Solar Panels - Advice Please?

Lpfsox

Hi folks

I want to have solar panels fitted to my house for hot water (I understand that for space heating they're not really suitable yet) and haven't a notion where to start.

The house was built in 2005/6 and I bought it as a new build in 2008. According to the builder it's got a B2 BER rating although I don't have anything other than his word on that.

There's only me and the odd visitor in the house although it's a 4 bed semi so I'd like to install a system which wouldn't necessarily deter any potential future buyer should I ever sell up, so would probably need to size it for 3/4 people.

What are my next steps? Is there a list of recommended installers or should I rely on word of mouth? Is there a ready reckoner of some sort so I could estimate costs? I'd like to refurb the main bathroom at the same time to remove the bath, retile and install a pumped shower system fed off the mains (not sure if I've explained that terribly well, but basically a non-electric shower using hot water from the tank but with a pump for decent pressure). Whether I do this in conjunction with switching to solar for DHW or at a slightly later stage will depend on costs & budget.

Would appreciate any advice folks please, and thanks in advance.

homer911

The SEI site has a list of registered installers, but the qualification if pretty easy to come by and its no guarantee of quality. Word of mouth is a better bet.

Lpfsox

Thanks Homer. Will try to do some sums to figure out a budget and then ask for recommendations for installers in the area.

MicktheMan

Lpfsox wrote: »

Hi folks

I want to have solar panels fitted to my house for hot water (I understand that for space heating they're not really suitable yet) and haven't a notion where to start.

There's only me and the odd visitor in the house although it's a 4 bed semi so I'd like to install a system which wouldn't necessarily deter any potential future buyer should I ever sell up, so would probably need to size it for 3/4 people.

Would appreciate any advice folks please, and thanks in advance.

Just curious and dont want to derail the thread but have you worked out how much you currently spend per annum heating your water?

Lpfsox

Mick

I haven't moved fully into the house yet (long story) so I don't have that sort of data. My primary motivation was really the whole use of green energy - I obviously have some flavour of hippy genes floating around me somewhere - a bonus would be a saving on the heating bill. As I say it's really just me anyway, I have an electric shower in the en-suite which I use so I use the heating system to heat water only for things like washing the floor etc and for the occasional bath which I'm planning to remove anyway in favour of another shower room.

There's no rush anyway so I can leave it for a while if costs are prohibitive.

MicktheMan

Lpfsox wrote: »

Mick

I haven't moved fully into the house yet (long story) so I don't have that sort of data. My primary motivation was really the whole use of green energy - I obviously have some flavour of hippy genes floating around me somewhere - a bonus would be a saving on the heating bill. As I say it's really just me anyway, I have an electric shower in the en-suite which I use so I use the heating system to heat water only for things like washing the floor etc and for the occasional bath which I'm planning to remove anyway in favour of another shower room.

There's no rush anyway so I can leave it for a while if costs are prohibitive.

Fair enough.
In my experience, the majority of households use approx 90% of oil/gas on space heating and 10% on heating hot water. So if you could save 10% on your space heating requirements by taking simple inexpensive steps such as upgrading airtightness and insulation then this, imo, is "greener" than saving 50% of your hot water requirement by installing solar.

Of course, solar panels on the roof make a statement of your greenishness but by improving the house fabric to reduce heatloss may be the greenest action you can take.:)

quentingargan

MicktheMan wrote: »

In my experience, the majority of households use approx 90% of oil/gas on space heating and 10% on heating hot water.

That ratio has changed dramatically over the years because houses are better insulated, and we now wash and shower more often than we used to.

It used to be considered that 3MwHrs were used on domestic hot water, but recent estimates suggest the average is now 5MwHrs. At the same time, space heating requirements have fallen dramatically.

Solar water heating also supplies hot water at a time when its supply from oil or gas boiler is far less efficient.

MicktheMan

quentingargan wrote: »

That ratio has changed dramatically over the years because houses are better insulated, and we now wash and shower more often than we used to.

