Triple glazed windows V's solar panel

Sparky78

I like to get both but my budget is very stretched.

What would be the better option in peoples opinion(cost is about the same)?

Upgrading my windows from double glazing(timber with no thermal break with double glaze krypton filled(glass pane u value 1.1) to triple glaze(glass pane u value .7).

Or

Installing 4 m2 of solar tubes for water heating.(I'll have an oil condencing boiler)

Thanks

sydthebeat

solar tubes... no question....


upgrading from 1.1 to 0.7 is only useful if you are at the very low end of energy values... ie at passive levels....

Sparky78

sydthebeat wrote: »

solar tubes... no question....


upgrading from 1.1 to 0.7 is only useful if you are at the very low end of energy values... ie at passive levels....

Walls will be u value .16 and sloped ceiling .14(only problem is velux windows and domer windows)

sydthebeat

Sparky78 wrote: »

Walls will be u value .16 and sloped ceiling .14(only problem is velux windows and domer windows)

you would still be quite a bit from passive levels so this reinforces my answer...

remember, the devil is in the detail...

definitely solar tube collectors..

Sparky78

sydthebeat wrote: »

you would still be quite a bit from passive levels so this reinforces my answer...

remember, the devil is in the detail...

definitely solar tube collectors..

Thanks for the advice. 1 less thing to worry about.

holdfast

Hard one to call, you need to estimate your hot water requirements before seeing the payback on solar. If you don’t use all the hot water produced then its a cost to you each day till you reach payback. You also need to look at what is providing space heating and its efficiency as the alternative to the solar. I looked at my case and estimated it would be 12 years before I hit a payback. HW costs are pretty low for the year in most houses

Going for Triple is not going to move you too far or save you too much unless you have a lot of it glazing. Make sure you are purchasing a good triple glazed window with frames insulated etc. At the difference your post suggests you don’t have above the normal amount of glazing. You are already at a low energy house u value and a good double glazing at this stage may be a better option as you will not make the passive standards (Germany ones)

You need the maths worked out for each case to see if one was more financial beneficial. But to put my neck on the line solar, just because I don’t want to make myself feel bad about having one.

blackiebest

In this country definately solar tubes, IMO

Fergus Wheatley

Change the hot water cylinder first, (fine if you're changing it anyway for solar). This will save about 2000 kWh a year, if you have a uninsulated (or poorly insulated) copper one already.

Then stick up solar panels. This equates to another 2000 kWh (for 6 sq meters).

In most houses hot water is about 1/3 of the whole heating bill. So the solar panels could knock 25% off the heating bill. Triple glazing won't get even close to this.

hope this helps

wardwil

As already stated - no brainer. Solar tubes. Check out the hybrid tube... cannot remember who puts them in. Also there is a deal on at the moment in Connaught Gold for solar.

Triple glaze for the saving and increased performance compared to the outlay it does not work out. Even a top quality window supplier will tell you this if they are not out to take every penny you have.

PM me for excellent window supplier.

sinnerboy

I agree with the advises above - solar panels for the reasons stated

AND also -

you will have no choice but to to use renew ables if you don't finish the build soon

http://www.boards.ie/vbulletin/showthread.php?t=2055500071

The requirements of the 2008 regs kick in very soon . They are onerous .

To get your max permitted CO2 emission rate down - you may also need to use a wood stove for your secondary heat source

Your BER assessor will advise having first done a DEAP ( Dwelling Energy Assessment Procedure ) analysis

Please take part in the poll in the link above when you have have made your choices

.

Lightning McQue

Folks

I would disagree with the comments made because a more accurate calculation needs to be made by one of the guys here who has DEAP.

Holdfast has given an accurate acount of what needs to be done to make an informed decision.

The last time I checked 5 sq metres of evacuated tube solar panels were €4400 less grant which gave a net cost of €2900.

You would need to use at least 175 litres of hot water every day for the next 15 years to make they pay. This assumes night rate electricity.

Therefore the question I will pose is will you use 175 litres of water every single day for the next 15 years. Thats a lot of showers!!!!!

On the other hand there is an old thread here on triple glazed windows and if you were to instal good quality alu-clad timber windows then after 20 years you would save yourself €9700 (my figures based on ESB). Good quality windows will last at least 30 years.

Remember the kids won't always be living with you so who's going to use all this solar heated hot water. The windows are permanent.

