Geothermal AND Solar??

Confused12

Hi all,

I'm hoping someone here may have the knowledge or experience to help me out as I've been getting conflicting advice from salespeople on this point.

I'm starting construction of a new house very soon and have decided for definite to install groundsource geothermal UFH. The question I have is - should I also install solar panels or should the head pump be sufficient? Some sellers have told me that, to do the best job, I should install both, while others have said that a correctly-sized heat pump will take care of 100% of my space heating and hot water. Who do I believe? Any help would really be appreciated.

Another thought I had was to put the money I would spend on solar into a HRV system for the house which would improve the efficiency of the heat pump. Would this be a good idea?

Thanks a million for your help!

emaherx

Geo Thermal requires quite a bit of Electricity to run. 5 - 6 KVA.
Solar gives hot water for free or very little 40-90VA pump.

Do both if you can afford it.
Geothermal to heat your home during winter. Solar for hot water during the Summer.

I personly didn't bother with Geothermal as It requires to much electricity to run and I plan on installing a Wind turbine and photovoltaic solar panels to produce most of my electricity requirements.

But I do have Vacume tube Solar panels and they provide most of my Hot water, even during the Winter.

Lightning McQue

On the basis of what I have been told it would take about 40 years for the solar to pay for itself if you were to instal solar and heat pump. However if the price of solar panels were to drop substantially then it might be worthwhile although I couldn't get any of the companies to tell me what that price should be. You could put in a coil for solar €150 plus the piping €1000 and then say in five or ten years time put in the solar. The price may have dropped by then who knows or may be the €1150 will have been wasted.

Anyway as regards HRV it is a good idea. I am going to spend the €6000 which I had planned for solar on air tightness. I couldn't get a proper quote for this either. From the hilarious of €2500 to €10000. So I am concentrating on insulation, air tightness, excellent windows and then heat pump in that order.

Lightning

emaherx

Lightning McQue wrote: »

On the basis of what I have been told it would take about 40 years for the solar to pay for itself if you were to instal solar and heat pump. However if the price of solar panels were to drop substantially then it might be worthwhile although I couldn't get any of the companies to tell me what that price should be. You could put in a coil for solar €150 plus the piping €1000 and then say in five or ten years time put in the solar. The price may have dropped by then who knows or may be the €1150 will have been wasted.

40 years I think that is a bit long.

I paid E5000 for solar system.
It heats all of my hot water at the moment and most of it during the winter(even heated my water to 60 degrees during frosty weather around Christmas) .
I think it would cost a lot more than 5 grand to heat all of my hot water for the next 40 years.

I think a grand extra for the piping required sounds like far too much surly the plumber who is being contracted to plumb the whole house would not charge that much.

HRV is not a bad Idea should cost a lot less than Solar for the system and money saved spent on insulation/ air thightness.

steifanc

http://www.guardian.co.uk/business/2009/mar/17/royaldutchshell-energy

intresting read of renewables

Quazzie

steifanc wrote: »

http://www.guardian.co.uk/business/2009/mar/17/royaldutchshell-energy

intresting read of renewables

Probably more suitable to the Green Issues forum, as it has no real relevance to the construction area of renewable energy

KAGY

emaherx wrote: »

40 years I think that is a bit long.

I paid E5000 for solar system.
It heats all of my hot water at the moment and most of it during the winter(even heated my water to 60 degrees during frosty weather around Christmas) .
I think it would cost a lot more than 5 grand to heat all of my hot water for the next 40 years.

