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Venstar T3900 thermostat

This Venstar programmable thermostat uses a c wire (24 vac) for its primary power. A "C" wire is required. It can not be used with a 2 wire system. A convenient home/away feature allows for quick setpoint adjustments. A vacation feature provides the ability to override the regular schedule and setback the thermostat during a vacation period.

About

The Venstar T3900 is part of the Thermostat test program at Consumer Reports. In our lab tests, Thermostat models like the T3900 are rated on multiple criteria, such as those listed below.

Manual operation: The ease of manually controlling the thermostat's temperature set-point, heating/cooling schedule, home/away and vacation features - when they are available.

Programming: The ease of creating a heating and cooling schedule considering, navigational, contextual and informational elements that make programming easier, and the number of steps.

Display: The ease of reading the display considering, character size, spacing, layout and contrast.

Features

Touch screen Touch screen Whether the display is a touchscreen or not.
No
Events per day Events per day Indicates the maximum events-per-day that can be added to a heating or cooling schedule.
4
Early recovery Early recovery Indicates whether or not the thermostat can trigger the heating or cooling process earlier than a scheduled time, in order to get the house to temperature by the scheduled time.
Yes
Auto changeover Auto changeover Indicates whether or not the thermostat can automatically switch from a heating system to a cooling system mode.
Yes
Auto daylight savings Auto daylight savings Indicates whether or not the thermostat can automatically adjust its clock based on daylight savings time.
No
Air filter reminder Air filter reminder Indicates whether or not an air-filter reminder is present.
Yes
Password protection Password protection Indicates whether or not the thermostat provides some sort of password protection or lockout - a code, key sequence or setting - which limits the ability to change the thermostat's settings.
Yes

Specs

Primary power Primary power The primary power source.
a C wire (24 VAC)
Backup power Backup power The backup power source.
N/A
Two wire compatible Two wire compatible Indicates whether or not the thermostat can be used in a 2 wire system.
No
C wire required C wire required Indicates whether a "C" wire is required to power the thermostat.
required
Power sharing Power sharing Indicates that when using a 2-wire setup, whether the thermostat draws power through the wires to charge a battery. This may cause some HVAC systems to operate unpredictably or erratically.
No
Warranty (yrs.) Warranty (yrs.) The length of time the thermostat is covered by its manufacturer for defects or repairs.
1 yr