You want to go around looking like Saddam, go for it. You're not too good at following the point though, are you? I was talking about working - many people wear a suit in work. When you're in a shirt, tie & trousers and some plank has turned the a/c down, you get horrible and sweaty - something I'm sure you like, but the ladies don't usually take to too well! If you're too cold all the time, wear a goddam vest!
And FYI ... people in hot countries have ICY cold office and shopping buildings (USA, Middle East, Far East, etc.). It's hot outside so they jump into cold taxi's or cars (or in some cases a lovely cool underground system, something LU claim isn't possible!!).
I already did this once for you and not very long ago. Would you like me to dig out the figures that demonstrate once again that you are talking nonsense?
You claim anything over 100mm of loft insulation is not worth it. Please convince me. Don't make it up.
Strange that current building rags are over 100mm and in 2007/8 they will be well over. Maybe you know something the BRE, the Germans, Dutch, Scandinavians and North Americans don't know.
Consider a detached property with an overall footprint of 8m x 8m and a height of 5m to the eaves. Floor is concrete throughout and there is a pitched, felted roof. Walls are brick and block with 50mm cavity insulation. All rooms are at the same temperature of 21 degrees, and the outside is -3 degrees. There are a total of 10 rooms with an average window size of 1.5 sqm in each, and patio doors
3m x 2m
Using the required U values from the Approved Documents to the Building Regulations:
Floor U = 0.25 Walls U = 0.35 Windows U = 2.0 Roof U = 0.16
Floor area = 64m^2 dT = 24 Heat loss = 64 x 24 x 0.25 = 384W
Window area = 21m^2 dT=24 Heat loss = 21 x 24 x 2 = 1008W
Wall Area = 8m x 5m x 4 = 160m^2 less 21m^2 windows net wall area = 139m^2 dt = 24 Heat loss = 139 x 24 x 0.35 = 1168W
Roof area = 64m^2 dt = 24 Heat loss = 64 x 24 x 0.16 = 246W
This comes to a total of just over 2800W In addition, in order to heat the average number of air changes of
1.5 per hour, additional heat of 3975W is required making a total of
6775W.
If the U value of the roof were increased to 0.36, which is the approx value if 100mm of insulation were used, the heat loss through the roof increases to 554W, the difference being 308W.
In other words, the saving is 308/6775 = 4.5%
In comparison to the walls and windows it's negligible.
If you were to take a slightly older property having twice the U values for each surface, the improvement gained by going for more than
100mm of insulation drops to between 2 and 3 %.
That depends on the type of insulation, of course. Frankly it's demonstrably window dressing to play the Kyoto game.
On a 3 year spread the initial cost of loft insulation to the money saved in heating using gas, levels out at 400mm. It starts to rise at around 500mm. The bottom line: 400mm is the optimum thickness over 3 years. In the longer term, over 3 years, the thickness level rises. Source: The Whole House Book, by The Centre of Alternative Technology.
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thicker the better.
Note: A reputable source is given.
And again...
In the book EcoHouse - A Design Guide, they gave a study that calculated in
1987 200mm was the optimum in walls at the then current fuel prices.
As fuel prices rise and the insulation manufacturing costs too, the whole payback calcs were skewed somewhat. So they calculated insulation levels on energy to make insulation. They came to the thickness of 650mm. The conclusion was that what constrains you is the detailing of the structure to hold as much insulation as possible.
That all assumes a house constructed on some sort of "eco-principle" from scratch. You don't say who "they" are, so it is not possible to determine the reputation of the material.
I did not base my illustration on that, and did not say that I was doing so.
I clearly stated that the illustration was on the basis of today's requirements from the Building Regulations and used figures to illustrate the point that in the overall context of a house built to those standards, the effect of the amount of insulation in the roof beyond 100mm becomes negligible.
I then illustrated what the case would be for less well insulated walls, and that is even less.
These are real-world examples from the typical housing stock of today.
Your material from CAT and elsewhere is interesting I'm sure, but I don't really think that the average person is going to insulate their walls with 650mm of material or even their loft with 500mm, so it's academic.
I've only just caught up with this thread because on Friday we went off and only got back last night.
We had the best two night's sleep - and days working too - we've had for weeks, despite sleeping on a hard earth floor.
We were at Bede's World, Jarrow (I can thoroughly recommend it) and living in a Dark Age long house.
The floor, as I said, is beaten earth. There were two ill fitting doors on the long walls, almost opposite each other.
Two unglazed and high windows could be shuttered but we didn't.
The roof was thickly thatched and overhanging, the ceiling high.
The building was timber framed, the infill was thick daub.
It was cool, delightfully cool. Even during the day when I was working over a charcoal firepot I was cooler than when I went into the sun. The hens stayed in the building rather than go outside. Spouse worked outside but under the shade of the eaves.
On Sunday morning we had very heavy rain and a long thunderstorm but I reckon (didn't measure it) that the temperature indoors stayed more or less the same as the rest of the time. The butter didn't melt, the milk didn't sour, the fruit and vegetables didn't wilt, we didn't sweat.
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