Will the GS366 work with my HVAC system?

Most likely, yes. The GS366 is designed for 24V low-voltage systems and works with most conventional setups (gas, oil, or electric) as well as heat pump systems. Not sure what you have? Use our compatibility check before you buy.

Does it work with heat pumps?

Yes. The GS366 supports heat pump systems, including the O/B changeover valve wiring used for switching between heating and cooling.

Does it support two-stage heating and cooling?

Yes. The GS366 is optimized for both single-stage and two-stage heating and cooling equipment, so multi-stage systems get the right level of output for the weather — comfort when you need it, efficiency when you don’t.

I don't have a C-wire. Can I still install the GS366?

Yes. The GS366 supports a Power Extender Kit (PEK) solution that provides continuous power in homes without a C-wire — older homes included. See the installation guide for wiring details.

How long does installation take? Do I need a professional?

Install it yourself in about 45 minutes. Everything you need for installation is in the box, including mounting hardware — just follow the included installation guide, wire by wire. Prefer not to DIY? Any local HVAC technician can install it for you.

Does it work with both 2.4 GHz and 5 GHz Wi-Fi?

Yes — and then some. The GS366 supports dual-band Wi-Fi 6 (802.11 b/g/n/ax on 2.4 GHz, 802.11 a/n/ac/ax on 5 GHz), so it connects to whichever band your router serves best.

Which voice assistants does it work with?

Amazon Alexa and Google Assistant, right out of the box. Set the temperature, switch modes, and more — hands-free.

What about Apple Home?

Apple Home support is coming via a future Matter update. When the over-the-air update rolls out, your GS366 will be ready — no new hardware needed.

How much energy will I actually save?

It depends on your home, your climate, and your habits — anyone who promises an exact number is guessing. What we can say: heating and cooling are the biggest energy expense in most homes, and the GS366 attacks the waste with Home/Away/Sleep schedules and smart temperature suggestions, so you stop paying to condition an empty house.*

What warranty and return policy do I get?

Every GS366 is backed by a warranty, and it's UL Listed and FCC compliant. If something goes wrong, we make it right.

Feature	Our Pick Siterwell GS366	ecobee Smart Thermostat Essential	Google Nest Thermostat
Price	$89.99 — launch pricing	$139.99†	$129.99†
ENERGY STAR®	Certification in progress*	Certified†	Certified†
C-Wire Solution	Power Extender Kit (PEK) support	PEK in box†	No C-wire needed on most systems; optional power connector†
Touchscreen	3.5" color touchscreen	Color touchscreen†	No touchscreen — side touch strip, swipe to adjust
Dual-Band Wi-Fi	Wi-Fi 6, 2.4 GHz + 5 GHz	—†	—†
Alexa + Google	Works with Amazon Alexa & Google Home	Yes†	Yes†
Apple Home (via Matter)	Coming via a future Matter update*	Apple Home compatible†	Matter support†
Warranty	Warranty included	3-year limited warranty†	1-year limited warranty†

Feature

Our Pick Siterwell GS366

ecobee Smart Thermostat Essential

Google Nest Thermostat

Price

$89.99 — launch pricing

$139.99†

$129.99†

ENERGY STAR®

Certification in progress*

Certified†

C-Wire Solution

Power Extender Kit (PEK) support

PEK in box†

No C-wire needed on most systems; optional power connector†

Touchscreen

3.5" color touchscreen

Color touchscreen†

No touchscreen — side touch strip, swipe to adjust

Dual-Band Wi-Fi

Wi-Fi 6, 2.4 GHz + 5 GHz

—†

Alexa + Google

Works with Amazon Alexa & Google Home

Yes†

Apple Home (via Matter)

Coming via a future Matter update*

Apple Home compatible†

Matter support†

Warranty

Warranty included

3-year limited warranty†

1-year limited warranty†

Warranty & Support You Can Count On.

A thermostat isn't something you should have to think about — and that's the point. The GS366 is built to quietly do its job, season after season, and it's UL Listed and FCC compliant, tested to the safety standards North American homes rely on. Then we back it with a warranty and a customer support team that actually answers. If anything goes wrong, we make it right. That's the whole policy.

