Domestic Energy: Myths and Misconceptions

S

sfag

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Folks I thought I like to start a thread of modern misconceptions in the building industry. There are a lot of myths out there that most people believe.

I'll get the ball rolling.

1. The silver foil on insulation has thermal benefit.
The truth is it does not - well at least none worth talking about. The insulation comes from the insulation - not a piece of foil. If it was that easy Kingspan would not be in business.

2. Double insulation is worth doing. Eg 60 mil on the cavity and 25 mil on the plasterboard.
The truth is it does not = 85 mil worth of insulation. The thinnest insulation will let most of the heat through only to heat the inner cavity. The heat will stay trapped to some extent. The thermal benefit has been proven to be negilible - not worth the expense.
Bit like a small sea wall letting some of the water past only to be stopped by a larger sea wall - pointless bothering with the small wall at all.

3. Heating the hot water cylinder by an alternative heating source is worth doing.
Its not. Its dirt cheap to heat a hot water cylinder - €1 a day via gas. No overly expensive high tech solution required. its a problem that does not need solving.

4. Domestic wind turbines work.
Fraid they dont.

5. Solar heating works.
personal view here - no it doesn't - not in this country at least. This one has been discussed to well on these boards. I know people who have it says it does work but I don't believe them - and they never crunch the numbers anyway. The sales pitch that says it works even on cloudy days is just snake oil talk. I just cant conceive how it can work. Its always cloudy - plain and simple.
 
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Re: Modern myths and misconceptions

I took this post semi-seriously until I came to the last line
"Its always cloudy - plain and simple."
this is patently untrue so I now have no faith in any of the other proclomations
 
Re: Modern myths and misconceptions

sfag, youre on a wind up obviously....

perhaps if you back up all your claims with hard evidence we will take you seriously....
 
Re: Modern myths and misconceptions

I was being serious.
The first three are fact. The last two are more subjective but I argue they are true.
As for cloud cover. Ireland's sky is roughy 90 percent cloudy 90% of the time yet people are still buying solar panels. Duh?

I seriously challange all of you folks to apply logical thinking before running with sales presented 'scientific theory'. If it doesent make sense in your brain in all probability it wont work. Solar is a good example of this.
 
Re: Modern myths and misconceptions

Unless you can back up your statements then they are your opinions. By saying they are facts does not make them facts. If you are so sure about them please add a few links so we can all judge for ourselves.
 
Re: Modern myths and misconceptions


dublin for 7 days. Almost all cloud. Dosent improve much in the summer either.

You could supply evidence that points 1 to 3 do work.
 
Re: Modern myths and misconceptions

1. The silver foil on insulation has thermal benefit. The truth is it does not - well at least none worth talking about. The insulation comes from the insulation - not a piece of foil. If it was that easy Kingspan would not be in business.
Click to expand...
It probably does nothing for convective heat transfer but helps for heat transfer via radiation.
The foil reflects IR radiation. A similar principle as to buildings being painted white to keep them cool inside, or why wearing white clothing is cooler than dark colours.
 
Re: Modern myths and misconceptions

sfag,

I agree with your point 4.I subscribe to Sustainability Magazine which took a neutral view of wind turbines and concluded that they are not worth installing.

I am fairly levelled headed guy like yourself and don't subscribe to ''green energy'' at any price.At the moment oil is cheap and quite possibly will remain so for the next 3 - 5 years.But just because you didn't dryline your external walls doesn't mean that its not a good idea.In fairness it has been proven to be a good idea that reduces heat loss and the insulation on the plasterboard can be up to 80mm.

Solar panels do work ''when installed properly''.A friend of mine has them and genuinely does not need to heat water by any other source from April - September.He didn't involve the SEI - he imported them directly from Germany himself.I have seen solar panels on new houses in the South East and they are about one third of the size of his but generally the houses are bigger.Probably installed by ''an approved installer''.His cost to supply and fit was the same as going thru SEI and claiming the grant but his panels are alot larger.

The only problem I can see is that people doing new builds don't allow for the cost of the greener technologies when they are designing their houses.If you are going to install these make the house smaller and include them in your cost.At the end of the day if you build an A-rated house for €40,000 more than a C-rated house your savings in energy use will be eaten up by higher mortgage repayments which leaves you with no saving at all.
 
Re: Modern myths and misconceptions

Light shines through even on cloudy days. Solar Panel do work, however it takes time to make the money back on them.
 
Re: Modern myths and misconceptions

isnt there some guy on here from Cork that has a website which tracks the temperature in his solar tank,
there should be sufficient data on that to answer some of the issues raised!
 
