Choosing the right diesel generator size for your Dom means the difference between powering everything comfortably and having a generator that trips breakers or wastes fuel. The most common mistake homeowners make is buying a generator based on square footage or “what the neighbor has” instead of calculating actual electrical load.
This guide provides a step-by-step method to calculate your home’s power requirements, understand starting vs running wattage, and select the optimal diesel generator size.
Korak 1: List Every Appliance You Need to Power
Not everything needs to run during an outage. Separate appliances into three tiers:
| Razina | Opis | Typical Load |
|---|---|---|
| Razina 1: Bitno | Hladnjak, freezer, bunar pumpa, sump pump, furnace blower, medicinska oprema, svjetla, router/modem | 3-5 KW |
| Razina 2: Comfort | Razina 1 + window AC or one central AC unit, bojler, mikrovalna pećnica, washer, televizor, računala | 7-12 KW |
| Razina 3: Full Home | Everything including central AC, electric oven, electric dryer, pool pump, EV charger | 15-30+ KW |
Korak 2: Calculate Running and Starting Wattage
Every motor-driven appliance (hladnjak, AC, bunar pumpa, furnace blower) draws 3-7× its running wattage for 1-3 seconds at startup. This starting surge (inrush current) must be covered by the generator’s surge rating.
| Uređaj | Trčanje Wattsa | Pokretanje Wattsa |
|---|---|---|
| Refrigerator/freezer (21 cu ft) | 700 | 2,200 |
| Chest freezer (15 cu ft) | 500 | 1,500 |
| Centralna klima (3 tona, 14 SEER) | 3,500 | 6,000-8,000 |
| Prozor AC (12,000 BTU) | 1,200 | 3,600 |
| Well pump (1 HP, 230V) | 1,500 | 4,500 |
| Sump pump (1/2 HP) | 800 | 2,400 |
| Furnace blower (1/2 HP) | 800 | 2,400 |
| Electric water heater (4,500W) | 4,500 | 4,500 (resistive) |
| Mikrovalna pećnica | 1,200 | 1,200 |
| LED svjetla (10 bulbs) | 100 | 100 |
| televizor + router + modem | 300 | 300 |
| Electric oven (single element) | 2,500 | 2,500 (resistive) |
| Clothes washer | 500 | 1,500 |
| Electric dryer | 5,500 | 5,500 (resistive) |
Korak 3: Apply the Load Calculation
Formula: Generator KW = (Total Running Watts + Largest Starting Surge) ÷ 1,000 × 1.25 (faktor sigurnosti)
Example calculation for a 2,000 sq ft home (Razina 2):
- Running total: Hladnjak 700 + Zamrzivač 500 + Well pump 1,500 + Furnace blower 800 + AC 3,500 + Svjetla 100 + Elektronika 300 + Mikrovalna pećnica 1,200 = 8,600 vata
- Largest starting surge: AC compressor = 7,000 vata (during the 2 seconds the AC starts, everything else is running)
- Total surge requirement: 8,600 + 7,000 = 15,600 vata
- S 25% faktor sigurnosti: 15,600 × 1.25 = 19,500 watts → 20 KW generator minimum
Recommended Diesel Generator Sizes by Home Type
| Home Type | Typical Size | Preporučeni generator | Estimated Fuel (24h @ 75% opterećenje) |
|---|---|---|---|
| Small apartment / tiny home (Razina 1 only) | 5-8 KW | 8 KW SC Series | 15-20 L diesel |
| Medium home 1,500 četvornih stopa (Razina 1 + partial comfort) | 10-15 KW | 15 KW YC Series | 30-40 L diesel |
| Large home 2,500 četvornih stopa (Razina 2, one AC) | 20-25 KW | 20 KW SC or 25 KW YC | 50-65 L diesel |
| Large home 3,000+ četvornih stopa (Razina 3, dual AC) | 30-50 KW | 30-50 KW SC/YC Series | 70-120 L diesel |
| Estate / farm with outbuildings | 50-100+ KW | 100 KW WC Series | 150-250 L diesel |
Important Considerations
Single-Phase vs Three-Phase
Most homes in North America use single-phase 120/240V split-phase power. Ensure the generator is configured for single-phase output. Trofazni Generatori can be used for homes but require a phase converter or careful load balancing, and you’ll only access 58% of the three-phase rating on single phase.
Continuous vs Standby Rating
Diesel generators have two power ratings: Stanje pripravnosti (ESP) for emergency use, tipično 100-200 sati godišnje, and Prime (PRP) for unlimited hours at variable load. For home backup, a standby-rated generator is sufficient and more economical. If you expect multi-day outages regularly, choose a prime-rated unit.
ATS (Automatski prijenosni prekidač)
A properly sized ATS is essential. It must match the generator’s output amperage. Za a 20 KW single-phase generator at 240V: 20,000 ÷ 240 = 83A. Choose a 100A-rated ATS. The ATS also determines whether you can power the entire house (whole-house switch) or only essential circuits (sub-panel with manual or automatic load shedding).
Skladištenje goriva
Diesel fuel stores well (6-12 months with stabilizer, 18-24 months in underground tanks), za razliku od benzina. Calculate storage needs: a 20 KW generator at 75% opterećenje troši približno 4-5 L/sat. Za 72 hours of continuous outage: 360L minimum. A 500L day tank provides a comfortable buffer.
FAQ
Q: Can I power my whole house with a 20 KW diesel generator?
A: For most 2,000-2,500 sq ft homes with one central AC, yes—with load management. Without load management, a 20 KW generator may struggle if the AC, electric oven, and dryer all run simultaneously. Adding a load-shedding controller ($300-500) automatically prioritizes essential loads.
Q: What happens if my generator is undersized?
A: Voltage and frequency sag under overload. Motor-driven appliances (AC, hladnjak) burn out from low voltage. The generator’s circuit breaker trips. Repeated overload shortens engine life. In worst case, the generator stalls while connected to the house.
Q: Is it better to oversize a home generator?
A: Slightly oversizing (20-30%) is good practice. Severely oversizing causes “mokro slaganje”—unburned fuel accumulates in the exhaust system because the engine never reaches operating temperature at very light loads. This reduces efficiency and damages the engine. Aim for 50-80% loading during typical outage conditions.
Q: How far from the house should a diesel generator be placed?
A: NFPA 37 requires a minimum of 5 feet from any openings (prozori, vrata, vents) i 5 feet from combustible walls unless the wall has a 1-hour fire rating. For noise comfort, 20+ feet is recommended. Check local codes—many municipalities have stricter requirements.
Q: Do I need a concrete pad?
A: Da, a reinforced concrete pad is standard. Minimum 4 inches thick, extending 6 inches beyond the generator base on all sides. For larger units (iznad 30 KW), 6-inch reinforced concrete is recommended. Pre-cast pads are available for smaller units.
Povezani članci
- Vodič za potrošnju goriva za dizel generator
- Diesel Generator for Construction Sites
- Diesel Generator Lifespan Guide
- Generator Noise Reduction Schemes
- Low Cost Diesel Generators Brand Evaluation
- Environmentally Friendly Generator Configurations
Recommended Home Backup Generators
- Serija SC dizel generatora — 20-80 KW, ideal for home backup
- Serija dizel generatora YC — 20-250 KW, ušteda goriva
