Choosing the right diesel generator size for your Hogar 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.
Paso 1: List Every Appliance You Need to Power
Not everything needs to run during an outage. Separate appliances into three tiers:
| Nivel | Descripción | Typical Load |
|---|---|---|
| Nivel 1: Básico | Refrigerador, freezer, bomba de pozo, sump pump, furnace blower, equipo medico, luces, router/modem | 3-5 kilovatios |
| Nivel 2: Comfort | Nivel 1 + window AC or one central AC unit, calentador de agua, microonda, washer, TELEVISOR, computadoras | 7-12 kilovatios |
| Nivel 3: Full Home | Everything including central AC, electric oven, electric dryer, pool pump, EV charger | 15-30+ kilovatios |
Paso 2: Calculate Running and Starting Wattage
Every motor-driven appliance (refrigerador, C.A., bomba de pozo, 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.
| Aparato | Vatios corrientes | Vatios iniciales |
|---|---|---|
| Refrigerator/freezer (21 cu ft) | 700 | 2,200 |
| Chest freezer (15 cu ft) | 500 | 1,500 |
| Aire acondicionado centralizado (3 tonelada, 14 SEER) | 3,500 | 6,000-8,000 |
| Aire acondicionado de ventana (12,000 BTU) | 1,200 | 3,600 |
| Well pump (1 caballos de fuerza, 230V) | 1,500 | 4,500 |
| Sump pump (1/2 caballos de fuerza) | 800 | 2,400 |
| Furnace blower (1/2 caballos de fuerza) | 800 | 2,400 |
| Electric water heater (4,500W.) | 4,500 | 4,500 (resistive) |
| Microonda | 1,200 | 1,200 |
| luces LED (10 bulbs) | 100 | 100 |
| TELEVISOR + 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) |
Paso 3: Apply the Load Calculation
Fórmula: Generator KW = (Total Running Watts + Largest Starting Surge) ÷ 1,000 × 1.25 (factor de seguridad)
Example calculation for a 2,000 sq ft home (Nivel 2):
- Running total: Refrigerador 700 + Congelador 500 + Well pump 1,500 + Furnace blower 800 + C.A. 3,500 + Luces 100 + Electrónica 300 + Microonda 1,200 = 8,600 vatios
- Largest starting surge: AC compressor = 7,000 vatios (during the 2 seconds the AC starts, everything else is running)
- Total surge requirement: 8,600 + 7,000 = 15,600 vatios
- Con 25% factor de seguridad: 15,600 × 1.25 = 19,500 watts → 20 KW generator minimum
Recommended Diesel Generator Sizes by Home Type
| Home Type | Typical Size | Generador recomendado | Estimated Fuel (24h@ 75% carga) |
|---|---|---|---|
| Small apartment / tiny home (Nivel 1 only) | 5-8 kilovatios | 8 KW SC Series | 15-20 L diesel |
| Medium home 1,500 pies cuadrados (Nivel 1 + partial comfort) | 10-15 kilovatios | 15 KW YC Series | 30-40 L diesel |
| Large home 2,500 pies cuadrados (Nivel 2, one AC) | 20-25 kilovatios | 20 KW SC or 25 KW YC | 50-65 L diesel |
| Large home 3,000+ pies cuadrados (Nivel 3, dual AC) | 30-50 kilovatios | 30-50 KW SC/YC Series | 70-120 L diesel |
| Estate / farm with outbuildings | 50-100+ kilovatios | 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. trifásico Generadores 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: Apoyar (ESP) for emergency use, típicamente 100-200 horas por año, and Prime (PPR) 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.
ETA (Interruptor de transferencia automática)
A properly sized ATS is essential. It must match the generator’s output amperage. por un 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).
Almacenamiento de combustible
Diesel fuel stores well (6-12 months with stabilizer, 18-24 months in underground tanks), a diferencia de la gasolina. Calculate storage needs: a 20 KW generator at 75% la carga consume aproximadamente 4-5 l/hora. Para 72 hours of continuous outage: 360L minimum. A 500L day tank provides a comfortable buffer.
Preguntas frecuentes
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: ¿Qué pasa si mi generador es de tamaño insuficiente??
A: Voltage and frequency sag under overload. Motor-driven appliances (C.A., refrigerador) 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 “apilamiento húmedo”—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 (ventanas, puertas, vents) y 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: Sí, a reinforced concrete pad is standard. Mínimo 4 inches thick, extending 6 inches beyond the generator base on all sides. For larger units (arriba 30 kilovatios), 6-inch reinforced concrete is recommended. Pre-cast pads are available for smaller units.
Artículos relacionados
- Diesel Generator Fuel Consumption Guide
- 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
- SC Series Diesel Generator Set — 20-80 kilovatios, ideal for home backup
- Grupo electrógeno diésel serie YC — 20-250 kilovatios, fuel-efficient
