What Size Generator To Run Furnace? (Complete Guide)
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Wondering what size generator to run the furnace so your family can feel warm and remain safe throughout the winter months?
In this post, we will find out what the right size generator is to operate a furnace and suggest a different type of generator that is suitable for the furnace.
Generally, the starting wattage required for a furnace is 1600 watts, while the running wattage is 600 watts.
So the right size generator for a furnace means having a generator that delivers more power than these starting and running wattages.
What Size Generator To Run Furnace?
To run a furnace, you will need at least an 1800-watt generator. The average furnace needs 1600 watts to start and 600 watts to run. So you will need on average 2000 watts generator.
| Size | Starting Wattage | Recommended Generator |
|---|---|---|
| Minimum | 1800 | A-iPower 1500 Watt Portable Inverter Generator |
| Medium | 2000 | WEN Super Quiet 2000-Watt Inverter Generator |
| Large | 2500 | Champion Dual Fuel Portable Inverter Generator |
Determining How Many Watts Does a Furnace Use?
A right-sized generator for a furnace means choosing a generator that can efficiently run a furnace.
Hence, wattage is a vital consideration when it comes to opting for the right size generator.
In general, most home furnaces use 3500 to 5000 watts of energy, which translates into 20 amps at 240 volts or 12 amps at a 120-volt circuit.
The best way to determine the required watts for your furnace is to check the user manual of the furnace.
The user manual may include the model number and either input voltage or output voltage.
Using this information, you can calculate the required watts for a certain furnace. The formula is:
Volts x Amps= watts
So if your furnace has a 20 amp draw and runs on 240 volts, then the required watts will be:
240V x 20A = 4800Watts.
In this case, if your furnace uses 12 amps per 120-volt circuit, you will require 250-300 amps at 240V or 167 amps at 120V.
It means a generator that can produce 300 amps or higher will be the right option to go for.
Read More: What Size Generator To Run Hot Water Heater?
Types Of Generators For Running The Furnace
Generators that can run a furnace are:
Gasoline Generators
It’s the most compact and cheapest type of generator that also produces less power compared to its other counterparts.
But when it comes to choosing the smallest generator, make sure it can produce enough power to keep the furnace running.
Natural Gas Generators
This natural gas generator is the best choice for the furnace.
This type of generator doesn’t need to be refueled frequently while producing greater wattage than gasoline or diesel models.
It does, however, cost a considerably higher price.
The power output of a natural gas generator ranges from 5000 to 30,000 watts, making it perfect for covering all requirements.
Read More: What Size Generator To Run a 2.5HP Compressor?
Diesel Generators
This diesel generator is also a popular option for running furnaces.
This type of generator is broadly available and able to produce the same power as natural gas generators while coming at a relatively lower cost.
The power output of the diesel generator ranges from 7000 to 45,000 watts, making it suitable for running furnaces and other appliances at the same time.
A few safety tips to follow to survive a winter power outage for a generator
If you have a gasoline generator, then the best suggestion for you is to place it outside.
You should also offer a shelter for the generator that is well ventilated and has a fire-resistant coating.
Using a generator will be a safer way to operate a furnace only if you take the necessary precautions.
The following are a few safety guidelines to follow during a winter power outage:
Stay away from the gas
If you inhale, the generator can produce carbon monoxide gas, which can cause serious damage if you inhale.
This is safe to use even if placed in a well-ventilated room, keeping the doors and windows open.
Read More: What Size Generator For 30 Amp RV?
Use a carbon monoxide detector
Use a carbon monoxide monitor while operating a generator to prevent the gas from getting into your home.
It’s also recommended to place the generator at a safe distance from the house.
Get extra fuel
If you don’t have a power outage problem, get some propane or gasoline to be prepared.
Charge batteries
If you have a solar generator, always keep it charged and store it properly, so you can use it whenever you need it.
Use the right size cord
Use good quality and outdoor safe cord that can properly carry the wattage from the generator to the furnace without getting burned.
Read More: What Size Generator Do I Need For An Oxygen Concentrator?
Keep the generator parallel
Keeping the generator in parallel will give a power boost that helps run multiple appliances along with the furnace.
Best Generator To Run Furnace
1. A-iPower AP1500i 1500 Watt Portable Inverter Generator Gas Powered
- Produces 1500 starting watts with 1200 running watts of clean and safe power for sensitive electronics, such as phones, televisions, laptops, and other electronics.
