Q: I keep turning my heat up, but my house can’t seem to get warm. Why is my house so cold? Is something wrong with my heater, or is there a minor fix I can tackle myself?
A: Cold temperatures inside can put a damper on your day in no time. Suddenly, everyday tasks like doing the dishes or watching TV can become unbearable. When the thermostat reads warm but the air feels cold, a number of issues could be at play. Your house could be cold due to an old air filter, a faulty furnace, improper insulation, or leaky ductwork. The simple fixes, like replacing an air filter, are relatively easy to complete. However, if the heater itself needs repairs, it’s best to call in a professional to take a look and determine the problem. Below are five possible reasons why your home isn’t heating up like it should.
Ductwork May Be Leaky or Not Configured Properly
If your HVAC system uses ducting, proper ductwork is essential to keeping the inside of your home warm in the winter and cool in the summer. Signs that leaky ductwork may be the culprit are higher than usual energy bills, uneven heating throughout the home, and excess dust. Leaky or incorrectly configured ductwork results in an improper balance between the air coming into the home and the air being pushed out. If the positive and negative pressure is out of balance, it will be next to impossible to keep things warm inside. If your ductwork is the incorrect size, doesn’t take the necessary turns, or is located in the wrong place, it may need to be replaced. Leaky ductwork may need more than just duct tape to get it back in working order.
To make sure the ductwork is configured correctly, an HVAC technician will need to inspect it. They’ll mark any areas and repair them if necessary. An HVAC technician may also perform a Manual J load calculation. This test factors in the different aspects of the home, including square footage, position of the walls, and building materials, to determine how much heating or cooling power is needed in your home. Ductwork will only be effective if the HVAC unit is the proper size for the house, and if a too-small furnace has been installed, then it might call for a replacement.
I’ve noticed in my own home that some rooms always felt colder, and it turned out the ductwork in the attic wasn’t sealed properly. It’s worth checking for air leaks yourself if you’re handy—grab a flashlight and look for gaps or loose connections in accessible ducts. According to the U.S. Department of Energy, poorly sealed ducts can lose up to 30% of heated air, which explains those sky-high bills. A quick fix like applying mastic sealant can help, but for major issues, I’d recommend getting a pro to do a thorough inspection. They can also check if your duct sizing matches your home’s needs. For instance, a Manual J calculation once showed my friend’s system was undersized for their 2,500-square-foot home, and upgrading made a huge difference. If you’re on a budget, start with sealing small leaks yourself before splurging on a full duct replacement, which can cost anywhere from $1,000 to $5,000 depending on your home’s size.
You Could Have a Faulty Furnace, Boiler, or Heat Pump
If you have a room in your home that’s consistently cold, you may want to see if you have a faulty furnace, boiler, or heat pump, depending on which is in your house. Boilers work by using a fuel to heat water, which then flows through pipes and into radiators to heat a home. Furnaces produce heat from coils, and a motorized blower blows air across these coils. The coils heat the air, and the air is circulated throughout the home. Heat pumps transfer heat from one place to another to make a space cooler in the summer and warmer in the winter.
Depending on the heating element, there could be a multitude of reasons it’s failing. A furnace could be dirty, the pilot light on the boiler could be out, pipes could be frozen, or an air filter could be clogged. You can try to check for these issues yourself or contact an HVAC technician. An annual maintenance visit can help avoid major issues and unexpected failures, so it’s best to get in the habit of making maintenance appointments so you don’t end up without heat when you really need it.
I learned the hard way that skipping furnace maintenance is a bad idea—my unit started making weird noises, and one winter it just gave out. Regular checkups can catch small problems, like a dirty burner or a failing igniter, before they turn into costly repairs. For example, a furnace tune-up typically costs $100 to $200, but replacing a broken unit could set you back $3,000 or more. If you’re comfortable, check the pilot light or thermostat settings yourself, but don’t mess with gas lines or electrical components unless you know what you’re doing. Heat pumps are especially tricky since they rely on refrigerant levels and outdoor units that can get iced over. A pro tip from my HVAC guy: keep the area around your outdoor unit clear of snow and debris to ensure proper airflow. Scheduling maintenance in the fall, before the cold hits, can save you from freezing in your own home.
