R-value
-- Effective 60!
by David B. South
 David B. South, President of the Monolithic Dome Institute |
First, it must be acknowledged that using standard calculations for R-value the Monolithic Dome does not exceed 27 to 30. By standard computations, we mean the summation of the Airforms, concrete, rebar and polyurethane foam will not exceed 30 in anyone's book, be it ASHAE Guide or an Insulation Guide of any kind.
So, why do we claim an effective R-value of 60? We have, on occasion, had our buildings checked by professional engineers to calculate the actual heat loss through the structure. This is done by having a measurement of the amount of heating and/or cooling inputs into the building matching the inputs with the degree days from local weather conditions and calculate the R-value which must be in place to make the equation balance. In every case, we have come up with an R-value in excess of 80. We use 60. We find it very defensible in all conditions.
Over the years we have had the occasion to check structure after structure, Monolithic Dome after Monolithic Dome and always find the R-value an effective 60 plus.
The California Handbook for Solar Energy is the only government publication we have been able to find which takes into account the thermal mass of the concrete when measuring heat loss. Simply stated, the concrete acts as a heat sink which slows the passage of heat back and forth through the wall or roof assembly.
Therefore, we claim an effective R-value of 60. We can defend that by actual practice. Our customers who have monitored their heating and cooling costs tell us that we are probably too low, that the R-value is actually higher. Obviously, with an effective R-value of 60 the structure is losing very little heat from conductance. Monolithic Domes lose very little air due to air leakage.
The function and purpose of the building makes the most difference in heating or cooling of the buildings. For example, a church with large crowds for two hours, one day a week, will have dramatically different cooling/heating needs and costs than a warehouse facility with many employees which is used every day.
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