SolarPV and Electric Cars

Shefwedfan

Deleted User wrote: »

External insulation is a rip off, then you can get problems with damp on older builds, read the relevant sections here on boards.

This is a bit mad....I see why you have your name

I have owned 2 houses in my life so far, first house was in Dublin, 4 bedroom semi. I lived in it for about 6 years and then stripped it down to bare walls. There was no cavity so I couldn't pumped. So all the interior walls I put insulated slabs onto them, new windows. Put special insulation on the floors to stop losing heat that way, replaced Oil boiler in back shed and moved to gas. Put gas boiler up into attic so no heat loss. All new radiators and new immersion tank.....etc etc, can't remember the other bits

Second house, I moved in about 12 months ago. Two sections in it, one section built in 80's and second in 00's. The section in 80's I stripped to bare walls. Pumped the cavity(both sections), put insulated slabs on walls again. Floor was not in good condition so I dug it up. Got mini digger and dug down do I could put in correct insulation and then put in new floors. When putting everything back in I used air tightness tape etc. Put in draft lobby, blocked off sun room with triple glazed sliding door....few other bits I can't remember, was lucky heating system is top of the range....new rads/cylinder...

You would not believe the difference in the house. If I flick on heating for any period of time the house is like oven. I expect to need at least 50% less oil, I finished the renovation about 3 months ago so now ready for next stage

My other big items where diesel for 2 cars, have reduced that by 50% and would love to reduce by 100% but no proper 7 seater around

Next one if electric as we use a lot of hot water and electricity. Solar PV makes perfect sense to reduce this bill.....

Insulation is king in my mind.....people sitting burning gas/oil in houses are f**king mental in my eyes if they can't be bothered to insulate properly....I walked into a friends house one day and he was sitting with electric fire. The oil boiler was not heating the room enough so he topped it up with electric heater, how mental is that?

man_no_plan

kceire wrote: »

You have solar thermal, generally, people go one way or the other.
If I went thermal, I wouldn't go PV and vice Versa.

Yeah I get that. There was no pv at the time.

The main point is that, no more than excess electricity, all the hot water doesn't equate to an energy saving unless it's needed, and I mean that for both systems.

Shefwedfan

I started to look at Solar for hot water, at the house normally we have immersion on 24 x 7. Not as much now as I installed timer but you are still looking at more than 12 hours per day.

The advantage of PV is that I can heat the water off PV which I am not sure was around before. PV cost has come down. Also I am looking to move towards electric for other items(car, maybe lawnmower)

Also I have 3 kids, 5 days a week they are in the house majority of the time. So they use electricity during the day so I will be able to use electricity that is generated by solar. Also plan would be to have 2 electric cars, so my car would charge at night and then Misses car would be charging during the day when Im in work

loyatemu

loyatemu wrote: »

I agree with MadLad here, the figures for external insulation don't add up. Our neighbours had it done and it cost over 13K; we spend about 1.3K per year on gas, so if the insulation cut that usage by 50% it would take 20 years for the investment to pay off. If I could borrow the 13K at 0% over 20 years, fine I'd do it; but otherwise I'll wait.

1300 on Gas ? I'd spend that between Oil and electricity. Though when we spend a full winter the heat might go up a few hundred.

I do hear people say Gas is a lot more expensive. + you pay rental Oil users don't pay.

Shefwedfan

Shefwedfan wrote: »

This is a bit mad....I see why you have your name

I have owned 2 houses in my life so far, first house was in Dublin, 4 bedroom semi. I lived in it for about 6 years and then stripped it down to bare walls. There was no cavity so I couldn't pumped. So all the interior walls I put insulated slabs onto them, new windows. Put special insulation on the floors to stop losing heat that way, replaced Oil boiler in back shed and moved to gas. Put gas boiler up into attic so no heat loss. All new radiators and new immersion tank.....etc etc, can't remember the other bits

Second house, I moved in about 12 months ago. Two sections in it, one section built in 80's and second in 00's. The section in 80's I stripped to bare walls. Pumped the cavity(both sections), put insulated slabs on walls again. Floor was not in good condition so I dug it up. Got mini digger and dug down do I could put in correct insulation and then put in new floors. When putting everything back in I used air tightness tape etc. Put in draft lobby, blocked off sun room with triple glazed sliding door....few other bits I can't remember, was lucky heating system is top of the range....new rads/cylinder...

