What Size Generator Do I Need For My Home?
July 16, 2022
Picking the right generator is a delicate process. Follow this guide if you have ever asked yourself, what size generator do I need for my home?
Choosing the Right Generator Size Is Critical
Power outages aren’t just inconvenient—they can damage food, pipes, and electronics. In Michigan, storms and grid issues make reliable backup power essential. A generator that’s too small won’t support key loads; one that’s too large wastes money on costlier fuel and installation.
How Generator Sizing Works: Key Concepts
Running Wattage vs. Starting (Surge) Wattage
Every device draws a base amount of power (running watts), but some appliances—especially compressors or motors—require a surge or startup wattage that may be 2–3× higher momentarily.
Safety Margin & Future Growth
Always add a 10–20% buffer above your current load to accommodate fluctuations or future expansion (e.g. adding HVAC, EV charger, or workshop).
Step‑by‑Step: How To Determine Generator Size for Your Home
1. Make a List of Essential Loads
Decide which appliances and systems you want to run during an outage. Common candidates:
- Refrigerator / freezer
- HVAC / furnace or heat pump
- Well pump (if applicable)
- Lights
- Water heater
- Medical / life safety equipment
- Garage door, sump pump, etc.
2. Collect Wattage Ratings
Check labels or manuals for running and starting watts. If specs are missing, use generic estimates (e.g. refrigerator ~ 700W running, 2,200W start).
What Size Generator Do I Need For My Home?
In The World of Generators, Wattage is King
If you have already kickstarted your generator purchase journey, you would have likely come across various wattages plastered across these machines. In most cases, picking the correct wattage is the most crucial aspect of selecting the best generator for your home. If you choose a generator with a wattage that is too small, the various appliances in your home will overload it, which may cause your generator to break down and also fry any device that you have plugged in.
On the other hand, if you pick a generator with a wattage that is too large, all your appliances will tend to be fine, but you will likely overpay for any fueling costs. So, you can expect to walk away with a lighter wallet if you choose an excessively large unit.
Starting/Surge vs Running Wattage
One of the core things to understand when planning to fix a generator is that not all watts are created equal. Each appliance in your home likely has a starting (surge) wattage, which generally indicates the quantity of extra energy required to kickstart a device. This value is generally much higher than the running wattage, which is the amount of power the appliance requires while running.
So, a device such as a hairdryer may have a running wattage of 1400W but may still require about 1800W to supply that initial burst of heat. On the other hand, refrigerators have a bad reputation for having a considerable disparity between running and surge wattage. These devices typically need about 100W to run but may never start if your generator does not supply at least 1200W.
When picking a generator, understanding the various listed power values is crucial to making the best decision. Fortunately, most manufacturers often list the running wattage separately from the starting watts a generator can supply.
What Size Generator Do I Need For My Home?
How to Determine the Correct Generator Size for Your Home
If you have been asking yourself, what size generator do I need for my home but have been unsure how to determine this value, you can follow these three core steps:
List Out All Appliances You Want to Power
The number of appliances you want to power while running your generator will always be the most crucial factor to consider when making a choice. In some cases, you may choose to leave out a couple of air conditioners or washing machines, especially if you believe that the odds of you running those appliances while your generator is on will be low.
Get the Running and Surge Wattage for All These Appliances
Next, you will want to dive through the information on each device to figure out its running and surge wattage. Fortunately, most manufacturers list these on the device specification, so they should be easy to find by studying its casing or conducting a quick online search. On the other hand, if you can’t find these wattage values, you can always use an estimation tool to land at a ballpark figure.
Tally it Up to See Your Final Requirements
Once you have the running and surge (starting) wattage for all the appliances you plan to use with your generator, grab a calculator and begin tallying these figures up. Your final value should be a fantastic indicator of the generator size to purchase for your home.
Alternatively, if you are unsure of your final figure and would like a helping hand, don’t hesitate to contact us at Osburn Services. We are an authorized generator specialist with expertise in installing generators for commercial and residential uses and will be glad to answer any questions you may have.
When power outages strike, a generator becomes a lifeline for keeping your home running smoothly. But to make the most of your investment, it’s crucial to choose the right size generator. Selecting a generator that's too small may leave you without essential power, while one that's too large could be unnecessarily costly. Let’s break down how to determine the right generator size for your home.
What Size Generator Do I Need For My Home?
Why Generator Size Matters
The size of your generator determines how many appliances and systems it can power during an outage. An undersized generator may struggle to run essential items like your refrigerator or HVAC system, while an oversized generator can waste fuel and increase operating costs.
Key Considerations for Sizing a Generator
- Assess Your Power Needs
Create a list of the appliances and systems you’d like to power during an outage. Include essentials like:- Refrigerator/freezer, Heating or cooling systems, Lights, Water heater, Well pump (if applicable), Medical equipment
- Calculate Starting and Running Watts
- Starting Watts: Some appliances, like refrigerators and air conditioners, require an initial surge of power to start up. This is higher than their running watts.Running Watts: This is the continuous power the appliance needs to operate.
- Consider Future Needs
If you’re planning home upgrades or additions, factor those into your calculations. A generator should accommodate not just your current needs but also potential future demands.
Common Generator Sizes for Homes
| Generator Size | Power Capacity | Ideal For |
|---|---|---|
| 3-5 kW | Running a few small appliances and lights | Small apartments or essential-only use |
| 5-7 kW | Essential appliances like refrigerator, lights, and sump pump | Small homes |
| 7-10 kW | Essentials plus HVAC systems | Medium-sized homes |
| 10-20 kW | Whole-home backup, including major appliances | Larger homes |
| 20+ kW | Full luxury home backup with pool heaters, etc. | Large estates or heavy power use |
Get Professional Help for Accurate Sizing
While you can estimate your power needs, consulting a licensed electrician or generator expert ensures accuracy. They’ll consider factors like load distribution, starting currents, and your home’s electrical panel capacity.
Ready to power up?
At Osburn Services, we understand that being stranded without power is one of the worst situations you can face. Being stuck in this situation often has a tremendous cost and can lead to losing several items. To ensure this does not happen, Osburn has remained committed to offering the installation of Cummins and Generac Generators and maintenance for all generator brands throughout the lower peninsula of Michigan.
On the other hand, if you want a generator but are not committed to paying immediately, we also offer flexible financing plans for all our customers. Contact us to learn more about why generators are a fantastic option for your home, and we will get back to you as soon as possible.
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