Updated: June 8, 2015

Best Thermostats Reviews: Programmable Thermostats

When it comes to heating and cooling your home, the oft over-looked thermostat is the silent gatekeeper that keeps your home or office at the temperature you want. The concept of the thermostat is pretty simple - you tell it what temperature you want to keep the room or building at, and it monitors the temperature and turns the heating and cooling system off as needed to maintain that temperature within 2 degrees or so. For heating, it turns the furnace on when the temperature falls too low, and for cooling, it turns on the AC when the temp gets too high. In this guide, we will take a look at how thermostats works, check out some new digital, programmable thermostats, and find out how to save money by using an EnergyStar compliant thermostat.

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How do programmable thermostats work?

There are two basic types of thermostats - mechanical and digital (with variations of manual and programmable of each). The mechanical thermostat is the old style. Most of us haven't looked inside a thermostat control box, but if you do, you'll usually find a coil of metal (actually 2 metals, called bi-metallic) attached to a glass vial filled with liquid mercury. Using special metals with certain heat properties, the metal coil contracts and expands as the room temperature changes. As it moves, the pivoting glass vial on top of it will tilt to one side or the other, and the liquid mercury (another metal) will pool on one side or the other, connecting or disconnecting the electric circuit and causing the furnace or air conditioner to turn on or off. There is normally a temperature slider bar for setting the desired temperature which affects the position of the coil and contact points for that temperature. Newer digital thermostats use thermistors (thermal resistors) to detect changes in temperature, and hence have no moving mechanical parts. The thermistor changes resistance as its termperature changes, so by connecting it to some chips and other electronics, the digital thermostat can easily detect the room temperature.

Most digital thermostats are powered by batteries, so you must remember to replace them each year. One big advantage over mechanical thermostats are the large, easy to read LCD screens that most digital thermostats offer. Instead of squinting and trying to read the graduated lines on a little bar, you can easily see the bright temperature displays on these newer models. Another big advance is in programmable thermostats. Programmable thermostats offer you the energy saving advantage of turning themselves down automatically (thus keeping the furnace off for longer periods) at certain times of the day, like after midnight when everyone is in a warm bed, or during the middle of the day when the family is out at the office and school. They can be set for certain time periods you prefer (heat comes on at 6:30, 10 minutes before you get out of bed, for example) and for certain days of the week. Of course, you could manually make the same changes, turning the temperature down before bed, back up when you get up, down when you go to work, etc. but this can be a hassle and is often forgotten, leaving the furnace or AC chugging away when no one is home to appreciate it. If you work at home or stay at home all day with kids, you may miss out on a lot of the energy savings promised by these devices. You can check out a list of the best-selling thermostats here - they carry all the leading programmable thermostat brands, at good prices. UPDATE OCTOBER 2014 - One of the latest products on the market is the Nest Learning Thermostat. Talk about smart, this unit will remember the temperatures that you like and program itself. You can connect the Nest to WiFi and control it from your smartphone, laptop or tablet. The features are endless and owners rate this as the most popular thermostat on Amazon. Check out the Nest Learning Thermostat here.


Honeywell Thermostats - Buying a New Thermostat

Who makes the best thermostats? Honeywell is probably the biggest maker of thermostat controls. Something like Honeywell's PRO 3000 digital thermostat is a very easy to use manual thermostat with digital LCD readout, powered by a battery. Two simple arrow buttons allow you to adjust your desired temp up or down, and a basic switch lets you select between heat, AC, or fan -- that's it. The FocusPRO is the next model up, with a larger display screen but the same basic features. They also make a digital version of their classic round thermostat look, called the Honeywell Pro T87 Round. You set the temp by twisting the outer ring. When it comes to programmable thermostats, Honeywell makes touchscreen models and versions with standard buttons. The touchscreen models are basically a white faceplate over a large green-colored LCD display screen. Touch the arrow icons to adjust temperatures and bring up menus for programming on and off times and temps -- very easy to use. They make 5-1-1 day versions (constant settings for week days, different options for both Sat. and Sun.), 5-2 day versions (separate weekday and weekend settings), and 7-day versions (customize each day of the week). If you are shopping for a new thermostat, check out ProThermostats.com to get started with some ideas. They have a "Help Me Find a thermostat" section that walks you through the options, depending on the type of heating system you have, what kind of electrical system you have for wiring, and what features you are looking for in terms of programmability, etc. They carry most of the big names in thermostats, including Honeywell, White-Rodgers, LuxPro, and Robertshaw. How much do thermostats cost? The cheapest programmable thermostat we saw was the White-Rodgers 1F78-151 Programmable (5+2) 1 Heat/1 Cool Thermostat, Battery Powered for $29. The LuxPro PSP600 Programmable (5+1+1 day) 1 Heat/1 Cool Thermostat was priced similarly on clearout pricing. At the higher end, we found the LuxPro PSP711RF Programmable (7 day) 1 Heat/1 Cool Thermostat w/ Remote Control for just over $120. The most expensive was the Robertshaw 9700i Programmable 1 Heat/1 Cool Battery Powered Thermostat at $147. A good mid-range unit should cost you about $50-$80. One of our favorites is the Honeywell Vision Pro Programmable Thermostat Large Screen for just over $100. We've had two of these in our home and couldn't be happier with them. They have big bright screens that make them easy to read and use that show current room temp and thermostat setting, and they can be used as 5-1-1 or 5-2 programmable thermostats. The batteries (2 AA) are easily replaced without having to take the unit off the wall. The round version of the Honeywell mentioned above sells for about $50, by the way. Also consider the Lux models - the TX9000 was the top-rated model at Consumer Reports, and it continues to get rave reviews by users for its simplicity and large screen. And at around $65, it's affordable as well. You can browse the entire selection of thermostats for sale here.

Installing a new thermostat

When installing a new thermostat, the first thing to figure out is how many zones you have. Most houses have only a single furnace and single AC unit, but a lot of larger or multi-level homes have multiple zones and multiple HVAC systems. This means a separate thermostat control for each zone. Installing a thermostat can be a little tricky, as there are a lot of wires involved. However, thermostats are low-voltage wiring situations. Replacing a digital with a digital is also easier than replacing a mechanical with a digital thermostat. If you are comfortable working with electrical wiring connections and are a B-rated DIYer, you can probably handle it -- just follow the directions that come with the thermostat. It's also pretty quick work for an electrician if you are more comfortable with that choice - certainly no more than a 1 hour job in most cases. Your thermostat location is probably already fixed, but keep in mind that for proper functioning, the thermostat should be located on an interior wall away from heating and cooling ducts so that is accurately reflects the average ambient room temperature.