House Hotter Than Thermostat Set? (4 Reasons And How To Fix)

Whether it’s the winter and you’re trying to warm up your home, or it’s the summer, and you’re trying to cool off, the thermostat might not read correctly due to not being level, power issues, leaks, cleanliness, or even a bad air-conditioning unit.

From ducts and insulation to batteries and dirt, there are all kinds of reasons sections of your home might be warmer than the number on your thermostat. So if you’re looking for ways to fix those problems, suggested temperatures, or how to check your thermostat, you’re in the right place!

What is the Recommended Temperature For the House in Summer and Winter?

While everyone has their comfort levels, there’s a general rule of thumb to follow to use less electricity and keep the general public happy. If you plan to be home, keep your house at 78 in the summer. Otherwise, bump it up to 88 since you won’t be there sweating.

For the winter, 68 is a good idea if you stay inside the majority of the time. However, if you’re out all day, drop that to 58 to keep your home from freezing while still saving energy. Of course, you might even go lower when you’re there to save money if you want to bundle up.

Why is the House Hotter than the Thermostat Reads?

The main reason that your house might not match with what the thermostat says is the weather. Obviously, there could be leaks, duct blockage, location in relation to the thermostat, or the other things mentioned above but those don’t need repeating.

Especially regarding recent surges in temperature highs or if you live in a southern region, the sun can be unforgiving and some AC units simply can’t keep up with the heat. Some people run the unit all day and still go up in temperature, with larger homes being more prone.

You might also notice the temperature higher in rooms closer to the edge of the house or with a lot of windows. Usually, the space near the front or back door or the garage will be warmer as well since that’s where air escapes then they open.

If you do have windows or a sliding door, a good option to keep the cold in while leaving as much of the heat outside as possible is to put up blackout curtains or reinforce the areas with cardboard or some form of blockage.

The truth is that setting your thermostat to a specific temperature doesn’t guarantee that your entire home will reach that number. All kinds of causes for this can stem from the thermostat itself or the air-conditioning unit, so let’s break them down and try to fix the issue.

1. Power Source Problem

The first thing to check is the source of the problem: The thermostat. Since it’s electronic, any problem with the power in your home can affect its performance. That means you could have a bad fuse or breaker, which an electrician would need to fix.

However, it could also be the wiring inside the device or where it’s at. If it’s the former, it might be time to replace your thermostat unless you can get it repaired, but the latter comes down to consideration or poor layout.

Thermostats gauge the temperature by the immediate area around them, so if they read cold, they’ll shut off. While this problem is far more familiar with heating due to heat sources, if your thermostat is over a vent or near a window in the winter, it may need to be moved and rewired.

It might also malfunction from being dirty because any amount of dirt or smoke can affect your thermostat. Remove the faceplate and look inside. If it seems unclean, use a soft cloth or brush to wipe it out and replace the cover.

There are Levels to This

If you have the faceplate off and notice that your thermostat isn’t level, that could be the root of your problem as well. Most thermostats use a mercury level to track the temperature and know when to turn on or off, so they have to be balanced for the gauge to read correctly.

With the cover off, unscrew the back from the wall enough to shift your thermostat. You might want to use a T-square or a laser level to ensure it’s appropriately set before screwing it back in and putting the cover on.

Welcome to the Thermostat Zone

In this case, zones refer to different parts of your house that the AC unit may or may not cover. Especially in larger homes, one unit might not be enough to get air to all sections, so the far rooms can be hotter than those closest to the unit.

The easy fix is either getting an AC unit with zone control that will let you choose where the air is focused or invest in a second or third unit. The former is most helpful if you know where you plan to be most of the time, like the living room, dining area, or bedroom.

However, remember that heat rises, so top floors are usually hotter since they’re also closer to the sun. So if you own a two-story home and the second floor is too warm, you might want to consider purchasing a second unit with thermostat controls upstairs.

Basements and crawl spaces tend to be cooler thanks to being surrounded by dirt and underground, but they also get more humid, so you might want to push air down if you plan to use yours as a game room or something.

2. Insulation or Duct Leaks

Many homeowners don’t realize that the insulation in their homes can develop leaks over time, but moisture, humidity, and age can all cause it to deteriorate naturally. In addition, since most insulation is in basements and attics, it can cause those areas to lose cold air to the outside.

However, you might also feel like cold air is reaching your laundry room or even the bathrooms but never seeming to get the rooms cooled down. The closer to the walls, the more likely it is that the insulation is letting air through.

Improperly sized windows can let air underneath the frame, but it could also be a bad seal on the window or door. The good news is that you can easily replace the gasket or use a tape measure to buy the right size for your home.

Ducts are how the air circulates throughout your house, so if there’s a leak at any point, it can cause issues with any room after that leak cooling off. But, like insulation, the good news is that you can fix it without too much trouble as long as you’re willing to do the work or pay someone.

Do it Yourself

If you choose to pay a contractor, you can step back and let them handle fixing the insulation, but you do have the option to do it yourself. Keep in mind before you take action that, depending on the space and materials used, it might end up costing about the same.

The main 2 rooms of your home to reinforce if they’re warmer than the rest are the attic and basement. Your goal is to achieve at least an R-38 level of insulation, which is how effective it is at retaining or preventing air.

Your first and quickest option can be insulating foam that comes in a spray can. It hardens pretty fast, especially if you set up a fan, and R-38 usually means around 10 inches thickness. The only negative here is that it doesn’t last as long, and you might miss a spot.

If you go the other direction, you’ll need plastic wrap or batting to create a vapor barrier. Batting is measured in density, and the denser, the less you’ll need for an R-38. Either way, lay out the material on the floor in overlapping layers and tape them down to secure them.

Once that’s done, use foam pads or spray to insulate on top. While the vapor barrier will do most of the work, the foam will act as a redundancy. It’s also a good idea to use a caulking agent or loose-fill bags for the angles because batting isn’t as strong in corners.

3. Dirty Ducts

On top of leaks, over time, your ducts can gather dust, fur, or several other things that can affect the air passing through. When these things build up, air might not circulate properly and leave areas of your house hotter. But, again, you can either hire someone or clean them yourself.

4. The AC Unit is Broken or the Wrong Size

The simplest answer might be that your AC unit is down for the count. The first thing to check is if it just needs a new filter or maybe a good cleaning, but you might need to replace the unit if that doesn’t work.

An excellent way to test if you need a new unit entirely is to try the heat. If it still works just fine, your unit might need to be cleaned or repaired. But, of course, it could also be the wrong size for the job, depending on your home.

If the unit’s too big, it can shut off after cooling the rooms closest to it because it reads the house as the right temperature. On the other hand, it might not have the pressure to get air to the entire house if it’s too small. If that’s the case, you might need to upgrade or get a second one.

How to Know if Your Thermostat is Working Correctly

As mentioned earlier, try turning on the heat if the AC isn’t working correctly. That would mean the thermostat is working, and it’s another issue. If it turns on and stays on long enough to start lowering the interior temperature, it’s working.

Otherwise, you might need to go through the above steps. Remove the cover and check for cleanliness, pay attention to the level to see if you need to adjust it, or note the location to move nearby objects or close a vent.


Areas of your home can be hotter than the thermostat reads if you’ve got a leak problem with insulation or ducts, you’ve got a cleanliness issue, the power in your home or the device isn’t functioning correctly, or the AC unit is the wrong size for your home.

Most of those are easily solvable, whether by hiring a contractor or electrician or doing it yourself. Still, it might take money, time, labor, or a combination of all three to make sure your thermostat matches the feeling in your home.