts per hour. With the one panel we have chosen it would produce 5 hours and 45 minutes of illumination If we switch to a 5w CFL we get 38 and one half hours of illumination quite a difference yes Central Air will use about 2000 to 2500 watts per hour.This rule is not hard and fast as units will vary as well as conditions Lets use 2000 per hour times 8 hours of use is 6,000 watts we need 28 panels just for the ac. Probably another 28 for the rest of the house Of course these panel must be true south at 5 degrees mounted With a years worth of electric bills and a site visit I could come allot closer but lets say you need 60 of these panels this system would provide 973kHw per month at my location of 5.5 sun hours per day This would be a grid tied system as most state rebates require a grid tied system to qualify for rebates
The watt is a measure of instantaneous output that can also be used as an hourly measure. volt at amp for hour = watt but also a 00watt bulb requires a 00watt power source, regardless of how long it is on, the 00watts is used as an instantaneous term here. Aircon starts at about 000watts and the new energy efficient bulbs are about 7-5 watts. If you have an electric cooker, that might use 3000 watts, your computer about 500 (very variabke these days though, many are now much lower than this) Your biggest concern would be storage, solar only works when the sun shines so you need a bank of batteries to charge during the day and provide power on demand, they require proper managenemt to ensure ther are charged properly and in turn, an inverter will be required to produce the AC power your appliances will need. It all represents a huge investment with a long payback time and you would still probably need to top-up with a generator during winter, or become ahmish.
To calculate an estimate of your power usage, follow the first link below. Although you can have whatever sized system you want (at a cost) those on solar power generally keep their power usage down by cooking on gas, not using an electric kettle, using low energy light bulbs. Powering AC would up your power requirements considerably. We run a medium sized house on 860 watts of panels in southern Spain (plenty of sunshine). That includes the washing machine, pool, and running two laptops and wireless network all day,and a ceiling fan on summer nights. Hower we cook on gas, would not consider AC, and the fridge runs on gas (though if the fridge had to be replaced I would buy electric and add an extra pv panel). For an overview of the equipment required and what it does, check the second link below.
It's virtually impossible to estimate how many panels would be required, without knowing your electrical usage, and where the house is located. I'll give our house as an example, but it could be off by a factor of 0 (not kidding) from yours. We have gas heat, no air conditioning, and no pool. We live in a dry, sunny area of California, and our roof is ideally oriented for panels. We would need 25 such panels, but we are grid-tied. If we wanted to disconnect completely from the electric company, we would need 20% more panels to compensate for battery inefficiencies. So, the estimate is 30 panels. Here are some caveats: ) Air conditioning, especially central air, could double or triple the estimate. 2) An area that gets less sun per year (northern US, for example) would need more panels. 3) Typically, when a house has grid electricity, they keep grid electricity when they get solar panels. It's much cheaper to use both in tandem. 4) That's a horrible price for the panel in the picture. You can find a 200-watt panel for less than that. 5) Other equipment is required besides the panels to run your house off solar. You can read up on it on the internet, or ask a professional solar installer for a free quote.
