- What is a Whole-Home Backup System?
- Whole-Home Backup Components: MID, MSP, and the Backup Load Path
- Partial Home Backup: Selecting Circuits and the Backup Load Panel
- How To Select Essential Circuits for Partial Home Backup
- Frequently Asked Questions
- Ready To Explore Ecoflow’s Scalable Backup Power Solutions With the Delta Pro Ultra X?
Whole Home vs. Essential Circuits: Choosing Your Backup Power Setup
- What is a Whole-Home Backup System?
- Whole-Home Backup Components: MID, MSP, and the Backup Load Path
- Partial Home Backup: Selecting Circuits and the Backup Load Panel
- How To Select Essential Circuits for Partial Home Backup
- Frequently Asked Questions
- Ready To Explore Ecoflow’s Scalable Backup Power Solutions With the Delta Pro Ultra X?
With extreme weather events, natural disasters, and power outages on the rise, more and more Americans are turning to home battery backup power systems to ensure the lights stay on during blackouts.
The good news?
There are more affordable and efficient options for home backup power than ever before.
The bad news?
More options can mean more anxiety when you're trying to make a purchase decision.
Many factors go into making the right choice for you, but one of the first decisions you need to make is how many of your home appliances and systems like lighting and HVAC do you want to operate during power outages?
And for how long between charges?
If budget isn't an issue, it's fully possible to buy a modular whole home generator or battery backup system that can power your entire home.
However, many homeowners choose to power only essential appliances or circuits.
Both options are viable, with whole-home backup offering maximum comfort and essential circuit backup providing emergency power at a more affordable price.
This article will walk you through how to make the right decision based on your individual requirements.
But before we dig into the details, what exactly is whole-home backup power?
What is a Whole-Home Backup System?
Whole-home backup systems use either batteries to store electricity, a generator to produce electricity (or a combination of both) to provide power for a substantial number of your appliances, rechargeable electronic devices, and chosen systems like heating and air conditioning (HVAC) and lighting.
While it's possible to purchase a whole home battery system like EcoFlow DELTA Pro 3 that allows you to plug appliances directly into the unit, most homeowners choose to integrate their backup with their electric circuit board and existing home wiring.
There are three basic options for integration with home wiring:
Automatic transfer switch
Manual transfer switch
Smart home energy management panel like EcoFlow SmartHome Panel 3.
As the name suggests, an automatic transfer switch quickly switches to backup power during a blackout, often within 20 milliseconds or less.
A manual transfer switch must be physically turned on by someone on-site to start providing backup power.
Smart home energy management systems like EcoFlow Smart Gateway (200A) offer additional benefits like remote monitoring/control, and intelligent load management which can save you significantly on electricity bills even when grid power is available.
Whole-Home Backup Components: MID, MSP, and the Backup Load Path
If, like most homeowners, you want seamless home battery backup power, integrating your chosen solution with your main household electricity panel is essential.
Main Service Panel (MSP)
The technical name is Main Service Panel (MSP), it's the central hub where the power line from your utility enters your house and it distributes AC (household) electricity to individual circuits then to the wall plugs and other outlets in your home.
Traditional MSPs distribute electricity and protect individual circuits from overloading with breaker switches…
Virtually everyone has experienced a circuit breaker switch being tripped by a high wattage appliance cycling on or by plugging in one too many appliances, such as a hairdryer.
Motor and compressor driven appliances like refrigerators and air conditioners require a significant influx of starting wattage which can temporarily overload a circuit.
Antiquated home electrical systems had fuse boxes for safety reasons.
Circuit breakers perform a similar function but don't require replacement each time they're accidentally tripped.
In a standard household electricity setup, the MSP is the not-so-smart brain of your system.
However in most backup applications its primary purpose is to house the individual circuit breakers.
Microgrid Interconnect Device (MID)
The Microgrid Interconnect Device (MID) is the automatic or manual transfer switch or other smart home interface that controls the connection between your MSP, your home backup system, and the utility grid.
Some portable power stations and other battery backup systems allow you to connect high-wattage appliances directly to the unit and don't require a MID or interconnection to the utility grid…
However, most homeowners prefer fully integrated whole home generators or battery backups to help ensure safety and convenience during a power outage.
MIDs perform several functions during a blackout:
In bidirectional, grid connected solar + storage systems, a MID automatically disconnects your solar generator from utility power, preventing potential injury to utility workers and further damage to infrastructure like transformers.
Grid-tied solar power systems do not work during blackouts.It quickly switches from on-grid power to off-grid electricity, often in 20ms or less, depending on the system. Fast autoswitching provides power at an almost imperceptible speed. However, if you're running a home office setup with desktop computers and external hard drives, a switchover time of <10ms is optimal as an uninterruptible power supply (UPS).
EcoFlow DELTA Max Pro Plus and RIVER 3 Plus portable power stations provide true <10ms UPS backup.
EcoFlow DELTA Pro Ultra X does too, but only if appliances are plugged directly into the unit. When integrated with EcoFlow Smart Home Panel 3, the switchover time is <20ms — hardly the blink of an eye but potentially enough to cause corruption in data storage devices that require constant connection to power to operate.
EcoFlow DELTA Pro 3 Solar Generator (PV400W)
MSP, MID, Home Backup Power and the Grid: How Do They Interact?
Any off-grid or on-grid home backup system that provides or generates power and connects directly to the utility grid — either one way for charging or bidirectionally for net metering applications — MUST have an approved auto-disconnection device, typically a Microgrid Interconnect Device (MID) or automatic transfer switch.
