# Solar Panels/Tubes



## Sasol (24 Feb 2009)

Hi, 
I have just started a new build - 2,600 sq ft story and a half, south facing. 

I have been talking to a plumber about heating the house and domestic water and he recommended Solar Tubes (Thermomax). Just wondering if anyone has experience of using these as opposed to the ordinary solar plates ??

Would they recommend them ? Do they actually heat the water sufficiently on cold/hazy/dull days ?

I'd also been interested in hearing peoples opinions of solar panels and/or heating in general as I have been in two minds whether or not to install solar. 

Some people I have been talking to swear by it but others they the investment does not equal the benefit to get got. 

Any help/opinions would be greatly appreciated.


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## Optimistic (25 Feb 2009)

We spent over 5500 euros on flat plate and they will never pay for themselves. I would have been better off burning the money.If I was back again I would not install them unless I had plenty of money. Make provisions, yes, to install at a later date, but I couldn't advise you to install them.  

We also spoke with several other people before we installed our solar system who said they were great and that they had heaps of DHW. I foolishly believed them and have to our own expense installed them. Like you we also have a south facing roof, 40 degree pitch and do not have sufficient DHW. Check this link.

[broken link removed]

all the best whatever you do, optimistic



Sasol said:


> Hi,
> I have just started a new build - 2,600 sq ft story and a half, south facing.
> 
> I have been talking to a plumber about heating the house and domestic water and he recommended Solar Tubes (Thermomax). Just wondering if anyone has experience of using these as opposed to the ordinary solar plates ??
> ...


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## PaddyH (25 Feb 2009)

Hi,

I installed 6 SQ Metres Flat panels in my new build 3 years ago - Initial Cost was €6000 (including installation) - Got a grant of €1800 approx. 300 litre Tank was supplied - so that was another saving - So real cost was €3600 approx - At that money they are worth it. The grant is gone now for new builds but I suppose there is more competition in the market.

The critical thing is not the panels but a well insulated hot water tank. My tank temp drops about 1 degree an hour on average - So it's 60 degrees at 10pm, it's 50 approx at 8am the following morning for showers etc. 

We're in the house 3 years now - We have 1 electric shower but have NEVER used it. In general we always have plenty hot water. Even last week the panels would have worked quiet well. Most people will have oil or some heating on for 1-2 hours a day which will also heat the water - most important thing is to keep it warm afterwards!

During the summer months on the good days the panels heat the 300 litre tank to 90+ degrees and even if the next 24-48 hours are dull etc the water is still hot.

I think the general research on this forum proves that electric showers are very expensive and that no matter how expensive oil gets it would be cheaper to get the oil to heat the water..........


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## Optimistic (25 Feb 2009)

wow, that is a high temp to achieve in summer. I NEVER achieved temps in those ranges. Hat pitch is your roof at? Do you mind me asking who supplied and fitted your panels? Do you mind me  ask where are you located?
Optimistic



PaddyH said:


> Hi,
> 
> I installed 6 SQ Metres Flat panels in my new build 3 years ago - Initial Cost was €6000 (including installation) - Got a grant of €1800 approx. 300 litre Tank was supplied - so that was another saving - So real cost was €3600 approx - At that money they are worth it. The grant is gone now for new builds but I suppose there is more competition in the market.
> 
> ...


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## PaddyH (25 Feb 2009)

Hi Optimistic,

I live in Kerry - Roof pitch is only 25 degress thanks to Kerry County Council! This doesn't help in the winter but maybe it does in the summer?

Panels installed by Solaris Energy (Macroom Co. Cork). I would say they source good panels as they have been at it for years - after sales service only ok. 

In the summer in a average day the panels heat the water to 60-70 degrees and on very good days to 90+ - I think the highest it got was 95


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## jsn (25 Feb 2009)

We have the tube kind. Brilliant during the summer. Never turn on the immersion during the summer, even have enough for baths. Have an electric shower but never been used. The heat coming from immersion is incredible during the summers months. We even had warm water last week when the sun was shining.


