Cost Benefit Analysis of Solar Panels

BorderGap · 28-03-2013 2:26pm #1

I'm hoping for a little help. I have a Grant oil burner in place along with a ACV Smartline 210L tank and I'm considering installing a couple of solar tube panels in order to provide hot water.

At present my hot water is zoned and set on a timer to heat using the oil burner for 1 hour per day (30mins morning and 30 mins evening) 365 days per year.

At the current rate, could someone tell me how much oil i'm buring per year and its cost for water heating only?

Thanks,
BorderGap

shane0007 · 28-03-2013 10:30pm

To heat 210 litres from 10C to 60C for one hour per day will take exactly 12.2kwh. With kerosene at a current cost of approx 9.5 cent per kwh and if your boiler is a standard efficiency boiler of say 75% efficiency & a system loss of say 10%, this will give an overall requirement of 18.8kwh. The now cost of that 210 litres is now 18.8 x 9.5 = €1.79 per day. Multiply this by 365 and this will give you €651.89 for the total year. This is, of course, assuming the water temperature has been completely used and is begining from 10C each day. If not, the annual cost would considerably drop to the realms of €450.00. This is also assuming 365 days and is not accounting for days away, etc.

Likewise, if your boiler is a HE boiler, the cost will also come down accordingly.

BorderGap · 29-03-2013 10:09am

Thanks Shane, by my calculations (assuming the price of oil increases at a rate of 10% per annum) a 30tube solar panel rack with a new tank would pay for itself in under 5 years.

Thanks again.

TPM · 29-03-2013 11:01am

One thing you also need to check is the amount of hot water you are going to use.
Generally this isnt an issue but I was recently talking to someone who had just put a deposit on solar panels. Turned out he had only one shower that was electric and no one in the house used the bath, Dishwasher for washing dishes. so basically would just be using the solar panels to heat water to wash hands. I would hate to think of the pay back time in that case.
After our chat he rang the rep to cancel the panels.

shane0007 · 29-03-2013 10:36pm

BorderGap wrote: »

Thanks Shane, by my calculations (assuming the price of oil increases at a rate of 10% per annum) a 30tube solar panel rack with a new tank would pay for itself in under 5 years.

Thanks again.

Solar is not going to satisfy 100% of your demand but more like 60%. So if the cost is €651.89 for year one, then satisfied by solar is €391.13. Solar will cost you €4,500 - €5,500 depending on system and component choices you make.
You cannot assume that oil will increase 10% YOY as inflation will also decrease the increase in price.
For solar, realistic ROI is 8 - 12 years depending on number in household & volume of usage.

Cheaper & the upcoming future is a product such as the Ariston NUOS. It will give you 200 litres of hot water from 10C for 60 cent per day or 250 litres for 75 cent per day. Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. If you use less water and the cylinder still has warm water from day before, the cost to reheat will decrease. No oil/gas required for back up so the only time you are turning on your boiler is to heat your rads.

NIMAN · 30-03-2013 12:24am

Does that Ariston NUOS system use solar panels, or the thermodynamic ones?

Also, whats the cost of that type of system likely to be? Sounds interesting.

shane0007 · 30-03-2013 12:37am

No they do not use any panel, however, the 250 litre has a coil that you could install solar panels to it.
It uses air. Air supply best from the attic and air exit to outside

Cost wise, depending on air ducting requirements - €3,500 - €4,000 including labour & vat.

patsyrockem · 04-04-2013 12:09am

Sounds good, looking at heating systems at the moment, can they be sourced in Ireland? Any links to where I can get more info? Thanks

shane0007 · 04-04-2013 8:10am

patsyrockem wrote: »

Sounds good, looking at heating systems at the moment, can they be sourced in Ireland? Any links to where I can get more info? Thanks

PM your email address & I will send you the brochure.
Yes they can be sourced in Ireland.

NIMAN · 04-04-2013 9:53pm

Can I PM you mine too?

shane0007 · 04-04-2013 10:04pm

NIMAN wrote: »

Can I PM you mine too?

