Has anyone got/ using solar panels on their house. Are they effective?

Question

I'm interested in getting some alternative energy source but am worried about how effective solar panels are.

Answer 1

I have solar panels on my roof for heating hot water.

When we were looking into it, we decided not to go for a PV (electricity) system, because they were much more expensive £10K+ and since they only last around 10 years, we’d never have saved anywhere near what we paid for them.

The hot water system only cost around £3K, so we’ll get much closer to saving money long term than the PV system. (Though probably never quite break even).

As to how effective they are; well, let me explain how it works first…

Our hot water tank is large – 210 litre – which, so I’m told, is about twice the size of a normal hot water tank.

The hot water is on a pressurised system, so it works on mains pressure (good for the shower!). This means that the water exits the tank through a pipe coming out of the very top of the tank and cold water enters at the bottom.

The tank is also a twin coil. One coil is about halfway down and heats only the top half of the tank – this coils is hooked up to the gas boiler. The other coil is at the bottom of the tank and heats the whole tank - this coil is hooked up to the solar panels.

Finally, there are two separate thermostats; one near the top, hooked up to the gas boiler, the other near the bottom hooked up to the solar system.

So, when the gas is heating the water, it only heats the top half and turns off when the thermostat reads 65°C.

OK, when the sun shines on the solar panels, it heats the glycol in the lower coil and this heats the water at the bottom of the tank. Warmer water rises above cooler water, of course, so this warm water rises up the tank. The more that this happens, the warmer the water in the top half of the tank gets, and so the less work the gas boiler has to do (when/if it turns on) to get the water to 65°C.

So, how effective is it? Well, here in London, in the winter it’s pretty rubbish. We’re lucky if we get 10°C of warming, even if it’s sunny all day. This is because, the days are short, and the sun is low down.

During the recent sunny March weather though, we’ve been getting 51°C (and remember, that’s the reading of the thermostat at the bottom of the tank – at the top it’ll be warmer.) So, the gas boiler only has to heat (at most) the last 14°C to get to the required 65°C.

During the summer though, it’s great. It regularly hits the 85°C cut off, and remember that’s 210L of 85°C hot water in a well insulated tank, so it lasts days.

In practice, we ended up turning off the automatic daily water heating with the gas boiler, and we only turn on the hot water for 10 minutes or so when we need to. In the winter that’s quite regularly, but in the summer that’s almost never. For example, during March, that 51°C is warm enough, so we tend to leave the gas heater off. We’ve also got into the habit of having our showers in the afternoon or evening, rather than the morning – so that we can take advantage of any hot water we might get from the sun during the day.

One point to make is that 85°C water is *HOT*! (You could probably make tea with it!) We have it set that high because you get the most out of it that way, *but*, until 2 days ago, we didn’t have any kids. You might not want to set it that high if you did have young children in the house who might scold themselves – and if you set it lower, it won’t be as good in summer months because you’ll be wasting heating potential.

Was it worth the £3000? I think so. Like most men I love a good gadget. I still get excited watching the temperatures on the display heat up on sunny days! Then again, that might just be because I’m very sad. LOL

Answer 2

Depends upon what you are after to be honest. If you are wishing to generate your own electricity, the best way (or so Im led to believe) is to use a turbine. You can use the power you create yourself, and when you have a surplus, sell it back to the national grid at about half what you would pay to recieve, incidentally. The bloke sat across the desk from me has been quoted installed and supplied 6KW turbine (big enough for a big old house) for 18 grand, and the company who quoted said he should start seing a return in about eight years. He does live in the west coast of scotland and has quite a bit of land out back too, so it wouldnr be suitable for a 3 bed semi in basingstoke...

If you want to use solar power to heat water, than photovoltaics is a better way. The idea is to use sunlight to pre warm the hot water system, often by pumping a water up onto your roof to be warmed up by the sun, and then stored in a holding tank ready for use. Many of these systems can be home built too, so they needn't cost much either, but there are many companies around who will supply and install the system for you.

Powerful and efficient solar pannels are hideously expensive, as each bank needs to be grown in labs, so untill the technology gets better, solar cells will be too expensive and photovoltaics will the main use of solar energy in the alternative market.

Hope that helps.

Answer 3

turn off your hot water heater and primarily go solar. price to output, solar cells suck. think tesla tubine and some form of making steam. TT is simple and super low maintenance. oh and scooter motor might would be the generator. 350 watts. running 8 hours about 2600 watts. certainly will have to reduce elect use in house, in all ways possible. It can be done. my elec bills average 50 bucks, i have potential to get away with it. your time gets moved around in the process though. like cooking outdoors, hanging clothes, batch heating water. your cooking fuel has to be free and hopefully easy. (i know this one) buying propane and charcoal is just moving fuel costs around.

Answer 4

It depends on the place your house is situated. The more sun you receive through the year, the most efficiency from solar panels.

Answer 5

they give you hot water and cut co2 emissions and apart from the initial expense pays off after a few years and the sun will shine as long as you live.....i dont have them as yet but in europe generally they have had them many years now
........FOXY

Answer 6

Not very efficient . It takes a very large area and they are susceptible to weather and wind.