Just a back of the envelope calculation for say 4 people using 50L of hot water a day each @ 65deg heated up from average of 10 deg
200kg * 4.2 kJ * 55K = 46200 kJ per day
46200 /3600 = 13 kWhr / day (rounded up)
13*365=4745kWhr per year

using electricity (immersion) 4745*18c/kWhr = €850
using electricity (heatpump COP = 3) costs €285
using boiler (80% eff maybe 6c / kwhr?) 4745/.8*6C = €356

so even if the panels would supply 100% of your water, using the heatpump figure (cos that's what the OP has) and emahersx figure of €5000 the pay back would be 5000/285 = 17 years

as I said, this is just back of the envelope stuff, and I haven't checked it out fully so feel free to question any assumptions or figures. The figure for litres of hot water is medium to high and would account for storage losses etc.

emaherx

KAGY wrote: »

Just a back of the envelope calculation for say 4 people using 50L of hot water a day each @ 65deg heated up from average of 10 deg
200kg * 4.2 kJ * 55K = 46200 kJ per day
46200 /3600 = 13 kWhr / day (rounded up)
13*365=4745kWhr per year

using electricity (immersion) 4745*18c/kWhr = €850
using electricity (heatpump COP = 3) costs €285
using boiler (80% eff maybe 6c / kwhr?) 4745/.8*6C = €356

so even if the panels would supply 100% of your water, using the heatpump figure (cos that's what the OP has) and emahersx figure of €5000 the pay back would be 5000/285 = 17 years

as I said, this is just back of the envelope stuff, and I haven't checked it out fully so feel free to question any assumptions or figures. The figure for litres of hot water is medium to high and would account for storage losses etc.

So with my boiler, it is closer to 15 years, still a lot less than 40. Solar produces damn near all of my Hot water, solenoid valve is turned down to zero at the stat to prevent Boiler from heating water. even if we allow for occasionally heating water from another source thats still this side of twenty years plus were not entirely sure of what assumptions you have made in your calculation.

plus 5000 extra onto the cost of building my house with payments over the next 30 years, dose not have much impact on my repayments anyway.

Lightning McQue

To borrow €5000 over 30 years will cost you €9660

Will there be 4 people using 50 litres of hot water 365 days of the year for the next 17 years?

What happens when the kids grow up and move out?

Airtricity/Bord Gais has reduced the price of electricity.

What is the lifecycle of the panels?

Will them become less efficient as time moves on?

What are the maintenance costs?

Why would an installer of heat pumps and solar panels advise me against installing solar panels?

As far as I know in new builds you will have to instal them or put in some form of renewable so you can only get a grant for one type of renewable.

It seems to me that if you could use the water in your washing machine/dish water you could make it worthwhile. At least you would use up the hot water unlike some of my colleagues at work who have to go home at lunch time to turn the hot water tap on to get rid of their solar heated water. What a waste of money!!!

Lighning

rayh

KAGY wrote: »

Just a back of the envelope calculation for say 4 people using 50L of hot water a day each @ 65deg heated up from average of 10 deg
200kg * 4.2 kJ * 55K = 46200 kJ per day
46200 /3600 = 13 kWhr / day (rounded up)
13*365=4745kWhr per year

using electricity (immersion) 4745*18c/kWhr = €850
using electricity (heatpump COP = 3) costs €285
using boiler (80% eff maybe 6c / kwhr?) 4745/.8*6C = €356

so even if the panels would supply 100% of your water, using the heatpump figure (cos that's what the OP has) and emahersx figure of €5000 the pay back would be 5000/285 = 17 years

as I said, this is just back of the envelope stuff, and I haven't checked it out fully so feel free to question any assumptions or figures. The figure for litres of hot water is medium to high and would account for storage losses etc.

Karl,
Having recently made a significant investement in a Solar system which I hope will provide me with about 75% of my space and DHW requirements.
Can I put another view on this matter.
You have made your calculations (back of envelope) based on current costs, however a Solar system (FP) erected today should operate for about 40 years.
Should the real savings not be calculated from the other end or at least incorporate some element of the likely changes its life span is likely to encounter.

KAGY

Lightning McQue wrote: »

To borrow €5000 over 30 years will cost you €9660

Doubling the payback period?

Lightning McQue wrote: »

Will there be 4 people using 50 litres of hot water 365 days of the year for the next 17 years?

That figure was just based on my recollection of some figure I heard. A bath is about 150 l (though not all at 65deg)

Lightning McQue wrote: »

What happens when the kids grow up and move out?

In todays recessionary times? Never

Lightning McQue wrote: »

What is the lifecycle of the panels?

