# Definitions

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### CFM50 {#cfm50-definition}

Is a unit of measurement that is taken when a blower door test is performed on the home. Stands for
$C$ubic $F$eet per $M$inute at 50 pascals.

### IAQ {#iaq-definition}

Stands for $I$ndoor $A$ir $Q$uality. We spend most of our time indoors, so having good indoor air
quality can help reduce illness and potentially improve the quality and longevity of life.

### LAIR {#lair-definition}

Stands for $L$eakage $A$ir $I$nfiltration $R$ate, which is a metric that compares the square footage
of the home and it's blower door number. This aids in determining if a home is controllable by
properly sized HVAC equipment or if [shell] improvements (air sealing and insulation) should be
considered.

### Load Caclulation {#load-calculation-definition}

A load calculation, also called a Manual-J, calculates the heating and cooling requirements for a
home. Each home has a unique heating and cooling load based on the direction it faces, the air
leakage, the location, the insulation values, the types and sizes of windows, among other factors.

### Shell {#shell-definition}

Shell is a term used to describe the enclosure of the house. It is often used when talking about air
leakage and insulation levels.

### SHR {#shr-definition}

Stands for $S$ensible $H$eat $R$atio. Sensible heat ratio is the ratio of work required by the air
conditioner to remove moisture, as well as maintain the sensible temperature. The higher the number
the better.

### TESP {#tesp-definition}

Stands for $T$otal $E$xternal $S$tatic $P$ressure, which is a metric used to determine how much
resistance the blower motor has to overcome for the airflow requirement of the system.

### WC {#wc-definition}

Stands for $W$ater $C$olumn, which is a unit of measurement for pressure.