Having a power inverter ready to run your sump pump during a power outage is a must as a homeowner.
In fact, when there is a power cut during a storm or local flooding it is when you need your sump pump most of all.
You might be considering whether to use a battery powered sump pump or a power inverter to keep your basement dry.
Well, in my experience a power inverter always wins out this battle.
Firstly, because battery powered sump pumps tend to offer way less performance, plus take up excess space if it is your second pump.
With a power inverter, you don’t have to replace or add a second pump. You can simply keep your front-line defenses working at full capacity.
You can even get inverters with automatic transfer switches and chargers so you’re instantly protected when the power goes out.
In this article, we’ll go through what size inverter you’ll need, the best options available, and all the other questions that pop into your head along the way.
In a rush? Check the top picks…
What Size Inverter to Run a Sump Pump?
To run a sump pump efficiently you will need at least a 1200 watt power inverter.
You might even need 2000 watts or more if you have a large pump or want to run other appliances at the same time.
You should also ensure your inverter has 20% more continuous wattage than your sump pumps running wattage. This is because inverters are not 100% efficient as they lose energy when converting DC to AC and running internal systems. Simply multiply the sump pump running wattage by 1.2 to get this minimum requirement.
It’s always better to go bigger than smaller.
If you try to use an inverter that’s too small, you risk quickly blowing a fuse or putting a lot of stress through your equipment. Neither is beneficial for long term usage.
Don’t Forget About Peak Power
These are pretty powerful inverters but it is necessary to cope with starting up and running a sump pump for prolonged periods. You need to be aware that a sump pump can pull 2 or 3 times its running wattage for a few seconds at startup. So you need an inverter with enough peak surge wattage to cover this demand.
So although a ⅓ horsepower pump uses around 800 running watts, it could use 2000 peak starting watts. And a ½ horsepower sump pump uses 1050 running but could use 3000 peak starting watts.
An inverter usually has double the peak power capacity to its continuous running wattage. This is why you would need at least a 1200 watt inverter that has 2400 watt peak power capacity.
How Many Watts Does My Sump Pump Use?
You should be able to identify the number of watts your sump pump uses in the technical information or user manual. For most domestic pumps this is usually between 500W to 1500W.
You could also get yourself a wattmeter. These are great little devices you can attach to appliances in order to get a live power reading. Highly recommended if you use a power inverter.
Does a Sump Pump Need a Pure Sine Wave Inverter?
A sump pump should be used with a pure sine wave inverter. This is because they are motorized appliances that need a smooth flow of electric current.
There are two types of inverters – pure sine wave and modified sine wave. Pure sine wave are better and more efficient as the alternating current more closely replicates what you get from the mains grid.
Modified sine wave inverters are cheaper but they deliver sharp steps in voltage flow which are not suitable for AC motors in pumps. It would run a pump but will lead to excess heat in the motor and reduce its working life considerably.
With a pure sine wave inverter, you will never be restricted in the type of electronics you can run, which is why they are highly recommended.
Best Power Inverters for Sump Pumps
Let’s take an in-depth look at the best inverters to run your sump pump.
Pump Sentry 1622PS 1800 Watt – Emergency Power Inverter
We’ll start off this list with an inverter specifically designed to run sump pumps. It even names Pump Sentry, always watching over and ready to jump into action.
This is the 1800 watt option which can handle up to a 1600 watt pump. Plus you can also get it in smaller sizes to suit your needs and budget.
Not only does it have the power you need but it’s intelligent too! It is able to charge your battery supply while also hooking up to the mains in order to detect any power outages. It automatically switches between battery and AC mains electricity when you need it too.
It is designed to be installed on a wall or other flat (dry!) surface, although makes sure it’s secure as it weighs around 20lbs (10kg).
If you want to make sure your sump pump runs smoothly, then this is the go too inverter. Get it, install it, and sleep well at night.
- Specifically designed for Sump
- Automatic switch
- In-built charger
- 1800W capacity
- No digital screen
- Limited size choices
PumpSpy Primary Sump Pump 1500W Inverter
Next we’ve got another dedicated sump pump power inverter. It’s not quite as powerful at 1500 watts but it’s not so expensive.
The pump spy does still offer all the essential features you’ll need. Get your pump running effortlessly thanks to the automatic transfer switch which changes to battery power as soon as there is a power outage.
Adding to this, it includes a 10A battery charger to keep your deep cycle battery juiced up. If you need a battery then match it with the PumpSpy 75Ah battery for perfect compatibility.
While it is a sump pump specific inverter, you can also run other appliances from the 2 standard AC outlets. This is really useful to add things such as lighting during an outage. No more fumbling around in the basement with a torch.
