On Fri, 23 Jan 2004 11:00:34 -0000, "Neil Jones"
wrote:



Here's my house as an exercise:-

Foot print ~ 70m2
Downstairs wall height ~ 2.1m
Upstairs wall height ~ 2.2m
Wall construction:-
downstairs 27 m solid wall construction U-val ~ 2.0
+ 8 m timber clad cavity wall construction U-val ~ 0.6
upstairs 27 m tile hung lath/plaster construction U-val ~ 2.0
+ 8 m timber clad cavity wall construction U-val ~ 0.6
Ground floor :- thick concrete + screed + covering U-val ~ 0.3
Ceiling Floorbaord/Joist/Plaster U-val ~ 1.6
Loft currently insulated with ~ 100mm mineral wool U-val ~ 0.5

Windows:-
Downstairs
2.2 m2 single glazed timber frames U-val ~ 4.8
5.9 m2 sealed double glazed units in plastic and metal U-val ~ 3.8
Upstairs
2.2 m2 single glazed timber frames U-val ~ 4.8
5.9 m2 sealed double glazed units in plastic and metal U-val ~ 3.8

Doors:-
6 m2 mixed construction U-val ~ 3.0

Air changes :- 1.5 per hour

Design parameters
=================
Outside temp -3 C

Downstairs temp 21 C (delta-T = 24)
Upstairs temp 18 C (delta-T = 21)

Heat loss - downstairs
======================
Floor = 70 x 0.3 x 24 = 504 W
Walls = (27*2.1 - 5.9 - 3) * 2.0 * 24 ~ 2295 W
+( 8*2.1 - 2.2 - 3) * 0.6 * 24 = 167 W
Walls Total = 2462 W

Windows = 2.2 * 4.8 * 24 = 254 W
+5.9 * 3.8 * 24 = 538 W
Windows Total = 792 W

Doors = 6 * 3 * 24 = 432 W
Ceiling = 70 * 1.6 * 3 = 336 W
Air changes = 70 * 2.1 * 0.36 * 1.5 * 24 = 1896 W

Downstairs losses = 6422 W

Heat loss - upstairs
====================
Floor = 70 x 1.6 x -3 = 336 W
Walls = (27*2.2 - 5.9) * 2.0 * 21 ~ 2247 W
+( 8*2.2 - 2.2) * 0.6 * 21 = 194 W
Walls Total = 2441 W

Windows = 2.2 * 4.8 * 21 = 222 W
+5.9 * 3.8 * 21 = 471 W
Windows Total = 693 W

Ceiling = 70 * 0.5 * 21 = 735 W
Air changes = 70 * 2.2 * 0.36 * 1.5 * 21 = 1746 W

Upstairs losses = 5951 W

Total losses for house = 12.3kW

Downstairs losses are 51.9% of total losses from house.

Losses through:-

Ground floor 4%
Downstairs solid wall 19%
Downstairs cavity wall 1%
Downstairs windows 6%
Ceiling to upstairs 3%

Roof 6%
Upstairs solid wall 18%
Upstairs cavity wall 2%
Upstairs windows 6%



These are quite typical numbers, Neil.

I guess that this is an older house with a new extension?

It's interesting to note that the losses are close to being the same
upstairs and downstairs.



..andy

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