It's a non-negotiable safety and electrical code requirement.
Even a home battery backup system that doesn't transmit electricity back to the utility grid requires a MID because you cannot have two independent power source (grid + battery power) connected to the same circuits simultaneously without a controller.
A MID, automatic or manual transfer switch, or smart home energy manager like EcoFlow Smart Home Panel 3 IS that controller.
In home battery backup and whole home generator systems that only connect one way to the utility grid, the MID performs the following functions:
Power Outage Detection: When utility power is interrupted, the MID automatically disconnects your power supply from the grid to prevent "islanding" which can harm workers and infrastructure.
Autoswitching your MSP to backup power from your home battery or generator system results in almost instantaneous off-grid electricity, often in 20 milliseconds or less.*
Autoswitching back to utility power when the grid goes back online.*
Restores one-way power flow from the grid.
* Doesn't apply to manual transfer switches.
Partial Home Backup: Selecting Circuits and the Backup Load Panel
Not everyone needs or can afford the luxury of whole-home backup power.
However, that doesn't mean you can't have the electricity you NEED during a blackout.
You've got options, including plugging essential appliances and devices directly into a portable power station like EcoFlow's DELTA 3 Series home backup systems.
Solar generators like EcoFlow DELTA 3 Ultra Plus + 400W Portable Solar Panel are also a viable choice.
Portable gas and inverter generators can provide partial home backup but must be operated outside a safe distance from your home — 20 feet at least — making them impractical for indoor plug-and-play power.
A power station is very convenient for small homes and apartments where many of your essential home appliances may be in close proximity to each other, such as in a kitchen or home office.
However, many homeowners opt for the convenience of partial home backup for essential circuits in their Main Service Panel (MSP) or a smart MSP-replacement like EcoFlow Smart Home Panel 3.
Even partial home backup that connects one way to the grid requires the same safety and electrical code requirements as whole home systems, because even a single circuit can't operate simultaneously with utility and a secondary power source at the same time.
No matter whether you choose a standalone solar generator or integrated partial home backup, you're going to have some decisions to make.
Unless the AC output and fuel source/battery storage capacity can support all the appliances and systems you want to start and operate simultaneously during an outage, you'll have to pick and choose what devices are a priority and which you can do without until the lights come back on.
Learn how to calculate your household power requirements here.
If you're integrating your backup with your MSP through a MID, you'll need to decide which circuits in your home you want to power and how much AC output you require for them to start and operate — and for how long.
The key component required to make partial home backup work is the Backup Load Panel (BLP).
The BLP, also known as an electrical sub-panel or critical load panel, is a smaller secondary service panel installed next to your MSP.
Once you've decided what essential appliances you want to back up, a licensed electrician or installer will migrate the circuits from the MSP to the BLP.
While the grid is up and running, the BLP typically receives power directly from the MSP.
When a power outage occurs, the transfer switch (MID) disconnects from grid power and directs backup electricity exclusively to the Backup Load Panel.
Circuits that are connected to the MSP — and the appliances they power — remain offline for the duration of the blackout.
How To Select Essential Circuits for Partial Home Backup
Which appliances and home systems you consider "essential" is very much a personal choice.
For example, in a location where temperatures rarely reach extremes of hot or cold, air conditioners and space heaters may be a luxury — both eat up a ton of power.
However, if you live in Phoenix, AZ or Anchorage, AL, AC and space heating may save your life during a heatwave or blizzard.
It can be helpful to prioritize your essential circuits into three categories.
1. Survival and Safety
Refrigerator/Freezer
Well pump (if needed)
Sump pump (to prevent flooding)
Furnace or space heater (for climate control in winter)
Window or portable air conditioner (for climate control in extreme heat)
Essential lighting
Critical medical equipment
2. Communication and Comfort
Internet modem and router (to stay informed).
Wall outlets for charging phones and laptops.
A television or home entertainment center.
A microwave or toaster oven for simple cooking.
3. High Power Loads to Avoid
Central Air Conditioning
Electric vehicle (EV) chargers
Electric stoves and ovens
Electric water heaters and clothes dryers
Frequently Asked Questions
How To Choose a Backup Power Supply?
For most homeowners, choosing the right backup power supply requires a compromise between budget, safety, and comfort. It's possible to backup every circuit, appliance, and HVAC system in your home during a blackout, but unless you have minimal electricity needs, it requires a significant investment. Partial home backup is often the best choice as it allows you to operate essential appliances during a power outage.
Can I Power My Whole House With a Backup?
Yes. Whole-home battery backup systems and generators have become more affordable in recent years. Solar generators, in particular, can not only keep the lights on during a blackout but also help you save significantly on energy bills, particularly if your utility provider offers time-of-use (ToU) rates (on-peak/off-peak demand pricing). Standby generators that burn fossil fuels may cost less upfront, but they have ongoing fuel costs and offer no return on investment.
Ready To Explore Ecoflow’s Scalable Backup Power Solutions With the Delta Pro Ultra X?
EcoFlow is the world's #1 manufacturer and direct-to-consumer retailer of portable power stations — from off-grid adventures to whole home battery backup and generator solutions.
EcoFlow DELTA Pro Ultra X is an expandable whole home generator + backup battery system that offers multiple charging methods including grid, solar, and gas generator power.
With modular expandability maxing out at 36kW of continuous power output and 184kWh of battery storage capacity, it can grow with you and keep almost any size home up and running during extended power outages.
Not only that, it can save you a significant amount of money on energy bills — something traditional standby generators can't do.
Check out our selection of portable power stations and solar generators today.