A reliable backup if you can’t afford the Pump Sentry above.
- Sump pump specific
- Automatic transfer switch
- 10A battery charger
- Multiple AC outlets
- Only available upto 1500W
- Only one size available
- No digital screen
AIMS Power 1250W Power Inverter Charger
AIMS Power is one of the leading names for industrial power inverters. The company delivers a wide range of products with reliability and function in mind.
We’re taking a look at the 1250W inverter charger here, but there’s plenty more options available if this is not quite enough capacity for you. What you will be getting here is 1250 watt continuous power and 3750 watts peak surge power. So you should not have any troubles firing up your pump.
This pure sine wave inverter also has a charging function in-built which delivers 35A high speed recharging for most types of deep cycle products. Adding to this, the automatic transfer switch gives you the automation you need for a sump pump. It’ll switch over as soon as the power goes out. You can even add a remote control too!
Although it’s not designed directly for sump pumps, it will do the job no problem, if not better than some of the dedicated pump inverters.
- Big peak power
- Automatic transfer switch
- Multiple size options
- Trusted brand
- 35A high speed charger
- No digital screen
- Very heavy (37lbs)
Ampinvt 3000W Pure Sine Wave Inverter Charger
This is a bit of serious oomph from Ampinvt!
What you’ll get here is a pure sine wave inverter with 3000W continuous output and a whopping 9000W peak surge capacity. You should have no problems running a domestic sump pump along with a number of other appliances.
It delivers a few differences from previous products on the list above. You’ll still get the essentials like a huge 60A battery charging function and a transfer switch that prioritizes mains electricity until the power goes down.
You can also use the in-built digital screen to monitor live power usage and voltages. In addition, it automatically senses the appliance’s frequency of either 50hz or 60hz in order to run a wider selection of tools.
If your batteries are running low the inverter goes into standby mode to avoid a complete drop in voltage and flat battery. Plus you can use eco mode to save battery energy during low power draw situations.
- High capacity
- High peak power
- 60A charger
- Automatic switch
- Digital screen
- Overkill for just a pump
Tripp Lite 1250W Power Inverter Charger
The team at Tripp Lite has a long-standing reputation when it comes to off-grid power solutions, particularly with power inverters.
I love this 1250W inverter charger Tripp Lite builds. It’s also available in 750 and 2000 watt options. It’s got everything you need in a rugged shell and heavy-duty build quality. The peak power can run 2500 watts for 10 seconds giving you enough for small and medium sup pumps.
2 AC outlets mean you can run multiple appliances easily which is very handy during a power outage emergency. There’s an automatic transfer switch setting so you can have a completely hands-off experience. No panic if there’s heavy rain when the electricity cuts out. You can also select different modes such as charging only if you need to ensure your batteries get fully juiced.
Despite its heavy-duty design, it’s much lighter than other competitors at just over 10kg. This makes it great for multiple use cases in vehicles too.
- Reputable brand
- Multiple size options
- Heavy duty
- Not too heavy
- Automatic switch
- 20A Charger
- No digital screen
Novolpal 1500 Watt Pure Sine Wave Power Inverter
Finishing off this list is a simpler, cheaper option that will still do a great job. If you don’t have a massive budget and will be happy with a straight up power inverter then this is your go-to choice.
This Novopal inverter offers 1500W pure sine wave output and 3000W peak power so will be able to cope with most things you throw at it. Plus you can also pick 2000W options too.
You’ll get plenty of versatility thanks to 4 AC outlets for multiple appliances, plus a remote switch with 16ft cable. It is much smaller and lighter as it doesn’t have an in-built charger or transfer switch. You’ll have to manually switch on and off when you need it. In addition, you’ll need a separate battery charger.
As a standalone power inverter, it’s a reliable option costing an arm and a leg.
- Good price
- Large peak power
- Remote switch
- 4 AC outlets
- No charging function
- No transfer switch
Sump Pump Considerations Before Purchasing an Inverter
By now you should have a better idea of what you need and what sort of products are available. If you’re still a little unsure, then keep reading for all the considerations when picking the best power inverter for your sump pump.
Size and Power
As we discussed at the start, the power capacity of your inverter is the most important thing. You should make sure it offers 20% more continuous watts than the running watts of your sump pump.
For example, don’t try to run a 1200 watt pump with a 1200 watt inverter, it won’t be able to cope. Instead just multiple pump wattage by 1.2 (e.g. 20%) to get your minimum inverter size. So 1200W sump pump x 1.2 = 1440W inverter.
Adding to this, double check the inverter has a decent peak power capacity which it can deliver for a few seconds. This should be at least double its continuous watt.
