# Anyone using Solar Panels as primary heating system?



## LiamC (22 Nov 2006)

Hi,

I'm preparing to build a new home early next year, one of the major decisions left is how to heat it. 
It will be 289 sq mtrs over 2 floors (both with underfloor heating) + a futher 60 sq mtrs of attic space that will be used as storage space and my comms room so just need to take the chill out of the air here (intend to use aluminium rads or similar for this area). 
Any company I have spoken to so far are pushing a ground source heat pump (love the idea but haven't bought into the fact that it will work, yet). Costs for heat pump & external works coming in around €20k.
Was thinking of using solar panels and some form of backup system (wood pellet, oil, lpg) for the colder months.
Has anyone done this or have any comments?
Thanks, LiamC


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## Mrs Aol (22 Nov 2006)

We are. We're building a house of 3500sq feet and running our heating and all hot water from from 11.7 sqm of solar panels. we have a pellet stove as back up. Our house will be complete in April so I suppose I'm not really of any help until then as to how it'll work out but I just wanted to tell you that it is done. Our supplier uses this set up on all their houses.


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## xt40 (22 Nov 2006)

relying on solar sounds like a crazy idea. itll be operating at its least efficiency  in winter which is when you will need it most. im not convinced about the payback on heat pumps but at least they do work.


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## ninsaga (22 Nov 2006)

Mrs Aol said:


> We are. We're building a house of 3500sq feet and running our heating and all hot water from from 11.7 sqm of solar panels. we have a pellet stove as back up. Our house will be complete in April so I suppose I'm not really of any help until then as to how it'll work out but I just wanted to tell you that it is done. Our supplier uses this set up on all their houses.



This is an interesting post. Could you share why you decided to use solar as a primary.. what calculations were done & what company you used.... installation costs etc. 

I would like to do similar but cannot find grounds to see how it will work.

ninsaga


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## AJL (25 Nov 2006)

Hi Mrs Aol,

interested too. I was of the same opinion that Solar panels are a no brainer fro DHW but for all round heating? how do you dump that amount of hot water that is produced by 11.7 sq m on a scorching hot July day?


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## serotoninsid (25 Nov 2006)

Can we expect to see a situation in the near future where the payback period will be economically realistic on solar heating?  If the number of consumers of solar is rising at the rate that it is currently, is it logical to expect that this kit can be mass produced and the capital cost come down as a result?


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## Optimistic (25 Nov 2006)

We have just built a 220 sq mtrs house with 8 sq mtrs of solar panels, using a pellet boiler as back up for heating. The solar panels are connected into a tank in tank system, 200 ltrs of DHW and 600 ltrs of buffer water storage.  I can't comment on what the solar panels will contribute yet, but the pellet boiler is a dream. Got ours from a guy in Cork who I know is commited to pellet boilers long term. Was selling them way before the present grants came on flow. This is important to me for back up in 10/20 years. I wonder how many of the suppliers will be around when the hype dies down some. If you want more info ask again and if I can help I will.  Optimistic


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## Mrs Aol (28 Jun 2008)

Hi Again I know this is an old thread but I did say i'd report back after a year so here it is.

Well our first year in new house is up today! We've used 1150kg of pellets. This is to run heating for 2000sqft (I'm here all day with 2 children so it needs to be warm all day) and all hot water for 2 adults and 2 children (including hotwater feeding dishwasher and showers (obviously we don't have electric showers!)).

We have about 12sqmt flat panels.

We reckon we didn't really figure out the best settings to have until about Dec. We were wasting pellets and heat but sorted now and I expect next years total to be lower (maybe by about 2 or 300 but that just a calculated guess on my part).

We're happy with the system the only complaint was that before we completely got the hang of it we were sometimes too hot - especailly when we had visitors - everyone knows now to come in a teeshirt and flipflops all year around!

Hope thats of interest.


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## huskerdu (28 Jun 2008)

Interesting post Mrs Aol. How much did the 1150kg of pellets cost you ?


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## ninsaga (28 Jun 2008)

This is very interesting 1.1ton of pellets...... were they bag or bulk. Perhaps you can share some info ie..... make of woodpellet boiler are you using? What type of house? Timberframe? Higher than nor insulation? etc

ninsaga


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## RMCF (28 Jun 2008)

As someone thinking of starting a new build in the next couple of years, I am finding this thread very interesting.

