The First Hour Rating (FHR) signifies how much hot water should be available for use when using a standard water heater with a full tank. Not only does this take into account the tank size but the recovery rate. This number is typically found on the upper right of your “Energy Guide” sticker. Heat pump & “instant” […]

The Flow Rate is a measurement for tank-less / instantaneous type water heaters based on the it can deliver with a specific temperature rise. (e.g. a system may be able to supply 3 GPM with a 40° rise but only 2 GPM at a 60° rise)

Framing Factor is the percentage of a wall assembly that is comprised of framing members instead of insulation (e.g. a conventionally framed wall may contain up to 25% wood while an wall may only be at 17%).

GDD or Growing Degree Day, is very similar to & but it is focused on crops. Instead of calculating this based off an arbitrary number, it is calculated off the crops minimum base temprature needed for it to grow. Growers can use the number of GDD’s required for a given crop and variety to reach maturity […]

GPR or Ground Penetrating Radar is a nondestructive means of viewing what lays below the surface. This has been popularized on shows like CSI where they use it looking for buried bodies. This , but also works well for detecting voids in concrete, detecting changes in topology, etc… It uses radio waves aka electromagnetic radiation to […]

Grade 1 insulation is considered a high quality installation job aka one with very minor defects based off of a 3 tier rating system originally developed by RESNET. Per the standards: Grade I installation requires that the insulation material uniformly fills each cavity side-to-side and top-to-bottom, without substantial gaps or voids around obstructions (such as […]

Grade 2 Insulation is considered a medium / moderate quality installation job. This is based off of a 3 tier rating system originally developed by RESNET. Per the standards: It is an installation job with moderate to frequent installation defects: gaps around wiring, electrical outlets, plumbing and other intrusions; rounded edges or “shoulders”; or incomplete fill […]

Grade 3 Insulation is considered a very low quality installation job based off of a 3 tier rating system originally developed by RESNET. Per the standards: Grade 3 shall be used to describe an installation with substantial gaps and voids, with missing insulation amounting to greater than 2% of the area, but less than 5% […]

Heat in it’s truest form is energy & when used in the building science field refers only to the transfer of this energy between or through items. It is not a measure of its temperature or the stored energy of the item. For More