Programmable thermostats used to be really expensive. But today, you can get one for as little as $25, about the same price as a non-programmable digital thermostat. But should you get one? Do programmable thermostats save money? Do they save energy?
If you have a conventional forced-air furnace and air conditioner, a programmable thermostat can save you $25 a month or more, especially in the summer and winter. But not if you have a heat pump. If you have a heat pump, you probably know it.
Why studies conflict on programmable thermostats
You can find some studies that say programmable thermostats use up to 30% less energy than conventional thermostats, and other studies that say they use up to 7% more energy. Look at who is conducting the studies. The study that says they use more energy is the State of Florida. In Florida, heat pumps are more common and winters are mild, so that skews the results. But even in Florida, your results will vary based on your cooling system.
In Missouri, where we have an actual winter as well as a hot summer, they make plenty of sense. I saved no less than 10 percent with one, and saved quite a bit more when I could be aggressive with it.
An Energy Star survey takes the entire country into account. A survey conducted by your individual state, or a neighboring state, may be more relevant for your situation. And the form of heating and cooling you have can make you an outlier even in your home state. When in doubt, ask your HVAC technician on your next service call. They know the variables, and most of the technicians I’ve talked to over the years have the most efficient system they can afford in their own homes. They’re usually very qualified to talk about what makes sense in your home.
Programmable thermostats and budget billing
I see comments on forums all the time that say, s”I don’t feel like this programmable thermostat is saving me money.” It’s not about feelings. Look at your bills. You’re either saving money or you’re not. If you put a programmable thermostat in and your bill stayed exactly the same, you may be on budget billing, where you pay the same amount every month and they adjust your monthly bill every 6 or 12 months.
But even if you have budget billing, you can tell if your programmable thermostat is saving you money. At the bottom of your bill, there’s usually a line telling you how far ahead or behind your current usage is from last year. Mine also has a bill telling me how my usage compares with my neighbors. If you’re not sure what any of it means, just call your utility’s customer service and ask. They’ll tell you if your bill is going to go up or down.
You can also ask them to take you off budget billing, but I find it’s convenient. It helps me avoid wild swings in my bills.
When programmable thermostats don’t save money
If you have a heat pump, especially a heat pump backed by geothermal, a programmable thermostat won’t save you money. Heat pumps heat and cool slowly and steadily, so if you let the temperature coast for 8 hours, they kick into their high, inefficient stage to catch up. And that catch-up time costs more than you save by letting the system sit idle.
But it all depends on the type of HVAC system you have. That’s true for heat pumps, but it’s not universal. When I had a conventional HVAC system, a programmable thermostat helped me drop my energy usage 19%.
How to save money with programmable thermostats
Chances are there are stretches of the weekday when nobody is home. That time may vary, especially if you’re a family with kids. In my household, at one point that window was as short as 9am to 2pm. But that’s still 21% of the day when no one was home, so there’s no point in heating and cooling the house when there’s no one there who needs it.
There’s also a time at night when you don’t need to run the system full force. You don’t want to let the system get too uncomfortable, but some people sleep better when the temperature is cooler, so in the winter, you can let the temperature drop, perhaps into the low 60s or even less. In the summer, I would let the system run about five degrees warmer overnight. Generally I found I could run the system like this from about 11pm to around 5am. That way everyone goes to bed and wakes up to a fairly comfortable temperature, but the system got a chance to coast while we were all asleep.
Weekends are a bit tougher. That’s the difference between a 5-2 and a 5-1-1 thermostat. When our kids were younger we typically had sports activities on Saturday mornings for a couple of hours, so we were probably gone from around 8:30 to 11 or 11:30, and on Sunday we’d go to church and then get lunch, so our Sunday schedule was similar enough we could have gotten by with a 5-2. But if your Saturday and Sunday schedules differ, you’ll want a 5-1-1.
The problem with programmable thermostats
The problem with this, of course, is sometimes you’ll deviate from the schedule. And when you do, inevitably someone overrides the schedule on the thermostat, sets it too high or too low because they think the system will heat up or cool faster when they set the temperature to something ridiculous, and now you’re heating at 80 degrees, or cooling at 68. And if the override doesn’t cancel automatically, which it doesn’t on the cheaper units, now your programmable thermostat is costing you big money instead of saving.
If your family can’t agree to a schedule and agree to either not use the override or to set the override back after a couple of hours, you’re better off with a learning thermostat like a Google Nest, which has sensors so it knows when people are home and active and when they’re not and adjusts automatically.
These cost more, but at least the cost has come down some in recent years. A straight programmable thermostat can pay for itself in a month. The payback time on a learning thermostat is more like 6-12 months, since they tend to start at $100 and range up to $250.
Admittedly there are issues with Nest thermostats, but you can certainly consider other models, like a Honeywell Lyric or Emerson Sensi.
Why saving energy is worth it
I’ve had some heated discussions with people over the years about energy savings. But the reality for most of us is that if we can save $25 a month, it’s usually worth it. Even if you don’t know what you’d do with an extra $25 a month, dump it into your retirement account, because you’re probably not saving enough for retirement anyway, and that extra $300 a year will help. If you’re not a high roller, saving energy is one of the fastest ways to save money on a low income.
Energy is much cheaper in the United States than it is in much of the world, and that’s led to some of our attitude towards how we use it. But even though energy is much cheaper here than it is in, say, Germany, energy isn’t getting cheaper. We’ve found new sources of natural gas in recent years, and that’s slowed the rate at which energy costs increase, but it’s only slowing it down. My local utility still asks for a rate increase every year, and they almost always get it. The only year in recent memory that they didn’t get one was when they had extended power outages and the speaker of the house was without power for a week.
The little things add up when it comes to saving energy and money
You can tell yourself the savings from a programmable thermostat is only $25 a month this year. But after a few years of rate increases, the amount will be more. And no matter who you are and how much money you have, you have better things to do with it than using as much energy as possible.
A programmable thermostat doesn’t make sense for me anymore because I have geothermal heating and cooling. But I couldn’t afford that when I was 28. One of the reasons I can afford geothermal now is because I did things like buying a programmable thermostat and efficient light bulbs when I was 28.