Alarm.com Smart Thermostat - Frequently Asked Questions

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Supported HVAC system types

Does the Alarm.com Smart Thermostat support multistage systems?

Yes, the Alarm.com Smart Thermostat is compatible with up to three stages of heating and two stages of cooling.

What is a multistage system?

Multistage systems use more than one level of heating or cooling (e.g., high, medium, and low) to save energy and keep the house at a more constant temperature. When the temperature is set, the system automatically adjusts the level of heating or cooling. The system will use the lowest level needed to arrive at the right temperature.

Single-stage systems have only one level of heating or cooling and need to turn on and off much more frequently to maintain a constant temperature. This uses more energy than multistage systems, and also results in more temperature fluctuation.

How to tell if a system is multistage:

Check the number of heating and cooling wires attached to the old thermostat by removing the cover (don’t disconnect the wires) and look for the letters and numbers found where the wires are connected to the thermostat. Heating wires are commonly labeled with a W (and are often white) and cooling wires are commonly labeled with a Y (and are often yellow).

If there is more than one wire for heating or cooling, then the system is a multistage system.

Example: A three-stage heat system can have three white W wires (labeled W1, W2 and W3). A two-stage cooling or heat pump system can have two yellow Y wires (labeled Y1 and Y2).

Is a multistage system the same thing as a multi-zone system?

No. A system can have multiple zones without having multiple stages, and vice versa.

Does the Smart Thermostat support systems with multiple zones?

Yes. The Smart Thermostat supports systems with more than one zone. Each zone can be controlled by its own Smart Thermostat. The Smart Thermostat is compatible with other Z-Wave thermostats; however, the system will work best and most efficiently if all thermostats in the house are replaced with Smart Thermostats.

What is a multi-zoned system?

A multi-zone system is an HVAC system set up so that different areas (zones) of the home can be heated or cooled separately. This can be done using separate thermostats for each zone, or by using a damper in the ductwork to direct hot or cool air to the selected zone.

Can the Smart Thermostat control variable-speed HVAC systems?

The Smart Thermostat can control many variable-speed HVAC systems which use standard 24 volt wiring (e.g., with R, G, Y, W, C wiring).

Note: The Alarm.com Smart Thermostats are compatible with general control of the variable-speed system. The Alarm.com Smart Thermostats will not be able to control the fan speed.

What is a variable-speed system?

Variable-speed systems change the fan speed to push more or less hot or cooled air through the vents. Many of these systems also use multiple stages to allow variable heating and cooling speeds.

Are some variable-speed systems incompatible with the Smart Thermostat?

Some variable-speed HVAC systems use proprietary communication between the thermostat and the main HVAC system to enable variable-speed control. Systems like these require a thermostat made by the same manufacturer as the main HVAC unit to fully access their features.

For help determining whether the variable-speed system is compatible with the Smart Thermostat, contact a local HVAC professional for help.

Can the Smart Thermostat control a humidifier or dehumidifier?

Yes. The Smart Thermostat HD and ADC-T3000 can control a humidifier or dehumidifier using the Z1 and Z2 terminals, while the ADC-T2000 with firmware version 1.5 + can control either a humidifier or dehumidifier using the Z terminal. For more information about humidity control, see Smart Humidity Control - Quick start guide.

Is the Smart Thermostat compatible with an external air baffle for fresh air?

The Smart Thermostat works with HVAC systems that have an external air baffle controlled by the central HVAC system programming.

Some systems rely on the thermostat itself (not the central HVAC system) to control the baffle. The Smart Thermostat will be able to support these systems using the Z terminal. This feature will be made available in the future by a firmware update.

What can the Z terminal on the Smart Thermostat be used to control?

The Z terminal of the Smart Thermostat can currently control:

A third heating stage.
Humidifier.
Dehumidifier.
O/B zoning on heat pump systems with both an O and B wire for the ADC-T2000. This option is not available on the Smart Thermostat HD or ADC-T3000 due to their separate O and B terminals.
- On the ADC-T2000, the O wire would go into the O/B terminal and the B wire would go into the Z terminal.

Setup and Configuration

Is an account with Alarm.com required to use the Smart Thermostat?

An account is required to configure the Smart Thermostat for the first time. Initial configuration can be done using the Alarm.com Alarm.com customer website, or by the provider. If a customer later cancels service, the Smart Thermostat will continue to function, and the customer will retain basic control of heat and cool modes as well as the target temperature. However, all advanced features and capabilities (such as Smart Thermostat scheduling and Away from Home overrides) will be lost.

The heat pump heats when it is supposed to be cooling. How can this be fixed?

Note: These steps only apply to the ADC-T2000. The ADC-T3000 has separate terminals for O and B.

Heat pumps have either an O terminal or a B terminal. When configuring the Smart Thermostat, the system prompts to select which terminal type the heat pump has. If the system heats when it should to be cooling, this means that the incorrect terminal type was selected at configuration.

Device questions

If the Smart Thermostat has batteries installed and also has the C-wire connected, will it act as a repeater on the home’s Z-Wave network?

Yes. The Smart Thermostat determines whether it will act as a repeater at the time it’s learned into your Z-Wave network. As long as the C-wire is connected and powering the Smart Thermostat (verify the HVAC system isn’t switched off at the breaker) when it’s learned in, the Smart Thermostat will repeat Z-Wave signals and improve the reliability of your Z-Wave network.

The Smart Thermostat has a strong Z-Wave range, so whenever possible learn it in with C-wire power to improve communication between all Z-Wave devices in the home.

What does it mean when the thermostat reads HOT instead of the temperature?

The Alarm.com Smart Thermostat will display HOT when the temperature reading exceeds 100 degrees.

What happens when the Smart Thermostat is affected by a power outage? Will the customer be notified when power is restored?

Alarm.com checks the Smart Thermostat (Smart Thermostat HD, ADC-T2000, and ADC-T3000) power level once per day. A power restoral notification will thus be sent a minimum of 24 hours after the initial power outage occurs. If there is not a power outage during the polling period, no outage will be reported.

What are the dimensions of the Smart Thermostat?

ADC-T40K-HD

Thermostat Depth: 1.07 inches
Thermostat Height: 4.7 inches
Thermostat Width: 4.7 inches

ADC-T2000

Thermostat Depth: 0.90 inches
Thermostat Height: 4.9 inches
Thermostat Width: 4.0 inches

ADC-T3000

Thermostat Depth: 0.70 inches
Thermostat Height: 5.0 inches
Thermostat Width: 4.1 inches

What is Emergency Heat (EMER) mode?

Emergency Heat is designed to heat the house quickly but energy inefficiently/expensively. Emergency Heat, labeled EMER, will bypass the Heat Pump and go directly to the Aux Heat. It is only available for the Alarm.com Smart Thermostat. From the Smart Thermostat, put the thermostat into EMER mode locally by holding the button.

Note: EMER will show on the thermostat with the regular Heat Mode indicator. If changed out of EMER mode at the thermostat (Cool/Auto/Off) and then back to Heat it will be regular Heat again, disabling EMER mode.

What is needed for EMER mode?

Alarm.com Smart Thermostat configured as Heat Pump
At least 1 stage of Aux heat