Yes, of course

BorderGap · 05-04-2013 9:07am

Shane,

above you state "Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. No oil/gas required for back up"
Then you go on to say that the "250 litre has a coil that you could install solar panels to it",

Why would you need to install solar if no back-up is required, or is it a case that solar is needed for back-up?

shane0007 · 05-04-2013 1:17pm

BorderGap wrote: »

Shane,

above you state "Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. No oil/gas required for back up"
Then you go on to say that the "250 litre has a coil that you could install solar panels to it",

Why would you need to install solar if no back-up is required, or is it a case that solar is needed for back-up?

The 200 litre version does not come with a coil so this can only be heated by the heat pump. It does however have a 1.5kw immersion. The back up is there for a number of reasons:
1. The heat pump will bring the temperature to 55C. If you wish to have 65C, the immersion is required to bring it from 55C to 65C.
2. Second reason is for heat up speed. It will take the 200L cylinder 4 hours to heat from 10C to 55C. If you wish to have it faster, i.e. 2 hours, the immersion is needed to do so.
3. There is a programme within the pcb that can be set to weekly or fortnightly bring the temperature to 60C or 65C to eliminate legionaires.
4. There is another programme that you set times for when you want hot water and at what temperature. For example, you set that you wish to have 55C at 7pm. It will calculate when it needs to turn itself on to reach that temperature at the set time, based upon its current temperature. If somebody came in at 5.30 & used up the hot water, it knows it will not not reach the set temperature, it can use the immersion to achieve it. This function parameter can be swtich on or off.

Secondly, the 250L version cylinder comes with a coil. This can be used for the heating coil or solar. It is not required, however, it is handy if you already have solar panels. Solar panels will give limited temperatures during cloudy, overcast rainy days and very little in winter months. Often, homeowners are topping up the cylinder temperature from their oil heating. If the solar does not perform, the heat pump will achieve the desired temperature, thus dramatically bring down the annual cost even further of the heat pump.
I am not saying install the NUOS & solar together from word go, but if somebody already has solar & want to reduce their winter heating bills, then the NUOS will very much compliment their existing solar installation.

blast06 · 05-04-2013 11:17pm

To heat 210 litres from 10C to 60C for one hour per day will take exactly 12.2kwh. With kerosene at a current cost of approx 9.5 cent per kwh and if your boiler is a standard efficiency boiler of say 75% efficiency & a system loss of say 10%, this will give an overall requirement of 18.8kwh. The now cost of that 210 litres is now 18.8 x 9.5 = €1.79 per day. Multiply this by 365 and this will give you €651.89 for the total year. This is, of course, assuming the water temperature has been completely used and is begining from 10C each day. If not, the annual cost would considerably drop to the realms of €450.00. This is also assuming 365 days and is not accounting for days away, etc.

Cheaper & the upcoming future is a product such as the Ariston NUOS. It will give you 200 litres of hot water from 10C for 60 cent per day or 250 litres for 75 cent per day. Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. If you use less water and the cylinder still has warm water from day before, the cost to reheat will decrease. No oil/gas required for back up so the only time you are turning on your boiler is to heat your rads.

Using the first calculations it would cost roughly €1000 per year if it were run on electricity instead of kersosene... say 15c a unit when a mix of night saver and day time rate are considered (probably more ... my day time unit rate is twice the night time as an example).
You then say that when using the Ariston NUOS it would cost €219 for 200l so say €250 for a 210l tank to compare with the first calculations.
This implies a constant COP for the NOUS of at least 4 by my calculations while the advertised is 3.7 .... and of course the figure of 3.7 will not be achieved 24/7/365 .... far from it over the last 2-3 weeks of cold weather for example.

shane0007 · 05-04-2013 11:35pm

blast06 wrote: »

Using the first calculations it would cost roughly €1000 per year if it were run on electricity instead of kersosene... say 15c a unit when a mix of night saver and day time rate are considered (probably more ... my day time unit rate is twice the night time as an example).

