Smart Thermostats in Summer — Cooling for Less

How a Smart Thermostat Saves in Summer

A plain thermostat holds one temperature all day, cooling an empty house just as hard as a full one. A smart thermostat is smarter about when to work. That timing is where the savings come from - your air conditioner runs when it matters and rests when it does not.

None of this means being uncomfortable. It means not paying to cool rooms that nobody is in, and not blasting the AC during the most expensive hours of the day. The thermostat handles the timing so you do not have to think about it.

• Not cooling an empty house - it lets the temperature drift up while you are out and cools back down before you return.
• Cooling less at night - a slightly warmer bedroom while you sleep uses far less power.
• Avoiding the priciest hours - it can ease off in the late afternoon when electricity often costs the most.
• Showing you the truth - energy reports show which days and hours cost you the most, so you can adjust.

Finding the Right Temperature

The most common question I hear is simply, what should I set it to? For summer, a good starting point is around 78 degrees while you are home and awake. From there you adjust to your own comfort, but small changes make a real difference to the bill.

You do not have to jump straight to 78 if you are used to cooler. Nudge it up one degree at a time over a week or two. Your body adjusts, and most people find they are perfectly comfortable a degree or two warmer than they expected once fans and shade are helping.

• Home and awake - around 78 degrees is the common recommendation for comfort with savings.
• Asleep - a degree or two higher is fine for most folks, and cheaper.
• Away from home - let it climb to 82 to 85; there is no one there to feel it.
• The rule of thumb - each degree warmer you can stand in summer shaves a bit off the cooling cost.

Pre-Cooling Before the Heat

One of the cleverest summer tricks is pre-cooling - cooling the house down a little in the morning or late morning, before the worst afternoon heat and before electricity gets expensive. The cool you bank early carries you through the hottest, priciest part of the day.

Many smart thermostats can do this for you automatically, especially if you are on a time-of-use electric rate or a peak program. Some brands call it pre-cooling or a rush-hour rewards adjustment. Even doing it by hand - cool early, blinds down, ease off after lunch - makes a real difference on a hot day.

• Cool a bit extra in the morning - while it is cooler outside, the AC works less to reach the same temperature.
• Ease off in the afternoon - let the house drift up a couple of degrees during the hottest, costliest hours.
• Close the blinds - keeping the sun out holds that morning cool in far longer.
• Ride it out - the house stays comfortable through the afternoon without the AC straining.

The Fan Setting - Auto vs. On

Your thermostat has a fan setting with two choices: Auto and On. This little setting confuses a lot of folks and quietly affects both comfort and cost. For summer, Auto is usually the money-saving choice.

For most homes in summer, leave it on Auto. Running the fan constantly costs money and, worse, can undo some of your AC's dehumidifying because moisture on the cooling coil gets blown back into the house. Circulate is a gentle option if some rooms feel stuffy.

• Auto - the blower fan runs only while the AC is actively cooling, then stops. This is the efficient, everyday choice.
• On - the fan runs constantly, all day and night, whether or not the AC is cooling. It uses more electricity and can blow warm, humid air around when the AC is off.
• Circulate - some thermostats offer a middle setting that runs the fan a few minutes each hour to even out temperatures. A reasonable compromise.

Building a Simple Summer Schedule

A schedule tells the thermostat what temperature you want at different times of day. Set it once and the house cools and eases off on its own. A good summer schedule follows your real day - cooler when you are up and about, warmer when you are asleep or out.

Do not aim for perfection on the first try. Set a rough schedule, see how it feels over a few days, and adjust a degree here or a half hour there. Within a week or two it will match your life, and you will stop thinking about the thermostat altogether.

• Open your thermostat app and find Schedule or Comfort settings.
• Set a Home temperature for daytime, around 78 degrees.
• Set a Sleep temperature, a degree or two warmer, for overnight.
• Set an Away temperature, 82 to 85, for hours the house is empty.
• Save it, then live with it a week and nudge the numbers to suit you.

Letting It Warm Up While You Are Out

The biggest summer savings come from not cooling an empty house. A smart thermostat can raise the temperature automatically when everyone leaves and cool it back down before you get home, so you walk into comfort without having paid to cool the couch all afternoon.

If your days are unpredictable, the phone-location method is wonderful - the house adjusts to when you actually leave and return, not a fixed clock. If your routine is steady, a plain schedule works just as well. Many folks use both together.

• By schedule - you tell it the hours the house is usually empty, and it eases off then.
• By your phone's location - called geofencing; the thermostat notices your phone has left and switches to an Away setting, then cools down as you head back.
• By its own sensors - some thermostats notice no one has moved for a while and ease off on their own.

Ceiling Fans and the Thermostat Together

A ceiling fan does not cool the air - it cools you, by moving air across your skin, the same way a breeze feels good on a hot day. Used with the AC, a fan lets you set the thermostat a few degrees warmer and feel just as comfortable. That is real money saved.

