Ua-value isn't a silver bullet

Ua-value is getting attention.

But the approach of "just keep improving Ua-value" ignores economics.

To get a comfortable environment, design while considering the optimal balance of insulation and equipment performance. That's what matters.

In other words, it's the design method that lets you thin the insulation.

We're a member of Passive House Japan, and there's a certification standard called Passive House.

This standard lets you compute insulation, solar gain, and heat-exchange efficiency in detail, and judge whether the performance is sufficient.

The calculation tool is PHPP — a quite capable piece of software. We plan to make full use of it going forward.