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Lux TX500UA – Universal Programmable Thermostat Review

Since 1914, LUX has produced a wide range of thermostats from manual to smart. These come on a decent budget and are filled with lots of features. One of its products LUX TX500Ua promises great features at a fair price. We shall give a detailed review of its specifications and features in this article.

LUX TX500Ua, can be used for a wide range of 24 volts single/multi-stage heating systems as well as single-stage cooling systems. However, these cannot be used for line voltage heating systems like electric baseboards.

It has a simple design, with the control push buttons secured inside the front panel. Only the temperature up/down and hold buttons can be seen on its front panel.

This programmable thermostat can be used to program different schedules for the weekdays and weekends(5- 2 programming). Not only this, but you can also set a separate schedule for each day of the week in its 7-day programming option. The number of periods for each day can be selected between 2 and 4 periods.

In case you do not need a routine and want to change the temperature manually, this thermostat has the provision for that too.

The thermostat program is protected from unauthorized hands, through the keypad lockout option provided.

The large display is quite useful to get an idea about the room temperature and helps to program effectively. It is designed to be read in any lighting conditions, as it is provided with a backlight.

Another unique feature is its programmable air filter timer, where you can set the time after which the thermostat would remind you to change the air filter. This boosts the timely maintenance of the machine.

This was just an overview of the product; let us dig deep into the features of this programmable digital thermostat.

Features of Lux TX500UA thermostat


If we talk about the design of LUXTX500a, it looks pretty standard. It comes in a rectangular shape, with the dimensions being 5.38x 3.38 x 1.1 inches. It has an LCD screen on its front and three long push buttons placed just right below the screen. The two of pushbuttons are the “UP/Down” buttons, which are clearly indicated by the respective arrows. Between these two buttons, there is a “hold” button, which can be used to hold the room temperature at a set value, for as long as desired.

The push buttons are made of resilient semi-soft plastic and hence are easy to push and use.

There are 3 slide buttons and two other pushbuttons too. These have been securely placed under the cover of the front panel. You will have to remove the cover every time you want to set/reset the fan, system, or other settings related to the control.


The LUX TX500a display provides all the vital information needed at one glance. You can see the room temperature on one side and the set value on the other side. Other than this, it displays the mode, time, day, and other options. You can read it under any lighting conditions as it has a backlight, which turns on for 10 seconds once any of the front panel buttons are pressed. It is long enough to see the current temperature and program. In case, there is a need for the prolonged back illumination, you will have to press any of the buttons while the backlight is still on. This will reset the 10-second timer so that the screen will be illuminated for an extra 10 seconds.

Programming & Operation

LUX TX500a offers a variety of programming options, which makes the operation easy. To start with, once you remove the front cover, you will see the various options to control the system.

If you have a blower fan connected to the heating system, then you have the choice to choose between the “auto” mode and “on” mode, for the fan operation. The auto mode runs the blower according to the need and is an economical option to choose from. However, if your home requires the constant operation of a blower fan, then you have the liberty to choose the “on” mode. It will run the fan continuously.

The system controls include: “heat”, “cool”, and “off”. While the heating and cooling system can be selected by switching to “heat” and “cool” modes, you can turn off the HVAC system by selecting the “off” mode.

There is an easy provision to change the system settings like day/time, temperature program, air filter program, and run option, all these through a sliding switch. This means there is no need to scroll down a menu and make the change in settings, a tedious process.

All you will have to do is slide the switch to the required settings, you want to change, and use the UP/DOWN and hold button to set a value.

In case you have an electric heating system whose heating coils have become inefficient, LUX TX500a provides an option to accelerate the heating process through the “emer” or emergency heating button.

Now, these were the highlights that accentuate its easy and efficient operation. Let us move on to its programming options.

As already mentioned, this thermostat provides the user with flexible programmable memory. You can choose the programming styles (5-2, 7, or manual) that suit your routine.

The 5-2 day programming style enables you to set a temperature program for the weekdays and weekends in two different combined processes. This means you can schedule different temperature settings for the 5 weekdays and 2 weekends.

In 7-day programming, you can create a different schedule for each day of the week. The manual option is for those who do not want the thermostat to follow a specific routine and are comfortable in changing the temperature manually according to the current condition.

This thermostat also provides the user to choose from 2 or 4 periods for a day.

Another great option that minimizes effort is the “copy” feature. This copies the routine of one day to another day. It eases the process of programming the same schedule for 2 or more days.

The set temperature can be changed whenever necessary through the temperature override option, whereas the temperature hold option allows setting the value at a particular temperature for a long time.

Apart from programming the temperature settings, this thermostat allows its users to set the temperature swings and calibration, in the unlikely case of the inaccurate and inefficient working of the thermostat.

Even though the thermostat comes properly calibrated at the factory, and needs not to be altered, there may be cases when it needs to be changed. The thermostat allows you to add or subtract 5F from the room temperature in such cases.


If you are someone who is handy around the house and are familiar with wiring, the installation of this 2-wire thermostat will be easy for you. The instruction manual has a well-described installation guide.

In case you need to use the heat blower fan, you will need to use the third “c” wire and connect it to the fan.


This thermostat boasts of being a universal thermostat, meaning it is compatible with all HVAC systems. Except that it is not.

We can say it is compatible with almost all HVAC systems which include:

Most single-stage 24-volt, heating, and cooling systems, 1-stage heat / 1-stage cool: gas, oil, or electric systems, Single-stage heat pump systems (without auxiliary or emergency heat), 2-wire hydronic (hot water) zone valves, Millivolt heaters (including wall heaters/gas fireplaces).

NOTE: IT is NOT compatible with:

120/240 VAC line-voltage systems (without a transformer, Multi-stage heat pump systems (with auxiliary or emergency heat), 3-wire hydronic (hot water) zone valves.

Power Source

LUX TX500a is dual-powered. This means it can be either operated with 2 AA alkaline batteries or can be powered by directly wiring to a 24 V source.

These were the significant features of this budget-friendly thermostat from the house of LUX products.

Let us take a quick look at its pros and cons before we wrap up this article.


  • Large, backlit display
  • Easy-to-use function buttons
  • The operation can be understood easily
  • The choice between 7-day, 5-2 day, and manual programming
  • A choice between 2 or 4 periods for a day
  • The program can be prevented from unauthorized hands, by locking it
  • Temperature override  and hold option


  • Pretty basic and standard look
  • The front cover is hard to open
  • Need to frequently open the front cover to access the control buttons

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