HeatLossJS
A small open source room by room heat loss calculator
Create html page, load heatloss.js tool with the following:
<script type="text/javascript" src="files/bothylab_data.js"></script>
<link rel="stylesheet" type="text/css" href="heatlossjs/style.css" />
<script type="text/javascript" src="heatlossjs/model.js"></script>
<div id="heatloss"></div><script>heatloss.init("#heatloss")</script>
Define your building in json object input definition (loaded in the first line above).
Examples:
Examples with notes on input values: