Why Is My House Cold Even With the Heat On?

Coming home to the heat not working in your house isn’t very fun — especially during winter and you’re paying for it to be warm! If you find yourself asking, ‘why is my house so cold?’ when the heat is on full blast, it’s time to start troubleshooting.

Why is My House Not Heating Up?

Your house may not be heating up due to several reasons: a malfunctioning thermostat, issues with your heating system, blocked air filters, or inadequate insulation. It’s important to check these components to identify and resolve the problem.

Let’s dive into each of these potential issues to see which one is yours. 

Your Heat Doesn’t Deliver

When your heating system is on but your house remains cold, it’s a clear sign that there’s an issue with heat delivery. This can be due to a variety of reasons:

Vents or Radiators Aren’t Giving Off Much Heat

If your vents or radiators are not emitting enough heat, it could be due to a blockage or malfunction within the heating system. Dust and debris can accumulate in ducts or on radiators, reducing their efficiency. Additionally, if radiators are cold at the top but warm at the bottom, this could indicate trapped air, requiring bleeding of the radiator.

Rooms Are Cold Even With Heating On

This problem often points to inadequate circulation of warm air. It could be due to blocked vents, a failing HVAC fan, or issues with the furnace itself. Ensure that furniture or drapes are not blocking your vents. Also, check if your furnace’s filter is clean, as a dirty filter can restrict airflow.

Home Has Oddly Cold Rooms

If certain rooms in your home are significantly colder than others, this could be due to poor insulation, leaks in ductwork, or an unbalanced heating system. Inspect the insulation in these rooms, including windows and doors, for drafts. Having a professional assess your ductwork for leaks or blockages can help resolve uneven heating.

Your Ductwork Needs to Be Resealed

Hold up a smoke pencil to the seams in your open ductwork, usually accessible through your attic, garage or basement. If smoke is detected, it indicates a leak. Seal these areas with foil-faced duct tape. Replace any old cloth-backed tape throughout the ductwork with foil-faced tape for enhanced durability.

Insulating Your Ductwork

Insulating your ductwork is crucial, especially in unheated spaces. Wrap all ducts with R-6 foil-faced fiberglass insulation, trimming it to fit and sealing the seams with foil-faced tape. This step is key to preventing heat loss and improving system efficiency.

Your Furnace Needs Inspection

For optimal furnace health and efficiency, it’s recommended to schedule yearly HVAC inspections with licensed technicians. Inspections help identify potential issues before the need for repair, as well as repairs that need to be made before they cause extensive damage. Plus, skipping annual checks can lead to unexpected breakdowns and may void your furnace’s warranty.

You Have Poor Heat Insulation

From freezing floors to warmth-sucking windows, there are many ways for heat to exit the home that keeps your house from warming up.

While newly constructed homes are often airtight, historical homes and houses with aging materials often need more attentive care to make the most of their insulation during the colder months of winter.

Addressing Window Heat Loss

Windows are a common source of heat loss. In older homes, windows may not be as energy-efficient, allowing warmth to escape. To combat this:

  • Seal Gaps: Check for and seal gaps or leaks around window frames with caulk.
  • Upgrade Window Treatments: Use heavier drapes or blinds for added insulation.
  • Install Window Insulation Film: Apply a clear insulation film to windows. This is an affordable solution that can significantly reduce heat loss.

Enhancing Door Insulation

Doors, especially external ones, can also contribute to heat loss. Some ways to fix this include:

  • Replace Weather Stripping: If you feel drafts around closed doors, replace old or worn weather stripping.
  • Install Door Sweeps: Fit door sweeps to the bottom of doors to block cold air from entering.
  • Insulate Mail Slots and Doggy Doors: Use brushes or specially designed covers to insulate mail slots and pet doors.

You Have High Ceilings

High ceilings can present unique challenges when it comes to heating, particularly if you have a vaulted ceiling. The issue arises because heat naturally rises, leading to warmer upper levels while the lower areas remain cooler. 

This can result in your heating system working overtime to maintain a comfortable temperature on the ground floor, leading to inefficiency and increased energy costs. If you have a ceiling fan in this area, set it to fan air down and enjoy a warmer lower level from this unexpected solution.

Your Heating System Doesn’t Cover the Whole Home

If your heat is on but the house is cold, your heating system could be mismatched with the size of your home. This is especially true in two-story homes that don’t have zoned heating.

With zoned heating, your home is divided into at least two ‘zones’. This is typically an upstairs and downstairs zone for a two-story home. You can then control the individual temperature of each zone within your home. 

How Do You Know if You Have the Right-Sized System? 

There are multiple factors to consider. The climate of where you live is a factor, as well as your home’s square footage.

Those two factors can help you calculate a British Thermal Unit (BTU) necessary to heat your home. Other factors to consider are high ceilings, how many stories your home has, your home’s insulation, how energy efficient your windows are and how many of them exist. 

Your Air Filters Are Clogged

Clogged air filters contribute to poor air quality in your home and are a serious strain on your HVAC system. This can decrease its output, increasing your energy bill.

Poor air quality and reduced efficiency are likely the issues you’ll notice. However, over time, clogged air filters can also cause irreversible damage to your HVAC system. Lint, fibers, mold and mold spores, pollen, dirt and dust are some of the items that are trapped by the air filter. If those particles and contaminants are built up, heat won’t get through as effectively — resulting in a house that’s cold even with heating on. 

Your system is working harder to heat your home, and if you combine this with some of the other common issues, the heat isn’t making it to your desired rooms. Routinely changing your HVAC air filters is arguably one of the most essential maintenance tasks homeowners need to pay attention to.

Stay Safe With John C. Flood

Improving your home’s heating efficiency can sometimes require professional intervention. The HVAC and heating pros at John C. Flood can identify why the heat isn’t working in your home and solve the problem quickly. Just call 703-214-5611 for same day service!

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