Indoor versus Outdoor Temperatures (1096 days)

Indoor-Outdoor temperature scatter-plot

This is a scatter-plot of indoor and outdoor daily maximum and minimum temperatures for a solar-passive house in Monash Street, Manilla, NSW. The house is not heated or air-conditioned.

Data in this graph are taken from two thermometers; one in a Gill-type thermometer screen seven meters from the house (photo in Gallery), and one on a wall in a core room of the house. The data are for the first three years of good screen readings.

The graph shows that indoor temperatures vary only 42% as much as outdoor temperatures. The outdoor temperature range is 45.9° (from -4.4° to 41.5°), but the indoor temperature range is only 19.4° (from 13.4° to 32.8°). Most indoor temperatures are within the “comfort zone”. Average temperatures are 17.8° outdoors and 22.3° indoors. The house raises the indoor average by 4.5° to near the ideal for comfort.

There is a similar three-year scatter plot for a solar-passive house at Bonnyrigg, near Liverpool, Sydney in “Energy Efficient Housing for New South Wales” by Ballinger, Prasad and Cassell.
Very likely the data is in this paper by John Ballinger:
I think Ballinger’s scatter-plot for a house near Liverpool must include daily maxima and minima as mine does. His extreme outdoor points are 40° and +1° (range 39°) and extreme indoor points 32° and 12° (range 20°). In broad terms these two houses seem to yield similar levels of comfort, but the Manilla house does it in a more extreme climate. Manilla’s daily temperature range is 15.5°, while Prospect Reservoir, near Bonnyrigg, has only 10.9°.

This post is one of a set of four back-dated to June 2010:
Indoor versus Outdoor Temperatures (1096 days) (This post.)
Indoor versus Outdoor Minima (1096 days)
Indoor versus Outdoor Maxima (1096 days)
Indoor/Outdoor Regressions for Maxima and Minima

This article was originally posted in the weatherzone forum thread “Indoor Climate” on 5th June 2010. It is backdated here to 15th June 2010 and made sticky 9th July 2014.


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