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## rebelgirl09 (25 Feb 2009)

Hi

We installed 60 solar tubes last summer and we find them excellent.  Apparently the Irish weather is more suited to tubes than flat panels as tubes work from day light instead of sunlight which is what the panels need.

We found a great company called Kedco, they are based in Cork but service the whole country, got great price, service and back up.

Good luck, solar is defo a good choice.


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## DavyJones (25 Feb 2009)

rebelgirl09 said:


> Hi
> 
> We installed 60 solar tubes last summer and we find them excellent.  Apparently the Irish weather is more suited to tubes than flat panels as tubes work from day light instead of sunlight which is what the panels need.
> 
> .




Are you sure about this? Can you tell me the make and model of panel?

I understand that tubular panels are marginally better because they catch the sun from different angles as it crosses the sky.


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## adder1 (25 Feb 2009)

the more tubes u install the more heat generated check out the following site for more info

www.eirgreen.com/Solar_Panels.html


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## bertie1 (26 Feb 2009)

I used Solar Panel Ireland in East Cork www.solarpanelireland.com to buy the tubes & we installed ourselves, 3000 sq ft house very long run of pipe from the panels to the cyinder , 100 tubes 4 manifolds . We had had 40C on a 450 liter cylinder ( on the bottom half where the solar is going into it) 3 days last week , the top of the tank was hotter. Last summer we still need the oil to give the cylinder a boost once every 3 days because the weather was so bad., but the summer before the water was hot nearly all the time. You cannot depend on it you need something else to boost the temperature on rainy days but on the sunny ones they are great.


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## Pinky&dBrain (27 Feb 2009)

I have went to a few self-build shows and while at the stands about solar panels each guy I spoke to said the same things that the tubes are better than the flat panel as they are more suited to the Irish climate, and as Rebelgirl09 said they work on light. 

This maybe of interest found it on the following website, [broken link removed]

*Summary of advantages; vacuum tubes over flat plate solar panels*
[broken link removed]Highly efficient heat generation even at low light intensities (e.g. on cloudy days) [broken link removed]Ability to achieve high temperatures [broken link removed]Improved aesthetics – modern, discreet and elegant design [broken link removed]Smaller footprint - less visually intrusive [broken link removed]Longer lifespan allowing greater return on investment [broken link removed]Each tube on the solar panel is individually replaceable meaning single defective tubes can be replaced rather than the entire panel


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## bamboozle (27 Feb 2009)

silly question, but what temperature does the tank need to be to have a 'hot' shower?


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## DavyJones (27 Feb 2009)

Hot water is recommended to be no higher than 60c.


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## bertie1 (27 Feb 2009)

The thermostat on your mixer is set around 38C for a shower but personally I like it a bit hotter between 40 & 45C .


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## rmdt (9 Mar 2009)

If you want the efficiency of a tube system, but the looks of flat plate, have a look at the solar focus panels.  I have fitted them and am delighted with the way they look, haven't got hot water up and running yet though so afraid I can't comment on performance.  As I live by the coast I went for these panels as the seemed to be the only ones which had a guarantee against salt corrosion.


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## clonboy (31 May 2009)

ok i know it was a great day today but just got my flat plate panels up and running, finally got my 300 litre tank filled last night, so at 7 pm this evening my controller was showing 67c at top of tank,, i am happy so far


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## LauraLu (2 Jun 2009)

My parents got the tubes in a month or two ago and they are absolutely raving about them. Even before the great weather this weekend every time they turned the tap on the water was hot. My mother had a bath last week and filled it to the top and the water was still scorching afterward- this was only after the week of rain so it was only 1 or 2 days of moderate weather.

They havent looked back. they havent used their t90 electric shower once. We are looking into getting them ourselves. If its like this in the Summer- we get more sun in the winter than the summer so im looking forward to see how they get on in the winter coming

BTW it was a local supplier and fitter (Dublin south west) who was great. In and out, very tidy and great value.


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## RVR (3 Jun 2009)

Saying tubes are better than panels is like saying cheddar is better than cream cheese.  But there are hundreds of different types of each so you can't lump everything into the same bunch.