It is quite high, figures quoted in other threads range from about 25years for tubes to nearly 40 years for flat panels. Don't know about pumps etc.

Lightning McQue wrote: »

What a waste of money!!!
Lighning

You're forgetting about the warm fuzzy feeling you get for helping the environment!

rayh wrote: »

Karl,
Having recently made a significant investement in a Solar system which I hope will provide me with about 75% of my space and DHW requirements.
Can I put another view on this matter.

Using it for space heating is another game altogether! Maybe you could jot down some similar calcs for your system.

rayh wrote: »

You have made your calculations (back of envelope) based on current costs, however a Solar system (FP) erected today should operate for about 40 years. Should the real savings not be calculated from the other end or at least incorporate some element of the likely changes its life span is likely to encounter.

The reason for the quick calc (again just to reiterate, it was during lunch time using figures I could remember) was to put figures on this discussion. IFF the system works well with minimal maintenance repairs, yes solar will save you money in the long term, and the payback period will reduce as energy costs probably inevitably go back up. But I know from experience with my heat pump when it went askew after 4 years of service that any servicing etc that needs to be done can stick years back onto payback. (an extra €400 on my elec bill and 300 call out!)

Retrofitting solar panels just for DHW if you already have a heat pump does not make economic sense in the medium term. 2/3 to 3/4 of the energy from the heat pump is already from the sun!

That being said if I had the money I would install them and link them up to the UFH too.

PeteHeat

Hi

The most efficient way to use a heat pump is for low temperature systems, for example a good UFH has a flow temperature of around 35c and a return temperature of 25c.

The higher the temperature requested the lower the COP will be, which could mean at times (even though they may be short) you have a heat pump performing like a big immersion heater, not very efficient.

Most reputable manufacturers back the principle of an additional heat source when using a heat pump, perhaps you might ask the next sales person if they recommend a Bi-Valent system.

Basically it means a second heat source working with the heat pump, if they dismiss the idea it could mean one of a number of things but the two that spring to mind are they are oversizing the heat pump or they haven't a clue about the systems they are selling.

Solar is a bit like insulation, neither will gve you an instant pay back however over time both pay for themselves and provide a decent return over their life time.

emaherx

Lightning McQue wrote: »

To borrow €5000 over 30 years will cost you €9660

Will there be 4 people using 50 litres of hot water 365 days of the year for the next 17 years?

What happens when the kids grow up and move out?

Airtricity/Bord Gais has reduced the price of electricity.

What is the lifecycle of the panels?

Will them become less efficient as time moves on?

What are the maintenance costs?

Why would an installer of heat pumps and solar panels advise me against installing solar panels?

As far as I know in new builds you will have to instal them or put in some form of renewable so you can only get a grant for one type of renewable.

It seems to me that if you could use the water in your washing machine/dish water you could make it worthwhile. At least you would use up the hot water unlike some of my colleagues at work who have to go home at lunch time to turn the hot water tap on to get rid of their solar heated water. What a waste of money!!!

Don't know why an installer would advise you against them, but one installer dose not have all of the answers. My neighbor has flat panels facing west, keeps complaining that his panels do nothing during the winter, Why would an installer do this especially since he has a south facing roof as well?

Lighning

My panels are tubes (heat pipe type) only the glass should require replacement.
Quotes from other threads suggest 5 to 10 euro a pipe in twenty to thirty years time.
This is the only servicing they need apart from maybe cleaning.

My children are only arriving in the next couple of weeks (Please God.)
Twin boys due in May. should be around for next 18 years at least.

Figure of 17 year pay back based on a previous posters figures (He may be making a lot of assumptions, half remembering figures he heard, have out of date figures or just making stuff up ).

I'm a farmer so I reckon they will require washing quite regularly once they discover where the farm is.( I know I do.)

I made sure to buy a large capacity washing machine with hot water Feed. 8kg Load. Don't understand why you would think this a problem. I wouldn't think the element in my machine has ever been used. Although the plumber looked at me funny when I asked him for the hot water feed, he said washing machines don't use them anymore!

