Cooling Load Rules Of Thumb

Offices, Commercial

 

General

Total Heat                         300–400              sq.ft./ton             (Range 230–520).

Total Heat                          30–40                  Btuh/sq.ft.          (Range 23–52).

Room Sens. Heat               25–28                  Btuh/sq.ft.          (Range 19–37).

SHR                                    0.75–0.93.

Perimeter Spaces               1.0–3.0                cfm/sq.ft.

Interior Spaces                    0.5–1.5               cfm/sq.ft.

Building Block cfm              1.0–1.5               cfm/sq.ft.

Air Change Rate                  4–10                   AC/hr.

 

Large, Perimeter

Total Heat                          225–275              sq.ft./ton.

Total Heat                          43–53                  Btuh/sq.ft.

 

Large, Interior

Total Heat                          300–350              sq.ft./ton.

Total Heat                          34–40                  Btuh/sq.ft.

 

Small

Total Heat                          325–375              sq.ft./ton.

Total Heat                          32–37                  Btuh/sq.ft.

 

Banks, Court Houses, Municipal Buildings, Town Halls

 

Total Heat                          200–250              sq.ft./ton             (Range 160–340)

Total Heat                          48–60                  Btuh/sq.ft.          (Range 35–75)

Room Sens. Heat               28–38                  Btuh/sq.ft.          (Range 21–48)

SHR0.                                 75–0.90

Air Change Rate                4–10                     AC/hr.

 

 

Police Stations, Fire Stations, Post Offices

 

Total Heat                          250–350              sq.ft./ton             (Range 200–400)

Total Heat                          34–48                  Btuh/sq.ft.          (Range 30–60)

Room Sens. Heat               25–35                  Btuh/sq.ft.          (Range 20–40)

SHR                                    0.75–0.90

Air Change Rate                 4–10                     AC/hr.  

 

Precision Manufacturing

Total Heat                          50–300               sq.ft./ton

Total Heat                          40–240               Btuh/sq.ft.

Room Sens. Heat              32–228                Btuh/sq.ft.

SHR                                   0.80–0.95

Air Change Rate               10–50                  AC/hr.

 

Computer Rooms

 

Total Heat                          50–150              sq.ft./ton

Total Heat                          80–240              Btuh/sq.ft.

Room Sens. Heat               64–228              Btuh/sq.ft.

SHR                                    0.80–0.95

Air Flow                              2.0–4.0               cfm/sq.ft.

Air Change Rate                15–20                  AC/hr.

 

Restaurants

 

Total Heat                          100–250              sq.ft./ton             (Range 75–300)

Total Heat                          48–120                Btuh/sq.ft.          (Range 40–155)

Room Sens. Heat               21–62                  Btuh/sq.ft.          (Range 20–80)

SHR                                   0.65–0.80

Air Flow                             1.5–4.0                cfm/sq.ft.

Air Change Rate                8–12                     AC/hr.  

 

Kitchens (Depends Primarily on Kitchen Equipment)

 

Total Heat                          150–350              sq.ft./ton            (at 85ºF space)

Total Heat                          34–80                  Btuh/sq.ft.          (at 85ºF space)

Room Sens. Heat              20–56                  Btuh/sq.ft.          (at 85ºF space)

SHR                                   0.60–0.70

Air Flow                             1.5–2.5                cfm/sq.ft.

Air Change Rate                12–15                  AC/hr.  

 

Cocktail Lounges, Bars, Taverns, Clubhouses, Nightclubs

 

Total Heat                          150–200              sq.ft./ton             (Range 75–300)

Total Heat                          60–80                  Btuh/sq.ft.          (Range 40–155)

Room Sens. Heat               27–40                  Btuh/sq.ft.          (Range 20–80)

SHR                                    0.65–0.80

Spaces                               1.5–4.0                cfm/sq.ft.

Air Change Rate                15–20                  AC/hr.                  Cocktail Lounges, Bars, Taverns, Clubhouses

Air Change Rate                20–30                  AC/hr.                  Night Clubs

 

Hospital Patient Rooms, Nursing Home Patient Rooms

Total Heat                          250–300              sq.ft./ton             (Range 200–400)

Total Heat                          40–48                  Btuh/sq.ft.          (Range 30–60)

Room Sens. Heat              32–46                  Btuh/sq.ft.          (Range 25–50)

SHR                                  0.75–0.85

 

Buildings w/100 percent OA Systems (e.g., Laboratories, Hospitals)

 

Total Heat                          100–300              sq.ft./ton

Total Heat                          40–120                Btuh/sq.ft.

 

Medical/Dental Centers, Clinics, and Offices

Total Heat                          250–300              sq.ft./ton            (Range 200–400)

Total Heat                          40–48                  Btuh/sq.ft.          (Range 30–60)

Room Sens. Heat              32–46                  Btuh/sq.ft.          (Range 25–50)

SHR                                   0.75–0.85

Air Change Rate               8–12                     AC/hr.  

 

Residential

 

Total Heat                          500–700              sq.ft./ton

Total Heat                          17–24                  Btuh/sq.ft.

Room Sens. Heat               12–20                  Btuh/sq.ft.

