Is my input sent anywhere?

No. The calculation runs in code in your browser; values are not sent to any server and are not stored.

Should I enter the nameplate value as the device power?

If possible enter the measured or manufacturer-typical draw. The nameplate maximum is often above the real draw and makes the cooling look larger than needed; for the safe side you can still run a scenario with the maximum value.

Why can electrical load and heat load differ?

The IT load and losses turn into heat; but if the UPS is in a separate room, its loss does not enter this room's heat load. The electrical consumption of the cooling units themselves is also not counted in this tool.

It means adding one spare unit to the number of units needed to cover the load (N). When a unit fails or is taken out for maintenance, the remaining units must still cover the load. For N+2, enter 2 in the spare units field.

Where do I find the PUE value?

PUE is the ratio of total facility energy to IT energy; it is best found by measurement. Without measurement, estimate it from the facility design or data from similar facilities and remember the result depends on it. The 1.6 on the page is only an example.

Where should I enter the electricity price?

Enter the unit price per kWh from your own tariff (whether it includes taxes and fees is your decision) in the currency you choose. The tool contains no tariff or exchange rate; the annual cost is calculated as if the load were constant.

Server room power and cooling calculator

How much power and cooling does your server room or network cabinet need? Enter the device list, UPS and distribution losses, growth margin and cooling unit capacity; see the electrical load, heat load, redundancy status, density per rack and airflow. If you enter PUE and a unit price it also works out the annual energy cost.

Free tool · Infrastructure

DevicesDevice list (name;W;qty;VA;power factor)

One device per line: name;watts;quantity. An empty quantity counts as 1. Optionally add VA and power factor (0–1): name;W;qty;VA;power factor. If W is empty it is calculated from VA and power factor. The W value should be the device's real (measured or typical) draw; the nameplate maximum overestimates.

14 devices, total 5,800 W

Losses and other loads

UPS loss

The UPS's own consumption (efficiency loss) as a percentage of the IT load. You set it from the manufacturer's efficiency data.

Distribution loss

Distribution losses such as cabling, PDUs and transformers, as a percentage of the IT load. Enter it from measurement or design data.

Lighting and other loads

Lighting, monitoring and auxiliary loads in the room other than cooling (W). The electrical consumption of the cooling units themselves is not included here.

Growth margin

A margin added to the design value for future equipment. Set it according to your capacity plan.

UPS and distribution losses are in the cooled room

If ticked, these losses are added to the heat load. Untick it if the UPS is in a separate room.

Cooling unit and redundancy

Cooling unit capacity (optional)

Cooling capacity of one unit, kW. Enter the manufacturer's (sensible) value at your operating conditions; if left empty, no redundancy calculation is made.

Installed units (optional)

pcs

Number of cooling units installed or planned in the room. If empty, only the required number is shown.

Spare units (N+…)

pcs

The number of units that may fail at the same time: 1 for N+1, 2 for N+2; 0 means no redundancy.

Rack density

Number of racks (optional)

pcs

The number of racks the IT load is spread over; density per rack is calculated.

Limit per rack (optional)

The kW per rack your rack, power distribution or cooling design allows; enter it from its documentation. If entered, an excess warning is shown.

Airflow

Air temperature difference ΔT (optional)

The inlet-to-outlet temperature difference of the air passing through the devices. Take it from device documents or measurement; if empty, airflow is not calculated.

Energy cost

PUE (optional)

PUE

Ratio of total facility energy to IT energy (at least 1). Enter it from measurement or the facility design; 1.6 is only an example value.

Electricity unit price

TRY / kWh

Price per kWh in the currency you choose; enter your own tariff (5 is only an example). Used when PUE is entered.

Annual operating time

hours

Hours per year the load runs; 8760 for continuous operation. The load is assumed constant.

Currency

Results

Total electrical load: 6.62 kW; 5.8 kW IT + 0.52 kW losses + 0.3 kW other
Heat load (to be cooled): 6.62 kW; IT + losses + other loads
Heat load, BTU/h: 22,595 BTU/h
Cooling tons: 1.88 tons
Design heat load with growth margin: 7.95 kW; With 20% growth margin: 27,114 BTU/h · 2.26 tons · design electrical load 7.95 kW
Total apparent power: 6,032 VA; 8 devices have no VA data; they were counted as W (power factor 1) in the total VA.
Units needed (N): 1; 7.95 kW ÷ 8 kW = 1 unit(s) (rounded up)
Total units with spares: 2; N+1 = 2 unit(s)
Cooling redundancy: N+1; Redundant and sufficient: with 1 unit(s) failed, capacity is 8 kW, required 7.95 kW
IT load per rack: 2.9 kW; 3.48 kW/rack with growth margin
Airflow (estimate): 1,268 CFM; 2,155 m³/h · 0.6 m³/s · ΔT 11 °C (19.8 °F)
Total facility power: 9.28 kW; IT 5.8 kW × PUE 1.6; non-IT share 3.48 kW
Annual energy: 81,293 kWh; 8,760 hours
Annual energy cost: TRY 406,464; 81,293 kWh × TRY 5.00