Will be inetrested to see what Mrs AOL pellets cost for the year.

And what the price of her entire setup was?


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## AJL (29 Jun 2008)

I have 5 m2 of solar panels for hot water. It barely heats the water in the winter but does a brilliant job in spring and summer, autumn. Still not convinced that solar panels for heating makes sense. 
I have an air to air heat pump. 3300 sq ft house. Heating bill around 800-1000 per year. The house is SIP panel so is very well insulated. This is the main reason costs are reasonable. Heat pump is expensive to run I reckon 80c to 1 euro per hour. But heating is only on for about 3 hours per day in winter. So one piece of advice is what ever the heating system insulate insulate insulate!!!!


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## Mrs Aol (29 Jun 2008)

Our house is not a conventional build. It's super insulated and very airtight. 

Pellets cost about 200euros per ton in bulk and 330 per ton bagged. We used 1.15 tons but as I said we wasted quite a few until we figured out the best settings (we had it set on and off then on again then off again several times a day - it's much better to have it on fewer times and for longer in our case twice). We used firestixx and a small amount of brites.

We have a Wamsler stove with integral boiler. 

It was all supplied and installed by our German builders. The cost was included in the price of the house but apparently it was 30K (as per sei application).

I don't understand how anyone who reads this can say solar panels don't make sense for heating. Surely less than 300euro for all heating and hotwater for 2000sqft speaks for itself.

I really don't mean to start an argument I just want to show that it is a possibility as alot of people (some supposedly in the know) seems to dismiss it.


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## ninsaga (29 Jun 2008)

Mrs AOL - thanks for posting. To summise, there is naturally alot of sceptism regarding using solar as...
1. there are some posters who have poor experiences
2. there are alot of outfits offering solar & for anyone interested in it - it is a bit of a minefield (the vacuum suppliers state that the flat panel stuff is crap - the flat panel guys state that the tubes are more expensive & need to be replaced after a few years etc). from personal experience this stuff held me back as it is difficult to get good independent information.

So this is why your experiences are of interest (well to me anyway!) as I would like to learn more about it.

It appears that your spend is really really low - so well done - looks as though you've made the right choice.

If you don;t mind sharing - that construction method did you go with? ICF, Poroton, Timberframe, SIP's, Ytong etc?

ninsaga


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## Vanilla (29 Jun 2008)

Am very interested in this and would like to ask Mrs. Aol=

Where do you store the wood pellets? Is wood pellet feeding automatic or manual?

How do you maintain the quality of the pellets- ie they have to be kept dry?

How are your electric bills in comparison with normal house- is there a loading for the pellet maintainence?

What kind of regulation do you have? 

Are the solar panels tubular or flat?

Did you get an SEI grant? I thought installers had to be Irish?

Is the Walmser stove the wood pellet boiler?

You said your house is airtight, do you have a controlled ventilation with recovery?

What is the normal temp set point in the house?

Does the boiler generate the domestic hot water? What size is your water tank?

Do you have triple or double glazed windows?

Whats the BER rating of your house, if you have one?

When does the boiler start and finish- for eg is it Nov to Feb?

How many solar panels do you have?

I know it's a lot of information but really am interested.


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## sas (30 Jun 2008)

Mrs. Aol previously posted this http://www.askaboutmoney.com/showpost.php?p=414794&postcount=2 which refers to the build method she used.

The company they used are referenced in this recent article in Construct Ireland [broken link removed]

Couple of things I'd like to point out.

These houses pretty much meet the passive house standard. This means you literally need little or no heating. Even in the depths of winter. 

I imagine the OP wants to know if a solar heating system can make a significant contribution to a "well built by irish standards" but nowhere near passive house. There is no evidence in this thread to suggest it can.

A house that needs very little heating is obviously going to be cheap to run. I would wonder in Mrs. Aols case if the solar heating system was removed from the house, would the pellet bills rise significantly, i.e. how much is it actually contributing?

I love the idea of a solar heating system. Regardless of what I've read however, I don't see anything that would suggest it's possible in any affordable way. Solar heating systems have been done in Germany\Austria from what I've read. But these depend on large thermal stores (up to 10,000 litre insulated storage tanks) that carry solar heated water over from the summer\autumn to be used in winter.