Nobody mentioned heating a 200L cylinder by standard electricity. A 3kw standard immersion would generally not be set up on night rate & would therefore be at a cost of circa 20 cent per kwh. You would also have to consider the heat losses from a standard copper cylinder. We were considering the cost of kerosene, solar & heat pump. This is a different angle/argument as the NUOS could then also be set up on alternating electrical tariffs such as night rate.

blast06 wrote: »

You then say that when using the Ariston NUOS it would cost €219 for 200l so say €250 for a 210l tank to compare with the first calculations.
This implies a constant COP for the NOUS of at least 4 by my calculations while the advertised is 3.7 .... and of course the figure of 3.7 will not be achieved 24/7/365 .... far from it over the last 2-3 weeks of cold weather for example.

The COP is based on an actual 2.775kw output from an input of 0.75kw. Hence, the COP of 3.7. Over test periods, maximum COP is based upon averages, unless you want manufacturers to calculate daily! It is also based upon where the air is taking from. It is also based upon annuals. For example, the actual annual running cost will be far less than quoted due to the cylinder temperature will generally not be dropped to 10C everyday of the year.
The air intake is also best taken from the attic space. In summer months, temperatures there is far exceed 15C.

blast06 · 06-04-2013 12:29am

Nobody mentioned heating a 200L cylinder by standard electricity.

I was using that to make a comparison between heating using a standard immersion versus using the heat pump .... and from this i am saying you would need a COP greater tan 3.7 to deliver on your figures

An re the COP of 3.7 .... even in an attic (and it must be a very drafty attic ??) i am struggling to see how this could definitely be achieved during say the last 3 weeks.
Don't get me wrong .... i am a fan of the technology - so much so that i am buying a Danfoss air to water heat pump for all heating and hot water in a new house under construction. The published COP for it is 4.3 but i don't expect to get this. Yet, i would get it if if the air temperature was a constant of 7 degrees and the water had to be heated to just 35 degrees ..... but that is not reality and thus i will not get a yearly average of 4.3 ... just as the NUOS system will not achieve 3.7 in a new part L house where you would have a 'cold' attic space if operating one of these in it.

I like the technology but i think it is being over-sold.

shane0007 · 06-04-2013 9:03am

I understand you are a fan but you are still missing the point. You are adding 2 + 2 & getting 5! You are looking at my figure of €250 & dividing that into your figure of €1,000 which is 4 but this is incorrect.
You need to look at the input wattage & the output wattage of the unit. 2.775 divided by 0.75 is 3.7. This is the COP. It is not based on a economical factor.
You are correct to base it upon temperatures as the lower the output, the lower the COP, however, equally the higher the temperature, the higher the COP.

Figures can only be based on an annual average & it is unreasonable to base them on daily or weekly figures as this would be splitting hairs. It may take a bit longer to reach temperature in colder times but it will be quicker in warmer temps.

The attic space is best because it is generally warmer than taking it directly from outside. In summer months, temperatures can be unbearable in attic spaces. It can be taken from a room, but this is not good practice as the room will need a vent to the outside and that room will have excessive external air pulled into it, thus cooling the room unnecessarily. It cannot be taken from a garage for obvious reasons, i.e. CO, etc. The unit is vented to omit directly to the outside because this is very cold air being omitted.

The reason I think IMHO that the NUOS is better than other similar ones on the market is due to a number of factors. The main one is it is safer. Everything is contained within the unit itself & only air ducts are run from the unit to the outside/attic space. There are no dangerous gases run in pipework to the roof. The gas is not installed on site by a varying expertise of installers.
Due to this factor, no specialist installer is required as the gases are not being touched, they arrive factory set & factory installed. Consistent quality control.
Secondly, the unit is very controllable. The immersion can be on or off or given certain parameters as to when you wish it to be allowed to come on. The PCB constantly monitors the existing temperature & calculates how long it will take to reach the desired temperature, thus maximising efficiency. The water temperature can also be adjusted but can have regular interval times to hit 65C to eliminate Legionnaires.
Thirdly, the cylinder is glass lined with an Anode, so it is suitable for all water types, such as wells, mains water, etc.
Fourthly, the cylinder is suitable for pressurising so it can be installed on both pressurised systems & vented systems.
Finally, the unit does not require an heavy circuit for the immersion due to it only being 1.5kw. It can be plugged into a regular socket or be wired to a socket circuit.

