Frame floor insulation over basements

[Gamaliel Lodge]

EDIT: OptiMiser now support this feature with separate floor over basement controls.

OptiMiser does not currently offer direct support for insulation in frame floors over basements.  We do plan to add support eventually, but so far there has been very little demand in our user base.  Basements typically have mechanical systems and/or duct work in them that partially condition the space making floor insulation irrelevant.  Please let us know if you work in an area where this is a significant issue.

There are currently two workarounds for modeling the impact of insulation in frame floors over basements:

1. Model the basement as an unconditioned crawlspace.  This method will tend to overestimate heating loads slightly, but will give you the best estimate of the benefit of adding insulation, where none is currently installed. (You can correct the overestimation and improve the estimate by editing the “% Tempered by Indoor” controls on the More popup, accessible on the full Crawlspace tab.  Set both the base and improved controls, as appropriate, to 50% for uninsulated and 30% for insulated.) 
2. Model the basement as a basement, but edit the assumed heating season average temperature.  Decreasing the assumed temperature will reduce the heating season loads.  This method most is appropriate if you are trying to model the impact of existing insulation and you have utility bills to help you calibrate the total loads.  In climates with significant heating loads, a 5-8 degree increase will probably produce an effect commensurate with a well insulated floor.

[Chris Mari]

We would greatly benefit from this functionality. We model runarounds in the “Frame Floor Not Over Basement or Crawl” tab regularly.

[Gamaliel Lodge]

Thanks, Chris. We will keep that in mind as we set priorities. It would be helpful, if you could privately email me a sample file, along with a description of the situation that you were trying to model.

[Eric Wheeler]

Our program would also benefit from the option to insulate floors over unconditioned basements. We run into this scenario regularly.

[Gamaliel Lodge]

OptiMiser does now support insulating frame floors over basements. The basement page now has a full set of insulation controls for floor insulation in addition to the set for wall insulation.

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