Publish Time: 2025-08-17 Origin: Site
If you're wondering what size generator to run central heating, electric furnace, and space heater during a power outage, start by listing each appliance and checking their power requirements. Add up the running and surge wattages for your central heating, electric furnace, and space heater to determine the total load. Choose a generator size that can handle all these systems comfortably, ensuring it includes a safety margin for continuous operation. Using a generator that's too small can cause overheating, shutdowns, or damage to your electronics. Selecting the right generator to run central heating, such as a reliable diesel model from UNIV, provides a dependable backup power source for your home during outages.
Add up the running and surge wattages of your heating appliances. This will show how much power your generator needs. - Pick a generator that gives 20% to 30% more power than you need. This helps stop overload and keeps your home warm and safe. - Standby generators turn on by themselves and power your whole house. They are best for long power outages. Portable generators work well for short times without power. - Ask a professional to put in your generator with a transfer switch. This keeps you safe and follows local rules. - Take care of your generator often. Test it every month. Check the fuel and oil. Use carbon monoxide alarms to keep your home safe.
To pick the right size generator for central heating, electric furnace, and space heater, you need to know how much power each one uses. Find out the running wattage, surge wattage, and add a safety margin for your generator. This helps stop overloads and keeps your house warm if the power goes out.
Running wattage means how much power your heating appliances use when they are on. Gas furnaces use electricity for the blower motor and ignition. Electric furnaces and heat pumps need more power because they make heat with electricity.
Here is a table that shows the usual running wattage for different heating systems:
Furnace Size |
Typical Running Wattage (Watts) |
|---|---|
Smaller Furnaces |
300 - 500 |
Medium Furnaces |
500 - 700 |
Larger Furnaces |
800 - 1,000+ |
Heat pumps use even more power than furnaces. Most heat pumps run on 240 volts and use 20 to 50 amps. This means they use about 4,800 to 12,000 watts. Electric furnaces use the most power. They often need between 10,000 and 50,000 watts, but usually run at about half that. For example, a 20,000-watt electric furnace may use about 10,000 watts each hour.
Space heaters use less power than central heating. Most space heaters use between 750 and 1,500 watts. They are good for small rooms, but you need a bigger generator for central heating in your whole house.
Heating System Type |
Typical Running Wattage / Power Use |
Heating Area Coverage |
Energy Consumption Example (8 hours/day) |
Monthly Cost Estimate (Electricity only) |
|---|---|---|---|---|
Space Heater |
~1,500 watts (1.5 kW) |
Small area (~150 sq. ft.) |
12 kWh (1.5 kW x 8 hours) |
~$50.40 (Texas rates) |
Electric Central Heating |
3,000 to 5,000 watts (3-5 kW) |
Whole home (~2,000 sq. ft.) |
24 to 40 kWh (3-5 kW x 8 hours) |
~$268.80 (at 8 kWh for 8 hours/day) |
Gas Furnace (electric use) |
~0.7 kWh over 8 hours (blower/ignition) |
Whole home (~2,000 sq. ft.) |
0.7 kWh (electricity) + natural gas fuel |
~$23.52 (electricity) + ~$38.40 (gas) |
Always check the label on your appliances for the exact numbers. If you do not see the wattage, use this formula: Amps times Volts equals Watts.
Surge wattage is the extra power needed when your heating system starts. Motors and compressors in furnaces and heat pumps need more power for a few seconds when they turn on. You must count this surge when picking a generator.
Furnace Type |
Average Running Wattage |
Minimum Generator Capacity (to handle surge) |
|---|---|---|
Gas Furnace |
600-1200 watts |
5,000 watts |
Electric Furnace |
10,000-50,000 watts |
15,000 watts (minimum recommended) |
Propane Furnace |
700-1500 watts |
N/A |
Electric furnaces need a much bigger generator for the surge. For example, a 15,000-watt generator is the smallest you should use for a big electric furnace. Gas furnaces need less surge wattage, but you still want a generator with at least 5,000 watts for central heating.
To find the total wattage, add up the running wattage for all your appliances. Then add the highest surge wattage from one appliance. This way, your generator can handle both normal use and startup surges.
Do not run a generator at its top power all the time. Adding a safety margin keeps your generator and appliances safe. Most experts say to add 20% to 30% more power. Multiply your total wattage by 1.2 or 1.3 to get the right size.
