Solar Power at Home

[Mayniac]

I'm also looking into solar energy for when I build the extension to my house. (The roof currently faces north).

I don't think that water heating will be the most economical option for me, as I live alone. With a small demand for hot water, the payback time will be a lot longer, and as I often work away from home it may well go to waste.

So I'm considering photovoltaics with an inverter connected to the grid. This will be making me money whether I'm at home or away. There is one case history here, and I've seen others.

Just another option to throw into the mix!

 

[marinyork]

Yes, I'd agree Mayniac. In terms of saving money and being better for resources and the environment I would agree.

 

[dellzeqq]

PV doesn't pay back as quickly as solar thermal. BC - without prying, are you in a suburb, out in the sticks, on a hill, in a valley....?

 

[marinyork]

That is generally true but some of the systems I know people who've had quotes seem overpriced.

 

[dellzeqq]

my brother has solar thermal which raises the temperature of the water sufficient for a very comfortable shower. It's impressive, and helps through energy price spikes. The bugger is that there are some technologies that really make sense if you get together with the neighbours - windpower comes in to its own at six houses, and geothermal makes sense at 300 sq.m.

In a general way though, you'll make a more meaningful commitment to sustainable energy by insulating the house to the nth degree and buying juice from a sustainable source. That doesn't give you the personal security of supply that we're all going to be rather wanting after 2015 when the grid may be giving us 'brown-outs'. And, BC, sorry for making the point, but the greatest contribution we can all make to sustainability is to...........drive and fly less. In smaller cars that we keep for 20 years.

 

[Yellow Fang]

I'm also looking into solar energy for when I build the extension to my house. (The roof currently faces north).

I don't think that water heating will be the most economical option for me, as I live alone. With a small demand for hot water, the payback time will be a lot longer, and as I often work away from home it may well go to waste.

So I'm considering photovoltaics with an inverter connected to the grid. This will be making me money whether I'm at home or away. There is one case history here, and I've seen others.

Just another option to throw into the mix!

There are instantaneous water heaters available. They are electric, but you only heat up the water as you use it. For low hot water demand it's probably more economic than anything else. They're mostly for wash basins, but if you want to have a bath then you can switch on your boiler half an hour before and switch it off the rest of the time. I was thinking of going this route because they appear to be a lot cheaper than solar hot water.

http://www.twenga.co.uk/dir-Garden-DIY,Home-heating,Instant-water-heater
http://www.ariston.co.uk/products-overview.php?t=3&id=0000000004


You could also have a look at wood pellet boilers. You would need storage space for the pellets though and a reliable source.

 

[Yellow Fang]

If you're building an extension, then a conservatory, as long as it is not heated, is a good way of pre-heating air. You can dry your wet clothes there too, avoiding condensation and mould in your house. Don't let me put you off, but photovoltaics are still quite an expensive way of generating electricity.

 

[marinyork]

Pellet can cost a lot more though. Depends on use.

 

[Danny]

About 20 years ago I lived in a house that had had solar panels fitted by the previous owners. During the summer they produced most of the hot water we needed, and even in winter they raised the temperature of the water enough to cut down on our gas bills.

Provided your roof is south or south west facing it is definitely worth investing in solar panels - provided your happy with a relatively long "pay back" period.

Unfortunately my house faces the wrong direction, otherwise I would happily have solar panels again.

 

[marinyork]

my brother has solar thermal which raises the temperature of the water sufficient for a very comfortable shower. It's impressive, and helps through energy price spikes. The bugger is that there are some technologies that really make sense if you get together with the neighbours - windpower comes in to its own at six houses, and geothermal makes sense at 300 sq.m.

In a general way though, you'll make a more meaningful commitment to sustainable energy by insulating the house to the nth degree and buying juice from a sustainable source. That doesn't give you the personal security of supply that we're all going to be rather wanting after 2015 when the grid may be giving us 'brown-outs'. And, BC, sorry for making the point, but the greatest contribution we can all make to sustainability is to...........drive and fly less. In smaller cars that we keep for 20 years.

The biggest contribution to sustainability would be to rip out the central heating and not have any. It's not like much of the able bodied adult population actually needs it at all.

 

[Globalti]

SOLAR HEATING IS THE NEW DOUBLE GLAZING! Beware! There are some scummy salesmen out there ripping people off. A decent 2m panel can cost as little as £1500. Have a look at these excellent systems: http://www.viridiansolar.co.uk/

I have already installed a (new) second hand 160 litre tank in the attic, in tandem with the existing tank. This summer I shall be fitting a Vridian panel to heat the new tank so that the water entering the existing tank is pre-heated. It's incredibly cheap and simple and won't cost £5000!

I recently saw an installation on a 2 bed semi-detached bungalow - the salesman had sold this old couple a five tube panel. Were they pleased? "Oh yes", they replied, "we get our water at 92 degrees C... my wife even burned her foot on the tap last week!" WTF? That's dangerously hot and complete overkill for an elderly couple. They paid £5300 for the system!

 

[Yellow Fang]

The boss at my last workplace told me his parents had had solar thermal water heating installed. They lived in a small market town, presumably off the gas network, and were getting concerned with the cost of heating oil. IIRC the installers charged them £9000 and then informed them they still needed to use electric if they wanted hot water in the morning. My boss said, 'Dad, you're 68. You'll never make your money back'. So yes, you have to be careful of sharks.

 

[Night Train]

There are still a lot of dodgy companies out there over selling the heat output and inflating the price.

Solar thermal can produce incredibly high temperatures if the flow rate is too low through the panel. They can certainly produce 200deg in the panel if pressurised and unable to flow so they are really dangerous for amateur tinkering.

Solar thermal is better then solar PV as it works in dull and cloudy conditions whereas PV only works with direct sunlight. On a sunny day 1000 watts per sq metre lands on the surface of the panel, on a cloudy summer's day the energy can increase to 1100 watts per sq metre due to the defuse nature of the sunlight.
It can also be effective when placed vertically on an east or west facing wall to collect early or late sun. It is better to face a vertical panel west as the panel will already be warmed by the day before it gets heated.

I did a 2 month MSc module on it in June-July 2007. It was heavily overcast and rained continuously and we still got reasonable temperatures on the solar thermal. The solar PV was a flat line with a tiny blip when the sun came out for a few minutes.

 

[Bad Company]

BC, sorry for making the point, but the greatest contribution we can all make to sustainability is to...........drive and fly less. In smaller cars that we keep for 20 years.

There may well be some truth in that BUT driving and sports cars are something of a passion for me - and Mrs BC.

 

[Bad Company]

PV doesn't pay back as quickly as solar thermal. BC - without prying, are you in a suburb, out in the sticks, on a hill, in a valley....?

In a listed building in a village. I have already spoken witht he listed building people and have agreement in principle to place the tubes on one section of roof - which is out of sight. Luckily that section faces South although it may be shaded by the building next door in the winter months when the sun is low. Trouble is I didn't check in the winter so I really don't know.