freddyuk · 06-04-2013 9:43am

Presumably once all the "warm" air is sucked out of the attic and expelled to outside the COP drops as the air being drawn is is getting lower and lower until it reaches the same as the ambient outside. 300 - 500 m3 per hour is a lot of air. So what is the efficiency like then?
The energy has to come from somewhere and in these units it is extracted from air inside the home and then expelled. If you have a warm environment such as a large commercial kitchen where you need to get rid of excess heat then these would be a great tool. Even better if you have somewhere to dump the dry cooled air coming out but in the average domestic home I am not sure they will be that good.
If the insulation between attic and living space is not perfect then you could be drawing the warm air from the house to heat the water?

shane0007 · 06-04-2013 9:52am

freddyuk wrote: »

Presumably once all the "warm" air is sucked out of the attic and expelled to outside the COP drops as the air being drawn is is getting lower and lower until it reaches the same as the ambient outside. 300 - 500 m3 per hour is a lot of air. So what is the efficiency like then?

If the sun is shining on the roof, then the space will be reheated just like a solar panel will be. I am in attic spaces all the time & when the sun is beating on them, sweat is rolling off me.

freddyuk wrote: »

If the insulation between attic and living space is not perfect then you could be drawing the warm air from the house to heat the water?

Warm air is not blocked or encouraged by the air above it but rather below it. If the insulation is poor, there is will be heat loss anyway. At least the heat loss will be put to good use rather than been lost to the atmosphere!

freddyuk · 06-04-2013 12:05pm

I get your argument but it does not answer the question. Let's just assume for a minute that it is an average Irish day? Or will this only be economical to run when the sun is out? If so then a solar thermal panel will be more effective as it will immediately heat water as soon as any sunlight hits it. If the sun is not out use the immersion which is heating pre warmed water from a thermal panel. Following your argument these will be a better unit for a bungalow but I would not buy one on the basis of your reasoning. I would need to know it was effective all year in all weathers.

shane0007 · 06-04-2013 12:23pm

freddyuk wrote: »

Let's just assume for a minute

Never assume as it will just make an (ass) out of (u) & (me)!!

freddyuk wrote: »

Following your argument these will be a better unit for a bungalow but I would not buy one on the basis of your reasoning. I would need to know it was effective all year in all weathers.

Honestly, it does not mind if it is installed in a bungalow or a two storey or even a dormer for that matter. It does not scream at the front door, grabbing at the door frame screaming "no, please not a two strorey".
They work all year round, more so in warmer atmospheric air temps, exactly the same way as an air to water heat pump heats a house for low cost. The only difference is you do not have to achieve air tightness as the cylinder already achieves this naturally. Otherwise the cylinder would leak water all over the place & that would be just silly....
In my own experience, I find solar thermal excellent but it has its limitations. The NUOS is an alternative that delivers what it says on the tin. It is cheaper than solar thermal also. The 200L costs €2,000 + vat & the 250L litre cost €2,250 + vat. Add in the duct work, fittings, some pipework & labour, it is much cheaper than its equivalent solar thermal.
It took me a while to accept it also as I was never a lover of heat pumps but this is different in so many ways & it has its place in the market.

06-04-2013 6:06pm

freddyuk wrote: »

I get your argument

why does it need to be a argument?