Don't know why I'd go home at lunch to turn on taps. System purges itself if it gets too hot.

Electricity prices have dropped for now! Sun will always be free.:p

I only have solar panels so I only required the one grant. I didn't know you could only get the one. I didn't subtract the grant from the 5000 cost anyway.

KAGY wrote: »

Doubling the payback period?


You're forgetting about the warm fuzzy feeling you get for helping the environment!

Retrofitting solar panels just for DHW if you already have a heat pump does not make economic sense in the medium term. 2/3 to 3/4 of the energy from the heat pump is already from the sun!

That being said if I had the money I would install them and link them up to the UFH too.

Doubling the payback??? Sure why not.
I got a loan of 250,000 to build my house. I managed to build the house and fit Solar panels with that budget. If I were to look at it that way, you may as well ask me why I am paying for a 500 Euro door for next 30 years or a 1 Euro Slate.
As far as I'm concerned they are part of the house. Same as my condenser oil boiler which I am paying for next 30 years. The panels will save me more per month than they will cost in repayments.

Heat pump energy is from the sun but it is not free. Requires a powerful pump to suck it out of the ground. Electricity costs may have fallen, but they will increase over time.
As will oil I know.

Oh and I forgot about the warm fuzzy feeling, its the reason I got them in the first place. I'm sorry I got blinded there for a while by potential savings.:)


This week I've had no central heating on in the house hopefully won't need it till the Autumn. I'm just using a wood burning stove in the sitting room, I'm still burning off cuts of timber from building the house. It also has a back boiler so I have loads of hot water.Oh and I will be paying for it for the next 30 years also:p.(just realized I'll be paying for the wood I'm burning for 30 years also.:eek:)

I also spent a small fortune on insulation

gizmo555

PeteHeat wrote: »

Solar is a bit like insulation, neither will gve you an instant pay back however over time both pay for themselves and provide a decent return over their life time.

A bit like insulation, but not a lot! :)

According to the SEI, for example, attic insulation will typically pay for itself in three years. According to posters in other threads, in the best case a cheaply sourced, well installed and optimally operated solar HW system may pay for itself in ten years, if all or almost all of the energy displaced is standard rate electricity. In practice, most installations would probably take at least twenty to thirty years.

Insulation, like some other energy efficiency measures such as heat recovery ventilation, adds to the comfort of your home. On the assumption that one can get all the hot water one needs one way or another, Solar HW does not.

Once installed, insulation requires no maintenance, has no operating costs and will last the lifetime of the building.

There are some situations in which solar HW may make economic sense, for example in a new build, or perhaps in a B&B, where peak hot water demand coincides with peak solar HW availability. For most existing houses though, retrofitting solar HW makes no economic sense at all. I realise and fully accept that there is an environmental argument too. In my view, however, we should prioritise energy demand reduction, instead of costly ways of replacing the fossil fuel energy we use.

Lightning McQue

Gizmo555

How does it make more economic sense in a new build?

7.59m2 of solar panel €3500
stainless steel pipe € 535
labour €1650
Total Cost excludes VAT €5685

So approximately €6500 vat inclusive although you probably could get them cheaper now.

So can you explain how it makes more economic sense in a new build???

Say it saves you €300 per year, payback is 22 years

I suppose the key question is will I need 7.59m2 of panels, so if I was to install say 1 or 2 panels would I be better off in the long run???

Lightning

gizmo555

Lightning McQue wrote: »

How does it make more economic sense in a new build?

Without getting into the specifics of the prices you've quoted, in an existing house one presumably has a functioning hot water system which will be replaced by the new solar one.

In a new build, one has to install a new hot water system from scratch - that cost will be incurred whether solar is installed or not. So, the cost of solar is the difference between a conventional HW system and the solar system. And, as Quentin Gargan has pointed out in another thread, it should be easier to install solar panels during construction, when for example, scaffolding is in place anyway - again this should reduce labour costs compared to a retrofit. Also, one could configure one's setup to take maximum advantage of the solar HW - e.g., HW cylinder located near clothes washer and dishwasher, hot water inlets on these appliances, no "Triton" type electric showers, etc.

