On a site visit in Portland this morning, the 2-ton cold-climate heat pump (COP about 3.4 at 30°F) ran on an 8 kW rooftop PV system and told the gas furnace, ‘thanks, we’ll call you in 2040’ — anyone else get emotionally attached when the greenest box in the house starts pulling hero numbers?
Love it — if you want even more “hero numbers,” set the dual-fuel lockout down around 20–25°F and use a 1–2°F afternoon preheat when PV is peaking to bank some BTUs. Your gas meter can nap, but watch defrost cycles at 30°F if ducts are marginal — are you seeing any short cycling on cloudy afternoons?
My tweak for those damp Portland mornings: switch to demand-defrost and drop airflow to about 350–380 CFM/ton around 30°F so the supply stays toasty and you don’t shred that 3.4 COP… , those morning defrosts can kneecap the “we’ll call you in 2040” brag fast. Quick ref to sanity-check models/settings: ccASHP Specification & Product List | Northeast Energy Efficiency Partnerships — are you on demand or timed defrost?
I’ve had good luck setting a long ‘compressor to aux’ delay — 60–90 minutes — and a slightly wider heat differential so the furnace doesn’t steal the call when a cloud drifts by. If recovery gets sluggish on those soggy mornings, shave the delay back a bit. Ecobee and a few OEM stats make this easy per mode.