Your installer is badly misinformed. If they are offering a Powerwall 3, you absolutely don't need 2 or 3 to power the whole house. One PW3 will provide enough output to power all of your non-heavy loads. More PWs get you longer backup duration, and more power to run heavy loads, but one PW3 can cover emergency needs for sure.The battery will partially power the house. I believe i choose 5 critical items to power. They offer a tesla power wall. A full house requires 2 or 3 total batteries.
We have a 9.9kW solar array and a single Powerwall 3, and we have whole-house backup, no sub-panel or critical loads panel required. Our HVAC is on load-shedding relays in case the grid goes down overnight or while we're away form the house, but absolutely everything else is powered by the Powerwall.
I suggest three things:
- In locations without VPP (where the utility can tap into your battery storage and pay you for it) or Time of Use cost differentials, the battery is essentially an insurance policy against grid outages, nothing more. You need to decide whether the extra cost of the battery is an insurance premium you're willing to pay. You will not get payback on the battery cost.
- If you only have one installer quote, get at least one more. Check Energy Sage to see other installers in your area.
- Do some research and decide what is important to you before getting any more quotes or deciding what to get. Installers will try and sell you on lots of things to pad their invoice (as in the battery offer above). Make a plan for what you really want and stick to it.
Hope this helps!
Statistics: Posted by PNWHiker — Thu Jan 09, 2025 5:01 pm — Replies 6 — Views 371