Offices, Commercial
- General 1.5–3.0 Watts/ ft²
- Private 2.0–5.0 Watts/ ft²
- Conference, Meeting Rooms 2.0–6.0 Watts/ ft²
Banks, Court Houses, Municipal Buildings, Town Halls
2.0–5.0 Watts/ ft²
Police Stations, Fire Stations, Post Offices
2.0–3.0 Watts/ ft²
Precision Manufacturing
3.0–10.0 Watts/ ft²
Computer Rooms
1.5–5.0 Watts/ ft²
Restaurants
1.5–3.0 Watts/ ft²
Kitchens
1.5–2.5 Watts/ ft²
Cocktail Lounges, Bars, Taverns, Clubhouses, Nightclubs
1.5–2.0 Watts/ ft²
Hospital Patient Rooms, Nursing Home Patient Rooms
1.0–2.0 Watts/ ft²
Hospital General Areas
1.5–2.5 Watts/ ft²
Lighting Rules of Thumb 103
Medical/Dental Centers, Clinics, and Offices
1.5–2.5 Watts/ ft²
Residential
1.0–4.0 Watts/ ft²
Apartments (Eff., 1 Room, 2 Room)
1.0–4.0 Watts/ ft²
Motel and Hotel Public Spaces
1.0–3.0 Watts/ ft²
Motel and Hotel Guest Rooms, Dormitories
1.0–3.0 Watts/ ft²
School Classrooms
2.0–6.0 Watts/ ft²
Dining Halls, Lunch Rooms, Cafeterias, Luncheonettes
1.5–2.5 Watts/ ft²
Libraries, Museums
1.0–3.0 Watts/ ft²
Retail, Department Stores
2.0–6.0 Watts/ ft²
Drug, Shoe, Dress, Jewelry, Beauty, Barber, and Other Shops
Watts/ ft²
Supermarkets
1.0–3.0 Watts/ ft²
Malls, Shopping Centers
1.0–2.5 Watts/ ft²
Jails
1.0–2.5 Watts/ ft²
Auditoriums, Theaters
1.0–3.0 Watts/ ft² (3)
Churches
1.0–3.0 Watts/ ft²
Bowling Alleys
1.0–2.5 Watts/ ft²
FREQUENTLY ASKED QUESTIONS
Lighting rules of thumb vary depending on the type of space. For example, offices typically require 1.5-3.0 Watts/ft², while precision manufacturing spaces require 3.0-10.0 Watts/ft². By using the appropriate rule of thumb for the specific space type, designers can estimate the lighting load and design the HVAC system accordingly. It’s essential to consider the specific requirements of each space, including the type of lighting, occupancy, and activities taking place.
Several factors can affect the accuracy of lighting rules of thumb, including the type and efficiency of lighting fixtures, the reflectance of surfaces, and the occupancy patterns of the space. Additionally, the use of natural light, task lighting, and other lighting strategies can also impact the overall lighting load. Designers should consider these factors when applying lighting rules of thumb to ensure a more accurate estimate of the lighting load.
Yes, lighting rules of thumb can be used to design energy-efficient HVAC systems. By using energy-efficient lighting fixtures and designing the system to meet the actual lighting needs of the space, designers can reduce the overall energy consumption of the building. Additionally, strategies such as using natural light, occupancy sensors, and dimming controls can further reduce energy consumption and improve the overall efficiency of the HVAC system.
Lighting rules of thumb directly impact HVAC system sizing, as the estimated lighting load is used to determine the required cooling capacity of the system. If the lighting load is underestimated, the HVAC system may be undersized, leading to inadequate cooling and discomfort for occupants. Conversely, if the lighting load is overestimated, the HVAC system may be oversized, leading to wasted energy and increased costs.
Yes, there are limitations to using lighting rules of thumb in HVAC design. These rules are general guidelines and may not accurately reflect the specific conditions of a particular building or space. Additionally, they do not take into account other factors that can impact the HVAC system, such as equipment heat gain, ventilation requirements, and outdoor air temperatures. Designers should use lighting rules of thumb as a starting point and consider other factors to ensure a comprehensive and accurate HVAC design.