Cylinders with heat pumps are a added option for home owners/installers when deciding upon individual hot water requirements, there will be times where they are totally unsuitable and other times where they make practical or financial sense.

dathi · 07-04-2013 6:02pm

did a quick google and found the following cops for your heat pump on an Italian site zeroinbolletta.com European sites are usually more forthcoming with information. cop at air temp 20* water 15-55* is 3.7(en255-3)
cop at air temp 7* water 15-55* is 3.1 and finally
cop calculated to (en.16147) is only 2.8 so as you can see the cop falls as the temp in the atic falls, so the cop of 3.7 is not the yearly average that you seem to think. but the max cop when the attic is at 20* having said that at least i was able to get these figures fairly easily unlike the other quasi solar heat pump that doesn't have any figures available.

shane0007 · 07-04-2013 7:21pm

dathi wrote: »

did a quick google and found the following cops for your heat pump on an Italian site zeroinbolletta.com European sites are usually more forthcoming with information. cop at air temp 20* water 15-55* is 3.7(en255-3)
cop at air temp 7* water 15-55* is 3.1 and finally
cop calculated to (en.16147) is only 2.8 so as you can see the cop falls as the temp in the atic falls, so the cop of 3.7 is not the yearly average that you seem to think. but the max cop when the attic is at 20* having said that at least i was able to get these figures fairly easily unlike the other quasi solar heat pump that doesn't have any figures available.

Nice to know exact COP at actual temps. Thanks.
I never stated the COP is the annual average. I inferred it was COP with an average temperature. I would think that anybody here talking technical data would have at least the basic understanding of COP & how heat pumps work. Average air temperatures in Ireland are between 8C & 20C.
I based my financial calculations on what it would cost to heat from 10C to 55C 365 days per year with a COP of 3.7. The cylinder will in most days not be heated from 10C but a higher temp. I did not deduct the lesser cost for this due to a lower COP at varying times as IMHO it would average itself out & give people a realistic running cost or possibly lower.

Nobody can give an accurate running cost because nobody has a crystal ball that can look into every individual's attic space & pre-empt the actual temp in that attic at the varying times & varying days & know what time the NUOs will be running at during those!

If you look at other similar technologies, such as air to water heat pumps for space heating, you will also see varying results due to unknowns, such as levels or air tightness, demand settings & levels of insulation. However, we can still evaluate the product based upon the stated COP. This is industry standard & best practice.

Have you a link to the exact info you posted as site is not forthcoming.

07-04-2013 7:21pm

dathi wrote: »

did a quick google and found the following cops for your heat pump on an Italian site zeroinbolletta.com European sites are usually more forthcoming with information. cop at air temp 20* water 15-55* is 3.7(en255-3)
cop at air temp 7* water 15-55* is 3.1 and finally
cop calculated to (en.16147) is only 2.8 so as you can see the cop falls as the temp in the atic falls, so the cop of 3.7 is not the yearly average that you seem to think. but the max cop when the attic is at 20* having said that at least i was able to get these figures fairly easily unlike the other quasi solar heat pump that doesn't have any figures available.

It's not Shane's heat pump, he's a installer who fits lots of different products.

There are pros and cons to every type of hot water system, the Nuos is sold along side cylinders, solar panels, combis etc... all made by the same manufacture, heat pump cylinders are just another option when hot water requirements/design are being looked at.

shane0007 · 07-04-2013 7:25pm

gary71 wrote: »

It's not Shane's heat pump

Haven't you heard? One of the largest manufacturers of products in Europe has been following this thread with eager anticipation & has decided to award me as their majority shareholder.

Trhiggy83 · 07-04-2013 8:14pm

shane0007 wrote: »

Haven't you heard? One of the largest manufacturers of products in Europe has been following this thread with eager anticipation & has decided to award me as their majority shareholder.

In fairness shane the thread started off talking about the Cost benefit of Solar panels, how did you get talking about air source heat pumps. Seems like you have a vested interest somewhere as you know too much about them.

Just an observation

07-04-2013 8:20pm

Trhiggy83 wrote: »

Seems like you have a vested interest somewhere as you know too much about them.

Just an observation

Shane is a independent installer and has no connection with the manufacturer.

Trhiggy83 · 07-04-2013 8:32pm

shane0007 wrote: »

Solar is not going to satisfy 100% of your demand but more like 60%. So if the cost is €651.89 for year one, then satisfied by solar is €391.13. Solar will cost you €4,500 - €5,500 depending on system and component choices you make.
You cannot assume that oil will increase 10% YOY as inflation will also decrease the increase in price.
For solar, realistic ROI is 8 - 12 years depending on number in household & volume of usage.

