Help... Solar energy is so confusuing...

Candles_2

Hi , Everybody. Please please please can somebody ( or everybody ) advise me on the solar debate.

I have read all the posts and they are really informative, but some threads are quite old and none really answer my questions.

Some background info - I am a single 40 year old woman . For the past 15 years I have been saving up to build a small 1 bed bungalow in my Moms garden. I am on very low income, so I want to keep my living costs to a minimum.

I am hoping to install under floor heating & was thinking that a solar thermal pannel or 2 on a south facing roof would help with the heating bills ,as UFH runs at a low temperture, but is constant , day & night.

I love the thought of being green & independant, but unfortunatley I can only afford it if its cost effective.

Any impartial advice would be lovely .

many thanks. x

Cardew

Welcome to the forum.

Solar heating(usually called solar thermal) is only to provide hot water for a hot water tank and not any form of heating.

Nearly all the warm water produced by solar thermal is during the summer months and virtually nothing during the winter.

Even for hot water it is totally non cost effective. You can spend several thousand pounds to save a few tens of pounds a year.

Candles_2

Hi again, thanks for the quick as lightning responce Mr Cardew - I thought that If i bought a thermal store ,which I think is a big tank , then I can use the hot water to heat the water pipes running through the floor..

& I hoped that the panels were good enough nowadays to work on light rather then sun . I realise that the boiler would have to help , but was hoping that the panels would cut my heating by at least 20%...

or am being too hopefull?

noncom_2

Solar Photovoltaic panels (ie the kind that generate electricity) will work quite effectively in light-but-not-sunny conditions (although better obviously in full sunlight). Solar Thermal will work much better in very bright conditions and cloudy days will not be nearly so good.

I would think that in your scenario (hoping to run underfloor heating) some sort of Heat Pump (Ground or Air Source depending on your location, size of garden etc) would be much more effective. The Renewable Heat Incentive (equivalent for heating of the Feed In Tariffs for electricity generation) will start next year, so I'd suggest hanging on until the details of that are known and see which system would fit the bill better.

Cardew

Candles wrote: »

Hi again, thanks for the quick as lightning responce Mr Cardew - I thought that If i bought a thermal store ,which I think is a big tank , then I can use the hot water to heat the water pipes running through the floor..

& I hoped that the panels were good enough nowadays to work on light rather then sun . I realise that the boiler would have to help , but was hoping that the panels would cut my heating by at least 20%...

or am being too hopefull?

You are correct, a thermal store is normally a big tank.

However a solar thermal system costing about £4,000 will produce in the region of 1,000kWh a year. If you have gas in your new bungalow that will save you in the region of £30 to £40 a year, and up to £100 a year if you heat with daytime electricity(the most expensive way of heating)

However nearly all of that 1,000kWh is produced in the summer when you don't need heating. If you take the 4 coldest months of the year Nov/Dec/Jan/Feb you will be lucky to produce 200kWh saving you about £6 to £20.

In money saving terms solar thermal - in any form - is a joke

Scott_McLean

Not sure about your quotes there Cardew. Certainly for c. £5,000 you can get a 3.4kW solar thermal system generating around 2,000 kWh per year and therefore under the RHI (@18p/kWh) earn about £360 a year plus a small saving of about £90 per year on current energy bills. Guaranteed for 20 years, this would pay itself off over twice on the initial investment. Plus it's income tax exempt and inflation linked.

Having said that, I agree with noncom that you would be wise to investigate an ASHP or GSHP assuming you are considering wet underfloor heating. This could work in conjuction with a solar thermal unit for hot water.

Ben84

Candles wrote: »

Hi , Everybody. Please please please can somebody ( or everybody ) advise me on the solar debate.

I have read all the posts and they are really informative, but some threads are quite old and none really answer my questions.

Some background info - I am a single 40 year old woman . For the past 15 years I have been saving up to build a small 1 bed bungalow in my Moms garden. I am on very low income, so I want to keep my living costs to a minimum.

I am hoping to install under floor heating & was thinking that a solar thermal pannel or 2 on a south facing roof would help with the heating bills ,as UFH runs at a low temperture, but is constant , day & night.

I love the thought of being green & independant, but unfortunatley I can only afford it if its cost effective.

Any impartial advice would be lovely .

many thanks. x

If you're building a new house, you have the opportunity to do a lot of positive things that reduce your energy consumption for minimal expense. Highly insulating the house is most affordable when it's first built, and good insulation is I expect better than most other options right now. It generally costs less, has no ongoing maintenance or costs, and it works all year whatever the weather to save energy. Significantly better insulated buildings also need smaller heating appliances, which can save money on the appliance. If your aim is to reduce your heating costs by 20%, then insulation can easily do this.

You don't have to give up entirely on solar either, and it doesn't have to cost more to use if you're building a new house. You could investigate passive solar. Ignoring the complex designs, there are many otherwise standard buildings that use basic design features such as the placement and size of windows, as well as the depth of the roof overhang to enhance solar gain in winter and reduce it in summer, resulting in a house that is more comfortable and costs less to heat/cool. All of these are standard features of a house, you'll be installing them anyway, but as it's a new build you have the chance to put them in the best place for little or no extra cost. The benefits of these small design considerations isn't insignificant either, mathematical models suggest you can collect a lot of energy from the sun through well placed windows, while reducing heat loss greatly by small or few windows in bad places. I've seen figures suggesting 10% or 20% reductions in energy consumption.

Water saving measures can also save a lot of money if you're metered, and energy too if you're saving heated water.

People who don't want to or cannot install solar PV or water panels have plenty of options for saving energy and even using renewable sources in their house.

craftymummy_2

As you want underfloor heating you should consider an air source heat pump. If you use an MCS installer and MCS approved equipment you will qualify for the renewable heat incentive .
Try ..http://heating.mitsubishielectric.co.uk/

If your system is installed by an Ecodan approved installer you also get an extended warranty and guarantee.
If not, ensure entire system design is done by someone who knows what the are doing. If you fit a multi coil cylinder you could also add solar thermal and reap that RHI at any time in the future as well. Make sure cylinder has an immersion with timer to protect against legionellas.

Mankysteve

I would agree with Ben. Massively insulation amounts would be your best bet combined with a heat exchanger, Research passive building.
http://en.wikipedia.org/wiki/Passive_house

IF the building has a south facing side large glass window with a over hanging roof calculated to block out the summer sun but let in the winter sun.

Solar energy is more than fancy panels electrics
http://en.wikipedia.org/wiki/Passive_solar_building_design

Maybe an air to air air source heat pump.
http://en.wikipedia.org/wiki/Heat_pump#Air-source_heat_pumps