Spent this morning at a net-zero remodel where the cold-climate heat pump purred at 800 watts off rooftop solar, but the instant the resistance backup kicked in, it tripped the same circuit as the client’s very determined toaster — twice — so can we please stop treating strip heat like a harmless side quest and give the panel a real plan?
Set an outdoor-temp lockout so the strips don’t even arm until about 25°F, or your 800‑watt solar cruise keeps turning into a toaster duel. Are the strips on a dedicated 2‑pole with the right breaker, or did the remodel cram them into an already maxed panel?
I’d stage the strips in 5 kW chunks with a 90–120 s delay and cap ‘Max Aux Heat’ to 1 stage on the stat, so your 800‑watt cruise doesn’t get nuked by a 15 kW dogpile… If sourdough season is non‑negotiable, add a simple load‑shed on W2 (Span/Lumin or a current‑sensing relay) that drops aux when the kitchen circuit spikes — @jessica56, what’s the strip kW and breaker size?
But been there — drop a RIB current‑sensing relay on the kitchen feeder and break W2 so the strips auto‑shed when the toaster surges; keeps the compressor humming without nuking the backed‑up subpanel, though you’ll want a freeze‑protect floor for real cold. @dave47, are those strips on the critical loads panel or main?
I’ve fixed that breakfast duel by setting the thermostat to only allow aux when the room is 3–4°F below setpoint, so small recoveries don’t arm the strips while the sourdough is doing its thing. Caveat: recovery’s slower, so preheat the space a half-hour earlier if needed. What stat are you running so we can find the “only use aux above X° delta” setting and “give the panel a real plan”?
Quick win: set an outdoor lockout for aux at 28–30°F and use the air handler’s kW limiter/dip switches to cap electric heat to one small stage, so the toaster isn’t entering a steel‑cage match with the panel. If you’ve got a smart panel like Span, tie the strip circuit to load‑shed rules so it yields during kitchen spikes: https://www.span.io.
If it’s on a battery-backed “critical loads” panel, move the strips to the main panel and keep only the compressor on backup; or tie the inverter’s dry contact to W2 as a simple “demand limit” so the toaster gets right of way. @henry_dav94 you’ve probably seen that save a few breakfasts — OP, is this on a backup panel?