Cheaper & the upcoming future is a product such as the Ariston NUOS. It will give you 200 litres of hot water from 10C for 60 cent per day or 250 litres for 75 cent per day. Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. If you use less water and the cylinder still has warm water from day before, the cost to reheat will decrease. No oil/gas required for back up so the only time you are turning on your boiler is to heat your rads.

gary71 wrote: »

Shane is a independent installer and has no connection with the manufacture.

I wasnt havin a go, just read the thread and thought it was odd considering the thread was about solar panels.

I did see he was an independent installer.

shane0007 · 07-04-2013 8:35pm

Trhiggy83 wrote: »

In fairness shane the thread started off talking about the Cost benefit of Solar panels, how did you get talking about air source heat pumps. Seems like you have a vested interest somewhere as you know too much about them.

Just an observation

We got talking about it because it is related to heating domestic hot water & has a direct comparison with cost benefits of same!

Sorry, no vested interest so I can't get you excited or even get you to perch on the edge of your armchair on that front. Whether they become the next big thing or only cross the threshold of a few bungalows, it won't make any benefit to me unless I install it. I merely offered it as an alternative. I have been installing solar panels for about 5 years now & have quite a number of them under my belt. I am a fan but I am reluctantly open to new technologies. I say reluctantly because I try to find fault with everything. I don't believe nor trust any salesperson. I like the NUOS, it's as simple as that. It is the first heat pump technology that tickled my senses.

Trhiggy83 · 07-04-2013 8:38pm

Cheaper & the upcoming future is a product such as the Ariston NUOS. It will give you 200 litres of hot water from 10C for 60 cent per day or 250 litres for 75 cent per day. Guaranteed hot water every day for annual cost of €219 & €273.75 respectively. If you use less water and the cylinder still has warm water from day before, the cost to reheat will decrease. No oil/gas required for back up so the only time you are turning on your boiler is to heat your rads.

How did you calculate the figure of 60 cent for 200 litres per day?

Trhiggy83 · 07-04-2013 8:45pm

shane0007 wrote: »

We got talking about it because it is related to heating domestic hot water & has a direct comparison with cost benefits of same!

Sorry, no vested interest so I can't get you excited or even get you to perch on the edge of your armchair on that front. Whether they become the next big thing or only cross the threshold of a few bungalows, it won't make any benefit to me unless I install it. I merely offered it as an alternative. I have been installing solar panels for about 5 years now & have quite a number of them under my belt. I am a fan but I am reluctantly open to new technologies. I say reluctantly because I try to find fault with everything. I believe nor trust any salesperson. I like the NUOS, it's as simple as that. It is the first heat pump technology that tickled my senses.

Wasnt having a go, i am a renewables person myself. i often hear great things about these different technologies but when you do the maths they often dont really add up. I am like you i suppose, i wont believe something unless i can see the logic.

Solar is still not really feasible at the moment as the payback is still quite long but the price should steadily drop in the next few years through mass production and efficiencies gained. At the moment the solar market is very competitive and this will only drive down prices.

shane0007 · 07-04-2013 8:52pm

I didn't. It is stated by nearly all manufacturers about their products & also the SEAI state this. It is also stated as UPTO 60% due the solar irradiation. In my own situation, I installed 40 tube Kingspan system in my own home about 4 & 1/2 years ago. Year 1 & 2 were excellent. I would say I had to top up the cylinder about 5 times from March to October. However, the last 2 years, I'd say I topped it up most days as they weather has been absolutely crap for the past 2 years.
I am now considering putting in the NUOS 250L cylinder, connecting to my existing solar & re-using the 300L as a buffer tank for my UFH. I was considering changing to LPG for modulation reasons but I can modulate out of buffer but that's a whole other thread!