SITERWELL Hardwired Smoke Detector Carbon Monoxide Detector 10 Year Battery, Meets UL217-9th Standards, Interconnected Smoke and Carbon Monoxide Detector Combo with Bilingual Voice Alerts,1 Pack

Siterwell

SITERWELL Hardwired Smoke Detector Carbon Monoxide Detector 10 Year Battery, Meets UL217-9th Standards, Interconnected Smoke and Carbon Monoxide Detector Combo with Bilingual Voice Alerts,1 Pack

Name: SITERWELL Hardwired Smoke Detector Carbon Monoxide Detector 10 Year Battery, Meets UL217-9th Standards, Interconnected Smoke and Carbon Monoxide Detector Combo with Bilingual Voice Alerts,1 Pack
Brand: Siterwell
SKU: STORE-GS886F-H02-1
Price: 63.99 USD
Availability: InStock

$63.99 USD

4.3

Quantity:

Siterwell SITERWELL Hardwired Smoke Detector Carbon Monoxide Detector 10 Year Battery, Meets UL217-9th Standards, Interconnected Smoke and Carbon Monoxide Detector Combo with Bilingual Voice Alerts,1 Pack

$63.99 USD

About GS886F-H02

2-in-1 Protection, 0 Worries: Because Your Family Deserves Smarter Safety.
Instant CO & Fire Alerts in One: Dual photoelectric + electrochemical sensors detect both threats – no need for separate alarms.
Fewer False Alarms, More Peaceful Cooking: Smart detection reduces nuisance alerts from cooking while maintaining fast response to real threats.
10-Year Dual-Power Assurance: AC/battery hybrid system with easy-swap backup.
Life-Saving Bilingual Alerts: Clear English/French voice warnings ensure every family member understands emergencies.
Every Alarm Sounds as One: Smart Interconnectivity links all alarms, cutting emergency response time when seconds matter most.

Model

GS886F-H02

Certificate Authority

ETL

Approved Standards

Conform to UL STD 217 9th Ed.& 2034 4th Ed.
Certified to CAN/ULC STD S531:2019&CSA STD 6.19:2017

RoHS、REACH

YES

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Don't know which one to choose? We have selected these products for comparison, and you can choose the one that best suits your needs!

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SITERWELL Hardwired Smoke Detector Carbon Monoxide Detector 10 Year Battery, Meets UL217-9th Standards, Interconnected Smoke and Carbon Monoxide Detector Combo with Bilingual Voice Alerts,1 Pack

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SITERWELL Smoke Detector 10 Year Battery Operated, Smoke Alarm with Photoelectric and Rlectrochemical Sensors, Fire Alarm with Bilingual Voice Alerts for Bedroom, Meets UL217-9th Standards (1 Pack)

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Product type

Smoke&CO hardwired interconnected detector

Smoke&CO standalone detector

Smoke standalone detector

Battery type

10-year backup battery

Built-in 10-year 3V lithium battery

Installation method

Hard wiring & screws & magnets

Screws & magnets

Bought a house and the seller replaced the smoke detector with this model. About 14 months after, smoke tripped the alarm. However I cannot get it to shut off without removing the power. Upon giving it power again, it constantly alarms. The test button does nothing except go into pairing mode, which it will resume blaring after.

I contacted support with a picture, the model number, purchase date, and symptoms and my situation including I am not the original purchaser. I was asked twice to provide information such as pictures, the model number, and proof of purchase. After repeating myself, I was told they would not honor any warranty claim without proof of purchase. Normally this is fine, but given many smoke detectors maybe purchased by property sellers, I find this unreasonable. Aside from the brain dead support, and lack of an unconditional product warranty for a device that failed one year after, despite being a 10-year product, especially a critical safety device, I give this a one star.

Looks like cheap Chinese

Looks like cheap Chinese stuff

Compatible with an asterisk...

The product itself is fine. I bought two of the combined smoke & co detectors to integrate with my other hardwired sitterwell smoke detectors. The disappointing part is these have a different mount & wiring harness.