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One Hot Room: Why is One Room Always Hot?

Living in Texas, triple-digit temps are a common occurrence. So it’s no surprise that a common complaint we hear about a home’s heating and cooling system is that it’s simply not keeping up with the demand. But more frequently, people talk about just one room being hot. It seems every home has a hot spot. It can definitely be frustrating to have most of your home at a comfortable temperature, but just one room uncomfortable.

While many of these hot spots can be fixed with just small adjustments, some require a little more work. And in some cases — you have to make a call on whether you want to truly fix the problem with an expensive repair, or make do with what you have.

In this blog, we’re sharing a few of the reasons why one room could get hot, while others remain comfortable.

Common Problems that Make One Room Hot

When one room is warmer than it should be, it is not an unsolvable problem. It is simply a matter of energy transfer. But the solution isn’t as simple. First, you need to determine what exactly is causing your space to receive less energy than other rooms. Then, our trained experts can help resolve the problem.

Problem 1: Your equipment is undersized

When a new HVAC is installed on a home a calculation is done to determine the heat load. The load is what determines the size of your HVAC equipment. Your load will change over the course of the day and definitely over the course of years.

When your equipment is undersized, you’ll experience a whole host of problems. One issue you may encounter is a room – or many rooms- being too hot.  Specifically, the room that is furthest from your air handler may feel warmer than others. That’s because the energy is being transferred and equalizing before it reaches the last space.

If the load in your home is more than what your air conditioner is sized for, then your course of actions are limited:

  • Use blackout curtains on your windows to prevent too much energy loss
  • Use devices that generate heat, like coffee pots and clothes dryers, sparingly. Isolate the heat to the room by shutting doors.
  • Utilize ceiling fans
  • Seal all of your windows and doors
  • Make home improvements to improve the insulation of your house, like replacing roof insulation or installing new windows
  • Add an additional HVAC system like a ductless mini-split to the culprit space. This reduces the load on your original system.
  • Replace your HVAC system with a larger, right-sized system.

Problem 2: Warm air is rising to your second floor

Graphical image demonstrating Hot Air Rising in a Space, which may cause one room to be hot. This image shows a house, with blue dots as cold molecules tight together and orange dots as warm molecules spaced further apart.

Perhaps it’s not just one room that is hot, it’s an entire floor of your home! An important science concept for air is that hot air rises in spaces. That’s because cold air is more dense than hot air.

So, as air moves in your home the coldest air will be at the lowest point and your warmest air will be at the highest point. If your entire second floor feels warm, then it could be a result of warm air naturally rising. Another cause may be poor roof insulation.

In this case, some possible courses of action are:

  • Changing your dampers or air vents to ensure air reaches the second floor
  • Put more insulation to your attic
  • Install a ventilation fan in your attic space – this will remove heat from your attic area quickly, so that it doesn’t return to the space
  • Add a new HVAC system for your second floor

Problem 3: Your Ductwork has Leakage Problems

Two pieces of ductwork showing how energy leaks through unsealed areas in cooling and in heating

If your ductwork has lost sealing over time, this can be a major problem for the comfort of your home. If your ducts are leaking, that means you are wasting energy cooling the interior spaces of your home where ductwork travels. In short: the energy that should be used to cool your rooms is not making it there.

Our team can identify leaky ductwork with a few simple tests. Here’s the good news: solving a duct leakage problem is relatively simple. Ducts will be re-sealed with mastic (not duct tape!). To ensure energy is making its way to your spaces and not your attic, we’ll make sure your ductwork is fully insulated.

There can be some complications in sealing ductwork, like if you have a tight crawlspace or hard-to-reach-places. In any case, it’s best to call in the professionals to help! Even if sealing your ducts doesn’t solve your problem, ensuring your ducts are working properly will greatly improve the efficiency of your home.

Problem 4: Your Thermostat is in a Poor Location

Graphic showing four examples of poor locations for thermostats. If a thermostat is near exterior doors, near AC registers, in direct sunlight, or on the same wall as an oven, it may cause a room to feel hot.

Air conditioners control the space temperature based on a sensor that is located in your thermostat. Think for a moment about where your thermostat is located. We bet it’s not in that room that’s too hot!

Contrary to popular belief, your air conditioning system does not sense the air temperature all throughout your home. Most A/Cs only sense temperatures in one single spot. So, that may be a reason why different spaces in your home experience different temperatures.

Thermostats don’t always end up being in the right location. This is especially true if there has been a remodel where doors, windows, or appliances have shifted around in your home.

Thermostats should never be located in spaces that could experience huge temperature swings. If your thermostat shares a wall with a clothes dryer, for example, your AC could be running a lot more than it needs to be. And in the winter, your heat may not kick on if the thermostat senses the space is warm.

Similarly, never place heat generating equipment, like a television, near a thermostat.

A professional can help you relocate a thermostat that not in the optimal location. Another solution is to add a temperature sensor to other spaces in the home, like your hottest room. Special thermostat systems can then determine an average of the space temperature and cool your home adequately.

Problem 5: The vents or dampers in your system need adjustment

Another potential problem that can cause a hot room is that the dampers or vents in your system require adjustment. There are many reasons that a system becomes unbalanced. Two of the most common are:

  • Room use – perhaps you or a previous homeowner are using spaces for different reasons. For example, an old nursery may be turned into an equipment-heavy office.
  • Renovation – An HVAC system will definitely become unbalanced if walls are added or removed.

Occasionally, we see vents that are completely closed in an effort to save energy or because an occupant was complaining about the temperature. Sometimes making this change is simple, and other times it can be difficult. So, we recommend calling a professional to assess the situation.

Every Home is Different

Every home is unique. When we try to troubleshoot hotspot problems, we have to assess each home individually. Sometimes, fixing a room that is too hot is as simple as changing a damper or a directional vane. And in other cases, a new system may need to be installed. So, we understand why homeowners feel like they are getting different answers from their neighbors. In fact, you may have totally different recommendations from different AC companies on the right solutions.

Do you have one room that’s hot? We can help

With over 30 years of experience in addressing hot spots, we can identify and solve the true source of your comfort problems.  Feel free to take it from your neighbors – we’re the best at resolving hotspots. Hire an award-winning professional HVAC team today and get your home back to being comfortable – in every space!


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