Insulation – 1st year’s performance

The insulation of this house was given top priority (see previous blogs #1 #2) so in this post gives an update on how this insulation has performed.


In December 2014 I starting recording temperatures inside and outside the house to measure the effects of the insulation during the winter. As can be seen from the graph (click for full size), average temperature inside the house during the 18 hours when we don’t have any heating on in the house, is 16c, whereas the average temperature outside over the same period has been 4c.

temperature data

temperature data

Hira eco house snowWe only have the wood stove for heating and almost without exception, the fire only needs to be on in the evening, after six or seven o’clock. The house then remains warm until the following evening.

To show this in more concrete terms, I recorded temperatures in the early morning, and again in the early evening, before the fire was lit again.

The lowest temperatures in the house are in the evening Hira eco house snow viewand after days that are particularly cold, windy or cloudy. Results are from recorded readings made are over a 3 or 4 week period, but on random days, depending on when I was around and/or remembered to make them.


During our first summer in 2014, while temperatures outside reached as high as 37c, inside rarely went above 28c. And while the windows were open most of the time, the reflective properties of the insulation still helped to keep the house cool by preventing the heat of the sun penetrating the roof and walls of the house. As a result, we only needed the moderate use of fans, mostly at night, and kept windows open to encourage air flow through the house.


About ifd66

From UK and living in Japan. I am very interested in sustainable development and in general ecology and conservation issues and solutions. Finished building a low impact family house in Shiga, Japan in 2013 and am now focused on using permaculture to develop our plot of land into a more sustainable, productive, and attractive space. My hope is that this blog is useful to those interested in similar issues and way of life.
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One Response to Insulation – 1st year’s performance

  1. Pingback: Insulation, insulation, insulation | Shiga Eco house project

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