Device breakdown

Device	Qty	Total W	Share
Server	8	3,600	62.1 %
Storage array	2	1,600	27.6 %
Switch	4	600	10.3 %

Calculation and assumptions

IT load (W) = Σ device W × qty. Losses = IT load × (UPS % + distribution %) / 100; that is, losses are entered as a percentage of the IT load. Total electrical = IT + losses + lighting/other.
Heat load = IT + lighting/other (+ losses, if the box is ticked). BTU/h = W × 3.412142. Cooling tons = BTU/h / 12000.
Design value = value × (1 + growth %). N = ⌈required kW / unit kW⌉; N+x = N + spares. Failure check: (installed units − spares) × unit kW ≥ required kW.
Airflow: CFM ≈ 3.16 × W / ΔT(°F) (sensible heat, standard air, sea level; 3.16 ≈ 3.412142 / 1.08). 1 CFM = 1.699 m³/h; a °C difference × 1.8 = a °F difference. W is the heat load with growth margin. Rack density = IT kW / number of racks.
Facility power = IT kW × PUE. Annual kWh = facility kW × annual hours (constant load). Cost = kWh × unit price.

The values you enter are processed in your browser; they are not sent to a server and not stored.

This is a preliminary sizing: it assumes constant device power, that all the heat goes into the room, and standard air properties. Altitude, humidity (latent heat), air management, containment and the real load variation of the devices affect the result; the mechanical and electrical design must be done by a qualified engineer. For cooling capacity, rely on the manufacturer's data for your operating conditions.

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How to use

A
Write the device list as name;W;qty (optionally with VA and power factor); enter UPS and distribution losses, lighting/other load and the growth margin from your own data.
B
If you wish, add cooling unit capacity and count, number of racks, ΔT, PUE and the electricity unit price; optional fields you leave empty are skipped.
C
See the electrical and heat load (kW, BTU/h, tons), redundancy status, rack density, airflow and annual energy cost; copy the result.

The relation between electrical load and heat load

Almost all the electrical power IT devices draw in a server room turns into heat, so 1 W of electricity means roughly 1 W of heat load. Converting heat load to BTU/h (1 W = 3.412142 BTU/h) and cooling tons (1 ton = 12000 BTU/h) makes it easier to compare with cooling equipment catalogues.

UPS and distribution losses turn into heat as well; but if the UPS is in a separate room, that heat stays there. That is why the tool asks whether to add the losses to the room's heat load. The total electrical load shows the power to be drawn from the grid or generator.

How to read redundancy (N+1)

N is the number of units needed to cover the heat load; N+1 means one more unit so that the load is still covered if a unit fails or is taken out for maintenance. The tool subtracts the number of spares from your installed units and checks whether the remaining capacity covers the required capacity.

Enter the manufacturer's sensible cooling capacity at your operating conditions as the unit capacity; nominal ratings are usually for different conditions. The growth margin is added to the design value, so headroom is left for equipment you add tomorrow.

Why airflow and rack density matter

To remove the same heat, the less the air temperature rises, the more air is needed. The relation CFM ≈ 3.16 × W / ΔT(°F) estimates the airflow required for sensible heat in standard air; compare it with the airflow values in the device documents. If the airflow falls short, hot spots and recirculating hot air can occur.

kW per rack shows the limit of the rack's power distribution and cooling design. At high density, solutions such as aisle containment, in-row cooling or liquid cooling may be needed; enter the limit from the documentation of your rack and cooling system.

FAQ

Is my input sent anywhere?: No. The calculation runs in code in your browser; values are not sent to any server and are not stored.
Should I enter the nameplate value as the device power?: If possible enter the measured or manufacturer-typical draw. The nameplate maximum is often above the real draw and makes the cooling look larger than needed; for the safe side you can still run a scenario with the maximum value.
Why can electrical load and heat load differ?: The IT load and losses turn into heat; but if the UPS is in a separate room, its loss does not enter this room's heat load. The electrical consumption of the cooling units themselves is also not counted in this tool.
What does N+1 mean?: It means adding one spare unit to the number of units needed to cover the load (N). When a unit fails or is taken out for maintenance, the remaining units must still cover the load. For N+2, enter 2 in the spare units field.
Where do I find the PUE value?: PUE is the ratio of total facility energy to IT energy; it is best found by measurement. Without measurement, estimate it from the facility design or data from similar facilities and remember the result depends on it. The 1.6 on the page is only an example.
Where should I enter the electricity price?: Enter the unit price per kWh from your own tariff (whether it includes taxes and fees is your decision) in the currency you choose. The tool contains no tariff or exchange rate; the annual cost is calculated as if the load were constant.

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