You would not believe the difference in the house. If I flick on heating for any period of time the house is like oven. I expect to need at least 50% less oil, I finished the renovation about 3 months ago so now ready for next stage

My other big items where diesel for 2 cars, have reduced that by 50% and would love to reduce by 100% but no proper 7 seater around

Next one if electric as we use a lot of hot water and electricity. Solar PV makes perfect sense to reduce this bill.....

Insulation is king in my mind.....people sitting burning gas/oil in houses are f**king mental in my eyes if they can't be bothered to insulate properly....I walked into a friends house one day and he was sitting with electric fire. The oil boiler was not heating the room enough so he topped it up with electric heater, how mental is that?

See I just wrote that the previous owners had the walls pumped and more insulation in the attic and the windows ok, could probably be renewed at some point, The oil boiler is a pretty new condenser unit. The Efel stove is very efficient and quiet fantastic. I might install a smaller one in the sitting room and run them both at times we don't need the whole house warm (warmer). It would replace the gas fireplace in the sitting room but I do like that.

If I paid what my Mother pays in Gas to heat her smaller bungalow built in 2003 I'd be looking at more insulation.

Insulation is great but it needs to come down in cost.

What about when the car is charged ? here does the excess go ? you see you'll still have far too much excess in the brighter months that will have to be dumped, with a FIT all the excess goes to the grid and can be bought back when needed. It's the perfect system.

Gumbo

Deleted User wrote: »

What about when the car is charged ? here does the excess go ? you see you'll still have far too much excess in the brighter months that will have to be dumped, with a FIT all the excess goes to the grid and can be bought back when needed. It's the perfect system.

Wouldn't be too much waste imo
Once the cylinder is full of hot water, and most will upgrade to a larger 300L cylinder to get the full benefit then the left over is used powering tv, or simply the kettle. I think the kettle pulls 2kw when on alone!

You can only use so much hot water in fairness , heating more than you need is a waste.

I'm not suggesting not to do it but in my opinion using a lot more energy (than you otherwise would) just to make use of the solar is a waste, it's dumping it no matter what way you look at it.

unkel

Deleted User wrote: »

You can only use so much hot water in fairness

Solar PV to heat your water is far less efficient per €1 invested than solar tubes. And Mad_Lad, maybe not now or not ever relevant to your family, but we (family of 5 with 4 females) use a LOT of hot water. We have pumped showers and we all do like our long powerful showers / big full baths a lot. I'd say we probably use 3 or 4 times the national average hot water (whereas we use only the national average in electricity before we got the EV)

So indeed that means that if we'd install PV, an immersion diverter would be useless. So basically, unless we get a decent FIT, I won't be going PV, as much as I'd like to

antoinolachtnai

Deleted User wrote: »

What about when the car is charged ? here does the excess go ? you see you'll still have far too much excess in the brighter months that will have to be dumped, with a FIT all the excess goes to the grid and can be bought back when needed. It's the perfect system.

Are you talking about being paid the market rate for the electricity (which will be pretty low) or being paid a guaranteed price subsidised by other electricity users?

unkel

From my figures above. Even if you are paid the highest daytime rate as FIT (which realistically is the best case scenario), the figures for pay back time are pretty miserable. About 13 years with a lot of assumptions bent in favour of going renewable.

unkel

unkel wrote: »

Solar PV to heat your water is far less efficient per €1 invested than solar tubes. And Mad_Lad, maybe not now or not ever relevant to your family, but we (family of 5 with 4 females) use a LOT of hot water. We have pumped showers and we all do like our long powerful showers / big full baths a lot. I'd say we probably use 3 or 4 times the national average hot water (whereas we use only the national average in electricity before we got the EV)

So indeed that means that if we'd install PV, an immersion diverter would be useless. So basically, unless we get a decent FIT, I won't be going PV, as much as I'd like to

The 4 females would want to be thought about energy conservation and not because they're females that that excuses waste. :pac:

The solar hot water tubes would be more suited there I's say.

antoinolachtnai

antoinolachtnai wrote: »

Are you talking about being paid the market rate for the electricity (which will be pretty low) or being paid a guaranteed price subsidised by other electricity users?

