Tampermonkey/Greasemonkey userscript that redirects https://www.ecobee.com/ (site root) to https://www.ecobee.com/consumerportal/index.html using document-start + location.replace to minimize flicker and avoid history pollution.

ecobee-homepage-to-consumerportal-redirect.user.js

// ==UserScript==
// @name         ecobee homepage -> consumerportal redirect
// @namespace    https://gist.github.com/ParkWardRR
// @version      1.2.0
// @description  Redirect ecobee.com to the Consumer Portal login (skips /consumerportal/*), early (document-start) with location.replace().
// @author       Your Name
// @license      MIT
//
// IMPORTANT (Violentmonkey): metadata must be at the very top of the file and formatted exactly. [page:1]
//
// @match        https://www.ecobee.com/*
// @match        https://ecobee.com/*
// @run-at       document-start
// @noframes
// @grant        none
// ==/UserScript==

(() => {
  'use strict';

  const TARGET = 'https://www.ecobee.com/consumerportal/index.html';

  // Don’t loop.
  if (location.hostname === 'www.ecobee.com' && location.pathname.startsWith('/consumerportal/')) return;

  // Redirect anything on ecobee.com -> portal.
  location.replace(TARGET + (location.search || ''));
})();