There are a number of features and technical phrases used in the selling literature of programmable thermostats that are often not explained properly or clearly. Below are a few of these terms explained for the layperson.


Cycling refers to how many times in a set period the heating or cooling system is programmed to come on. A HVAC (heating, ventilation and air-con) system can also said to cycle when it comes on in response to a fall or rise in temperature.

Swing Control

This is a useful function that allows you to set up a range within which the thermostat responds to changes in temperature. So, for example, if the thermostat is set to 80 degrees and the swing is set to plus/minus 1 degree it means that the heating won't cycle until the room temperature falls to 79 degrees and the air-con won't come until the room hits 81 degrees. Swing control can stop your furnace, heat pump or air-con continually clicking on and off. Constant cycling of your HVAC system can soon wear out parts. Lux Products makes programmable thermostats with good swing control functions.

Adaptive Recovery or Smart Recovery

This is when a programmable thermostat has the ability to 'learn' how long it takes to heat or cool a room. This means the thermostat finds the optimum time to turn on before you get home from work or wake up in the morning. In other words, instead of turning on the heating/cooling high to reach a programmed setting, the thermostat will turn on the heating/cooling plenty of time before to allow the room to gradually reach optimum temperature. This feature saves you money and stops the HVAC systems from being over-worked. The Honeywell VisionPro 8000 and the Lux TX9100E 7-Day Universal Programmable Thermostat both have adaptive recovery functions.

Override / Hold

The normal programmable thermostat works on pre-programmed settings for every second of the day. If, however, you take a day off work or you're too cold or you stay up late you can override the pre-programmed settings. With override you can change the room temperature without changing your programmed schedule. Override saves time and hassle. Override is also called 'hold' because you are effectively putting your programmed setting on hold until you switch hold off.

Vacation Mode

This is a type of hold. Vacation mode allows you to set one temperature for the room or house (you probably need more than programmable thermostat if you live in a big house) while you are away on holiday. This again doesn't interfere with your 7-day programmed settings. Vacation mode can save you money and add protection to your house by preventing extreme weather from freezing your pipes. Honeywell, Lux Products and Hunter all have vacation mode on their programmable thermostats. It is normally a standard feature.


This confusing set of numbers means that the programmable thermostat is limited to just 2 programs: namely, the setting for the 5 days of the week, and the 2 days of the weekend. 5+2 programmable thermostats are the most basic program options.


This is the next step up from the '5+2'. 5-1-1 programmable thermostats have three program slots: weekday, Saturday and Sunday.


This is the best. A 7-Day programmable thermostat allows you to program in your heating and cooling requirements for each day of the week. And of course within each day you can program 4 different periods: 'morning', 'day', 'evening' and 'night'.

Energy Star

The Energy Star certification is a government backed scheme to promote home appliances that work more efficiently than similar home appliances. By doing so the appliance reduces carbon emissions and helps combat climate change. Essentially an Energy Star mark is a sign of a 'green' product. Since programmable thermostats are very environmentally products they are nearly all Energy Star rated. I would avoid any that are not.

These are just some of the technical terms you are going to encounter if you start shopping for a programmable thermostat. Remember to take your time, read reviews and even ask your neighbor before choosing a programmable thermostat.