Heat Sensor for Garage

[rswenson11]

We just completed the construction of our new home in Washington state and installed Google Nest Protect smoke detectors throughout the house.  When we went to receive our final, the inspector called out our builder for not installing a heat sensor in the garage.  Apparently this is a new requirement that the building inspector did not catch when they did the wiring inspection, the electrician did not catch or our builder did not catch.   They did not wire for it.   From reading in the community comments, it appears that there is no way to use the existing Google Nest Protect smoke detectors we purchased with either a 3rd party wired or wireless heat detector.  I am reaching out to the Google Nest Community page to get a confirmation of this before we replace these.  

[MplsCustomer]

@rswenson11 

We don't have Nest Protects, but don't they include a heat sensor?

Heat sensor

Heat sensor enables Nest Protect to detect sudden rises in temperature.

https://support.google.com/googlenest/answer/9251133

A heat sensor allows Nest Protect to detect sudden rises in temperature. If Nest Protect senses a rapid rise in temperature, it becomes more sensitive to smoke. You get an earlier alert, and more time, to handle an emergency.

https://support.google.com/googlenest/answer/9251134

[rswenson11]

They apparently do, but no details on Google's website about how they work.  The bigger issue is that they recommend the smoke detectors not to be installed in a garage due to temperature swings and false CO2 alarms due to the exhaust.  I might just install one anyway

[MplsCustomer]

@rswenson11 

I forgot about that aspect (not installing smoke detectors/carbon monoxide detectors) in garages.  We have a detached garage and our home is 95 years old, so I'd never heard of the heat sensor requirement. The Nest Protect in your garage might have false alarms.

[toby_wan_kenoby]

Do we have any information what temps the heat sensor is sensitive to. I have 5x Tesla PowerWalls installed in my garage. The inspector requires a heat sensor due to the batteries. I would like to add a 2nd Gen Home Protect but have no info on the heat sensing functionality to give to the inspector. 

[YesMan]

Rapid heat rise sensors operate on the basis of heat rise rate, not so much a temperature threshold. If I am not mistaken the rate rise has to be at least 8.3°C (15°F) per minute to trigger.  This may be achieved electronically or via a mechanical air chamber with a reatricted vent (causes a chamber bulge that closes a mechanical contact).

I had previously suggested via a community post to google to offer a software switch to only enable rapid heat rise, but I am guessing this wouldn't fly as there would be local laws dictating what would be approved.

Realistically, Google/Nest should release a garage-only product which would also be cheaper without the additional smoke and CO2 sensors.