It used to be considered that 3MwHrs were used on domestic hot water, but recent estimates suggest the average is now 5MwHrs. At the same time, space heating requirements have fallen dramatically.

Quentin,
my point still stands (I think:)). If you take your 5MwHrs figure for dhw, this equates to less than 250L heating oil saved (assuming solar produces 50% dhw). This gives a payback of appox 25 yrs at todays oil price on a 5000 euro investment. What is the average expected lifespan of a solar system?
Now if this 5000 was invested upgrading the thermal fabric of the average house (D1 on ber scale) resulting in a 10% reduction in the space heating requirement then this, imo, is better for both the householder and the environment over the lifetime of the investment.

quentingargan wrote: »

Solar water heating also supplies hot water at a time when its supply from oil or gas boiler is far less efficient.

On a well designed dhw heating system using oil or gas the time of year shouldn't affect the efficiency.

jaymela

I was thinking of getting of solar panel for my home to get rid of the electricity bills and all and i am not aware of the procedure and best quality materials required for it.Do i assemble it or these are available in the market easily?

<SNIP>


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quentingargan

MicktheMan wrote: »

Quentin,
my point still stands (I think:)). If you take your 5MwHrs figure for dhw, this equates to less than 250L heating oil saved (assuming solar produces 50% dhw). This gives a payback of appox 25 yrs at todays oil price on a 5000 euro investment. What is the average expected lifespan of a solar system?
....

On a well designed dhw heating system using oil or gas the time of year shouldn't affect the efficiency.

Hi Mick, Many households use an immersion during the summer, and 2500KwHrs woudl cost them about €400. Many systems are being installed for about €3,500 to €4,000 after the grant. That is 9 to 10 years payback, even assuming that energy prices don't change over that time.

Yes - a well designed system will have better efficiency heating water, but it will always be more efficient if it is heating the immersion on its way to the radiators. There are losses in heating boiler, flue, pipework etc., and these losses might be better or worse depending on the situation.

I agree with you that the low-hanging fruit of insulation should come first. I've seen solar panels going into houses that had NO loft insulation. Mad... That IS eco-bling at its worst. But a family in a well insulated house with the heating off for 8 months of the year can expect a reasonable return on investment from a well designed solar water heating system, and flatplates have a lifespan of over 40 years.

BryanF

jaymela wrote: »

I was thinking of getting of solar panel for my home to get rid of the electricity bills and all and i am not aware of the procedure and best quality materials required for it.Do i assemble it or these are available in the market easily?

not that simple, give a bit more detail about your home first

1. how old
2. insulation in walls, floor, attic
3. type and age of windows
4. drafts?
5. vents?
6. heating type
7. fuel consumption / cost of heating/hot water : total fuel bill per year
8. floor area

Basically you want an energy assessor/arch to advise you on where best to spend your money or at least in what order.

to simply answer your question 'solar' means solar PV & solar thermal. solar thermal will reduce your water heating by circa 30-50% depending on the households flexibility. in an existing home forget about solar thermal for space heating...
solar pv can generate elec, but at the moment it is cost prohibitive.

rectory1

hi sorry just joined boards. i got a domestic hot water heat pump fitted instead of solar and its working fab , have a look around before u do anything. i found it advertised on a well know website if u want to know more send me a message:)

BryanF

rectory1 wrote: »

hi sorry just joined boards. i got a domestic hot water heat pump fitted instead of solar and its working fab , have a look around before u do anything. i found it advertised on a well know website if u want to know more send me a message:)

May I ask how much electricity it is using, in say January ?

rectory1

the running costs are stated to be around 150-160 euro for the year i have noticed a huge decline in my esb as i used to be using the immersion the whole time

BryanF

rectory1 wrote: »

the running costs are stated to be around 150-160 euro for the year i have noticed a huge decline in my esb as i used to be using the immersion the whole time

that's interesting.. using an immersion up until now.. and now trusting the statements made by a website.. and willing to offer a recommendation from this company...

may i ask how long the guarantee is for? and what maintenance you need to do? and what the expected life of the unit is? oh, and did you get any data, IAB/ BBA certs or case studies from the manufacturer?

would you be willing to purchase an energy monitor (they cost about 50€) and come back to us this time next year and let us know roughly what the spend on the Heat pump is, thanks:)

thaddeus

MicktheMan wrote: »

Fair enough.
In my experience, the majority of households use approx 90% of oil/gas on space heating and 10% on heating hot water. So if you could save 10% on your space heating requirements by taking simple inexpensive steps such as upgrading airtightness and insulation then this, imo, is "greener" than saving 50% of your hot water requirement by installing solar.

