How to think about home battery installation and its value
Adding home batteries is a great way to enjoy peace of mind and be prepared for grid outages. Batteries allow you to store energy produced by your solar system to use when you choose, such as at night, when your utility charges more, or during an outage.
Sometimes at Zenernet, homeowners ask us about the possibility of whole home battery backup. In this post, we’ll explain what that means, how feasible it is, and how to understand the value of installing home batteries.
What is Whole Home Backup?
Simply put, whole home backup means having a solar and battery storage system sufficiently robust to supply the energy needs of the entire home – from heating and cooling to major appliances down to the reading lamp on your nightstand – during a utility outage.
You might also hear people refer to “going off the grid.” Technically speaking, “going off the grid” would mean being entirely and permanently self-sufficient in your energy needs. Going fully off-grid is extremely challenging, and most homeowners we talk to are only interested in having a backup for a temporary utility outage, so that’s what we’ll focus on in this post.
The important thing to remember when considering battery backup is that not all of the electrically-powered devices in your home are created equal. They aren’t equal in the demand they place on your home’s electrical system, and they also aren’t equal in importance to you and your family.
Most of the electrical outlets in your home – the kind that you would plug a lamp or a phone charger into – are 15 amp receptacles on a 15 or 20 amp circuit. Major appliances, such as water heaters, HVAC systems, well pumps, and pool and hot tub heaters typically require their own dedicated 30 to 50 amp circuit breakers.
The complexity of home battery systems increases with the amount of circuits that require backup – especially 30 to 50 amp circuits.
The other major factor to consider when planning home battery installation is the amount of time between charges that battery backup can support. The more circuits there are pulling power from a battery system, the quicker the batteries will drain – just as performing more demanding tasks on a laptop, like streaming a movie or joining a video call, will cause that laptop battery to drain faster than simply typing a document.
While long-term whole home backup – where all devices and appliances run normally in the home for a day or more – is possible to design, it is quite expensive and can require significant electrical work on top of the battery system installation itself.
With that said, many homeowners can find significant value in battery installation without achieving whole-home backup. Ensuring a few select outlets and appliances maintain power for an extended period during an outlet greatly improves peace-of-mind and preparedness for such situations, and is much more approachable for most homeowners.
Who Should Consider Battery Backup?
Homeowners who can get the most value out of battery backup are those who live in areas with frequent utility outages, either due to rolling blackouts or severe weather. A homeowner who lives in an extremely hot climate, for example, might find it a worthy investment to install a backup system that will allow them to use their air conditioning during a utility outage.
How to Think About Battery Backup
If you live in an area where conditions make adding battery backup to your solar system attractive, then the next step is to think about what you actually want to back up and for how long. Which rooms, devices, or appliances do you need to ensure will keep operating during an outage to minimize discomfort and disruption for your family? How long do you think you’ll realistically need to rely on your battery system to power them?
When our energy consultants discuss the subject with homeowners, we find it helpful to think of three “tiers” of battery backup. These aren’t preconfigured, cookie-cutter systems that we sell; the particular components used can still be customized according to your preferences and budget. They’re just a way of thinking about what level of backup you want to achieve.
The essential tier is designed to give you peace of mind by backing up your most essential appliances at an affordable cost. Battery systems at this tier typically include a single 30-50 amp breaker, and up to 6 kW of continuous power for up to 10 hours – enough to get you through most brief utility outages.
The advanced tier aims to balance backup capacity and cost. It offers up to three 30-50 amp breakers and up to 10 kW of continuous power for a multi-day outage.
Finally, for those homeowners who have the need and the financial resources to approach whole home backup, there’s the premier tier. This is the option if your goal is to minimize disruptions from utility outages for prolonged periods. Systems at this tier typically include six 30-50 amp breakers for major appliances, and up to 15 kW of continuous power for multiple days of interruption in your utility service.
It’s important to note that even with premier tier battery systems, you will not be able to power your home as normal indefinitely. The more power is used, the faster your batteries will drain – just like with any battery-powered device. However, a system in this tier combined with a mindful approach to power usage during outages will allow you to minimize disruptions and maintain access to your devices and appliances.
Most of the homeowners we work with will get the most value out of battery backup at the essential or advanced level. This will allow you to power the systems most essential to your family staying comfortable during a temporary utility outage without breaking the bank.
If you have more questions about battery backup, including how to add backup to an existing residential solar system, you can always schedule a convenient remote consultation with one of our energy consultants.