It would have to be subsidised by the tax payer. It would have to be higher than the market rate, at least the night rate cost, then you get back what you pay, the perfect situation.

At least we'd get something back for our money compared to giving it to wind energy investors and getting absolutely nothing back.

unkel

Deleted User wrote: »

The 4 females would want to be thought about energy conservation and not because they're females that that excuses waste. :pac:

It's not waste when it is heated up by the sun for free.

Yeah waste of water alright. In the land where water is so scarce that we have to pay a lot of money for it. Oh wait, things have changed again with Irish water

Not if you're on a well, but just think of all those chemicals needed to make our water "Safe"

Actually OT but speaking of wells, since we're now on a well , every time I go to my Mothers and drink the water I instantly notice how disgusting it is..... weird.

The solar hot water panels makes the most sense if you need a lot of hot water. A tank does us heated this time of year on night rate.

antoinolachtnai

Deleted User wrote: »

antoinolachtnai wrote: »

Are you talking about being paid the market rate for the electricity (which will be pretty low) or being paid a guaranteed price subsidised by other electricity users?

It would have to be subsidised by the tax payer. It would have to be higher than the market rate, at least the night rate cost, then you get back what you pay, the perfect situation.

At least we'd get something back for our money compared to giving it to wind energy investors and getting absolutely nothing back.

Renewables are subsidised by electricity users from the PSO, not by the taxpayer.

You think it is a good idea to take money from less wealthy electricity users and give it to you in the form of a production subsidy for your sub-scale inefficient generation? But it is not ok to pay operators who generate efficiently?

Surely it makes more economic sense to subsidise efficient production, if anything is going to be subsidised?

air

antoinolachtnai wrote: »

You think it is a good idea to take money from less wealthy electricity users and give it to you in the form of a production subsidy for your sub-scale inefficient generation? But it is not ok to pay operators who generate efficiently?

Surely it makes more economic sense to subsidise efficient production, if anything is going to be subsidised?

There is essentially zero economy of scale in efficiency terms as far as solar PV is concerned, in fact small scale PV is likely to be more efficient as it will be consumed at the point of production with zero distribution losses.

Now financial economy of scale is a different kettle of fish but there's no argument for not providing small scale producers with at least the same FIT as those offered to larger scale producers.

Gumbo

I'm currently considering PV or Thermal.
I am ignoring any possibly FIT when considering this and I'm still one the wiser or anyway closer to making a decision.

They both have their pros and cons. I think I'll flip a coin.

air

kceire wrote: »

I'm currently considering PV or Thermal.
I am ignoring any possibly FIT when considering this and I'm still one the wiser or anyway closer to making a decision.

They both have their pros and cons. I think I'll flip a coin.

I'd go with PV and a heat pump water heater.
I haven't heard of anyone in the know installing solar thermal in the past 3 years or so.

rolion

Hi,

Reading the thread with great interest.
Some posts are funny than others....

Anyone here have any numbers ,practical examples of systems installed and in use ,when comparing and/or arguing about PVs vs solar tubes !?
Anyone can show some graphs and / or numbers on how a solar tube performs at a lower and higher peaks ?
Same, graphs for lower and higher good Sun days for PVs ?
Anyone can generate a graph on generation VERSUS consumption of a solar PV system installed on a roof (theoretical max 2kw) and what's happening when you press on the kettle ?
How long time takes for a number of solar tubes to warm up or heat a 300l cylinder ?
How many hours and days takes for a common installed PV system to divert the electricity in to a immersion heater of a 300l cylinder without AND with people in the house !?

Re FIT, forget it, never will happen here. I "push" down the wires most of the days 20KWh for free and I still hate FIT if it comes.

My advise: if you like renewables, you do them without asking for a ROI or financial data...it will make your life easier and you can enjoy the look and feel of the PVs or Tubes with a clearer mind.

