The HTRC

The Homeowners & Trades Resource Center

Diffuser

A diffuser is meant to diffuse or scatter an object. For a forced-air heating &/or cooling system, the diffuser is a register or grille attached to the ducts to spread the conditioned air around. For tubular skylights or light fixtures, the diffuser is a cover plate or panel that scatters the light.

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Duct Blaster

A Duct Blaster is a piece of test equipment manufacturered by the Energy Conservatory for testing Duct Leakage. Many commonly refer to the testing of duct leakage by this name which is incorrect, but shows some good or maybe just some lucky marketting chops.

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EER

EER or Energy Efficiency Ratio is how they originally rated cooling appliances like your HVAC or window mounted unit. This rating takes the cooling capacity in Btu/h and divides it by the energy input required in watts (Btu/W-h). Unlike the , this measurment is only taken when it reaches its steady-state and is measured at 80°F indoors and 95°F outdoors.

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Emissivity

Emissivity or in shorthand ε or e is a percentage of how much heat an item can radiate as compared to a black body (1.0). A low value indicates low emissivity while a higher value indicates a higher emissivity – the higher the number the more accurate a temperature reading you can get with an infrared camera. […]

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ERV

An ERV stands for Energy Recovery Ventilator (though some like to change the word energy with “enthalpy”) is a device that is designed to exchange stale indoor air air from the outside while preconditioning it. The ERV accomplishes this by passing both streams of air through a filter which allows for the transfer of heat & mouisture between the […]

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Evaporator coil

The main purpose of the Evaporator coil (which can looks like a regular radiator or even a tent) is to allow the hot incoming air to cool down quickly by passing through it (aka sensible heat). Because the temperature of the coil is so cold it also acts as a condensing surface to help remove the moist humid air […]

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Exfiltration

Exfiltration describes air flowing outward through the building envelope which is the opposite of infiltration. In the summer months this area will tend to be towards the lower portion of the building due to “summer stack effect”, while during the cooler months this tends to be located up higher due to normal stack effect. For MORE

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Exhaust Only Ventilation

An exhaust only ventilation system is where one or more fans (generally bath fans) is used to exhaust air from a house (generally 24×7 though some are on timers) and make-up air is supplied “passively” (i.e. through cracks & holes in the walls, through insulation, critter dens, etc…). This type of vetilation strategy is used primarily […]

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Fenestration

The word fenestration comes from the Latin word “fenestra” which roughly translates to opening or window. When used in the building field it basically refers to glass; aka windows, skylights, door with glass, sliding glass doors, &/or curtain walls. For MORE

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FHR

FHR or First Hour Rating 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” […]

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