Air Conditioning Calculator
Calculate the required cooling capacity and electricity costs of an air conditioner for your room. Free online tool, includes 2026 reference values and savings.
Required cooling capacity
3.0 kW
10,202 BTU/h
Electricity cost / season
€125.58
ca. 359 kWh
Recommended size
12.000 BTU (ca. 3,5 kW)
The calculation is based on approx. 80 W/m² base capacity plus surcharges for windows (solar radiation), number of people and insulation. Electricity costs are estimated with a SEER value of 4 (typical split air conditioner).
Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.
FAQ
Frequently Asked Questions
How much does it cost to run an air conditioner?
A typical room air conditioner (2.5 kW cooling capacity, about 0.9 kW power consumption) costs approximately 0.30-0.40 euros per hour at current electricity prices. Running it 8 hours daily for 3 months costs 200-300 euros.
What types of air conditioners are there?
The main types are split systems (fixed installation, most efficient), monoblock/portable units (flexible, less efficient), and central air conditioning. Split systems have the best cooling performance per watt.
Which electricity prices are baked into the calculation?
An average household electricity price of about 36 ct/kWh is used (Germany 2026). Actual prices vary by provider and tariff — the calculator allows you to enter your own value.
Guide
Quick Answer
The air conditioning calculator computes the required cooling capacity for a room and the annual operating costs of an air conditioner.
What is the Air Conditioning Calculator?
The air conditioning calculator computes the required cooling capacity for a room and the annual operating costs of an air conditioner.
How does the Air Conditioning Calculator work?
Enter the room size, ceiling height, window area and orientation. The calculator determines the required cooling capacity in kW and the annual electricity costs at typical usage. Split and portable units are compared.
Key Data and Facts
Rule of thumb: approx. 60-100 watts cooling capacity per sqm. Electricity consumption: 300-500 kWh/summer. SEER value (efficiency): higher is more economical. SEER 6.0 or above = energy class A++.
Step-by-Step Guide
How to calculate the right cooling capacity step by step: 1. Determine the room size: measure the length, width and ceiling height of the room. Room volume = L x W x H. 2. Estimate the cooling capacity: rule of thumb for well-insulated rooms: about 60 W per m2. For poorly insulated rooms or attics: about 80-100 W per m2. Large window areas facing south or west increase the demand by 15-20 %. 3. Take additional heat sources into account: each person about 100 W, PC/monitor about 150-300 W. 4. Choose the device type: split air conditioner (SEER 5-8, quiet, efficient, permanently installed) or monobloc unit (SEER 2-3, mobile, louder). 5. Calculate the operating costs: power consumption = cooling capacity / SEER x operating hours. Costs = power consumption x electricity price. 6. Pay attention to energy efficiency: SEER 6.0+ = A++, SEER 8.0+ = A+++. The higher the SEER value, the lower the operating costs.
Calculation Example
Room 25 m2, well insulated: cooling capacity = 25 x 60 = 1,500 W (1.5 kW). Split unit with SEER 6.0: electricity consumption = 1,500 / 6 = 250 W. At 500 operating hours/year: 125 kWh = 46 EUR/year.
Sources · E-E-A-T
Official sources
Calculations are based on applicable German laws and official data:
- Bundesministerium für Wirtschaft und Klimaschutz
- Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA)
Full methodology at Methodology.
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