In actuality every collector (whether vacuum tube or flat panel) performs differently.  Yes, IN GENERAL vacuum tubes are more efficient than flat panel as they are better at collecting and retaining diffuse radiation in cloudy weather.  However some models have great efficiency and some have very poor efficiency so this is not always true.

Quality of glass, quality of insulation, quality of materials, etc etc all affect the performance of the panels.  This affects how well they collect and retain heat.  This affects the efficiency of the panel greatly.  

We ran a T*SOL comparison on 2 vacuum collectors with the same aperture area from the SEI registered list last year and one was 45% more efficient than the other.  Buyer beware!!!

If you're interested we have a short guide on our own website.  Just google "solar collector efficiency equation" with Pages from Ireland on if you want to read more about it.  It's a bit dense but it has some graphs showing the difference between performance in Flat vs Vacuum.

Cheers

Des


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## bamboozle (4 Jun 2009)

we've had our solar panels up and running a few weeks now, we're getting temperatures of about 55-60 degrees for the last week and the temperature drops about 5-7 degrees overnight.
am plesantly suprised with these temperatures as the panels are west facing.


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## sman (4 Jun 2009)

one issue our plumber raised with us when deciding between the two - very easy to break vacuum tubes + kids playing football/hurling in garden = bad idea. We have a bungalow so may not be an issue with 2 story but still was something we nevr thought about. had more or less  decided on tube s but this has changed our mind


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## RVR (4 Jun 2009)

sman said:


> one issue our plumber raised with us when deciding between the two - very easy to break vacuum tubes + kids playing football/hurling in garden = bad idea. We have a bungalow so may not be an issue with 2 story but still was something we nevr thought about. had more or less  decided on tube s but this has changed our mind



This is true sman, flat panels are more resiliant, but bear in mind tubes can be easily replaced if broken (replacement glass tubes are in the order of 30-50 euro to buy).  If someone manages to break a flat panel with a sliotar or football the whole thing generally has to be replaced!


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## GregorSmyth (11 Jun 2009)

Try that
best regards Gregor

[broken link removed]


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## alister (1 Jul 2009)

Hi,


  Using solar panels is a great way to generate clean and renewable electricity to power remote appliances, or even the average home. There are two main forms of solar cells in existence today, and these are; "solar electricity panels" and "solar hot water panels". The two different technologies allow us to either generate electricity for our homes or to heat the water we use.
  As time goes by, we begin to see new and more efficient solar panel designs. This is making the use of photovoltaic power over fossil fuels, much more viable to homeowners and businesses.

_____________________________
[broken link removed]


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## MacTheKnife1 (1 Jul 2009)

GregorSmyth said:


> Try that
> best regards Gregor
> 
> [broken link removed]



Very nice - so is it panels or tubes then?!


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## abbey925 (6 Jul 2009)

Hi,

Just starting a self-build at the moment. We were all for installing the tubes instead of the flat panels as the general consensus is that the tubes are more efficient. However we have just received three quotes from plumbers. Two strongly advised against putting in the tubes as from their experience they can be quite problematic. The third actually refused to do our plumbing if we installed the tubes! We are building a two-storey house so balls should not be a problem. Has anyone experience of tubes causing hassle? Hadn't heard any bad stories up until now.


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## bertie1 (6 Jul 2009)

The only hastle I can can see from the tubes is that you have to leave a bit of scaffold up so you can put in the tubes ( into the manifold)  when all the plumbing is complete & the ESB is switched on. Apartenetly they could damage the manifold if they were put in & there is no water in the system.


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## villa 1 (6 Jul 2009)

Thermomax tubes appear to be the best quality in ireland at the moment and are manufactured in northern ireland. Tubes are approximately 10% more efficient than flat panels but it is a good idea to fit a heat dump on the solar circuit and a mixing valve on your hot water supply to your sanitary appliances. Hope this helps


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## marcole (15 Jul 2009)

HI did you get sorted on the solar? I have done a lot of work with both tubes and flat panels so could maybe answer your questions or see if you have a good price?