Pure Sine Wave
You will also require a pure sine wave power inverter. Pure sine wave is the best type of inverter which is needed to run AC motors in sump pumps. You should avoid using cheaper modified sine wave as it will lead to your pump’s motor running with excess heat.
A handy feature to have on your inverter is a charging function. Inverters that can also charge your deep cycle batteries are known as inverter chargers. If you don’t have an inverter charger, you will need a separate battery charger device to recharge your deep cycle batteries from the mains. So it often makes sense to kill two birds with one stone and get an inverter charger. The only drawback is the added price but you need to replace the energy in your batteries somehow?
Automatic Transfer Switch
Inverters with automatic transfer switches are awesome. They enable your inverter to switch from running appliances via mains electricity to off-grid battery power. They are very common on boats that regularly switch between onshore electric hook up and off-grid power.
The main benefit to this is the automation. During a power outage, you don’t need to worry about switching your inverter on to run your pump. It will automatically work! Handy if it’s in the basement or you are away from home. Without an automatic transfer switch, you will have to go and switch on your inverter manually.
Modern power inverters come with a range of different outlet types. Most commonly you’ll find 3 pin AC, hardwiring terminal blocks, and USB ports. To be honest, you’ll probably not have too much need for loads of USB ports.
For a sump pump, the ability to hardwire everything to the inverter via a terminal block is great. It will help keep things running smoothly and keep up with the high demands of your pump.
You might also consider the number of standard AC outlets like you get in the wall socket at home. If you want to run multiple appliances you can get inverters with 2, 3, 4, and more AC outlets. Could it be useful to plug in things like lighting?
You always need to consider safety with this sort of electronics. You will be creating a powerful electric circuit that has the potential to go wrong. You want to make sure your appliances and personal safety is not at risk. For example, if you overload an inverter and it doesn’t shut down it could melt and catch on fire!
Always ensure your inverter has the standard protections against overheating, overload, overvoltage, undervoltage, and short circuits.
So how much does a power inverter to run a sump pump cost?
You will be looking at anywhere between $300 to $1000, depending on the size and quality of your inverter. You need something that can do the job you require. So you could pick up a 1000W pure sine wave inverter for around $300. If you want a top of the line inverter charge with a transfer switch it will be more like $600+.
I advise against going any cheaper than this as you won’t get the performance you need. You are likely to be getting an unreliable low powered option. The last thing you want is to blow a fuse or have equipment that’s not fit for purpose during an emergency power outage.
How Do You Power a Sump Pump with an Inverter?
It’s not too complicated to run a sump pump with an inverter. To make it work you will need an inverter and a deep cycle battery. An inverter is designed to pull energy from a battery and convert it into AC electricity needed to run home appliances.
Here’s the easiest way to do power a sump pump with an inverter:
- Ensure your deep cycle battery is fully charged.
- Connect your inverter to the battery using the red/positive and black/negative cables and terminals.
- Plug your sump pump into the AC outlet on the inverter (Just like plugging into a mains wall socket.)
- Switch on your inverter and pump to make it run.
You can also get an inverter with an automatic switch which you connect to the mains. The pump will run from mains electricity until the inverter detects a power outage. When an outage is detected it immediately switches to battery power in order to run the pump.
How Long Will a 12V Battery Power a Sump Pump?
Working out how long a 12V battery runs a sump pump depends on the pump power and battery capacity. For example, a 750W sump pump could run for 1.3 hours from a 100Ah capacity battery.
To work it out runtime with any 12V battery and any sump pump I have created this formula:
(10 x battery capacity in Ah) divided by sump pump running watts = runtime.
Let’s say you have a 100Ah battery and 750W sump pump.
(10 x 100Ah) ÷ 750W = 1.3 hours.
FAQ about Inverters and Sump Pumps
Now it’s time for your most frequently asked questions!
The best way to run a sump pump without electricity is to use an inverter and deep cycle battery. With the right size inverter, you can run your pump at full power without any downtime. An inverter with a transfer switch will automatically kick in as soon as a power outage occurs.
Yes a 3000 watt inverter will be able to run most domestic sump pumps. The average sump pump uses between 700 – 1500 watts, so it will be plenty of power.
Final Words on Power Inverter for Sump Pump
That’s a wrap, everything you need to know about power inverters to run a sump pump.
You’ll need a decent bit of power, at least a 1200W inverter if not bigger. Plus you should ensure it delivers pure sine wave for best performance.
Remember to choose a high quality reliable product. You don’t want it to stop working during an emergency storm when you need it the most.
Add to this, automatic transfer switches and charging functions make for a complete hands off experience once installed. You can sleep peacefully without having to worry.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.