For example, if your total running and surge wattage is 10,000 watts, pick a generator with at least 12,000 to 13,000 watts. This extra power helps your generator last longer and lets you add more appliances later.
Tip: Pick a generator that is a little bigger than what you need. This helps stop overloads and keeps your house safe.
UNIV diesel generators are a good choice for backup power. They give steady power for big loads like electric furnaces and central heating. Diesel generators from UNIV are strong and made to last a long time, so they are great for running central heating during long power outages.
When you want to know what size generator to run central heating, always check the running and surge wattage for your gas furnace, electric furnace, and space heater. Add a safety margin and pick a generator that can handle the total power. This makes sure you have the right size generator to keep your house warm and safe.
If the power goes out, you need a good generator. There are two main types: portable and standby. Portable generators need you to set them up each time. You also have to fill them with fuel often. They use gasoline or propane and can be loud. You must keep them outside for safety. These are good for short blackouts. They can run space heaters or a few things in your house.
Standby generators turn on by themselves when the power stops. They connect to your house’s wiring. They use natural gas or propane and do not need refueling during long blackouts. Standby generators are quieter and can handle bad weather. They can power your whole house, even central heating and electric furnaces. A professional must install a standby generator. It gives you strong backup for your whole home.
Feature |
Portable Generators |
Standby Generators |
|---|---|---|
Power Output |
Limited, suitable for essential or smaller loads |
Higher, powers entire home including heating systems |
Operation |
Manual start and setup |
Automatic start during outages |
Fuel Type |
Gasoline or propane, frequent refueling |
Natural gas or propane, extended operation |
Installation |
No installation needed |
Professional installation required |
Noise and Weather |
Louder, less weather-resistant |
Quieter, weather-resistant |
Cost |
Lower upfront cost |
Higher upfront cost with installation |
Application |
Temporary use for limited heating |
Ideal for full-home backup during long outages |
Tip: Pick a standby generator if you want easy, automatic power for your whole house when the lights go out.
UNIV diesel generators give strong and steady power for big jobs. You can use a diesel generator for many hours without stopping. Diesel generators last a long time and do not need much fixing. They use less fuel and cost less to run for a long time. Diesel fuel is easy to store and find, even far from town. UNIV diesel generators are great for central heating and electric furnaces. They save fuel and give steady power, so they are good for full-home backup.
Diesel generators give strong power for big needs.
They can run a long time without refueling.
They are easy to take care of and rarely break down.
UNIV diesel generators are made to work all the time.
Whole-house generators give power to your whole home during blackouts. These generators start by themselves in just a few seconds. They connect to your home’s main power box and use natural gas or propane from a pipe. You do not have to add fuel. Whole-house generators can run everything in your house, even central heating and electric furnaces. You stay warm and safe with no breaks. Standby generators are best for big homes that need lots of power. They keep your heating working during long blackouts.
Whole-home backup generators power all your things.
They start on their own and do not need you to set them up.
A professional installs them for you.
You get steady heat and comfort during any blackout.
Note: A whole-house generator is best if you want easy, automatic power for your heating and other things in your home.
It is best to let a professional install your generator. Electricians or trained technicians know the safety rules and local codes. They pick a safe spot for your generator. It should not be in a place that floods and must have good airflow. After they finish, inspectors check the wiring and exhaust. You need a permit before work starts. The technician helps you get this permit. Professionals connect your generator to your house with a transfer switch. This switch keeps everyone safe by stopping power from going back to the grid.
Aspect |
Details |
|---|---|
Inspection Requirements |
Local authorities check the wiring, grounding, and exhaust after installation. |
Permits |
You must get a permit, and inspectors sign off when it meets the rules. |
Zoning and Clearance |
Laws say where you can put your generator on your property. |
Professional Installation |
Only licensed electricians or certified technicians should install generators. |
Electrical Connections |
You must use a transfer switch to connect to your home’s power. |
Transfer Switch |
The switch must be put in right for safe power use. |
Post-Installation Testing |
The whole system is tested after it is set up. |
Training and Maintenance |
Technicians show you how to use it and plan regular checks. |
Tip: Never hook up a generator straight to your home’s panel without a transfer switch. This can send power back into the lines and hurt workers.
