If the entire life cycle analysis of buildings is studied that is the energy used to construct, maintain and demolish a building and all the energy used operating the building then nothing comes close to earth in terms of minimal energy consumption. Recent research shows earth buildings in Australia using half the power, or operational energy of their neighbours (Soebarto).
The energy consumed in sourcing materials and in construction is the embodied energy. The embodied energy figures for raw earth are a small fraction of other materials. (see figures below).

Data from various sources including Intermediate Technology Development Group and the Centre for Alternative Technology. Taken from Earth Building by Lawrence Keefe.

Also read our Earth Building page to see how earth building is appropriate, renewable, sustainable building technology.

It is certainly my experience and that of people who also live in earth buildings. In fact all homes built with heavyweight or mass walls have stable internal environments because the thermal mass balances daily and even day to day fluctuations in temperature. So in relation to climate, time of day and season earth walled homes offer a reasonable temperature inside compared with outside without heating or cooling.

This comfort may not be perfect all year round though depending on your climate it may negate either the need for heating or cooling for most of the year and offer a predictable, even, gentle radiant coolth or warmth from heavy mass wall surfaces. This is called free running with natural conditioning.

Furthermore thermal mass allows the building to balance and store any applied heating or cooling energy and to maintain thermal comfort and efficiency with minimum air changes.

Yes, moderatelty to perfectly so. Thermal Mass should be coupled with Appropriate Climate Responsive Design Principles for the best results with the Autonomous Building being the ultimate goal of the best design. I would also recommend the use of thermal mass walls internally not just for exterior walls.

We will ignore trial and error and the observations and wisdom of billions of people from around the world over the past 11,000 years who developed and are living in local vernacular climate responsive earth buildings.
Yes. Recent Adelaide University research papers have revealed earth homes are using half the energy of their neighbours and this is the subject of further research. Research at Newcastle University with “Think Brick” has proved uninsulated cavity brick buildings (mass buildings) are out performing light well insulated buildings in energy efficiency.

This is what most people believe because earth buildings work so well. The truth is that, whilst earth buildings are thermally efficient, most earth walls are average insulators when tested with the same equipment and testing criteria as bulk and reflective insulation. It is well understood and hotly debated amognst insulation manufactures thar reflective and bulk insulation have differing values in winter and summer. What is not reconised in this country is that mass has different values as well. The Effective "R" value of earth is different according to solar orientation, exposure and colour for example (McHenry). Mass, reflective and bulk insulation are completely different in the way they behave. Only mass has thermal inertia and capacitance.

Mudbrick walls 250 mm thick and Rammed earth walls 300mm thick have roughly the same “R” value as an uninsulated cavity double brick wall roughly R 0.5 (in Australia). However, earth walls and other mass walls have great “Y” values, admittance. Admittance is about energy uptake and release over time. Admittance is responsible for the thermal flywheel affect that works to balance and maintain comfort in mass buildings.