Heat Calculation

Structuralism

Hi guys

Trying to calculate the required amount of wattage to heat each room of my house. Does anyone know what is the actual formula for that? I have checked some websites but each have given me a completely different answer! So what is the real formulation?!
Thanks in advance.

Pincher

http://www.plumbnation.co.uk/heating-calculator.php

How Does a Heating Calculator Work?

First you need to measure the dimensions of the room that you are looking to heat, measure its glazed areas, and establish what lies below and above that room. Once you have your measurements you are now ready to begin the heating calculation:
Type of Room – e.g. living room, hallway, etc.
Height – the height of the room in metres.
Width – the width of the room in metres.
Length – the length of the room in metres.
Type of Windows – e.g. double glazed with plastic frame, singe glazed with wooden frame, etc.
Glazed Area (m2) – e.g. multiply the height by the width of the window.
Number of External Walls – e.g. an external wall will form the outer surface of the property.
Type of External Walls – e.g. insulated brick cavity, 220mm solid brick, etc.
What is Below the Room – e.g. heated room, soil under a concrete floor, etc.
What is Above the Room – e.g. pitched room insulated, flat roof uninsulated, etc.
Once you have entered your details hit the calculate button and you will be issued with the exact Watt / BTU ratings. You will also be issued with a list of recommended radiators that we supply.
You can use the Heating Calculator as many times as you like for as many rooms you need, however you must perform a separate heating calculation for each room that you intend to heat.

Premier_2

http://www.diydata.com/planning/ch_design/sizing.php