[Greenbuilding] Fireplace questions

[Johnsbone@gateshead.plus.com]

You are correct, the fact is 66% of the thermal heat of a fire (open or
enclosed) goes up the chimney, as very hot air, and in most open fire homes,
that hot air exaust drags in 'cold air' through all the gaps in the
construction of the house, floors, walls, doors, windows, and ceilings.

The 1960s and 1970's house in the UK had no specific thermal insulation in
its new build construction. The ordinary U-value of a external wall was 3.0
w/m2/k and the roof was around 5.0 w/m2/k (RSI-0.20 = R-1.13)
These are very poor values, and the real difference being the lack of wind
chill on the occupants of an unheated space, when compared with those same
folks being outside the building. Little better than an open ended cave!

The recent Building Code (Building Regualtions) changes in the Uk have
concentrated on this "air tightness" factor. With the moto "build tight and
ventilate right". As of 2006 all new build homes have to be air-pressure
tested before occupation, and the house construction are loss has to be less
than 10 M3/M2/Sec. (or about 0.5 an "air change" per hour.)

In general Terms:
The minimum insualtion value for a (new build) roof in the UK is now 0.16
("U" value) or RSI-6.25 = R-35.46
The minimum insualtion value for a (new build) wall in the UK is now 0.35
("U" value) or RSI-2.86 = R-16.23
The minimum insualtion value for a (new build) floor in the UK is now 0.25
("U" value) or RSI-4.00 = R-22.70

All Door and Windows Glass MUST be double glazed with a minimum insualtion
U=Value of 1.8 (RSI-0.556)
Your windows area design can not exceed an glass area of more than 25% of
the total floor area.

You can do Total Energy calcuamtions to vary these, but the Dwelling's
Maximum Energy Target can not be exceeded. Unless you add in some renewable
energy. This is calulated in Carbon Emmission Equivelents. (CO2)

John Bone, BSc Hons, MBEng
Building (Code) Regulations - Building Engineer (UK)

----- Original Message ----- 
From: "Corwyn" <corwyn at midcoast.com>
To: "David Delaney" <ddelaney at sympatico.ca>
Cc: "Greenbuilder list" <
Sent: Wednesday, November 08, 2006 7:11 PM
Subject: Re: [Greenbuilding] Fireplace questions

> On Nov 08, 2006, at 10:56, David Delaney wrote:
> At 08:56 AM 08/11/2006, Corwyn wrote:

>> People heated their houses for centuries with fireplaces.
> > They heated mainly themselves by huddling around the fire to intercept
thermal radiation.  The fire didn't really heat
> > anything that it could  not see.
> > It never does.
> > My experience of a couple of houses in England in the 70's is that
houses "heated" by fireplaces were as cold as outside
> > except in front of the fireplace. And I did damn nearly freeze in them.
>
> And the insulation in them was what?
>
> Thank You Kindly,
> Corwyn
> Kermit didn't know the half of it...
> http://www.greenfret.com/
> corwyn at greenfret.com