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## marcole (15 Jul 2009)

We have tubes and can recommend them, they were very easy to install and work in the winter as well as the summer. Do you want the prices? They came from kedco and they sort a good installer so maybe that is the difference.


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## david ross (18 Jul 2009)

bamboozle said:


> we've had our solar panels up and running a few weeks now, we're getting temperatures of about 55-60 degrees for the last week and the temperature drops about 5-7 degrees overnight.
> am plesantly suprised with these temperatures as the panels are west facing.


There are two types of *solar panels* or  solar cells suitable for domestic use. 
*Flat Panel Arrays* and , (more than one) Evacuated tubes are  available in different heights and widths. 
 Most are about 1m2.                     Evacuated tubes work on the same principle  as the flat panel solar cells, but due to their design are far more 
                     efficient  at collecting solar energy Evacuated tubes have been around for years and are  extensively used in Canada, 
Germany, China and England. Evacuated tubes use a twin glass tube made of borosilicate glass which makes them extremely durable. 

This type of design allows maximum absorption with minimal reflection. The top of the tubes are fused together and all air within the tubes is pumped out at the same time the tubes are exposed to extremely high temperatures.  
This "evacuation" of the gasses forms a vacuum, which is an important factor in the performance of the evacuated tubes.

                    Due to the vacuum process the tubes are  extremely efficient at collecting heat from  solar energy
                     A vacuum is excellent  at insulation which is why the tubes were designed as such. 
                     The vacuum prevents  any heat loss from the tubes due to the highly efficient insulation properties.  
                     The inside tube could be as hot as 150C while the outer tube is cold to the  touch.

                     Due to this design evacuated tubes out  perform the flat panel models and collect maximum  even in bad  weather.


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## ciaranie (20 Jul 2009)

Hi, I have 4 flat panels on my south facing garage and I'm very happy with them. These days we always get 50degress in the tank. I found that the solar controller needed a bit of tweeking to help it along. For instance the start up function was turned off. This features monitors the panel temp in the morning and starts pumping fluid up to the panel to help it heat up quicker.It's also good for overcast days when the sun isn't shining to get them started. When turned of it heats the fluid in the panel, pump comes on then pumps cold fluid into the panel which then knocks the pump off. It never started pumping before 10am before I switched it on, now it's pumping from about 7.30am. Also the difference temp setting between the panel temp and the tank temp was far to high. The panel had to be 8degrees above the bottom of the tank to start the pump, changed to 6degrees and works far better. All these are trial and error though. The only thing I find funny about my system is, in March one very good Sunday we had 80degrees at the panel and 72degrees in the tank, now we get nowhere near them temps even with the sunny longer days. Has anyone else come across this? Also has anyone else adjusted their solar controller for the better? I think the factory setting just don't suit Ireland.


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## quentingargan (13 Apr 2010)

This is quite an old post, which I just stumbled on (while searching for something else) but if you're still awake on this one, then you are right to have changed the temperature difference setting on your controller, but not the "start up" one. The start-up one is really for a very specific type of vacuum tube (direct flow) where water can get quite hot inside the tube, but not at the manifold (where the probe is). This doesn't apply to either flatplates, or to most heat-pipe vacuum systems. 

As to why your system would appear to have deteriorated - this can be subjective. Sometimes a household will use no hot water one day, so the cylinder starts off at 60 degrees from the day before, gets brought up to 72 quite quickly. If you start the day with the cylinder at 20 or 30 degrees, its a different matter. But if you have four panels, I assume that equates to about 8 sq m. Your cylinder should be well above 50. I wonder if there is something else you have accidentally reset? If you pm me your controller type, I may be able to help.


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## canine (28 Apr 2010)

anyone have any reports on these guys " Ecolodge Renewables Ltd " ,they seem almost too cheap


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## quentingargan (28 Apr 2010)

Just be aware that when they describe a 4 sq m panel, they mean gross area. The actual aperture area can be calculated by dividing the grant by 300. In the case of the 4 sq m panel, that's actually 2.95. Also the systems don't include a heat dump, or provide the facility for one. When you go away on holidays, or don't use the hot water, the panel will boil, degrading antifreeze, and keeping the whole system under steam pressure until sundown. I'd always prefer to see a heat dump used, especially with vacuum systems which can reach 220 degrees.


