The heating boiler is selected based on the heat that the building loses on the coldest day: heating the heat and fresh air with the heat passing through the wall, roof, window and floor. In factory and warehouse halls with high ceilings, more than half of the load often comes from leakage and door opening; in the uninsulated sheet metal hall, on the other hand, conduction predominates, and the load of the same hall grows by 5 times. The magician hall collects the loss of roof, wall, floor (EN ISO 13370) and air exchange from the area, height, insulation type and the outside temperature of the province; fast m² method for office, school and residence, detailed heat loss, fresh air battery and shower room are also on the list.
Which building and consumer wants how much heat?
| Consumer | Typical capacity | Heat load (motor) | Fluid |
|---|---|---|---|
| Factory hall / warehouse | 100 × 50 × 8 m, insulated sandwich panel, Manisa, 18 °C | 205 kW (176,000 kcal/h; 41 W/m²) | hot water 80/60 °C · steam aerotherm 1–3 bar g |
| Same hall, uninsulated sheet metal | single layer sheet metal, L 5.8 W/m²K | 1,020 kW (876,700 kcal/h; 204 W/m²) | hot water 80/60 °C |
| Building heating (fast m²) | 2.000 m², partial insulation, Izmir | 120 kW (103,200 kcal/h; 60 W/m²) | 80/60 °C (old) · 70/55 °C (insulated) · 45/35 °C (from the ground) |
| Building heating (detailed) | wall 8.000 m², window 3.000 m², roof and flooring 3.000 m² each, Antalya | 355 kW (305,700 kcal/h) | 80/60 °C |
| Fresh air faucet | 60,000 m³/h, Ankara, without recycling | 643 kW (553,100 kcal/h); 257 kW with 60% recovery | 80/60 °C · steam 1–3 bar g |
| Factory shower room | 20 nozzles, 9 L/min, 40 °C, 30 min | 88 kW with boiler; 352 kW without boiler | 80/60 °C |
How many kcal/h is calculated per square meter?
| Building insulation level | Izmir (0 °C) | Istanbul (−3 °C) | Ankara (−12 °C) | Erzurum (−21 °C) |
|---|---|---|---|---|
| Old building without insulation | 94 W/m² · 81 kcal/h | 108 W/m² · 93 kcal/h | 150 W/m² · 129 kcal/h | 193 W/m² · 166 kcal/h |
| Partial insulation (1977–1994) | 60 W/m² · 52 kcal/h | 69 W/m² · 59 kcal/h | 96 W/m² · 83 kcal/h | 123 W/m² · 106 kcal/h |
| New, TS 825 level | 28 W/m² · 24 kcal/h | 32 W/m² · 28 kcal/h | 45 W/m² · 39 kcal/h | 57 W/m² · 49 kcal/h |
The values are for square meters of the net heated area (internal temperature 20 °C, continuous heating). +15% is added for morning heating in the intermittent (closed at night) operation. The quick method is derived from the building class averages in Germany and is only a preliminary estimate; a detailed heat loss calculation must be made for the project. Example: A 2,000 m² partially insulated office in Izmir requires 120 kW (103,200 kcal/h); the wizard recommends 125,000 kcal/h with line loss and growth margin, and 150,000 kcal/h in a discrete operation.
Example: 10.000 m² production hall, Manisa
The insulated sandwich panel production hall is heated by ceiling radiant panels.
| Input | Value |
|---|---|
| Hall | 10.000 m² base (width: length = 1 : 2 → 70.7 × 141.4 m), 9 m height |
| Insulation | sandwich panel: roof 0.35 · wall 0.45 W/m²K; 10% of wall door and window (U 3.0) |
| Leakage + door opening | 0.4 1/h |
| Temperatures | operating zone 18 °C · Manisa −3 °C |
| Heater | Ceiling Radiant Panel (×1,0) |
- Transmission 7,625 W/K + air exchange 12,060 W/K, 413 kW with a difference of 21 K (355,400 kcal/h; 41 W/m², 4.6 W/m³)
- 477 kW = 410,500 kcal/h with 5% line loss and 10% growth share
- Hot water boiler recommendation: 425,000 kcal/h, flow 80 °C, ≈ 21 m³/h circulation, ≈ 54 Sm³/h natural gas at full load
- If hot air aerotherm is chosen, the load is ×1.15 (475 kW) and the recommendation is 475,000 kcal/h; steam 3 bar g ≈ 800 kg/h steam in steam aerotherm
- The same hall would be 1,944 kW and 2,000,000 kcal/h with uninsulated sheet metal
Heating boiler type, temperature and pressure
For building and factory heating, the heating boiler is a low-pressure hot water boiler: 80/60 °C in an old building with radiators and aerotherms, 70/55 °C in an insulated building, 45/35 °C for underfloor heating. In coal and biomass burning plants, the stoker boiler provides automatic feeding. District heating reduces the superheated water boiler pipe diameter and pump energy by 110–180 °C in OIZ and long-line campuses. If there is process steam in the factory, the heating can be fed from the same steam boiler, with a steam aerotherm or a steam-water exchanger; Up to 6 t/h, a package type and hybrid type steam boiler is suitable for a header type steam boiler. It vaporizes 1.69 kg/h ≈ 1 kW with 3 bar g of steam.
How to do the calculation?
0.335 W·h/(m³· K) is the volumetric heat capacity of the air; floor loss is found by EN ISO 13370. f is the heater coefficient: 1.15 in hot air aerotherm because hot air rises to the ceiling, 1.0 in radiant panel and underfloor heating. The outside temperature is taken from the provincial project table (Özkol, MMO 1999; Bulgurcu and Koçyiğit 2023, TESKON). The default line loss is 5% and the growth share is 10%; items such as fresh air coil and shower room are added to the same list.
Use the wizard at the top of the page to calculate with your own building; Boiler Capacity Calculator for all sectors. Use the steam boiler capacity tool to convert a known load into a steam flow rate.
The results of the wizard are predictions to give a preliminary idea; boiler selection should be finalized by on-site exploration and engineering calculation. Contact us for free pre-engineering support.