Help & Advice

There are many ridiculous claims made about Thermal Mass.  Some come from ICF companies that claim the concrete has some mystical thermal qualities.  The mass of the concrete core acts as a stabiliser for temperature change. rather than as a heat capacitor.  If the concrete is accepting heat then the insulation is not working. 

We have seen architects wanting to strip the internal insulation layer away. The thinking is that exposed concrete will give benefit from thermal mass effect.  This is completely crazy thinking.  The concrete can act as a thermal store to some degree. However,this will be accepting heat from the house and giving it back when the house cools down during the night.  Some argue that it is to accept the heat from the low level winter sun. This happens which happens for about three hours on a handful of days each winter.  One architect had a meeting hall stripped of insulation to create thermal mass effect. However, he had only designed high-level clerestory windows in the wall! 

The adobe houses of the South Western USA are the best example of ideal thermal mass.  These heavy mud homes have solid thick walls that accept the heat of the desert sunshine during the day.  At night the heat in the walls is surrendered back to the chilly night air.  Most heat goes to the outside but some goes to the inside which is now also cooling in the evening and night.  The next morning the mass structure is cool and ready to be warmed up again.