Example Data Table
| Room type |
Area |
Windows |
People |
Insulation |
Likely result |
| Bedroom |
18 m² |
3 m² |
2 |
Good |
Low to medium capacity |
| Office room |
35 m² |
7 m² |
6 |
Average |
Medium capacity |
| Retail shop |
75 m² |
18 m² |
14 |
Average |
High capacity |
Formula Used
Floor area: Area = Length × Width
Room volume: Volume = Area × Ceiling Height
Envelope load: Q = U × A × ΔT
Solar load: Qsolar = Window Area × Solar Factor × Shading Multiplier
People load: Qpeople = Occupants × 130 W
Equipment load: Qequipment = Equipment Watts × Diversity
Lighting load: Qlighting = Floor Area × Lighting Density
Ventilation sensible load: Q = 0.33 × m³/h × ΔT
Ventilation latent load: Q = 0.83 × m³/h × Humidity Difference
Total design load: Total = Subtotal + Duct Loss + Altitude Allowance + Safety Factor
BTU per hour: BTU/h = Watts × 3.412142
Cooling tons: Tons = BTU/h ÷ 12,000
How to Use This Calculator
Enter the room dimensions first. Add outdoor and indoor design temperatures. Enter total window area. Select insulation, sunlight, and roof exposure. Add people, lighting, equipment, ventilation, duct loss, altitude, and safety margin. Press the calculate button. Review the result above the form. Use CSV or PDF for reporting.
Construction Cooling Load Planning
A cooling load estimate is an early sizing guide. It helps a designer compare room heat gains before choosing equipment. This calculator uses building inputs that matter on site. It checks floor area, ceiling height, walls, roof, glazing, people, lights, equipment, and outside air. The result is not a certified Manual J report. It is a practical planning value for construction discussions.
Why Daikin Capacity Needs Care
Daikin systems are offered in many nominal sizes. A correct load estimate keeps the selected capacity closer to the real building demand. Oversized equipment can short cycle. It may remove less moisture. Undersized equipment may run without reaching comfort. A balanced estimate protects comfort, efficiency, and budget.
Heat Gains Used Here
The calculator separates envelope load, solar load, internal load, and ventilation load. Envelope load comes through walls, roof, and glass. Solar load enters through windows. Internal load comes from occupants, lights, and appliances. Ventilation load comes from outdoor air entering the space. Each part is converted to watts, kilowatts, BTU per hour, and cooling tons.
Construction Inputs Matter
Small field choices can change the result. Better insulation lowers wall and roof gains. Double glazing reduces conductive window gain. Shading lowers solar gain. Tighter construction reduces air changes. LED lighting reduces internal heat. A good estimate should reflect the actual drawings, specifications, and room use.
Using Results Responsibly
Use the suggested tonnage as a starting point. Compare it with available indoor and outdoor unit data. Check local weather, room orientation, duct losses, fresh air rules, and manufacturer limits. Large projects may need block loads, zone loads, diversity, latent checks, and code review. Final selection should be confirmed by a qualified HVAC professional.
Practical Site Review
Before ordering equipment, review the room again. Confirm window sizes. Note afternoon sun. Check roof exposure. Count regular occupants. List computers, kitchen equipment, or machines. Verify ventilation plans. Then rerun the estimate. This reduces guesswork and supports cleaner construction decisions.
For larger homes or shops, calculate each major room separately. Add the loads only when one system serves all areas. When zones differ, size each zone by its own peak condition. This method gives clearer equipment notes for bids and submittals during review today.
FAQs
Is this calculator only for Daikin systems?
It is written for Daikin planning, but the heat load method is general. Always compare the final result with current model capacity tables.
Can this replace a professional HVAC design?
No. It gives a planning estimate. Final sizing should use local codes, drawings, climate data, manufacturer data, and professional review.
Why is window area important?
Windows add conductive heat and solar heat. Large sunny windows can raise cooling demand quickly, especially on west-facing walls.
What does insulation level change?
Insulation changes the assumed U-values. Better insulation lowers wall and roof heat gain, which may reduce required cooling capacity.
Why include humidity difference?
Outdoor air can bring moisture into the room. The calculator adds latent load from humidity difference and air changes per hour.
What is duct loss allowance?
Duct loss covers heat gain, leakage, and imperfect distribution. Use a higher allowance for long ducts or unconditioned spaces.
Why add a safety factor?
A safety factor gives extra margin for uncertainty. Keep it reasonable, because too much oversizing may reduce comfort and efficiency.
What is one cooling ton?
One cooling ton equals 12,000 BTU per hour. The calculator converts watts into BTU per hour, then divides by 12,000.