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## RMCF (2 May 2010)

I have a great location for solar panels on the back of my house, and the south facing roof is 2 storeys high so would be safe from any potential damage.

I sit out the back the odd day, and even when its not that hot (like last couple of weeks), I'm amazed at how much heat my back garden gets. Due to this I got to thinking that solar panels/tubes might be a decent buy, if I coudl get them with a grant.

But from all the posts I have read, it appears that they might never actually pay for themselves. I'm not the sort of fool who would buy a thing just to be eco-friendly. It would still have to save me money.

I like the idea of always having hot water on tap but if I could do it cheaper using electricity then the solar would be a non-starter.


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## quentingargan (2 May 2010)

While I wouldn't regard environmentalists as fools, the strictly financial viability of solar panels depends on a number of factors;

*Energy Inflation *What price trends you expect will apply to other energy over the life of the system. If you believe in peak oil, then all bets are off on what might happen when this recession bottoms out. The last time demand exceeded supply, oil prices went up by 700%, or by $120. Many expect the prices to go to $200 or $300 per barrel very quickly. 

*Panel Prices* It could be argued that installation prices are falling (and they have done in recent years because solar moved from being a niche product, into the mainstream), but we are also reaching peak copper, and energy prices are starting to have a serious bearing on the price of other components of a panel, such as aluminium. Margins in the industry are screwed to the floor and I would expect prices to rise in coming years.

*How much hot water you use* - If you only take frugal showers, there are only two people in the house, and you use a dishwasher and washing machine that can't be filled with hot water, etc., then you may find your hot water useage is reduced

*Your Heating System* If you already have a very efficient hot water system such as a gas fired combi boiler, then the savings will be reduced. But most houses have the heating turned off for six months of the summer. During that time, the hot water comes from either an immersion heater, or by switching on a boiler, heating boiler, flue and miles of pipework just to heat a cylinder in the hotpress

*Your existing cylinder *- this will be replaced with a solar one. If the existing cylinder is wasting heat, then there will be year-round savings on this. Changing the cylinder is a substantial chunk of the cost of a solar installation. 

At current energy prices, a solar water heater can give a payback period of about 12 years in situations where the the existing heating system is as above. Thats a return of over 8%. I think the new government solidarity bond is offering about half that?

In my own situation, our central heating is off for 8 months of the year. I fill our washing machine with hot water from the tap (using a short hose on the tap in the utility room) and we like baths. Its a no-brainer for someone in an energy efficient house whose heating is off all the time. A bit more difficult to say for an old and cold house with a really efficient pellet boiler that is on a lot of the time.


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## canine (5 May 2010)

What questions should I ask the solar panel system sales people ,Ive had 3 to my door now and each one has a different pitch ,I honestly yhink they dont know what they,re selling


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## villa 1 (5 May 2010)

1. Ask them if they have an Irish plumbing/heating training background and have they completed the solar installers course (SEI regitered). Not a dodgy cert that was picked up from under a mushroom in a forest!!
2. Is their product tried and tested.
3. Have they insurance.
4. References from previous satisfied customers.


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## quentingargan (6 May 2010)

I would be inclined to put these the other way around. Like references at the top of the list. Everyone is going to say that their product is tried and tested, and to my mind the SEI registered training is of mixed quality. 

I think you need to have a clear idea of what you want yourself. For example, you should know yourself whether you want flatplates or tubes rather than being open to persuasion by the door-knockers. Tubes have a longer operating season because of their better insulation, but will need to have the tube part replaced after about 20 years. With the Chinese vacuum flask system, replacement flasks are about €5 each, but the single glass tube type would be way more expensive at that stage. Flatplates, by comparison, are a lot more durable and should last 40 years. They are more aesthetically appealing to some, but also more expensive to fit. 