SHR                                    0.80–0.95

 

Apartments (Eff., One-Room, Two-Room)

 

Total Heat                          350–450              sq.ft./ton             (Range 300–500)

Total Heat                          27–34                  Btuh/sq.ft.          (Range 24–40)

Room Sens. Heat               22–30                  Btuh/sq.ft.          (Range 20–35)

SHR                                    0.80–0.95           

 

 

Motel and Hotel Public Spaces

 

Total Heat                          250–300              sq.ft./ton             (Range 160–375)

Total Heat                          40–48                  Btuh/sq.ft.          (Range 32–74)

Room Sens. Heat               32–46                  Btuh/sq.ft.          (Range 25–60)

SHR                                    0.75–0.90           

 

Motel and Hotel Guest Rooms, Dormitories

 

Total Heat                          400–500              sq.ft./ton             (Range 300–600)

Total Heat                          24–30                  Btuh/sq.ft.          (Range 20–40)

Room Sens. Heat               20–25                  Btuh/sq.ft.          (Range 15–35)

SHR                                   0.80–0.95           

 

School Classrooms

 

Total Heat                          225–275              sq.ft./ton             (Range 150–350)

Total Heat                          43–53                  Btuh/sq.ft.          (Range 35–80)

Room Sens. Heat               25–42                  Btuh/sq.ft.          (Range 20–65)

SHR                                    0.65–0.80

Air Change Rate                 4–12                    AC/hr.  

 

Dining Halls, Lunch Rooms, Cafeterias, Luncheonettes

 

Total Heat                          100–250              sq.ft./ton             (Range 75–300)

Total Heat                          48–120                Btuh/sq.ft.          (Range 40–155)

Room Sens. Heat               21–62                  Btuh/sq.ft.          (Range 20–80)

SHR                                   0.65–0.80

Spaces                               1.5–4.0                cfm/sq.ft.

Air Change Rate                12–15                  AC/hr.  

 

Libraries, Museums

 

Total Heat                         250–350              sq.ft./ton             (Range 160–400)

Total Heat                         34–48                  Btuh/sq.ft.          (Range 30–75)

Room Sens. Heat              22–32                  Btuh/sq.ft.          (Range 20–50)

SHR                                   0.80–0.90

Air Change Rate               8–12                     AC/hr.

 

Retail, Department Stores

 

Total Heat                          200–300              sq.ft./ton             (Range 200–500)

Total Heat                          40–60                  Btuh/sq.ft.          (Range 24–60)

Room Sens. Heat              32–43                  Btuh/sq.ft.          (Range 16–43)

SHR                                  0.65–0.90

Air Change Rate               6–10                     AC/hr.  

 

Drug, Shoe, Dress, Jewelry, Beauty, Barber, and Other Shops

 

Total Heat                          175–225              sq.ft./ton             (Range 100–350)

Total Heat                          53–69                  Btuh/sq.ft.          (Range 35–115)

Room Sens. Heat               23–54                  Btuh/sq.ft.          (Range 15–90)

SHR                                   0.65–0.90

Air Change Rate                6–10                     AC/hr.  

 

Supermarkets

 

Total Heat                          250–350              sq.ft./ton             (Range 150–400)

Total Heat                          34–48                  Btuh/sq.ft.          (Range 30–80)

Room Sens. Heat              25–40                  Btuh/sq.ft.          (Range 22–67)

SHR                                   0.65–0.85

Air Change Rate                4–10                    AC/hr.  

Malls, Shopping Centers

 

Total Heat                          150–350              sq.ft./ton             (Range 150–400)

Total Heat                          34–80                  Btuh/sq.ft.          (Range 30–80)

Room Sens. Heat               25–67                  Btuh/sq.ft.          (Range 22–67)

SHR                                    0.65–0.85

Air Change Rate                6–10                    AC/hr.  

 

Jails

 

Total Heat                          350–450              sq.ft./ton             (Range 300–500)

Total Heat                          27–34                  Btuh/sq.ft.          (Range 24–40)

Room Sens. Heat               22–30                  Btuh/sq.ft.          (Range 20–35)

SHR                                    0.80–0.95           

 

Auditoriums, Theaters

 

Total Heat                          0.05–0.07           tons/Seat

Total Heat                          600–840              Btuh/Seat

Room Sens. Heat              325–385              Btuh/Seat

SHR                                   0.65–0.75

Air Flow                            15–30                  cfm/Seat

Air Change Rate               8–15                     AC/hr.

 

Churches

 

Total Heat                          0.04–0.06             tons/seat

Total Heat                          480–720              Btuh/seat

Room Sens. Heat               260–330              Btuh/seat

SHR                                    0.65–0.75

Air Flow                              15–30                  cfm/seat

Air Change Rate                  8–15                   AC/hr.

 

Bowling Alleys

 

Total Heat                          1.5–2.5             tons/alley

Total Heat                          18,000–30,000 Btuh/alley

Air Change Rate               10–15                AC/hr.

 

All Spaces

 

Total Heat                         300–500              cfm/ton@20°F $T

Total Heat                         400                       cfm/ton ± 20%@20°F $T

Perimeter Spaces             1.0–3.0                  cfm/sq.ft.

Interior Spaces                 0.5–1.5                  cfm/sq.ft.

Building Block cfm           1.0–1.5                  cfm/sq.ft.

Air Change Rate               4                           AC/hr. minimum

Total heat includes ventilation. Room sensible heat does not include ventilation.

 

FREQUENTLY ASKED QUESTIONS