Also the build cost referenced in the above link (i.e. 3x stand build) would put that type of build beyond most peoples pockets. However, as an aside, I would like to note that at this point in time it's looking possible to get passive spec. for about 20% over standard build price. It wouldn't be the eco friendly breathable timber frame route but it wouldn't require much heating either.


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## RMCF (30 Jun 2008)

Well no harm but a cost of 3x the standard build cost is not really acceptable, even for the most securely insulated house in the world.

I don't see how you could justify spending that amount of money - it would not pay for itself. 

I was thinking that I would be spending around €150k on my build, but spending approx €400k would be folly. That extra money would buy a lot of oil.


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## Gaothfar (6 Sep 2008)

Hi,
Can you plumb a dishwasher into the hot supply - to take advantage of the 'free' hot water from solar panels?
Thanks


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## Mrs Aol (6 Sep 2008)

Yes, we have our dishwasher using the hot water from our solar panels.


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## aircobra19 (6 Sep 2008)

I was under the impression that most modern machines don't take a hot feed any more. I can't remember the reason.


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## Vanilla (7 Sep 2008)

It's because a dishwasher uses very little hotwater so if you 'open' the hot water tap the dishwasher actually fills with the first small amount of cold water in the pipes, then the pipes are full of the hot water coming after which is never used and thus is wasted.


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## tsherman (8 Dec 2008)

I'm not sure If anyone is still interested, but I'm a Grad student in Architecture and we built a house last year for a competition (The Solar Decathlon) and it ran off nothing but solar for everything! We used vacuum tubes for our solar hot water. We ran showers, dishwasher, and any hot water for cooking (as determined as average use by the competition) consecutively for 5 days during the competition. We never once ran out of hot water. We had an electric backup hot water heater but only had to use it initially the first day to bring the water temp up for the first run, but that was it.

You may be able to find some useful information through the competition website (all the manufactures should be listed). Or this solar technologies website.
http://www.solardecathlon.org/
http://www.thermomax.com/index.php

From my limited but thorough experience the vacuum tubes can't be beat. They are much more efficient and can insure heat even through winter! In combination with a wood pellet boiler could be a deadly and cost effective system. It's claimed that vacuum tubes on a well insulated house can pay for itself in 3 to 7 years.


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## sfag (8 Dec 2008)

Mrs Aol said:


> Our house is not a conventional build. It's super insulated and very airtight.
> 
> Pellets cost about 200euros per ton in bulk and 330 per ton bagged. We used 1.15 tons but as I said we wasted quite a few until we figured out the best settings (we had it set on and off then on again then off again several times a day - it's much better to have it on fewer times and for longer in our case twice). We used firestixx and a small amount of brites.
> 
> ...


 
dont understand your conclusion there.
You have shown how efficient your pellet heating is. 
You dont separate the solar afrom the pellets.
How can you say the solar is working.

Regarding solar. 
it just doesent make sense..
it nees sun in the winter time - in the evening. How can it work?

You mention 30 grand for your system - is that jus the solar & the pellet boilers. My large gas boiler cost 2 grand. ???


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## sfag (8 Dec 2008)

tsherman said:


> I'm not sure If anyone is still interested, but I'm a Grad student in Architecture and we built a house last year for a competition (The Solar Decathlon) and it ran off nothing but solar for everything! We used vacuum tubes for our solar hot water. We ran showers, dishwasher, and any hot water for cooking (as determined as average use by the competition) consecutively for 5 days during the competition. We never once ran out of hot water. We had an electric backup hot water heater but only had to use it initially the first day to bring the water temp up for the first run, but that was it.
> 
> You may be able to find some useful information through the competition website (all the manufactures should be listed). Or this solar technologies website.
> http://www.solardecathlon.org/
> ...


 

Interesting that - it proves that solar is pointless. 
5 days in my house with showers, sinks, dishwashers and washing machines every day will cost me €1 a day.

Your elaborate experiment saved you 5 quid. 

All comparisons are redundant unless you compute the price of comparisons. 
It is astounding how many people think heating the hot water clyinder is some sort of break through. 

central heating is the where the expense is.


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