Not too long ago, if you had a furnace, you had a manual thermostat. You could change its setting or leave it alone. You had no other choices. Now you do, and so now you have to choose the right thermostat.

Programmable thermostats came along with great expectations for saving energy and money. But only if you programmed them correctly.

Even more recently, we have smart thermostats. You don’t even have to be home to make it do your bidding.

Heating and cooling account for about half of your home energy costs. Lighting, cooking, and all your various gadgets each account for much less.

The location of your thermostat matters. If it’s too close to large furniture, or where it gets direct sunlight or drafts, it can be difficult to regulate the temperature.

My thermostat is located in an interior hallway. When it’s nice and warm (or cool), the temperature in the rest of the house can be uncomfortable.

So I have a battery-operated remote control that I keep in the living room. It makes all the difference in the world.

Nowadays, you can still get a manual thermostat if you really want one. You probably want something more high tech. But with such a wide range of options, how do you choose the right thermostat?

Manual thermostats

In the 1970s, I knew a retired heating contractor who liked to tell stories about his working life. At one home, the man of the house had installed the working thermostat on a floorboard behind the sofa. His wife constantly fiddled with the easily visible one.

At the time, the standard advice was to set the thermostat and leave it at the same temperature all the time. Indeed, that was wiser than trying to micromanage the temperature.

Some people thought setting the temperature warmer or cooler than you wanted it made the thermostat work faster. False.  It only made the house too hot or cold. They had to readjust later on.

Constantly changing the set temperature makes the furnace or air conditioner stop and start inefficiently. It uses extra energy and costs more money.

As it turns out, however, leaving the temperature the same all the time also wastes energy. If no one is home for eight hours or more during the day, set the temperature higher in the summer and lower in the winter during that time. It saves as much as 15% on your energy costs. When you’re on vacation, it saves even more money to set the temperature even higher (or lower) until you return.

It’s still possible to buy manual thermostats. They cost less upfront and, being simpler in design, last longer. On the other hand, they are less precise and accurate than other designs. If you want to take advantage of different settings at different times, you have to remember to change it manually. It’s probably not the right thermostat anymore.

Programmable thermostats

A programmable thermostat saves the effort of remembering to change the thermostat settings. It can also save money.

Energy Star used to certify programmable thermostats. Consumers found them too difficult to program.

According to a study made in 2015, 40% of people who owned programmable thermostats didn’t use them to set schedules. Without proper programming, they save no money, so certification stopped in 2009.

With a programmable thermostat, you can set a schedule on which it will adjust the temperature. Enter the time everyone wakes up, the time the last person leaves for the day, the time the first person gets back home, and the time everyone has gone to bed. Then determine the temperatures you want during each period.

Once you have chosen your settings, you don’t have to think about it until you go on vacation or until it’s time to program it for air conditioning instead of heating.

Programmable thermostats cost more to buy than manual ones. Being more complicated, more things can go wrong with them, so they won’t last as long. It is also more complicated to match the right thermostat with your home’s HVAC system. Not all of them work well with all systems.

The company that inspects and maintains your system will help you choose the best programmable thermostat for it. (You do have it inspected regularly, don’t you?)

You also want your technician to install one that you can easily program. The earlier models could be very confusing. Later models have more intuitive touch-screen programming. A programmable thermostat saves you money only when it’s programmed correctly. Some homeowners throw in the towel and treat it like a manual thermostat. And programming mistakes can actually wind up using more energy and costing more money.

Smart thermostats

Smart thermostats represent the latest technology. They run on wi-fi, which means you can control them through an app on your phone. They can also provide reports on how the system is working and warn you when it’s time to change the air filters.

Some smart thermostats use multiple sensors throughout the home to enhance the balance of temperature in various locations.

Just keep in mind that the more buzzers and whistles your system has, the more energy it takes to run them. That can cut into your savings.

When smart thermostats came along, Energy Star started a new certification for them in January 2017. As of April  2019, it had certified 45 models of smart thermostats. In the meantime, non-internet-connected programmable thermostats have adopted some of the features of smart thermostats. Although Energy Star no longer certifies them, they have become easier to program.

If you forget to adjust a programmable thermostat before you leave on vacation, there’s not much you can do about it. With a smart thermostat, you can check it from wherever you are and potentially save a lot of money.

Some smart thermostats work with occupancy sensors or geofencing. Instead of relying on a preset program, they can adjust the temperature depending on who is actually at home. Some of them respond to voice commands, eliminating the need to change anything manually. They might even notice and respond to your habits.

The biggest advantage of a smart thermostat is also its biggest drawback. Whatever you can control from your phone, a hacker can take over. Security concerns may offset the advantages of an interactive system.

If you already have a programmable thermostat and understand how to use it, you probably don’t need to consider upgrading to a smart thermostat.

How to choose the right thermostat

I suppose that you probably won’t want a manual thermostat. You just need to choose between programmable and smart thermostats. Then, you need to choose the best model for you.

First, decide whether you want all the extras that come with a smart thermostat. If you care about nothing but simple programming, or if you’re leery of the risks of someone hacking the system, choose a programmable thermostat. It’s less expensive and more secure.

If you want a smart thermostat, you need to choose which features matter to you. There’s no point in buying features you won’t use.

Second, consider your system. A furnace with central air works on different principles from a heat pump, for example. Some thermostats won’t work with some systems. If you have separate heating and cooling systems, you may need separate thermostats to control them.

Older homes may have only two low-voltage wires. Most programmable thermostats work there. Smart thermostats also require a common wire, called a C-wire, to provide power for WIFI and other features. Your HVAC technician will know what wiring your home has and what, if any, adjustments you need to make for the thermostat you choose.

If your choice needs a C-wire and your home’s wiring doesn’t have it, you may be able to have an adapter installed or have an electrician install one. Some models of smart thermostat claim to work without a C-wire, but some HVAC professionals don’t recommend that option. It can damage some of your equipment.

Choosing the right thermostat takes more thought than it did a generation ago. The improved technology makes it worth the effort.

Sources:

3 dumb things you do with your thermostat that cost you money / MSP Plumbing Heating Air. August 22, 2014
Ask our experts: are programmable thermostats worth it? / Tuckey. December 13, 2019
Manual vs smart thermostats: which is best for you? / Service Champions Heating and Air Conditioning. May 18, 2018
Thermostat buying guide / Consumer Reports. April 30, 2019

Photo credits:
Programmable thermostat. Some rights reserved by Advanced Telemetry
Furnace. Public domain from Wikimedia Commons
Thermostat remote. My photo
Air conditioner. Public domain.
Energy Star. Source unknown