One thing. Never ever sign a contract during a house call. There are companies putting pressure on people to sign for a project with promised discounts on the night. The deals are some of the worst I have ever seen in this business. Q


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## sh2010 (13 May 2010)

I am a first time poster so please forgive me if I am asking something that seems very dim, we have planning permission for a two storey house and are planning to use solar panels to heat both water and to power either underfloor heating or wall panel heating, from reading this thread it seems very controversial as to the benefit of solar panels, can you tell me does anyone have experience of using solar panels for heating as well as water and how successful they are.
thanks in advance


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## villa 1 (13 May 2010)

Keep the solar panels/tubes for heating hot water alone. Using them for anything else is a complete waste of time and needless capital expense. Anyone pushing solar panels to satisfy space heating or underfloor heating requirements is living in cuckoo land.


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## Charlie 07 (13 May 2010)

Even if panels were used for space heating in we'll say October/beginning Noverber and end February/March/April (when they could at least contribute to space heating). Then use other means for November Jan Feb when panel have no real imput


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## villa 1 (13 May 2010)

As I've said in so many previous posts new house builders are spending away glutinous amounts of money on heating systems that will never pay for themselves nor the environment for that matter. Keep the systems simple and by all means get as much benefit from the sun, re solar panels/ tubes. (when it is out!!) It is absolute madness having to supplement heating needs when solar is non existent and you have to satisfy your heating needs with another heat source.


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## Ceist Beag (13 May 2010)

villa_1 we've been advised that an air-water heat pump is they best solution for us. We have existing plumbing in place hooked up to rads in each room and spend a lot of time at home so find that currently we have to turn the (oil burner) heating on a lot to keep the house warm. There is some improvement needed in insulation which we're planning to tackle but do you have any views on air-water heat pumps as a means of heating the house (and water)?


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## villa 1 (13 May 2010)

Air to water heat pumps are fine once the outside air temps don't fall to freezing or near it. But look what happened this year, prolonged cold snap. This led to the efficiencies of these heat pumps (COP) to drop drastically leading to increased electic bills. Maximise on your insulation levels, install a condensing oil/gas boiler for space heating and supplement this with solar panels/tubes for domestic hot water.


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## Ceist Beag (13 May 2010)

Thanks villa_1, is good to hear different views as our architect is quite firm in his belief that the air-water heat pump is a better alternative so I think we need to discuss this with him a bit more before making any decision.


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## spc13 (14 May 2010)

Just something to look out for, for potential solar system purchasers - if you do choose solar, try and dodge the glass lined storage tanks. they are appealing due to their cost (about 1/2 the price of stainless steel) but only last a couple years - especially in areas where water is more agressive (e.g. Galway). Personally, as someone working in the industry for a number of years, im not convinced the payback period for solar justifies the initial spend.
it will be hard to beat a condensing heat/hot water combi boiler or condensing boiler c/w high output pressurised cylinder combo.

Might be worth a mention -a brand new product nearly available - Domestic Micro Combined Heat & Power unit (CHP) from the Baxi group. it produces enough free electricity to power a house. Too early to comment, but may prove to be the next generation fad!


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## quentingargan (14 May 2010)

spc13 said:


> Personally, as someone working in the industry for a number of years, im not convinced the payback period for solar justifies the initial spend.it will be hard to beat a condensing heat/hot water combi boiler or condensing boiler c/w high output pressurised cylinder combo.
> 
> Might be worth a mention -a brand new product nearly available - Domestic Micro Combined Heat & Power unit (CHP) from the Baxi group. it produces enough free electricity to power a house. Too early to comment, but may prove to be the next generation fad!


 
As far as I know, that CHP unit will only be available on Bord Gais, not on propane, for another year. It produces 1kw of power while running. If you only run your boiler for 3 to 4 hours a day, that's going to be 4kwhrs per day?

Q


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## Mystic Oil (14 May 2010)

I am told (by someone that I know in the industrial CHP business) that this company http://www.cerespower.com/ are about to launch both an NG and LPG unit in the Irish market. The economics of the LPG unit would appear to be questionable, given the price we pay for the gas here, compared to NG.

4kWh is more than I use in a day


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