On the other hand, the SEI Greener Homes Scheme grant of €250/m2 up to a max of €1,500 for flat plates or €300/m2 up to a max of €1,800 for tubes is not available for new builds. One has to be living in the house for a year to be eligible. I suppose you could try to get around this by installing a system which is prepped for solar with the right cylinder and pipework into the roofspace, etc, then after you're in the house a year, submit your grant application and fit your panels. Might be wise to check if this is OK with the SEI before embarking on this path though!

Even taking into account all the above points, I remain firmly in the sceptic camp as regards solar HW and if I was building a new house myself, I would make very careful costings before coming to a decision.

That said, there are worse payback periods - I'm replacing the windows in my house and the price difference between double and triple glazing was a bit more than €2k. I gave the two U-values to a BER assessor who had surveyed my house and he concluded triple glazing would save me 4 kWh a year - payback period somewhere around 3,000 years! :pac:

emaherx

Lightning McQue wrote: »

Gizmo555

How does it make more economic sense in a new build?

7.59m2 of solar panel €3500
stainless steel pipe € 535
labour €1650
Total Cost excludes VAT €5685

So approximately €6500 vat inclusive although you probably could get them cheaper now.

So can you explain how it makes more economic sense in a new build???

Say it saves you €300 per year, payback is 22 years

I suppose the key question is will I need 7.59m2 of panels, so if I was to install say 1 or 2 panels would I be better off in the long run???

Lightning

Labour cost on a new build is lower if installed by same plumber as rest of heating System (plumber on site anyway).
Subtract cost of standard tank from solar tank.(house requires a tank anyway)
Subtract the grant (unless used already on something else).
Small increase on cost of building house, skimp on something else to make up diffrence.

of course it makes more economic sense on a new build.

gizmo555

emaherx wrote: »

Subtract the grant (unless used already on something else).

What grant?

emaherx

gizmo555 wrote: »

What grant?

OK, Sorry I see its not available for new builds.
The other points are still valid

Lightning McQue

Gizmo555

I'm replacing the windows in my house and the price difference between double and triple glazing was a bit more than €2k. I gave the two U-values to a BER assessor who had surveyed my house and he concluded triple glazing would save me 4 kWh a year - payback period somewhere around 3,000 years! :pac:[/quote]

You have made a mistake here.

4kw/h*size of house* energy cost (ESB)

Say 300m2

so 4*300m2*15.69/100 = €188.28 year

€2000/188 = 10.62 years

So if energy prices increase then this reduces your payback period which will happen when the economy improves. However the electricity market is becoming more competitive.

Could you pm the names of the companies you obtained quotes from for the triple glazing and why did you go with these particular co's.

Lightning

gizmo555

Lightning McQue wrote: »

You have made a mistake here.

4kw/h*size of house* energy cost (ESB)

No, it was 4 kWh in total. Thinking about it, I may have misunderstood him - it could have been 4 kWh per sq mtr of glazing annually. Either way, the energy savings are pretty negligible in a temperate climate like Ireland's.

Actually, the maths is not that hard to work out. The quoted whole unit U-values of the two window types are 1.2 and 1.6 - a difference of 0.4 w/m2/K.

Let's say you want an average indoor temperature of 21C. In my part of the country, according to Met Eireann, the average of the mean monthly temperatures for Oct to Mar, when I would normally have my central heating on, is about 6.5C, a difference of 14.5C.

So the double glazed windows would be losing to the outdoors an average of an extra 14.5 x 0.4 watts of energy per sq mtr, or 0.14 kWh per day per sq metre - a total of ca. 25 kWh saved during the heating season per sq mtr of triple glazing. We're talking about energy for space heating here, which in my case is from oil. The current cost is about 7c/kWh, or €1.75 of annual savings per sq mtr.

Now, these calculations are pretty simplistic, but I suppose they give you some idea.

Lightning McQue wrote: »

Could you pm the names of the companies you obtained quotes from for the triple glazing and why did you go with these particular co's.

Will do later.

