When do you need a 30kW burner and when 60kW? Or 120kW for a mid-size hotel? Pellet burner sizing is not a simple “bigger is better”: an oversized burner runs continuously at low load, efficiency drops, flue emissions and soot go up. An undersized burner never catches up, runs constantly at 100%, and wears out early.
This is a selection guide based on the AXINAR burner range: Apoplim AP20 / AP30 / AP45 for homes, and Tsovea TS75 / TS95 / TS120 / TS150 for larger installations.
How to calculate required power
The base equation is:
Required power (kW) = Area (sqm) × Insulation factor (W/sqm)
The factor depends on insulation:
- Good insulation (new home rated A+ or A): 60 to 80 W/sqm
- Average insulation (building from 2000 to 2010, KENAK or original Exoikonomo standard): 100 to 130 W/sqm
- Poor insulation (old building, single glazing, minimal insulation): 150 to 200 W/sqm
AP20 (20 kW): for apartments and small homes
- Fits: 80 to 150 sqm with average insulation, 100 to 200 sqm with good insulation
- Automation: auger auto cleaning
- Typical use: single-family homes in Thessaloniki, Larissa, mountain areas replacing an oil burner
AP30 (30 kW): the most common size
- Fits: 150 to 250 sqm with average insulation, 200 to 350 sqm with good insulation
- Automation: auger auto cleaning
- Typical use: mid-size single-family homes, maisonettes, small businesses
AP45 (45 kW): large homes or small apartment blocks
- Fits: 250 to 400 sqm with average insulation
- Automation: auger auto cleaning
- Typical use: guesthouses, apartment blocks with central heating, small event halls
TS75 (75 kW) and TS95 (95 kW): commercial spaces
- Fits: 500 to 900 sqm of commercial space
- Automation: double auger auto cleaning
- Typical use: hotels, gyms, greenhouses, small industrial spaces
TS120 (120 kW) and TS150 (150 kW): industrial spaces
- Fits: >1000 sqm industrial or greenhouse applications
- Automation: double auger auto cleaning
- Typical use: factories, large agricultural facilities, tourism resorts
Quick selection table
| Area | Insulation | Recommended |
|---|---|---|
| 80 to 150 sqm | Average | AP20 |
| 100 to 200 sqm | Good | AP20 |
| 150 to 250 sqm | Average | AP30 |
| 250 to 400 sqm | Average | AP45 |
| 500 to 700 sqm | Any | TS75 |
| 700 to 1000 sqm | Any | TS95 |
| 1000 to 1400 sqm | Any | TS120 |
| 1400+ sqm | Any | TS150 |
Factors that shift the choice
Number of hot water points
If the burner also serves domestic hot water (300+ L tank, multiple bathrooms), add 8 to 10 kW for recovery.
Underfloor vs radiators
Underfloor heating runs at lower water temperature (35 to 45°C), and the burner runs more efficiently. Rated power doesn’t change, but load rate is steadier.
Operating hours
If the burner runs only 6 to 8 hours a day (e.g. commercial space with overnight shutdown), you can pick a slightly larger size for faster recovery.
Ceiling height
A space with 4 to 5 meter ceilings (warehouse, greenhouse) needs 30 to 50% more power than a home of the same area.
AXINAR’s Apoplim and Tsovea series cover every installation size, from a 100 sqm apartment to a 2000 sqm industrial space.
- AP20 / AP30 / AP45 with single auger auto cleaning for homes
- TS75 / TS95 / TS120 / TS150 with double auger auto cleaning for commercial
- Analog power modulation for maximum efficiency
- Compatible with all oil boilers
Request a quote
Tell us: square meters, insulation type, operating hours, presence of domestic hot water. We reply with a burner proposal within 24 hours.
See also: Complete boiler power per square meter guide, Pellet burner vs complete pellet boiler.
