Setup

The house’s location, floors, leakiness and equipment, and which sensor sits where. The cooling and airflow models are estimates built from these settings, not certified engineering.

Recalculate a model now normally runs every hour

Location

ZIP Latitude override Longitude override Timezone

Conditioned volumedefaults until measured

Floor area ft² Ceiling height ft Setpoint °F Occupants

Walls, roof, and windows UA pieces · leave blank to inherit

Envelope UAor leave UA override blank

Wall area ft² Wall U Roof/ceiling area ft² Roof U Floor area (if UA) ft² Floor U UA override Btu/h·°F

WindowsN/S/E/W glass · SHGC · shade

North glass ft² South glass ft² East glass ft² West glass ft² SHGC Window U Shade factor

Blower door · ACH50measured whole-house leak

ACH50 is the measured air changes per hour at 50 Pa. CFM50, C_total, and envelope-link C are derived. Clearing ACH50 falls back to assumed envelope C and 0.35 ACH.

ACH50 Power-law n Allocation Source Notes LBL N-factor (rule of thumb) ACH fallback Internal sensible Btu/h Internal latent Btu/h

Installed plant PD chart · two identical splits

Two Carrier 26TPA8 2-ton two-stage condensers (R-454B), each on a 59TP6 40k furnace and a CVAMA2517 TXV coil. Each return has an Aprilaire MERV 10 media filter. Upstairs has an Aprilaire 8145 fresh-air ventilator. Attic supply and return are modeled as R-8 flex (effective R-6.4 after a labeled 20% compression derate) with a house-typical length × diameter — edit the runs if you tape them. Capacity is interpolated from the published detailed-cooling table — there is no installer AHRI card. The 8145 knob is often minutes per hour — if 26 means 26 min/hr, set the unit to minutes. BME680 tiles subtract Bosch’s 1.33°C LP heater offset from raw firmware T and remap RH so dew point stays put — that is not an Ecobee calibration.

Electricity tariff Chariot Bright Nights · Oncor

Daytime 6am–11pm is Chariot 5.69¢/kWh plus Oncor 6.0295¢/kWh. Bright Nights 11pm–6am zeros the Chariot energy line only — Oncor 6.0295¢/kWh still applies, so the night is not free. Chariot $9.95 and Oncor $4.06 monthly bases are included in the window average. The EFL 35% nights assumption is not used as the operating mix — the hours here are the mix.

Sold · built · measured KB Salerno 3474 · 24h window · not a HERS rating

Sold is the Salerno sheet: HERS 58 and $196/month are whole-house annual software. Built is two 26TPA8s, upstairs 8145, MERV 10, measured ACH50. Measured indexes are this window: I_s = kWh / (demand kBtu / s) on hold-set hours (setpoint ≥ 72°F). I_EER2 compares to listing EER2 14; I_18 compares to seasonal SEER2 18. Neither is a RESNET rating. Cooling $ is a share of $196, not a bill variance.

Ecobee read-only log, not a control surface

Ecobee closed the developer portal and no longer issues API keys. Sign in with the same email you use at ecobee.com. The password is used once to get tokens and is not stored. This is the consumer login Home Assistant 2026.3 uses — HomeKit and Matter cannot give compressor runtime, which Cooling needs. We never write setpoints, holds, or equipment. Thermostats and remotes become stations you can assign to a room. Unlink deletes tokens only; history stays. Official partner contracts are not required; the login can break if Ecobee changes Auth0.

Backfill from Backfill to

Ecobee fetchesappend-only

Mechanical exhaust prescribed CFM when on · not ACH50

The hood and fans depressurize the airflow network only while switched on here. Defaults off.