Of course, solar panels on the roof make a statement of your greenishness but by improving the house fabric to reduce heatloss may be the greenest action you can take.:)

24% of an average household's energy is dedicated to water heating and 60 % is dedicated to space heating From this SEAI publication: http://www.seai.ie/Publications/Your_Home_Publications/Householders_be_your_own_energy_manager_guide.pdf

As houses become better insulated with improved building regs the proportion of energy dedicated to water heating will increase.

MicktheMan

thaddeus wrote: »

24% of an average household's energy is dedicated to water heating and 60 % is dedicated to space heating From this SEAI publication: http://www.seai.ie/Publications/Your_Home_Publications/Householders_be_your_own_energy_manager_guide.pdf

Lets tease this out
I don't know where or how SEAI gather their data so lets look at this more closely:
According to SEAI the average BER rating of an existing house is a D1 or 237.5 kWhr/m2/yr. This figure represents the primary energy for space heating, dhw and lighting. It does not include cooking or tv/pc/playstation/lamps etc.
So going on your seai ref above this amounts to 90% of energy use in the home and therefore the normalised rating is 237.5/90*100 = 264 kWhr/m2/yr. Lets assume the average house is 140m2 then according to your seai ref the average house uses 264*140*.24 = 8870 kWhr or approx 878 liters of oil for dhw. This same house then uses 264*140*.6 = 22176 kWhr for space heating (approx 2196 liters of oil). Or to put it another way, between dhw and space heating an average house burns nearly 3100 liters of oil per year!

If this is indeed the case, then, imo, any money to be invested should be in the direction of the building fabric/heating system/controls (space and dhw) and not into solar.

thaddeus wrote: »

As houses become better insulated with improved building regs the proportion of energy dedicated to water heating will increase.

I agree in principle but in practice the energy performance of many houses fall way short of what it ought to be on paper.

thaddeus

MicktheMan wrote: »

Lets tease this out
I don't know where or how SEAI gather their data so lets look at this more closely:
According to SEAI the average BER rating of an existing house is a D1 or 237.5 kWhr/m2/yr. This figure represents the primary energy for space heating, dhw and lighting. It does not include cooking or tv/pc/playstation/lamps etc.

The SEAI figures are very similar to the Energy Saving Trust figures in the UK - can't find the reference now but I always used 25% as the figure from their data till I found the SEAI reference which seemed to back it up. Anyhow your calculations are just expressing this percentage in a different way - What I was trying to do here was show that your assumption that water heating at home comprises 10% of total energy use was incorrect it's actually on average 24% or so.

If this is indeed the case, then, imo, any money to be invested should be in the direction of the building fabric/heating system/controls (space and dhw) and not into solar.

I don't think anyone will disagree with you that the first thing to do is approach space heating when considering energy efficiency at home but the fact still remains that a significant proportion of household energy is dedicated to water heating.

As time progresses and the space heating efficiency of the building stock increases this proportion of energy dedicated to water heating will also increase as will the price of oil/gas. If you accept we are near or in peak production of fossil fuels then it's not much use to your pocket cutting your heating requirement by 50% and then the cost of fuel doubling.. Sooner or later this will need to be addressed solar is part of the solution as an easy and cost effective way of heating water in the long term.

Whilst space heating should be prioritised, it's not a matter of which to do - improve space heating or water heating? It's a matter of how do we afford to do both..

paddyandy

Confusion is stock in Trade and they will supply you with endless amounts of it.