How to Size a Generator for an Old Age Home

A Guide for Retirement Centres, Frail Care & Elderly Facilities

Choosing the right generator size is critical for old age homes, retirement villages, and frail care centres. At Generator Boys, we help elderly facilities across South Africa find the perfect generator to ensure safety, comfort, and uninterrupted care during power outages and load shedding.

Why Proper Generator Sizing Matters

An undersized generator can overload and fail, while an oversized one wastes fuel and increases costs. Correct sizing ensures:

Reliable backup power for essential medical equipment
Continuous heating, lighting, and cooling
Uninterrupted kitchen and refrigeration operations
Cost-effective and efficient performance
Peace of mind for caregivers and families

Step 1: List Essential Equipment

Start by identifying all the critical systems that must remain powered during an outage. These usually include:

Oxygen machines and other medical devices
Fridges and freezers
Heating and cooling systems
Emergency lighting and security systems
Kitchen appliances
Communication systems (Wi-Fi, phones, intercoms)
Water pumps or pressure systems

Step 2: Calculate Power Usage

Check the power consumption (in watts) of each appliance. If only amps and volts are listed, use this formula:
Watts = Volts × Amps

Add up the wattage of all equipment to get your total running load. Also consider the starting (surge) load, which applies to equipment like fridges and pumps. These require more power for a few seconds when starting up.

Step 3: Convert to kVA and Add a Buffer

To convert your total wattage to kVA (kilovolt-amps), use this formula:
kVA = Total Watts ÷ 0.8 ÷ 1000

Then add a 20–30% safety buffer to account for future expansions or additional load.

Example:
If your total power requirement is 16,000 watts:
16,000 ÷ 0.8 = 20,000 VA → 20 kVA
Add 20% buffer = 24 kVA generator recommended

Step 4: Match Generator Size to Facility Type

Facility Type	Estimated Generator Size
Small care home (1–10 residents)	10–20 kVA
Medium facility (11–30 residents)	20–40 kVA
Large retirement village or complex	50–100+ kVA (custom setup)

Note: Always base the size on actual load, not just the number of residents.

Step 5: Select Features for Elderly Environments

When choosing a generator for an elderly care facility, prioritise:

Silent diesel operation for minimal noise
Automatic changeover switch (ATS) for instant response
Fuel efficiency for long-term savings
Remote monitoring and alert systems
Easy access for regular servicing