Is your room temperature lower than the thermostat setting? If so, you may have a malfunctioning thermostat. 

This common HVAC issue can disrupt comfort and signal deeper problems within your heating and cooling system. Whether you're dealing with inconsistent temperatures or your system won't stop running, understanding the root cause is crucial for maintaining home comfort. 

Let’s look at some of the possible reasons why your thermostat won’t change temperature. We’ll provide troubleshooting tips you can try out to fix these problems as well as preventative measures you can use to avoid them altogether in the future.

Signs of a Malfunctioning Thermostat

When your thermostat malfunctions, several telltale signs can identify the underlying problem:

• Temperature Inconsistencies: If you notice your room temperature is lower than the thermostat setting, your system may be short-cycling. This issue particularly affects rooms farthest from your HVAC unit, creating noticeable comfort contrasts throughout your home.
• Non-Stop Operation: An AC or furnace that doesn't shut off upon reaching the desired temperature often indicates failed thermostat wiring or calibration problems. These issues can cause your thermostat to send incorrect signals to your HVAC system, resulting in inefficient operation and increased energy costs.
• Erratic System Behavior: Unusual sounds or irregular cycling patterns from your heating and cooling system may point to thermostat communication problems that require professional attention.

Possible Causes of a Thermostat That Won’t Change the Temperature

Below are some of the most common reasons for a malfunctioning thermostat:

1. Incorrect Thermostat Settings

• Thermostat Mode Mismatch: If the thermostat is set to the wrong mode — such as using the heating mode when cooling is desired — it can seriously impair home comfort. 
• Fan Settings Impacting Temperature Regulation: The fan settings on the thermostat can also affect the overall temperature regulation in your home. For example, if the fan is set to "on" instead of "auto," the fan will run continuously, which may lead to temperature inconsistencies throughout different areas of the house.
• Incorrect Scheduling or Programming: Many modern thermostats come with programmable features that allow homeowners to set specific temperature schedules. Incorrect scheduling or misconfiguration can lead to heating or cooling at inappropriate times, resulting in higher energy bills and discomfort.

2. Thermostat Placement Issues

• Impact of Poor Placement: Poorly positioned thermostats can cause cycles of overheating or overcooling, dramatically affecting comfort levels and causing the HVAC system to work harder than necessary. Over time, this leads to excessive wear and tear.

3. Dirty or Malfunctioning Components

• Dust and Debris: Accumulation of dust and debris can impede the function of the thermostat’s sensors, leading to incorrect temperature readings and inefficient system operation. Regular cleaning and professional HVAC maintenance are essential to prevent dust accumulation.

4. HVAC System Problems

• Insufficient Refrigerant: Cooling systems require a specific amount of refrigerant to function properly. A low refrigerant level can hinder the system's ability to cool effectively, leading to warmer indoor temperatures and potential system damage.
• Aging or Damaged Components: Over time, HVAC components can age and wear down, impacting their performance. Professional HVAC inspections and maintenance are important to identify and address any aging or damaged parts before they lead to significant issues.

5. External Factors

• Weather Damage: Extreme weather conditions, such as heavy storms or intense heatwaves, can damage HVAC systems externally. Make sure that outdoor units are regularly protected and checked for damage.
• Insulation Issues: Poor home insulation can greatly affect indoor temperature regulation. Drafty areas can allow heated or cooled air to escape, leading to discomfort and elevated energy expenses. Regular checks and improved insulation can promote better energy efficiency and comfort.

Troubleshooting Steps

Step 1: Check and adjust thermostat settings

Always ensure that the thermostat is configured to the appropriate setting for the season — “heat mode” vs “cool mode” and “auto” vs “on”.

Step 2: Inspect thermostat placement

The placement of a thermostat is crucial for accurate temperature readings. If the thermostat is located near drafts from windows or doors, in direct sunlight, or close to heat-producing appliances, it may not accurately sense the ambient temperature, leading to inefficient heating or cooling. Ensure the thermostat is placed in an area where it can accurately assess ambient temperatures.

Step 3: Replace or clean filters

Dirty air filters restrict airflow, causing the HVAC system to work harder and run less efficiently. This can lead to poor temperature control and increased energy usage. Replace and clean air filters regularly as recommended by the manufacturer.