Have fun....

BoatMad

Re FIT, forget it, never will happen here.

You forget that a FIT system did exist here and a number of PV users are on it still

Gumbo

air wrote: »

I'd go with PV and a heat pump water heater.
I haven't heard of anyone in the know installing solar thermal in the past 3 years or so.

Don't plan on retrofitting an A2W pump now as it's circa 7k to get done.
Regarding Solar Thermal, most new builds that go solar are thermal here in dunlin that I am on. Probably 20% of them are PV.

They will start coming more popular though as the costs have reduced significantly and the 1kw required for Part L compliance is easily achieved.

BoatMad

kceire wrote: »

Don't plan on retrofitting an A2W pump now as it's circa 7k to get done.
Regarding Solar Thermal, most new builds that go solar are thermal here in dunlin that I am on. Probably 20% of them are PV.

They will start coming more popular though as the costs have reduced significantly and the 1kw required for Part L compliance is easily achieved.

can see any point in solar hot water, most of the heat is wasted as far as I can see

Solar PV energy , at least is in a form that can be widely exploited

air

kceire wrote: »

Don't plan on retrofitting an A2W pump now as it's circa 7k to get done.

I'm not talking about that, I'm talking about a water tank with a small heat pump on top, they're about 1k. They take heat from the room but this will also help dehumidify. I'll dig up a link for one.

I have both PV and thermal myself. Thermal isn't justifiable economically for all but the most intense users of hot water in my opinion.
I did mine DIY so it was economic but if I was starting now I'd just go PV + HPWH.

BoatMad

HPWH.???

Gumbo

air wrote: »

I'm not talking about that, I'm talking about a water tank with a small heat pump on top, they're about 1k. They take heat from the room but this will also help dehumidify. I'll dig up a link for one.

I have both PV and thermal myself. Thermal isn't justifiable economically for all but the most intense users of hot water in my opinion.
I did mine DIY so it was economic but if I was starting now I'd just go PV + HPWH.

Thermodynamic?

Edit. Yeah I've heard of these HPWH. hey work in the same way as a fridge does but in reverse.

I'm leaning towards PV if the figures for installation can be agreed and they stack up.
I'll need a bigger hot water cylinder though and the solar thermal included a 300L stainless steel one so just have to weigh them
Both up over the next few weeks.

air

BoatMad wrote: »

HPWH.???

[url]Http://lmgtfy.com/?q=hpwh[/url]

air

kceire wrote: »

Thermodynamic?

No, Thermodynamic is snake oil.
One like this

[url]Https://www.amazon.com/American-Standard-HPWH50G-AS-Electric-Water/dp/B01IEJ1PXE/[/url]

There are European equivalents but I'm on my phone, will post an EU version later

Shefwedfan

air wrote: »

I'm not talking about that, I'm talking about a water tank with a small heat pump on top, they're about 1k. They take heat from the room but this will also help dehumidify. I'll dig up a link for one.

I have both PV and thermal myself. Thermal isn't justifiable economically for all but the most intense users of hot water in my opinion.
I did mine DIY so it was economic but if I was starting now I'd just go PV + HPWH.

I looked at this, so you buy a system that pulls heats out of the house, turns it into hot water and then pumps cold air into house if you want. So if you live in hot climate you could pull the heat from the house to heat the water and then push cold air back in. In the meantime you are getting hot water

Seems very dodgy in Ireland to be honest. I found the one company that seemed to know a few things about it but once I started digging it didn't make sense. They actually recommended PV to connect to it longer term as it is hard on electricity

So you would have PV running to power the system to get hot water. It is very popular in Germany etc as they have very hot climate and use as air conditioning.....

https://www.ish2017.com/uploads/tx_ccmyaddress/ish2017-454455/01_katalog_EN_2016_web.pdf

Gumbo

air wrote: »

No, Thermodynamic is snake oil.
One like this

[url]Https://www.amazon.com/American-Standard-HPWH50G-AS-Electric-Water/dp/B01IEJ1PXE/[/url]

There are European equivalents but I'm on my phone, will post an EU version later