Lightning McQue

There is a thread on the site about triple glazing and the way I did the calculation was the way it was done in that thread. A number of guys were discussing the merit of double glazing and triple glazing and used average annual increases of say 10% in energy costs for the next 20 years to decide whether triple glazing was worthwhile.

I also found another report which compared the lifecycle of window materials which made interesting reading- alu-clad were much better than pvc or timber.

So on that basis it appeared to me that it was worthwhile investing in triple glazed windows.

What I did was get a quote for double glazed pvc windows and then I asked the company to triple glaze some of the windows and I compared this to to the lowest quote I got for triple glazed alu-clad and the difference was €12k. After 20 years the windows would have paid for themselves and according to the report I mentioned above they would last for at least 35 years.

Its like these solar panels/heat pumps you dont know who to believe and whether you are wasting or saving money.


lightning

gizmo555

Lightning McQue wrote: »

There is a thread on the site about triple glazing and the way I did the calculation was the way it was done in that thread. A number of guys were discussing the merit of double glazing and triple glazing and used average annual increases of say 10% in energy costs for the next 20 years to decide whether triple glazing was worthwhile.

Well, we're straying a bit off-topic now, but I suppose it's a good general illustration of the need to maintain a healthy skepticism when looking at payback periods for energy efficiency measures. While I accept it's not all about money and we need to consider the environment, it stands to reason that in general, measures with the shortest payback periods will have the greatest environmental benefit too.

For example, for less than half the extra cost of triple glazing, I'm installing an inset wood-burning stove into an existing open fireplace. This will both save energy by stopping hot air whistling up the chimney and allow me to displace some oil use with wood - a carbon neutral energy source. I hope to be able to scavenge a fair bit of wood for free and save money on that too!

Lightning McQue wrote: »

I also found another report which compared the lifecycle of window materials which made interesting reading- alu-clad were much better than pvc or timber.

So on that basis it appeared to me that it was worthwhile investing in triple glazed windows.

There are plenty of double glazed alu-clad windows out there - that's what I'm buying. It's not an either/or decision.

Lightning McQue wrote: »

What I did was get a quote for double glazed pvc windows and then I asked the company to triple glaze some of the windows and I compared this to to the lowest quote I got for triple glazed alu-clad and the difference was €12k. After 20 years the windows would have paid for themselves and according to the report I mentioned above they would last for at least 35 years.

I would check your figures carefully - I can't believe you'll save anything remotely like €600 p.a. by going for triple glazing. Don't forget too that if you have south facing windows, triple glazing will actually reduce solar gain and offset some of the improved insulation value.

Think about mixing and matching - maybe triple glazing only on north facing windows?

Have a look at this discussion on greenbuildingforum.co.uk:

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=527

Lightning McQue wrote: »

Its like these solar panels/heat pumps you dont know who to believe and whether you are wasting or saving money.

You're right there!

KAGY

PeteHeat wrote: »

The higher the temperature requested the lower the COP will be, which could mean at times (even though they may be short) you have a heat pump performing like a big immersion heater, not very efficient.

Excellent point and one I didn't take account of; However, with a heat pump you should be heating a bigger volume of water up to a lower temperature (my thermostat is set at 40-45deg) I ignored this point because I think they cancel each other out. Lets split the difference and bring the payback down to ooohhh, let's say 14 years!

hmmm starting to sound doable!

emaherx wrote: »

My children are only arriving in the next couple of weeks (Please God.)
Twin boys due in May. should be around for next 18 years at least.

Figure of 17 year pay back based on a previous posters figures (He may be making a lot of assumptions, half remembering figures he heard, have out of date figures or just making stuff up ).

I'm a farmer so I reckon they will require washing quite regularly once they discover where the farm is.( I know I do.)