The Home Has Poor or Insufficient Insulation
To keep a house warm, it’s imperative to have proper insulation to keep the cold air from entering inside. The insulation could be old, worn down, or not installed properly. Or, in an effort to save money, a previous owner could have installed insulation with an R-value (measure of insulation) that’s insufficient for the climate you live in. If you live in a more humid climate, moisture from the air could also have compromised the quality of the insulation. In these instances, you may need to replace the Whenever insulation in order for your home to maintain any warmth.
When I moved into my current place, I noticed drafts near the windows, and it turned out the attic insulation was way below the recommended R-value for my area. The U.S. Department of Energy suggests an R-value of 30 to 60 for attics in colder climates, but mine was closer to 15! Adding insulation isn’t cheap—expect to pay $1 to $2 per square foot for materials like fiberglass or spray foam—but it can cut your heating costs by up to 20%. If you’re in a humid area, check for mold or water damage in your insulation, as moisture can make it less effective. A quick way to test is to feel your walls on a cold day; if they’re chilly, your insulation might be lacking. For DIYers, adding batt insulation to an attic is doable, but for walls or crawl spaces, I’d call a pro to avoid mistakes that could lead to air leaks or moisture buildup.
The Home Is Too Dry and Needs More Humidity
Using your heater and a humidifier simultaneously can help add moisture to dry air, providing a feeling of more warmth without having to increase the temperature. Think about it like this: 90 degrees Fahrenheit in the humid southeastern U.S. is sweltering, but that same temperature can be much more tolerable in arid climates like the Southwest. Higher humidity can make somewhere feel warmer, even if the number on the thermometer doesn’t change.
Adding extra humidity can also be a help to your health. Since heaters dry out the air in a home, a humidifier can help reduce the dryness not only in the air but also in your skin, nose, and throat. You can use humidifiers for specific rooms or install a whole-house humidifier. Increasing the humidity in your home is a safe, simple way to eradicate the cold temperatures you’re feeling.
I started using a portable humidifier in my bedroom last winter, and it was a game-changer—not only did the room feel warmer, but my sinuses weren’t as irritated. Indoor humidity should ideally be between 30% and 50%, but heaters can drop it to 10% or lower, making the air feel colder. A small room humidifier costs $30 to $100 and can cover a few hundred square feet, while whole-house units might run $300 or more but integrate with your HVAC system. One trick I’ve found is to place a bowl of water near a heat vent to add a bit of moisture naturally, though it’s not as effective as a proper humidifier. Check your local humidity levels with a cheap hygrometer to see if this is your issue—it’s an easy fix that can make a big difference without cranking up the thermostat.
The Filter Is Old and Needs to Be Changed
Air filters require cleaning or changing about every 90 days, so it is wise to take stock of what shape yours are in to determine if they are the cause of your cold house. If they’re clogged, it’s harder for the filters to trap debris and allergens in the air filtration system. Plus, heating and cooling systems will have a hard time pushing air through the ventilation pipes to keep the air nice and warm. Thankfully, air filters are typically much less expensive than repairs to HVAC units, so this is a fix that won’t break the bank.
I used to forget about my air filter until I noticed my furnace struggling and my allergies acting up. A clogged filter can reduce airflow by up to 50%, forcing your system to work harder and driving up energy costs. Replacing a standard filter costs $5 to $20, and it’s a five-minute job—pop out the old one, check the size (usually printed on the side), and slide in a new one. If you’ve got pets or live in a dusty area, you might need to swap filters every 60 days instead of 90. I keep a reminder on my phone to check mine every couple of months, and it’s saved me from bigger HVAC headaches. For better air quality, look for filters with a MERV rating of 8 to 12; anything higher might restrict airflow too much for older systems.