Step 4: Test batteries and wiring connections

Low or dead batteries in a battery-operated thermostat can result in complete loss of functionality. It’s important to regularly check and replace batteries to ensure proper operation. Likewise, inspect the wiring for visible damage. Frayed or disconnected wires can lead to a loss of conductivity.

Step 5: Schedule professional HVAC maintenance if necessary

If you don’t know how to perform any of these troubleshooting steps or you don’t feel comfortable doing them yourself, call an HVAC professional. Especially in situations where you risk fire or electric shock, it’s important to rely on HVAC experts who possess the right training and equipment for the job.

Preventative Measures to Avoid Future Issues

• Regularly maintain your HVAC system
• Replace air filters as recommended
• Upgrade to a programmable smart thermostat for better temperature control
• Improve home insulation

When to Call a Professional

Professional HVAC technicians are trained to diagnose and repair thermostat issues quickly. If your thermostat is not reaching the set temperature, timely intervention can help prevent costly repairs down the road. That said, it’s important to know when to call on these professionals.

Some of the scenarios in which it’s time to call a professional include:

• Complete HVAC system failure
• Issues with electrical components
• Installing new batteries doesn’t help
• Cleaning and adjusting the placement of the thermostat doesn’t fix the problem

Conclusion

Now that we understand some of the common reasons why your thermostat won’t change temperature, it’s time to reinforce the importance of scheduling regular HVAC maintenance to prevent these issues from happening in the first place. If your thermostat won’t change temperature and the troubleshooting tips outlined in this guide don’t resolve the problem, contact T.Webber for knowledgeable thermostat solutions.

At T.Webber, we specialize in thermostat maintenance and repair. We know how to quickly identify and resolve issues, saving you from the time, frustration, and risk associated with DIY repair.

In order to make sure your home is comfortable year-round, it's important to have the right-sized HVAC system. Having accurate measurements for your home is critical for recommending the appropriate-sized HVAC system. Understanding air conditioning sizes can help you make informed decisions for your home's comfort needs.

Oversized air conditioners cause short cycling, higher electricity costs, temperature swings, uneven cooling, and wear and tear on your system. Undersized air conditioners take longer to cool, which causes discomfort and high electric bills. This is why finding the right size for your home is so crucial. With our help, you’ll be able to determine the appropriate size AC unit for your needs.

The Basics of Air Conditioner Sizing

BTUs

A BTU, or British Thermal Unit, is a measurement that indicates how much energy your air conditioner needs in one hour to remove heat from your interior air. You should calculate the BTU of your HVAC system using the square footage of your home, insulation quality, temperature zone, and ducting.

AC Size vs. Space

An oversized air conditioner can cause discomfort by cooling the air faster than it can dehumidify the space, leaving you with a humid and sticky environment. Additionally, oversized units cost more to purchase and run—and they require more repairs. They don't filter the air as well as properly-sized units, resulting in less removal of pollutants like dust mites, mold, allergens, and viruses. On the other hand, an undersized AC unit will run constantly and increase your energy bills.

Factors Affecting AC Size Requirements

Room Size and Layout

The square footage of the area you plan to cool influences the size of the AC unit that you need. Exclude the spaces you don’t intend to cool, such as corridors and sunrooms. Treat rooms that cut through to each other as single rooms, like an open kitchen without a door, for example.

Different room shapes also impact the total square footage of the area you plan to cool. Rectangular or square-shaped rooms, triangular rooms, circular rooms, and multidimensional homes all have their own formulas for calculating square footage.

Climate and Location

Your local climate plays a factor in the size of your air conditioner. A home in a mildly hot region will have different cooling requirements than one in a hot and humid climate. If you reside in a hotter area, your HVAC system will work harder to achieve and maintain the proper inside temperatures than in a home residing in a cooler region.

Insulation and Windows

You may be able to downsize your air conditioner thanks to efficient insulation, which keeps heat out in the summer and in during the winter. To maintain a reasonable temperature in a home with inadequate insulation, a larger unit is required. To keep your area cool, you'll need more cooling capacity the more windows you have, especially if they're larger and less energy-efficient. The largest effects are from windows facing south and west.