€3400 supply and fit from at least one of the companies I spoke to about this system.

air

Shefwedfan wrote: »

I looked at this, so you buy a system that pulls heats out of the house, turns it into hot water and then pumps cold air into house if you want. So if you live in hot climate you could pull the heat from the house to heat the water and then push cold air back in. In the meantime you are getting hot water

Seems very dodgy in Ireland to be honest. I found the one company that seemed to know a few things about it but once I started digging it didn't make sense. They actually recommended PV to connect to it longer term as it is hard on electricity

So you would have PV running to power the system to get hot water. It is very popular in Germany etc as they have very hot climate and use as air conditioning.....

https://www.ish2017.com/uploads/tx_ccmyaddress/ish2017-454455/01_katalog_EN_2016_web.pdf

http://www.ariston.com/ww/Air_sourced_water_heaters

There are also split models with an outdoor unit if you're concerned about cooling the room that it's in too much. If you only ran the heat pump part in summer though this wouldn't be too much of a concern, you could just leave a window open.

As for "hard on electricity" this sounds like total nonsense, they use 2-4 times less electricity than heating the water with an immersion heater, that's their whole reason for existing.

Finally, they don't "pull heat out of the house" either. They concentrate heat from a room into the tank. If the water is used, yes the room will be cooler than before. If it's not used, it will leak back into the room again and the room will actually end up hotter than without it due to the compressor's power consumption.
Easy enough to calculate if it's going to be a problem in a particular room at a given rate of consumption of hot water.

I can't comment on pricing kceire, I don't deal with Irish installers but there is a 100L version available for just over €800. Installation of an integrated unit shouldn't be any more complex than a standard copper cylinder. The only difference would be that power is wired to the heat pump unit instead of the immersion element.

Granted you want a bigger tank, I couldn't find pricing for the 240L version (Ariston Nuos PRIMO 240) with a quick search.

800 Euro's, lets see.

Use the Immersion, 3.5 Kw for an hour a day say, that's 3.5 Kwh per day costing 22 cent on night rate 6.5 C/Kwh.

So if you use the immersion on night rate for 365 days that would cost 80 Euro's a year. /800 = 10 year pay back. Now , this is immersion water heating only. For us with Oil heating it makes 0 sense because most of the year the water is heated with oil with the central heating.

And the average life of a heat pump I've read on boards is 10 years ?

unkel

Deleted User wrote: »

Use the Immersion, 3.5 Kw for an hour a day say, that's 3.5 Kwh per day costing 22 cent on night rate 6.5 C/Kwh.

Are you having a laugh? 3.5kW for an hour? That would barely wash the left middle side of my right testicle. We need at least 50 times that for our daily washing routine. You seem to represent an extreme lifestyle choice out here, but I do not want to subscribe to your system.

air

Furthermore kceire is installing a tank anyway so it's the marginal cost of the heatpump version Vs a normal tank you need to consider.
For the all in one unit the heat pump is entirely indoors, it should last a lot more than 10 years.

n97 mini

unkel wrote: »

Are you having a laugh? 3.5kW for an hour? That would barely wash the left middle side of my right testicle. We need at least 50 times that for our daily washing routine. You seem to represent an extreme lifestyle choice out here, but I do not want to subscribe to your system.

3.5kw is approximately the energy required to heat a 100 litre tank. It's fairly standard.

Unkel I think yours is the extreme out there. You seem to take pride that you can pump 300 litres of hot water into the drain quicker than you can plug in your Ioniq!

air

n97 mini wrote: »

3.5kw is approximately the energy required to heat a 100 litre tank. It's fairly standard.

No, it's not.
First of all you mean kWh when you write kW.

Assuming 8C incoming water and heating the water to 60C, the energy required is 52*4185*100=21762000 joules = 6.045kWh
However that assumes no losses, in reality the tank will lose heat during the 2 hours it takes to heat up, so will likely take 7kWh (2 hours of a 3.5kW immersion) to reach temperature.
The immersion will then have to cut in again to maintain temperature during the day just to replace losses, even assuming no usage.
Including losses the total is more likley to be closer to 7.5kWh to heat 100L and maintain it at temperature for 8-12 hours - so over double your estimate.