This pairing is one of the best-kept secrets of a comfortable, cheap summer. The AC handles the humidity and the base temperature; the fan gives you that last touch of comfort for almost nothing. If your fans are smart too, a routine can start them alongside the cooling.

• Set the thermostat a few degrees higher - a fan can make 80 degrees feel like 76.
• Run the fan counter-clockwise in summer - most fans have a small switch to change direction; counter-clockwise pushes air down for a cooling breeze.
• Turn fans off in empty rooms - a fan cools people, not rooms, so it wastes power spinning where no one is.
• A fan uses a tiny fraction of the electricity an air conditioner does.

Humidity - The Hidden Half of Comfort

On a muggy day, the air feels heavy and sticky even when the temperature is not that high. That is humidity, and it is a big part of summer discomfort. Your air conditioner removes moisture as it cools, which is why a properly running AC makes a room feel fresher, not just cooler.

If your house feels clammy even at a cool temperature, humidity is usually the culprit. Some thermostats show the indoor humidity right on the screen. Comfortable indoor humidity in summer is roughly 40 to 50 percent. If yours stays high, a whole-house dehumidifier may be worth asking an HVAC professional about.

• Let the AC run in real cycles - short blasts do not pull out as much moisture as steady cooling does.
• Keep the fan on Auto - running the fan constantly can blow collected moisture back into the house.
• Use a dehumidify or comfort setting - some smart thermostats can favor moisture removal on sticky days.
• Run bathroom and kitchen vents - they carry steam and cooking moisture outside.

Reading Your Energy Reports

Most smart thermostats keep track of how much your heating and cooling ran, and many send a monthly summary by email or show it in the app. These reports turn a vague worry about the bill into something you can actually see and act on.

You do not need to study these like homework. Just glance at them now and then. If one week ran much longer than usual, it may be a heat wave, blinds left open, or a filter that needs changing. The report points you to where a small change would help most.

• How many hours your air conditioner ran each day.
• Which days cost the most - usually the hottest ones.
• How you compare to a typical home or to last month.
• Tips the app suggests, like nudging the temperature up a degree.

Peak-Time Programs That Pay You

Here is a genuine way to make money from your thermostat. Many electric companies run programs where, on the hottest days, they gently raise your thermostat a couple of degrees for a few hours to ease strain on the power grid. In return, they pay you - often a signup bonus and a credit each season.

The temperature change is small and only happens a handful of times a summer, usually late afternoon. Most folks barely notice it, especially with a ceiling fan running. Check your electric company's website or give them a call and ask if they have a program for smart thermostats.

• You enroll once - often called a rush-hour rewards, energy savings, or peak-time program.
• On a few hot afternoons - the utility nudges your thermostat up a couple of degrees for two or three hours.
• You get a bill credit - typically a signup reward plus seasonal credits.
• You can opt out - if a particular day is unbearable, you can override it on the thermostat.

Eco and Automatic Modes

Smart thermostats come with money-saving modes that do some of the thinking for you. The names differ by brand, but they all aim at the same thing: comfort when you need it, savings when you do not, without you fiddling with settings.

You do not need every feature switched on. Pick one that fits how you live - a simple schedule, or an automatic away mode - and leave the rest alone. Overloading a thermostat with clever settings usually leads to confusion, not savings. Simple and steady wins.

• Eco or Away mode - a set-back temperature the thermostat uses automatically when the house is empty.
• Learning - some thermostats watch your habits and build a schedule for you over the first week or two.
• Home and Away Assist - switches between comfort and savings based on whether anyone is home.
• Comfort or Eco balance - a slider on some models to lean more toward comfort or more toward saving.

When One Room Stays Too Warm

Almost every house has that one room the AC never quite reaches - an upstairs bedroom, a sunny den, an addition over the garage. The thermostat reads the temperature where it hangs, not where you are, so that far room can bake while the hallway feels fine.

Room sensors are one of the most useful extras for summer comfort. They let the thermostat prioritize the room you are in, so you are not freezing the downstairs to cool an upstairs bedroom. If the imbalance is severe, an HVAC professional may find a duct or airflow problem worth fixing.

• Add a remote room sensor - many thermostats support a small sensor you place in the warm room, so it cools based on where you actually are.
• Use a schedule with the sensor - tell it to follow the bedroom sensor at night and the living room by day.
• Adjust the vents - opening the far room's vents and slightly closing a cold room's can help balance the flow.
• Close the blinds in the sunny room during the afternoon.

Staying Cool in a Heat Wave

On a stretch of very hot days, your air conditioner works hard and the bill climbs. A little planning keeps you comfortable and safe without letting costs run away. Comfort and health come first here - especially in real heat, do not tough it out to save a few dollars.

Give your air conditioner a fair chance by keeping the setting reasonable. On an extreme day, an AC set to 68 may run nonstop and still not reach it, wearing itself out and running up the bill for nothing. A steady, sensible setting with fans and shade keeps you comfortable and the system healthy.