Some posters here have suggested triple glazing your north facing windows and double glazing the rest which is a good idea. I obtained quotes on this basis from local windows cos for pvc windows and then compared these to triple glazed foreign alu-clad windows. The difference was €11000. Two different products though.

Since I am putting in a heat pump I wont get a grant for the solar panel so the payback for the evacuated tubes is 22 years.

Wardwill can you pm your window supplier please.

Thanks.

Lightning

sydthebeat

Lighting, i wonder if youve misread the question...

it wasnt a solar collectors versus nothing query, it was solar collectors versus triple glazed windows query.

assuming firstly that the OP can upgrade from DG to TG for the €2900 youve quoted (which i sincerely doubt) then...

the question is simply one of which element will reduce energy demand by the most.... and theres no question that solar collectors will.

Theres more to reducing energy demand than just "pay back" periods.. these are purely arbitary arguments..

Lightning McQue

Syd

You've made a mistake in relation to the €2900.

I said in the post that it was at least €11000 to upgrade all the windows to triple glazing.

I wouldn't get a grant for the solar panels so the cost of the solar was €4400 (grant was €1500 so 4400-1500 = 2900). The panels don't pay for themselves. If you take the cost of the panels away from the triple glazing then your cost for triple glazing is €6400. The windows will save you €9700 over 20 years.

I dont believe that you will use all the hot water - 175 litres per day. So you could always put in the pipework for the solar panel and when the prices of solar drop further then may be instal the solar panel.

I suppose you could always say in three years time apply for a grant to instal solar if the SEI is in existence.

Anyway the choice was solar verses triple glazing ie €4400 verses €11000. Which one will save me the most money in the long-term? That is the question that is so difficult to answer.

Methinks the windows.

Lightning

sinnerboy

A DEAP calc would tell . Remember - TG windows will not count towards B Regs requirement for renewables- solar panels will

sydthebeat

in your case lightning.. your TG is NOT 'saving' you anything....

if you think spending €4400 on solar collectors would have a 15 year return period, then spending €11,000 on upgrading from DG to TG would have a return period exponentially of that figure....

you seem to be taking the requirement to change your windows into the equation. well, alu-clad DG should last just as long as alu-clad TG... similarly hardwood DG should last as long as hardwood TG.... this doesnt affect the OPs query at all....

the question is simple.... does solar collectors, on a per € spent basis, save more energy than triple glazing.. .and the answer is a clear and apparent YES....

triple glazing, in a moderately constructed dwelling can actuallty have the affect of restricting more solar heat gain than witholding within the dwelling. Its only when you are at passive levels does the benefits of triple glazing outweigh negatives.

sydthebeat

sinnerboy wrote: »

A DEAP calc would tell . Remember - TG windows will not count towards B Regs requirement for renewables- solar panels will

im working on a prov DEAP at the moment, ill show results as soon as i have them...

Lightning McQue

Syd

The ABCDE rating does not concern me. I am going to spend as much as I can to make the house as energy efficient as possible within reason. When I asked the local window supplier why he triple glazed the windows in his house he laughed, not personally at me but you know that kinda laugh to say well you sorta know that triple glazing is better.

The double glazed pvc window had a uW of 1.43.

The triple glaze window had a uW of 1.0

The uValue of the the floor was 0.126, Wall 0.18 and roof will be 0.10.

An air to water heat pump will be installed.

Closed combustion stove and insert.

I will be making the house as airtight as possible so aiming for 3.

So if you want to punch these figures into DEAP it would be very interesting to see what it shows up.

Lightning

bladespin

Solar definately, it will give the most noticable difference, reducing the cost of heating and hot water, TG while great is only slightly better that DG (working correctly) on a 'normal' house.

Lightning McQue

Bladespin

When I asked a supplier of heat pumps/solar panels should I instal a solar panel he told me straight that the solar panels would not pay for themselves. Put the money into better quality windows.

I am not like some of the posters on this site who are flogging solar panels who are constantly telling us how good solar panels are yet there is report on this site from a chap in the Tipperary Institute who appears to offer a different perspective on solar panels and there payback periods etc.

At least the information is unbiased.


Lightning

bladespin

Lightning McQue wrote: »

Bladespin

When I asked a supplier of heat pumps/solar panels should I instal a solar panel he told me straight that the solar panels would not pay for themselves. Put the money into better quality windows.