Shefwedfan

kceire wrote: »

€3400 supply and fit from at least one of the companies I spoke to about this system.

I got price of €3200, was over 10 months ago

Shefwedfan

air wrote: »

http://www.ariston.com/ww/Air_sourced_water_heaters

There are also split models with an outdoor unit if you're concerned about cooling the room that it's in too much. If you only ran the heat pump part in summer though this wouldn't be too much of a concern, you could just leave a window open.

As for "hard on electricity" this sounds like total nonsense, they use 2-4 times less electricity than heating the water with an immersion heater, that's their whole reason for existing.

Finally, they don't "pull heat out of the house" either. They concentrate heat from a room into the tank. If the water is used, yes the room will be cooler than before. If it's not used, it will leak back into the room again and the room will actually end up hotter than without it due to the compressor's power consumption.
Easy enough to calculate if it's going to be a problem in a particular room at a given rate of consumption of hot water.

I can't comment on pricing kceire, I don't deal with Irish installers but there is a 100L version available for just over €800. Installation of an integrated unit shouldn't be any more complex than a standard copper cylinder. The only difference would be that power is wired to the heat pump unit instead of the immersion element.

Granted you want a bigger tank, I couldn't find pricing for the 240L version (Ariston Nuos PRIMO 240) with a quick search.

Sorry I was giving a high level view of item. Didn't realize you wanted full spec. As mentioned above my price was 3200. Can't see how you think it is 800 quid based on a link in German? Who does installation? It is not as easy as sticking in immersion tank. How did you come up with that? You have to run ducting out of the system to the room you are pulling the heat from. Also then to room you are pushing out cold air.

Even if you do buy from Germany, who will maintain the unit? This is the problem with the original external heat pump. Loads of Jonny come heating specialist installed them and then legged it, now home users left with system nobody can maintain or get parts

You are correct it is nowhere near as hard on electricity as the immersion but the installation person did mention the one I looked at has a solar PV feed option. So you use PV to power it.

I was about to install it and had a chat with a guy on one of the forums here, he mentioned about Solar PV with divertor so I left that unit. Why buy 2 units at over 3k per unit when I can buy one unit just a little bigger.....

My moto is do it once and do it proper. If that means a few extra quid then I don't mind paying it. Too many half assed installations in Ireland and useless after 3 years because something breaks.

I would be concerned if any company comes out and can only do solar water. From what I can gather they need no certification to do solar water and that is why you have another load of Jonny Solar Specialist running around the country.....for PV they need certification...

Shefwedfan

Deleted User wrote: »

800 Euro's, lets see.

Use the Immersion, 3.5 Kw for an hour a day say, that's 3.5 Kwh per day costing 22 cent on night rate 6.5 C/Kwh.

I wouldn't like to sit beside you in work....do you wash with hot water at all?

KCross

Shefwedfan wrote: »

Even if you do buy from Germany, who will maintain the unit? This is the problem with the original external heat pump. Loads of Jonny come heating specialist installed them and then legged it, now home users left with system nobody can maintain or get parts

I would be concerned if any company comes out and can only do solar water. From what I can gather they need no certification to do solar water and that is why you have another load of Jonny Solar Specialist running around the country.....for PV they need certification...

Poor ould Jonny is getting a very bad rep!

Fair dues to him though, he can put his hand to anything!

KCross

unkel wrote: »

Are you having a laugh? 3.5kW for an hour? That would barely wash the left middle side of my right testicle. We need at least 50 times that for our daily washing routine. You seem to represent an extreme lifestyle choice out here, but I do not want to subscribe to your system.

air wrote: »

No, it's not.
First of all you mean kWh when you write kW.

Assuming 8C incoming water and heating the water to 60C, the energy required is 52*4185*100=21762000 joules = 6.045kWh
However that assumes no losses, in reality the tank will lose heat during the 2 hours it takes to heat up, so will likely take 7kWh (2 hours of a 3.5kW immersion) to reach temperature.
The immersion will then have to cut in again to maintain temperature during the day just to replace losses, even assuming no usage.
Including losses the total is more likley to be closer to 7.5kWh to heat 100L and maintain it at temperature for 8-12 hours - so over double your estimate.