- Complete with A-iPower’s “Low idle” technology for an extended run time of 4 hours at 100% load and 6.5 hours at 50% load.
- Equipped with a low oil alert light and low oil automatic shutdown, helping keep your generator performing year after year.
- Powerful 79cc OHV 4-Stroke engine provides an abundant power supply yet runs at a super quiet operation of only 52 decibels.
- Light weight and compact at only 46 pounds, making your tailgate or camping experience as smooth as possible.
2. WEN Super Quiet 2000-Watt Portable Inverter Generator w/Fuel Shut Off
- Ultralight body weighs in at a mere 39 pounds for easy transport and storage
- Extremely quiet operation comparable to the sound of a normal conversation according to the US Department of Health and Human Services
- Produces 2000 surge watts and 1700 rated watts of clean power for safe charging of sensitive electronics (phones, tablets, televisions, computers, etc.)
- Fuel shutoff maximizes the generator’s lifespan by using up the remaining fuel in the carburetor before shutting down
- Includes two three-prong 120V receptacles, one 12V DC receptacle, two 5V USB ports, and a two-year warranty
3. Champion Power Equipment 2500-Watt Dual Fuel Portable Inverter Generator
- DUAL FUEL: Operate your 2500-watt portable generator right out of the box on either gasoline or propane, plus at only 39 pounds, this inverter is one of the lightest 2500-watt inverters in the industry
- QUIET OPERATION: With an ultra-quiet 53 dBA from 23 feet, enjoy 2500 starting watts, 1850 running watts and up to 11.5 hours run time on gasoline, and 1665 running watts and up to 34 hours on propane
- PARALLEL READY: The optional, sold-separately clip-on parallel kit enables this inverter to connect with another 2500-watt Champion inverter to double your output power. GFCI Outlets : No
- CLEAN POWER: Includes two covered 120V 20A household outlets with clean electricity (less than 3% THD), a 12V automotive-style outlet, plus a handy dual port USB adapter
- CHAMPION SUPPORT: Includes 3-year limited warranty with FREE lifetime technical support from dedicated experts
FAQs About Right Size Generator To Run Furnace
How Much Wattage Is Required To Run A Home Furnace?
A home furnace is typically a light-duty appliance that doesn’t need much wattage to keep running.
Most gas-fired furnaces require around 600 watts of electricity to keep running.
Can A 2000 Watt Generator Run A Furnace?
A 2000-watt generator is powerful enough to run an oil or natural gas furnace.
The starting wattage of these furnaces is 1600 watts, and the running wattage is 600 watts.
A 2000-watt generator, on the other hand, is capable of running multiple lights, a radiant heater, and a couple of fans.
What Is The Quietest Generator For A Furnace?
When choosing a generator for a furnace or other appliance, the sound level is an important factor, especially for a sensitive family or neighbor.
The YAMAHA EF2000iSv2 Gas Powered Portable Inverter will be the right option to keep the environment calm while getting the job done.
Will a 3500 watt generator run a furnace?
A 3500 watt generator can certainly run a furnace, provided the furnace is not too large or power-hungry.
Can I power my furnace with a generator?
The answer to this question depends on the size of your furnace. If you have a small furnace, then you may be able to use a portable generator to power it.
However, if you have a large furnace, then you will need a larger generator to power it.
Will a 1000W generator run a gas furnace?
No, a 1000 watt generator is not enough to run a gas furnace. The starting wattage for most furnaces is between 2000 and 3000 watts.
Will a 5000 watt generator run a furnace?
Yes, a 5000 watt generator will run a furnace.
Can a 6500 watt generator run a furnace?
A 6500 watt generator can indeed run a furnace, however, it is not recommended to do so for extended periods of time.
It is best to use a generator that is specifically designed to power a furnace, such as a standby generator.
How many watts does a furnace draw?
It depends on the type and size of the furnace. Generally speaking, most furnaces will require between 3000-4000 watts to operate.
If you have a larger or more powerful furnace, it may require up to 6000 watts.
Will a 5500 watt generator run my furnace?
In general, a 5500 watt generator should be able to power a furnace without any problems.
Will a 4000 watt generator run a furnace?
If you have a 4000 watt generator, you should be able to run a furnace without any issues.
Final words
Whether you want to be prepared for a harsh winter or a power outage, a generator is an all-in-one solution.
Throughout the guide, we have explained what size generator to run the furnace and offered some ideas for determining your own.
Hopefully, getting the right size generator for the furnace will be a straightforward task for you, so you can enjoy warm air on those cold days.