The 20/20/20 rule helps keep you safe from carbon monoxide and fire. Put your generator at least 20 feet from your house, doors, and windows. This stops bad fumes from getting inside. Wait 20 minutes after turning off the generator before adding fuel. This lets the engine cool down and lowers fire risk. Put a carbon monoxide alarm near where you sleep. It costs about $20. Test the alarm every month to make sure it works.
Note: Experts and the CDC say 20 feet is the shortest safe distance for your generator. Always check your local rules for more safety steps.
Taking care of your generator keeps it safe and ready. Look for leaks, damage, or trash around it. Check the oil, coolant, and fuel before each use. Run your generator every month for 20-30 minutes at half power. This keeps the engine working and the battery charged. Change the oil and filters as the maker says. Clean or change air filters and check spark plugs often. Keep the area around your generator clear so it does not get too hot.
Test your carbon monoxide alarms every month.
Have a professional check your generator once a year.
Listen for odd sounds or look for smoke when it runs.
Only use the fuel the maker says is safe.
Item |
Inspection/Testing Frequency |
Notes |
|---|---|---|
Standalone household CO alarms |
Check and test at least once a month |
Press the test button and clean it; follow the maker’s instructions |
Generator system |
Get a professional check once a year |
This includes checking wires, exhaust, and controls |
Safety Reminder: Do not skip maintenance. A generator that is well cared for keeps your home and family safe during blackouts.
It is important to pick the right size generator. The chart below shows how much power each heating appliance uses. You can look at this chart to guess what size generator you need for your house.
Appliance |
Running Wattage (Watts) |
Recommended Generator Size (kW) |
|---|---|---|
Space Heater |
1,800 |
2 |
Gas Furnace |
600–1,200 |
5 |
Electric Furnace |
10,000–20,000 |
15–22 |
Heat Pump |
4,800–12,000 |
10–16 |
If you want to use more than one heater, add up their wattages. Then, find the highest surge wattage from any appliance. Pick a generator that is about 10% bigger than your total power needs. This keeps your generator safe and helps it last longer.
Tip: If your house is big and has many heaters, you might need a generator that is 22 kW or more. This will run all your appliances and keep your home warm if the power goes out.
Think about fuel type and cost when you choose a generator. Diesel generators use about 0.1 gallons of fuel for each kW hour. They are good for big jobs like running an electric furnace. Natural gas generators use about 100 cubic feet for each kW hour. They connect to your home’s gas line, so you do not have to refill them often. Propane generators burn cleaner and are quiet. They use fuel at about the same rate as diesel, measured in gallons per hour.
Generator Type |
Fuel Consumption Rate (per kW hour) |
Key Features |
|---|---|---|
Diesel Generator |
~0.1 gallons |
High efficiency, strong for electric furnace |
Natural Gas Generator |
~100 cubic feet |
Easy supply, good for whole-home backup |
Propane Generator |
Similar to diesel, gallons per hour |
Clean, quiet, easy to store |
Inverter Generator |
Variable, more efficient |
Adjusts output, saves fuel for smaller loads |
A bigger generator costs more, but it gives better power and works well. Diesel generators cost more at first, but they save money because they use less fuel. If you want to run central heating or an electric furnace for a long time, a UNIV diesel generator gives strong and steady power.
Note: If your generator is too big, you waste fuel and money. Choose the right size generator for your house and heating needs.
To pick the best generator for heating, do these things: First, write down every heating appliance you have. Check how many watts each one uses. Next, add up all the running and surge wattages. Then, choose a generator that can handle all the power you need or more. Always let a professional put in your generator. Make sure you follow all safety rules.
The right size generator keeps your house safe and warm when the power goes out. It stops pipes from freezing and saves you money on repairs. UNIV diesel generators give strong backup power for your whole home, so you feel calm and safe.
First, write down every heating appliance you want to use. Look at each label to find the running and surge wattages. Add up all the running wattages from your appliances. Then, find the highest surge wattage from one appliance and add it to your total. This number shows how much power your generator needs.
Yes, you can use both if your generator is strong enough. Add the wattages for the central heating and the space heater together. Your generator must give more power than this total. Always add a little extra power for safety.
If your generator is too small, it can get overloaded. This might make it stop working or break your appliances. You could lose heat if the power goes out. Pick a generator with more power than you need to stay safe.
Check your generator before you use it each time. Run it once a month for about 20 to 30 minutes. Change the oil and filters when the maker says to. Test your carbon monoxide alarms every month. Doing these things keeps your generator safe and ready to use.