Congrats hope all goes well!

emaherx wrote: »

Oh and I forgot about the warm fuzzy feeling, its the reason I got them in the first place. I'm sorry I got blinded there for a while by potential savings.:)

This week I've had no central heating on in the house hopefully won't need it till the Autumn. I'm just using a wood burning stove in the sitting room, I'm still burning off cuts of timber from building the house. It also has a back boiler so I have loads of hot water.Oh and I will be paying for it for the next 30 years also:p.(just realized I'll be paying for the wood I'm burning for 30 years also.:eek:)

I also spent a small fortune on insulation

Of course, with a higher amount of water usage it makes more sense.
You've got a farm, start planting trees!
And you've done it the right way round with the insulation. A lot of people with jump for the new technology without looking at the figures first.

Lightning McQue

Gizmo

The saving per year was €212 using a combination of general domestic and night rate electricity. I made an assumption that fuel costs would increase by 8% per year. This was the average increase which can be found on the SEI website. The cumulative saving after 25 years was 15k.

Who knows what way ESB prices will go but there is more competition in the market at the moment.

The same applies to solar panels - if they were to fall substantially then they could be worthwhile.

Lightning

gizmo555

Lightning McQue wrote: »

The saving per year was €212 using a combination of general domestic and night rate electricity.

Are you using electricity for space heating?

Lightning McQue

Gizmo555

I am currently building a house which is on hold. It is my intention to instal an air to water heat pump which is why I used the electricity unit cost of 15.69c.

The average yearly increase in electricity over the last 9 years is 8%.

As with everything it depends on budget.

May be Kagy can confirm whether he installed a heat pump plus solar panels. Why did he do this if the payback on solar panels is 40 years?


Lightning

holdfast

have both geo and solar, I worked out payback time is 15 years myself on the solar. over the last two years this is what I the found heat pump set to heat water to 55 degs, not enough for DHW ( too cold for herself grand for me but could be warmer) I use an imersion (2.5kw) for 15 mins to top up heat during end oct to mid march. You need a an immersion that is on a programmer as a back up or oil burner with a system link. My belief is that heat pump will not provide DHW requirements.

I think anyone using solar panels for space heating may not be a good idea. because of the poor output on the panels when you need them i.e. in winter.


total energy bill last year was 1000 euros. Not estimated this years as i haved added over 120 sq m with a hrv, stove, back poarch and south facing conservatory at entrance. Dont expect bill to increase by much as heat pump still in around two hours a night running time. Best of all solar DHW this weeks is heating the water to 70 degs.

PeteHeat

Lightning McQue wrote: »

Gizmo555

I am currently building a house which is on hold. It is my intention to instal an air to water heat pump which is why I used the electricity unit cost of 15.69c.


Lightning

Hi,

Have you considered using a buffer store for your system ? they work very well with heat pumps and UFH systems.

It is also possible to connect your solar to the hot water cylinder and when this up to temperature say 65c it can switch over to the buffer so there is no waste and the ufh can draw heat to the north facing rooms at any time.

This prevents the problem of some rooms being colder than others and calling for heat all the time the heat pump is on.

Personally I believe every UFH system should be working through a buffer (heat store) regardless of the heating system used (oil, gas, pellet, heat pump) because the heat in each room remains stable without boiler cycling.

KAGY

Lightning McQue wrote: »

Gizmo555
May be Kagy can confirm whether he installed a heat pump plus solar panels. Why did he do this if the payback on solar panels is 40 years?

No I only went for the heat pump! If I was to start from scratch now I don't know what I'd do - probably something like rayh and use solar for both water heating and UFH. so possibly never have to use the HP on the day rate?

BTW and possibly off topic, my ESB bills probably total around 1500 - 2000 pa so I know that I should have spent more money on insulation (and got a better builder!)

Lightning McQue

PeteHeat wrote: »

Hi,

Have you considered using a buffer store for your system ? they work very well with heat pumps and UFH systems.

It is also possible to connect your solar to the hot water cylinder and when this up to temperature say 65c it can switch over to the buffer so there is no waste and the ufh can draw heat to the north facing rooms at any time.


Am I correct in thinking that you would locate your buffer tank beside your hot water cylinder upstairs in the hotpress?

Surely connecting your solar to the hot water clinder for space heating isnt financially worthwhile since the amount of sun is very small in the winter time?

Lightning