A home gas generator should not be selected by adding appliance ratings alone. Starting currents, priority loads, phase configuration, fuel supply and automatic operation all affect the result. An undersized generator may trip or stall, while excessive capacity increases purchase and operating costs.
Step 1. List the essential loads
Start with the equipment that must operate during an outage. A typical list includes the heating boiler and pumps, refrigerator, lighting, internet equipment, security system, well pump and several backup sockets. Electric cooking, water heating, air conditioning and vehicle charging can increase demand substantially and should be evaluated separately.
Step 2. Allow for starting current
Electric motors briefly draw more than their normal running power when they start. Pumps, compressors, refrigerators and air conditioners are common examples. Simply adding the figures on the nameplates is not enough: the design must consider the largest likely simultaneous start and include a practical operating margin.
An indicative calculation
| Load | Running power | Important detail |
|---|---|---|
| Boiler and circulation pumps | 0.3–0.8 kW | Include pump starting current |
| Refrigerator | 0.2–0.5 kW | Short starting surge |
| Lighting and internet | 0.3–0.8 kW | Mostly continuous load |
| Well pump | 0.8–2.0 kW | High current at start |
| Backup sockets | 1–3 kW | Depends on the operating plan |
After starting currents are checked, this example may require a generator in the region of 8–13 kVA. It is an illustration rather than a finished design: the correct rating depends on the actual equipment and electrical arrangement.
Single-phase or three-phase
If the house and its priority loads are single-phase, a single-phase generator is usually simpler to operate. A three-phase generator is appropriate when the building has the corresponding supply and genuine three-phase loads. Loads must be distributed between phases to avoid excessive imbalance.
Natural gas or LPG
Natural gas can support convenient long-duration automatic operation where a suitable connection and approved design are available. LPG is useful where there is no gas main, but fuel storage and delivery must be designed correctly. Many GENERAC models can operate on either fuel; the exact configuration and settings must be confirmed for the selected model.
When an automatic transfer switch is useful
An automatic system monitors the utility supply, starts the generator during an outage and transfers the building back after power is restored. This is especially useful in a home with heating, pumps or security equipment. The switchgear must match the generator rating, phase configuration and electrical design.
Checks before purchase
- total running power and motor starting currents;
- single-phase or three-phase arrangement;
- available fuel type and gas pressure;
- installation position, ventilation and exhaust routing;
- noise requirements and clearances from the building;
- maintenance access;
- compatibility with the building’s transfer equipment.
Selecting a GENERAC generator
The gas generator catalogue includes models for homes and commercial properties. A BASTION LTD engineer can review the load schedule, select the generator and controls, and prepare an installation estimate. Call +38 063 793 29 29 for a consultation.
