Hey! We’ll fix why your Nest is not saving settings (changes revert / “won’t stick”) and get stable control again. Quick checks so we don’t guess:
• Which device: Nest Thermostat (2020 mirror), Nest Learning Thermostat (Gen 3/4), or Thermostat E?
• Are you controlling it from the Google Home app, the Nest app, or both?
• What won’t save: schedule, temperature setpoint, mode (Heat/Cool/Heat•Cool), fan schedule, Eco temps, or Home/Away settings?
• When you change a setting, do you see an error (e.g., “something went wrong”, “can’t connect”, “device offline”), or does it “save” then revert later?
Once I know those, I’ll give the fastest path to stop Nest thermostat settings reverting.

Perfect — with the 2020 Nest Thermostat, “not saving” is usually one of these (and we’ll test them in a clean order):

1) An override is changing it back (most common):
• Eco triggered by Home/Away routines or presence settings → your comfort temp gets replaced by Eco temps.
• Auto-Schedule / learning style features (model dependent) → new schedule entries appear or your edits get replaced.
• Google Home automations or “Home/Away” routine → mode/temperature changes when phone location says Away.

2) Cloud sync isn’t completing:
• Thermostat is offline briefly, weak Wi-Fi, or router blocks traffic → Home app shows the change but Nest doesn’t keep it.
• Phone-side issues: VPN, aggressive battery optimization, background restrictions, stale app cache.

We’ll do a “fast fix” first (stop overrides), then lock in the connection, then (only if needed) reset/re-add so settings save normally in the Google Home app.

Great — then we start with overrides. This is the fastest way to stop Google Nest thermostat settings reverting.

Step 1 — Check if Home/Away is forcing Eco (Google Home app)
1) Open Google Home → tap your thermostat → Settings (gear).
2) Find Eco / Eco temperatures and note what they’re set to (these are the “fallback” temps).
3) In Google Home, open Automations (or Routines) → look for Home / Away routines that include the thermostat (Eco or temp changes).
4) Temporarily disable any routine that touches thermostat temperature/mode so we can test clean behavior.

Step 2 — Stop the “Away” trigger from your phone
• In Google Home → Settings → Presence sensing / Home/Away (wording varies) → confirm what decides if you’re home (phone location, Nest devices, etc.).
• For a quick test, set it so it doesn’t auto-switch for the next hour (or remove the thermostat from Away actions).

After this, try setting a temperature and wait 10–15 minutes. If it no longer flips to Eco by itself, we’ve found the main “not saving settings” cause.

Nice work — Eco override is one big piece. Now let’s solve the “Nest schedule not saving / edits revert” part.

Step 3 — Make sure a “Hold” or temporary change isn’t masking the schedule
• On the thermostat screen, check if it shows Hold, Temporary, or a hand icon (model dependent). If there’s an active hold, the schedule can look like it’s ignored.
• Cancel the hold (or switch back to following the schedule). Then test schedule behavior again.

Step 4 — Confirm you’re editing the right schedule source
With some setups, users edit schedule in one place but a routine/automation is effectively overriding it. Do this quick “single source of truth” test:
1) In Google Home → Thermostat → Schedule, make ONE obvious change (e.g., 7:00 AM set to 21°C/70°F).
2) Save, then force a sync: fully close Google Home app and reopen it.
3) Then check the schedule on the thermostat itself (or re-open Schedule) and confirm the entry is still there.

If it disappears, it’s usually a sync/connection issue (Wi-Fi or account). If it stays but the temperature still changes at odd times, a routine/automation is still touching temps behind the scenes.

That “offline for a minute” is a huge clue. When the thermostat drops offline (even briefly), you get the classic Google Home app not saving Nest settings symptom — it looks saved, but the cloud never commits it.

Step 5 — Stabilize the connection (fast checks)
• Make sure the thermostat is on the correct Wi-Fi and has a solid signal (avoid a far mesh node). If you have mesh Wi-Fi, try connecting Nest to the main router node if possible.
• Reboot your router (one clean restart).
• If your router combines bands, ensure your thermostat stays stable on the band it supports; avoid frequent roaming between nodes.