I am not like some of the posters on this site who are flogging solar panels who are constantly telling us how good solar panels are yet there is report on this site from a chap in the Tipperary Institute who appears to offer a different perspective on solar panels and there payback periods etc.

At least the information is unbiased.


Lightning

I have no vested interests here either but solar does pay for itself (over time), looking from my own point of view (30yr old house, DG, insulation upgrade started recently etc) putting TG in would make very little real differece while Solar would provide free hot water and heat (some).

As paybacks go I would have to wait about 20 years for Solar to be worth while, TG would be significantly longer : as an upgrade from DG that is if I was building then TG to start with would be a much shorter payback time.

The biggest gains come from insulation definately but I wouldn't imagine there would be massive gains to be had moving up from DG to TG.

sydthebeat

Lightning McQue wrote: »

Syd

The ABCDE rating does not concern me. I am going to spend as much as I can to make the house as energy efficient as possible within reason. When I asked the local window supplier why he triple glazed the windows in his house he laughed, not personally at me but you know that kinda laugh to say well you sorta know that triple glazing is better.

The double glazed pvc window had a uW of 1.43.

The triple glaze window had a uW of 1.0

The uValue of the the floor was 0.126, Wall 0.18 and roof will be 0.10.

An air to water heat pump will be installed.

Closed combustion stove and insert.

I will be making the house as airtight as possible so aiming for 3.

So if you want to punch these figures into DEAP it would be very interesting to see what it shows up.

Lightning

lightning,

give me average floor areas (Gf.. FF etc), average floor to ceiling heights, dwelling description (semi-d, detached etc), how you will be ventilating, how many bathrooms you have, how big your living room is, and roughly the sq m of glazing on each elevation.. please.

ill then input as best i can.

but to be honest, your house, if not yet built, will need to conform to 2008 regs and whilst you definitely are describing a good spec, its always a good idea to get a DEAP assessment done before work commences to ensure you will be building in accordance with regulations...

eg should your ATW heat pump actually turn out to have a COP of 2.9 then you wouldnt comply with building regulations....

Lightning McQue

Syd

If I can I will pm the drawing to you because I dont have the software to open it so I cant give you exact figures.

Ventilation will be MVHR.

The dimplex heat pump has a COP of 4.10 at +7/W35, COP of 3.4 +2/W35

Thanks.

Lightning

Lightning McQue

Syd

Any news on this

Lightning

sydthebeat

lightning, i wont get a chance to look at it until teh weekend, ill let you know on monday...

Lightning McQue

Syd

Thats great, thanks.

Lightning

sydthebeat

Lightning McQue wrote: »

Syd

Thats great, thanks.

Lightning

lightening, ill confess, ive been too busy (thankfully) to put your dwelling through the software.....

but my findings regards the question of triple glaze versus solar panels has thrown up the following information.

basically, if you are upgrading from a double glazed unit of about 1.5 u value, then triple glazing will make a equitable significant saving as compared to installing say 6 sq m of tube collectors.

so basically, if you are planning on installing windows of 1.6 or worse, then upgrading to triple glazed windows of 0.9 u value is worth it.
However, if installing better than 1.5 windows, then solar collectors are a better....

that being said, i was using default figures for solar tubes, which from experience, tend to be very bad in comparision to actual product details....

Leadership

Here is a general question with tripple glazed windows would you lose solar gain? My (future) home is south facing so we have been advised to use tripple glazed windows on the north windows and double glazed on the south to maximise the solar gain.

BTW getting more and more quotes back from solar companies to fit 6m2 of tubes plus 300l stainless steel tanks and fitting for €2900 > €3500.

Lightning McQue

Syd

Thanks for that. But I am a little confused by your post.

Ok, upgrading to a triple glazed unit of 0.9 is better than installing solar panels.

However did you mean that if you are installing "worse" rather than better than 1.5 windows, then solar collectors are better?

Perhaps you could answer the following question:

the double glazed A rated Uw = 1.43

The gW solar gain is 0.45 on the A rated window.

The cost of the double glazing is €22k.

I priced the windows as per what Leadership did below and the cost was €26k

The triple glazed Alu-clad was €38k.

Do you think its worthwhile putting in the triple glazed window?

I would really appreciate your comments because I have to make a decision about the windows shortly and I am leaning towards just double glazing south facing/triple glazing the north facing windows.

Thanks.

Lightning