Re: Modern myths and misconceptions

i think it was irish eco plumbing is the website / guy you mean
 
Re: Modern myths and misconceptions

bamboozle said:
isnt there some guy on here from Cork that has a website which tracks the temperature in his solar tank,
there should be sufficient data on that to answer some of the issues raised!
Click to expand...


follow the link to see the temerpatures on the tank

[broken link removed]

interesting reading
 
Re: Modern myths and misconceptions

sfag said:
dublin for 7 days. Almost all cloud. Dosent improve much in the summer either.

You could supply evidence that points 1 to 3 do work.
Click to expand...

We're not the ones stating their unproven opinions as fact. Generally the person making an assertion has to try to prove it.

However, I'd agree with you on renewable energy, very often it's not worth it. Solar panels for DHW are a marginal decision.

Oil is now $40 a barrel, in the summer it was $150. No-one can know what it will be in 3-5 years.

SSE
 
Re: Modern myths and misconceptions

I'm on sfag's side ......... the green/eco mafia are hell bent on pushing their (not too well thought out) agenda. Get your insulation done 100%, throw away your radiators and get fanned convectors (a few minutes will heat up the room) and keep the energy in. Install point-of-use water heaters. I did all this recently in an old farmhouse conversion and the savings are huge. A warm house with hot water on demand. Not a tank of water unless you require it ........ more often than not, you need to wash a few plates/utensils etc. Or for having a shave in the morning. Install an electric shower. I didn't get a BER - don't need to as it is for our own use. But I know when I'm warm. For the record I mushroomed 50mm Xtratherm onto the 21" thick stone walls, dropped the ceilings to 7'6". 300mm of rolled-out insulation above these. Dug out the old damp concrete floors, DP membrane, concrete, 4" insulation, chicken wire and 3" semi-dry floor screed.
 
Re: Modern myths and misconceptions

I don't think it's a case of being on anyone's side. The OP posted his/her opinions as Gospel on this and another thread without a shred of evidence for any of the assertions made. Still not sure if he/she was being serious or is just a wind-up merchant, a forum character if you will.

Just because your solutions worked for you doesn't mean they are universally applicable in all situations. The only part of that which is unquestionably correct is "...keep the energy in....". You could support your pattern of use with a combi boiler, for example, to give one alternative.

SSE
 
Re: Modern myths and misconceptions

I don't think sfag is winding anyone up, but it shouldn't be left alone to the one making the assertions to prove their point, if you disagree with his opinions you should provide evidence to show that he is wrong, if for nothing else only to educate the rest of us.
 
Re: Modern myths and misconceptions


1. heat is transfered by three methods... conduction, convection and radiation. The closed cell nature of any foam insulation ie polystyrene, polyurethane etc counter acts both conduction and convection but not radiation. Radiation heat transfer is counter acted by reflective surfaces thus the reason for the foil layer on kingspan / xtratherm insulation. So in this point, you are completely incorrect.

2. There is some merit behind this point, as it is ALWAYS better to have your insulation as one continuous element, which may contain layers. But in some instances a second layer of insulation inside a block leaf is an appropriate way to insulate. Personally i do not like this construction and when ever it HAS to be specified, i would insist that the drylining insulation does not exceed 0.5 times that of the cavity insulation.

3. This is simply a case of 'the straw that breaks the camels back'. At the moment renewables such as solar MAY be uneconomicalm, but there is one constant that we all can count on. That is, fossil fuel prices WILL rise.... fact. Sun energy costs will not rise,and will, in fact, fall. Also under 2007 Part L regs renewables HAVE to be included in your dwelling. This does not include the personal choice many people make to provide a renewable energy source from an ecological point of view. It would be a very sad world if all everyone saw was the bottom line figure.

4. This is a silly statement. obviously they DO work, but to what degree is the question. All the points listed above in 3 are also applicable here.

5. Im glad youve included the caveat that this is your own personal view, because again you are incorrect. I know of a dwelling in Cork completely heated by solar power also, both space and water heated. I have witnessed many control panels showing heating in the region of 25-35 deg on cold cloudy winter days. I have seen temperatures in the region of 80-90 on hot summer days!! To explain it simply there is heat in all light. the only way no heat can be transfered is if there is no light ... ie night time. Clouds do not block out sunlight altogether, they simply diffuse it.....

One thing i would agree with is simeons point about green/eco buisness. There has been a large swell in a supposed 'green' industry over the last few years. Many people find it a minefield when making decisions on buildings. For every person advocating a product theres another to lambast it.... all anyone can do is to try to get clear independant advice and trust their gut.
 
Re: Modern myths and misconceptions

Yes solar heating is overrated in Ireland. It only works 100% in July and August and 50% for May June and September. Outside this it is pretty useless.
 
Re: Modern myths and misconceptions

Hmm...beginning to sound like:

Modern myth and misconception No. 6 -

sfag knows what he's talking about.

 
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