Step 6 — Remove phone-side blocks that break sync
On your phone, do these “quick wins” (they fix a lot of cases where settings won’t save):
• Turn off any VPN or ad-blocking DNS temporarily.
• Allow Background App Refresh (iOS) or disable aggressive Battery optimization for Google Home (Android).
• Update Google Home app to the latest version.
• Force-close the app and reopen after changes.

Step 7 — Clear app cache (Android) / reinstall (iPhone)
• Android: Settings → Apps → Google Home → Storage → Clear cache (and if needed, Clear data and sign back in).
• iPhone: reinstall Google Home to refresh cached auth/sync state.

After doing Steps 5–7, try a single schedule edit again. If it keeps saving reliably, we’re done. If not, we move to account + device reset.

Good progress. Now we check the last “silent overrides” that make it feel like Nest isn’t saving settings when it actually is saving — but another feature changes the target later.

Step 8 — Check for schedule-follow behavior
On many thermostats, a manual change is temporary until the next schedule point. So if your schedule says “6:00 PM = 20°C”, and you set 22°C at 5:10 PM, it may snap back at 6:00 PM (that’s normal schedule behavior).
✅ Quick test: make a manual change and see if it holds until the next schedule event time.

Step 9 — Turn off features that can rewrite or bias temps (model/account dependent)
In Google Home → Thermostat → Settings, look for any of these and disable temporarily for testing:
• Auto-Schedule / learning (if available for your model)
• Seasonal Savings (can adjust temps for “efficiency”)
• Sunblock / similar comfort features (Learning Thermostat models)
• Anything labeled Energy, eco suggestions, or adaptive

Step 10 — Verify Home/Away didn’t re-enable
Sometimes Home/Away routines get re-enabled or another household member has a routine that touches Eco. Double-check: Automations → Away routine → thermostat actions are still OFF.

If after Steps 8–10 you still see random reverts, we’ll do the reliable “clean re-pair” (remove + re-add) so cloud sync stops glitching.

Absolutely — here’s the fast, high-success “clean re-pair” that fixes stubborn Nest thermostat settings not saving and schedule sync problems.

Step 11 — Restart the thermostat (quick, safe)
• On the thermostat: Settings → Restart. (This refreshes Wi-Fi + app sync without wiping your home.)

Step 12 — Remove and re-add the thermostat in Google Home
1) Google Home → Thermostat → Settings → Remove device.
2) Restart your phone (optional but helps with Bluetooth/Wi-Fi discovery stability).
3) Google Home → “+” → Set up device → New device → scan the QR code on the thermostat / follow pairing prompts.
4) During setup, keep your phone on your home Wi-Fi (not cellular-only), and avoid Private Relay/VPN during the pairing step.

Step 13 — If problems persist: Reset Network (not full factory)
If you frequently see offline drops, do a Network reset on the thermostat (keeps most device identity but refreshes Wi-Fi credentials). Then reconnect to Wi-Fi and test schedule saving again.

Step 14 — Last resort: Factory reset
Only if nothing else works: Settings → Reset → Factory reset, then add it back to your home. This clears corrupted config that can cause “changes revert” bugs.

Yes — multi-user homes can absolutely create “phantom reverts,” especially if multiple people can control the thermostat or if permissions are mismatched.

Step 15 — Check home roles and who can edit
• Google Home → Settings → Household / Home members → confirm everyone is in the correct home and has permission to control devices.
• Ask: does anyone have an automation (Home/Away, bedtime routine, “leave home” routine) that changes thermostat settings? Even a single routine can make it look like the thermostat won’t save your settings.

Step 16 — Confirm you’re using the same controlling account
If one phone is signed into a different Google account (or an old Nest account vs Google account migration situation), changes can fail to sync or appear to “undo.” Make sure the device is owned by the correct primary home and everyone is controlling it from that same home.

If you want, tell me: iPhone or Android for each person + whether anyone uses the Nest app too. I can point out the exact settings that cause the most common Google Home thermostat changes not saving issues.

Awesome — that’s exactly the pattern we want.

Summary: When Nest is not saving settings, it’s usually an override (Eco + Home/Away routine, automations) or a sync issue (brief offline drops, app cache/auth problems). Disable thermostat-changing routines first, then stabilize Wi-Fi/app sync, and only if needed restart/reset and re-add the thermostat to Google Home. If you ever see changes revert again, open the chat and we’ll pinpoint the exact setting (Eco, schedule, automation, Wi-Fi, or account permissions) in minutes.