Just to clarify!... 7.5kWh's would cover unkel's testicle then?

n97 mini

air wrote: »

No, it's not.
First of all you mean kWh when you write kW.

Assuming 8C incoming water and heating the water to 60C, the energy required is 52*4185*100=21762000 joules = 6.045kWh
However that assumes no losses, in reality the tank will lose heat during the 2 hours it takes to heat up, so will likely take 7kWh (2 hours of a 3.5kW immersion) to reach temperature.
The immersion will then have to cut in again to maintain temperature during the day just to replace losses, even assuming no usage.
Including losses the total is more likley to be closer to 7.5kWh to heat 100L and maintain it at temperature for 8-12 hours - so over double your estimate.

Yes, meant 3.5kw/h.

You're making assumptions, as do I. Mine are different, and based on what we actually do.

Water sitting in tank in hotpress overnight will warm to ambient temperature. So starting temp is closer to 15C when timer flicks on at 7am. Water is ready for showers at 8am. Raising it to 45C is a delta of 30C. Assuming no losses that's 3.5kwh. We have no further requirement for hot water during the day as we've a dishwasher.

(We actually heat by gas now as our system is fully zoned. Our starting temp is usually between 20 and 25C, as it's rare a full tank will be used in a day so there will be some heat left over from the day before. EDIT: before anyone mentions it, our water is heated once a week to 65C to keep bacteria at bay).

Well I'm guessing it takes about 1 hr to heat the hot water tank, that's why I came up with 6.5 cent per day or per hour, roughly.

2 of us shower once a day, the 2 boys 1.5 and 3 don't use much hot water yet. Even after we shower there's plenty of hot water left.

Even if we were using twice the hot water it doesn't justify an 800 Euro heat pump at today's electricity costs which I've no doubt will get cheaper again.

air

Shefwedfan wrote: »

Can't see how you think it is 800 quid based on a link in German? Who does installation? It is not as easy as sticking in immersion tank.

Yes it is as simple as sticking in an immersion tank if you get an all in one unit.

I never said it was possible to supply and install one of them for 800 euros, I simply was showing that they could be bought for that much.
I'm sure you could get one delivered for 900 or so and pay a plumber 300 or whatever the going rate is to install it. A far cry from 3200/3400 at that.

air

Deleted User wrote: »

Even if we were using twice the hot water it doesn't justify an 800 Euro heat pump at today's electricity costs which I've no doubt will get cheaper again.

Have you once again missed the part where he's doing a refurb and replacing his tank anyway?
So the cost is 800 minus the supply cost of a bog standard cylinder - which would be at least a few hundred.

n97 mini

air wrote: »

Have you once again missed the part where he's doing a refurb and replacing his tank anyway?
So the cost is 800 minus the supply cost of a bog standard cylinder - which would be at least a few hundred.

I paid 130 euro for mine from CDV in Coolmine. Standard copper job with built-in insulation.

air

Good man, kceire wants a bigger one though. Granted he'll have to pay more than 800 for a larger tank version of a heat pump water heater also if he wants one.

Shefwedfan

air wrote: »

Yes it is as simple as sticking in an immersion tank if you get an all in one unit.

I never said it was possible to supply and install one of them for 800 euros, I simply was showing that they could be bought for that much.
I'm sure you could get one delivered for 900 or so and pay a plumber 300 or whatever the going rate is to install it. A far cry from 3200/3400 at that.

I noticed you didn't include the bit about maintenance/parts etc

Do it once and do it right.......

air

Maintenance / parts for a fixed appliance?
When was the last time you had a repair man out to look at your TV set or fridge freezer?
If you had a problem outside warranty any refrigeration engineer worth his salt should be able to sort it out.
It should require zero maintenance in it's lifetime, much the same as a fridge freezer.

I'm not selling the bloody things btw, just making what I thought was a helpful suggestion to the OP.
I'm sure there's someone locally selling similar units at a half reasonable cost if local hand holding is important to you.