Ceiling Height

AC size estimations are typically made for 9-foot-tall ceilings, which are normal for most modern homes. Taller ceilings increase the volume of air that has to be cooled, sometimes needing an air conditioner with more BTUs.

Number of Occupants

People produce their own body heat. This means the more people living in your home, the more BTUs are needed to offset the extra heat.

Heat-Generating Appliances

Large appliances such as dishwashers, washers, and dryers tend to generate a lot of heat when in use. You’ll need to compensate for this by increasing the number of BTUs in your home.

How to Calculate the Right Air Conditioner Size

Step-by-Step Guide

1. Measure the square footage of your room or home.
2. Use a BTU calculator or chart to calculate the needed cooling capacity.
3. Make adjustments for specific factors like insulation, climate, room orientation, windows and doors, and regular home occupants.

AC Size Chart

• 100-150 sq ft: 5,000 BTUs
• 150-250 sq ft: 6,000 BTUs
• 250-300 sq ft: 7,000 BTUs
• 300-350 sq ft: 8,000 BTUs
• 350-400 sq ft: 9,000 BTUs
• 400-450 sq ft: 10,000 BTUs
• 450-550 sq ft: 12,000 BTUs
• 550-700 sq ft: 14,000 BTUs
• 700-1,000 sq ft: 18,000 BTUs

Common Sizing Mistakes to Avoid

Oversizing or Undersizing

Oversizing HVAC systems can lead to increased utility costs from short cycling and installation costs, as well as a shorter lifespan due to wear and tear from repeated cycles. Undersized systems may struggle to maintain a comfortable temperature with inefficiency and inadequate cooling, leading to frequent repairs and early system breakdowns in severe weather conditions.

Ignoring Specific Home Factors

In load calculations, the heating and cooling needs of your house are evaluated according to climate, insulation, and square footage. Ignoring these factors can cause inaccurate estimates and lead to an incorrectly sized system.

Not Seeking Professional Help

A professional HVAC technician uses industry-standard calculations to accurately assess the design of your air conditioning system, which ensures the correct fit for your specific needs.

Recap

Deciding on a new AC unit needs a lot more thought than “How much will it cost me?” You need to consider the size of your space, how powerful the unit is, and other unique factors of your home. Even if you’re on the right path, we recommend you hire professional HVAC technicians like the ones at T. Webber. We provide the Hudson Valley with comprehensive air conditioning services, including installation, maintenance, and repairs.

Contact T. Webber, your local HVAC professional, for a consultation.

Making sure your AC keeps you cool all summer long and for years to come requires keeping up with routine air conditioner maintenance. Proper maintenance prevents several problems and provides an opportunity to correct minor issues because they turn into major disasters. At T.Webber Plumbing, Heating, Air & Air Conditioner, we’re excited to announce our pre-season AC tune-up special to get your AC ready for the hot days ahead!

Why You Need Professional AC Maintenance

Your air conditioner is a complicated system consisting of filters, fins, coils, ductwork and more, all of which require a bit of TLC from time to time. Neglected systems are more likely to break down and fail to operate at peak efficiency, resulting in repair expenses and higher operating costs.

Hiring an HVAC technician for AC maintenance is the best way to ensure that your home’s cooling system is well taken care of. In addition to basic tasks like cleaning and replacing filters, an HVAC tech will service the system’s internal components to ensure that everything is working properly. They’re also well aware of several warning signs that could indicate an impending problem, and they can address these issues because they cause system failure.

Pre-Season AC Tune-Up Special

The best time to have your air conditioner serviced is before it breaks down and prior to the hottest days of summer. Since you haven’t used your AC in a few months, now is the perfect time to make sure everything is taken care of and in good working order.

To help you get the best deal on taking care of your cooling system, we’re offering our incredible pre-season AC tune-up specials!

• Schedule by April 30^th and get your pre-season air conditioning tune-up for just $99
• Schedule by May 15^th for a $119 tune-up
• Schedule by May 31^st and get your air conditioner tuned up for $139

We’re also offering some other great deals. Check them out!

When you’re ready to schedule your pre-season AC tune-up special, contact us today by calling 845-234-4175 or 914-752-4230.