Trhiggy83 · 07-04-2013 9:11pm

shane0007 wrote: »

I didn't. It is stated by nearly all manufacturers about their products & also the SEAI state this. It is also stated as UPTO 60% due the solar irradiation. In my own situation, I installed 40 tube Kingspan system in my own home about 4 & 1/2 years ago. Year 1 & 2 were excellent. I would say I had to top up the cylinder about 5 times from March to October. However, the last 2 years, I'd say I topped it up most days as they weather has been absolutely crap for the past 2 years.
I am now considering putting in the NUOS 250L cylinder, connecting to my existing solar & re-using the 300L as a buffer tank for my UFH. I was considering changing to LPG for modulation reasons but I can modulate out of buffer but that's a whole other thread!

If the solar is not contributing a whole amount, it is no harm to look at alternatives. I would be sceptical about the COP on the NUOS as specified by suppliers as there is a lot of variables that could affect the performance as mentioned previously. Considering you said the system cost between 3-4k to install, I would find it hard to justify this unless i was confident that the system will achieve a minimum specified COP consistently.

shane0007 · 07-04-2013 9:26pm

Trhiggy83 wrote: »

I would be sceptical about the COP on the NUOS as specified by suppliers as there is a lot of variables that could affect the performance as mentioned previously. Considering you said the system cost between 3-4k to install, I would find it hard to justify this unless i was confident that the system will achieve a minimum specified COP consistently.

I wouldn't be. As per Met Éireann, the average air temperature in Ireland is between 8C & 20C. According to the new information we have from that Italian site, at 7C the COP is 3.1 & at 20C it's 3.7. If we average those figures, that gives us an average COP of 3.4, which I will take that energy back to me at over 3 times what I put in as very good. Even at 3.1, it's very good.
Cost IMHO is very reasonable. Remember this includes a glass lined cylinder so well issues are eliminated. Compared to a 40 tube Kingspan system of about €5,500 with s/steel cylinder installed, it ain't bad either.

dathi · 08-04-2013 11:32am

sorry shane when i said your heat pump i thought that you had one installed in your own house wasn't implying that you were selling them. getting back to the way you calculated the yearly cost with 20* and cop 3.7 the month with the highest mean temperatures is July ,and the 30 year mean temp for july at johnstown castle wexford is 15.6* oakpark carlow 16* so even on the best month of the year the heat pump wont be able to average a cop of 3.7 and here in kilkenny we average 53 air frost days which would demolish the cop even more. the only way to work out running costs for a given amount of water per year would be to use the 30 year monthly mean temps to work out a monthly mean cop and use that to work out the kw needed .again i want to say that i am not against heat pumps or this product.you said in one post that most posters understand cops that is true but most readers and consumers don't realize that the cop quoted is the max performance under lab conditions with a stable heat sourse and the products once installed will not preform to those levels

shane0007 · 08-04-2013 2:19pm

I think you are reading too much into it. Even at 7C, the COP is 3.1. Averages over 10 year periods vary by a maximum of 10% according to PVGIS.
So what is the average temperature within your attic space when the outside temp is say 10C?
My point is & let me give you all your arguments & say the temperature everyday will be 7C winter & summer, the COP is 3.1. It is still 3.1 times the energy you are putting into the system & by anybody's standards that is not a bad return. How many people around the country are leaving the immersions on constantly with a 3kw immersion? Stick in a NUOS & its well...... self explanatory.

Enda78 · 30-01-2014 11:06pm

Hi Shane,

I've been following your conversation of the Ariston Nuos with great interest and was hoping that you could also send me on the details as its something that I'm very interested in for a new build but am finding it very hard to get any information.

Is it o.k to pm?

Enda

shane0007 · 30-01-2014 11:30pm

Enda78 wrote: »

Hi Shane,

I've been following your conversation of the Ariston Nuos with great interest and was hoping that you could also send me on the details as its something that I'm very interested in for a new build but am finding it very hard to get any information.

Is it o.k to pm?

Enda

Of course you can

81wall · 18-07-2015 8:31am

Hi Shane 007
i have read a lot of your posts about the aristron nons 250litre , im a first time user of boards , would it be possible to private message you and pick your brain????

Cost Benefit Analysis of Solar Panels

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