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Our homes are modeled to use 40%-60% less energy

than a home built to code


Energy models help us build more energy efficient homes


An energy model is a software program that estimates how much energy a building will consume.  The model  uses a home’s specific construction selections to generate its energy use estimate.  Example inputs to an energy model include...


  • Is the building brick or siding?

  • Where are the windows, how large are they and how efficient?

  • What kind of heating and cooling system?

  • How much insulation is there and where?

  • How air tight is the home?


As a builder, we use the modeling data to compare how different construction choices affect energy use.  The model guides our decision making.


What is a HERS Score and how does it help YOU?


Our energy modelling softaware is REM/Rate and it generates a Home Energy Rating Sytem Score or HERS score.  A HERS score is the industry standard for measuring home energy performance.


A HERS score compares predicted energy use of a home to the same home built to the IECC 2006 code (the “Reference Home”).  The Reference Home has a score of 100.   If a house has more insulation, a tighter envelope or better performing windows, the HERS score will be lower than 100, indicating what percent more energy efficient it is.


True Turtle homes have the potential to be net zero energy!


The diagram shows how the HERS score works.


HERS 100 = REFERENCE HOME To get a HERS score, a home is modeled two ways:  how the home was actually built compared to the same home built to the ICC 2006 code (the Reference Home).


HERS 120-140  Score of most energy inefficient existing homes. Which use 20-40%+ more energy.


HERS 85 Energy Star homes use 15% less energy than a code built home. 


HERS 60-40  True Turtle homes typically achieve a HERS 40-60.  They are modeled to use (without solar) 40-60% less energy than a code built home!


HERS 0 = NET ZERO HOME  A home that is modeled to produce as much energy as it consumes.


True Turtle homes with PV systems in the 4-6kW range are projected to have HERS scores in the 0-15 range...that’s near net zero!



Although we as builders would love to say that what is predicted or modeled will come to pass, we cannot.  Energy use is utterly personal.  Some people use a lot, some use a little.  A couple could buy a house, or a large family.  With such unknown factors controlling actual energy performance, True Turtle LLC and CAT Consulting offer no guarantees whatsoever on energy performance or the ability of this building to be net zero.  

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