• Pre-cool in the morning - bank the cool early while it is cheaper and easier.
• Close blinds on the sunny side - keep the afternoon sun from heating the house.
• Run ceiling fans where you are, so a slightly warmer setting still feels fine.
• Do not set the thermostat below normal - it will not cool faster and the AC may struggle to keep up.

Setting It for a Trip Away

Leaving for a few days in summer is a fine chance to save. There is no need to keep the house cold for an empty home - but you do not want to switch the AC off entirely either, as that can let heat and humidity build up and harm the house.

Turning the AC completely off in a humid summer can leave a house muggy and, over a long trip, invite musty smells or worse. A warm hold around the mid-80s protects the home cheaply. Being able to check the temperature from your phone while away is a real comfort.

• Set it warmer, not off - around 82 to 85 degrees keeps humidity in check without cooling an empty house.
• Use a Vacation or Hold mode - most apps have one that holds a set temperature until you return.
• Set it to resume before you get home - so the house is comfortable when you walk in.
• Check it from your phone - a smart thermostat lets you peek and adjust from anywhere while you are away.

When the House Won't Cool Down

If your house is not getting cool, do not panic - it is often something simple. Work through these calm checks before assuming the worst, and you may well fix it yourself or at least know what to tell a professional.

A dirty filter is behind a surprising number of cooling complaints - a smart thermostat can even remind you to change it. If the filter is clean, the vents are clear, the outdoor unit runs, and it still will not cool, it is time to call an HVAC professional; you may be low on refrigerant or have a failing part.

• The setting and mode - make sure it is set to Cool, and to a temperature below the current room reading.
• The air filter - a clogged filter chokes airflow and is the most common cause of poor cooling. Replace it.
• The vents - make sure supply vents are open and not blocked by furniture or rugs.
• The outdoor unit - check the outside AC unit is running and not buried in leaves, grass, or debris.
• A frozen coil - if you see ice on the unit or lines, turn cooling off and let it thaw, then check the filter.

Buying a Thermostat and Getting Rebates

If you do not yet have a smart thermostat, summer is a fine time to add one - and you may not pay full price. Many electric and gas companies offer rebates that knock a good chunk off the cost, and some even give one away for joining a savings program.

Installing a thermostat means working with low-voltage wiring behind the wall plate. Many folks do it themselves, but if you are at all unsure - or your system needs a C-wire added - that is a job worth having done right. I am glad to install it and set it up so it works from day one.

• Check for utility rebates - look on your electric or gas company's website, or ask, before you buy.
• Confirm it fits your system - most homes are fine, but some heating and cooling setups need a specific model or a wire called a C-wire.
• Pick a well-known brand - the popular ones are reliable, well supported, and work with the apps you likely use.
• Consider room-sensor support - handy if you have a room that runs hot.

Controlling It by Voice and Phone

Once your thermostat is smart, you can adjust it without getting up or even being home. A word to a speaker or a tap on your phone changes the temperature, which is a genuine comfort on a hot day or when you are away.

You do not have to use voice or the app if you do not care to - the thermostat on the wall still works like an ordinary one, and your schedule runs whether you touch anything or not. These are conveniences, there when you want them, ignorable when you do not.

• By voice - "set the temperature to 78," "make it cooler," or "what's the temperature inside?"
• By phone - open the app to see and change the setting from your chair or from across town.
• Quick nudges - most apps have plus and minus buttons for a fast one-degree change.
• Away checks - peek at the house temperature while traveling and adjust if a heat wave hits.

A Simple Plan for a Cool, Cheap Summer

You do not have to do everything at once. A calm plan is a sensible setting, a simple schedule, and a couple of good habits, added over a week or two. Here is a sensible order to get comfortable and thrifty.

Set it up, live with it a couple of weeks, and adjust a degree or a half hour to suit you. Before long you will forget you ever fussed with the thermostat, and the summer bill will be the pleasant surprise. That is the whole idea - comfort you do not think about, savings you do not chase.

• First: set it to Cool, around 78 when home, with the fan on Auto.
• Next: build a schedule - cooler when up, warmer asleep and away.
• Then: add the habits - close afternoon blinds, run ceiling fans where you are.
• After that: ask your utility about a peak-time rebate program.
• Finally: glance at your energy report now and then and nudge as needed.

What's in the 27-page PDF

• How a smart thermostat saves money in summer
• The right temperature, and the small changes that add up
• Pre-cooling before the hottest part of the day
• The fan setting, and when to use Auto
• Energy reports and utility peak-time programs
• Keeping cool in a heat wave without a shocking bill

Why I wrote this

I write these as printable handouts because a guide you can keep in a drawer beats a web page you have to find again. No jargon, no judgment, no rushing. If you'd rather have someone sit beside you and go through it together, that's a flat $99 first visit with the 30-day follow-up included — serving Portage County from Atwater, Ohio. — Bill