5 signs your AC is on the fritz.


As long as you’re cool and dry, you don’t generally need to know more about your air conditioning system. Until you need a new one. Here’s what to know. 

5 signs that something’s wrong with your HVAC system.

Think there might be something wrong with your HVAC system? If you notice any of these signs, it's time to call an HVAC specialist and get it replaced.

Sign #1: There’s almost no air coming out of the vents in your air conditioning system. 

In the summer, no amount of ice cream and wishful thinking will break the swelter like a central air conditioner can. But if the vents are barely breathing, you’re going to have to stand a whole lot closer to them to get cool — and spend more on your utility bill in the process. 

Poor airflow happens when your HVAC unit is overworked. The causes of that extra strain can be everything from dirty filters to incorrectly sized ductwork — anything that messes with the pressure in your cooling system and causes the blower to work over time. If you’ve been spending the last couple of days lying on the patch of tile directly below your AC vent, it’s time to call a technician.  

Sign #2: Something smells bad — and it’s coming from your duct system.

Sometimes airflow isn’t the problem. If the air circulating through your AC unit smells bad, you’re probably dealing with one of two common HVAC issues: electrical problems or mold. 

If your system isn’t draining correctly, it breeds mildew and mold, which collect around the unit’s indoor condenser coil. This sort of must also develops when there’s a leak in one of your ducts, allowing moisture into your ductwork. Even worse, mold is light. If spores are collecting inside your ducts and central AC, they’re also being carried into the rest of your home — and no amount of air freshener is going to cover the smell or protect you from the potential of airborne illnesses and health issues. 

Then there’s the burning smell. If you turn on your air conditioner and your house smells like it’s on fire, it probably means the insulation around the wires in your AC system are beginning to wear thin. Leaving the situation to get worse is dangerous — it smells like it’s burning because it could literally start a fire.

As soon as you smell something burnt coming from your AC or heating system, call an HVAC contractor to come check it out.

Sign #3: The central air is on, but your house still feels like a swamp. 

Damp air in your home is a sign of a different problem than an overworked AC unit or spores in your vents. Most modern central air conditioning systems are built to fight humidity by condensing hot, moist air into liquid, which is drained from the building. But the evaporating coil that transforms humidity into drainage water can break.

Moist air feels hotter than dry air (even dry air at lower temperatures), so removing humidity requires both cooling the space and keeping it cool by reducing the amount of water in the air. If you’re using an old system, humid temperatures will mean running the AC longer.

Overuse affects your home’s seasonal energy efficiency, costing you money and overwhelming your HVAC system. If walking through your home suddenly feels like wading through a pool of warm water, contact an air conditioning installation specialist to come take a look. They might even suggest extra measures you can take, like installing a dehumidifier to help your AC system keep pace in the summer swelter.  

Sign #4: Your energy bill is double what it was the same time last season. 

Let’s say you’re working on your monthly budget. And your utility bill is twice as expensive, even though the weather is roughly the same as it was last year — winter was just about this cold, summer this hot.

It could be your electricity company charging you for something else (like calibrating a new meter outside your home), but there’s a good chance that something is wrong with your home’s temperature control system. It’s easy for your energy efficiency ratio to slip (and your energy bills to spike) if any single part of your HVAC system is compromised. 

Maybe you haven’t realized that you’re keeping the air on twice as long, or setting the room to be twice as cold. Spiking energy costs shouldn’t scare you into buying a whole new air conditioner system. It’s possible your old system works just fine, there’s just a broken link waiting to be fixed.

To figure that out, hire a professional to give your home an energy audit and check all of the components of your cooling and heating systems to make sure everything is in good shape.  

Sign #5: The repair costs for your old unit are more expensive than buying a new one.

A well-maintained air conditioning system should last you around 15 years. That said, it’s not unusual to run into big issues around the 10-year mark. If that happens, consider seriously whether the repair costs are worth saving your old system.

Every year, the appliances that make up new HVAC systems get more efficient — and if technology continues to advance at this rate, it’s likely this will always be the case. With that in mind, sometimes a full replacement makes more sense. 

Not sure whether it’s time to give up on your old clunker of an AC system? Compare the energy efficiency you’re getting from your current appliances with what’s on the market using Energy Star and SEER ratings. There should be a sticker with the rating on it on your old appliance — if there isn’t, look online.

Get a free estimate from a great HVAC specialist near you.

Tips for installing a new air conditioning unit.

air conditioning units

If all signs are telling you to replace your unit, use these tips to ensure the installation process is done right:

Tip #1: Pick the right air conditioning unit: efficiency, size and cost.

Start by going next door and asking what your neighbors have in their home. Best case scenario, they’ll help you find a model that’s right for a home your size, in your climate. Worst case scenario, they don’t know — and now you have someone to shop with. 

Appliances with the highest SEER — or Seasonal Energy Efficiency Ratio — rating also tend to be more expensive. Most people will likely find a good option within the mid-range, opting for air conditioners that are rated at around 14 SEER. In fact, the highest level SEER products (the most powerful, bone-chillingly cold ACs on the market) are more expensive to fix and aren’t necessarily more reliable. Go with a SEER value that makes sense for you.

Tip #2: If your home has a duct system, it’s the first thing to check.

Fun fact: Not all cooling systems require air ducts. Mini-splits, which are popular in Europe, are like central air conditioning and heating pumps in that the compressor is outside the home, and the handling units (that the air is blown through) are indoors.

But unlike central AC systems, each and every air handling unit in the house connects back to the outdoor compressor — making it easier to control your home’s temperature from room to room. If you don’t have a duct system in place, you might try the mini-split system instead. 

If you do have a duct system, make sure you have it inspected by a professional before deciding on a new air conditioning system. If your ducts need to be replaced, it will change the scope (and cost) of your project in a big way — and that’s important to know before you put money down on a new, state of the art unit.

Tip #3: Come to terms with the humidity and air quality inside your home. 

Central air conditioners do more than just cool your home — they also control humidity and air quality. If you live in a particularly humid area, central air conditioning systems are the best option for filtering excess moisture out of your home. This alone helps with air quality — it’s easy to run into mold problems when your house is eternally muggy.

But if you’re dealing with other outside contaminants, ask your HVAC contractor to install a whole-home purifier when putting in your cooling system. 

Tip #4: Know what to ask your HVAC contractor.

Not every HVAC technician you talk to will have the same definition for an “air conditioning replacement.” Make sure you’re on the same page with some simple questions about things that most HVAC pros will be really impressed you know anything about. 

For example, consider asking:

  • Does your estimate include installation and the cost of a new HVAC unit?
  • What size HVAC system is right for my home? 
  • What HVAC manufacturers do you generally use? Which is best? 
  • Will you be handling all of the necessary permits? 
  • How long will installation take? 
  • What will regular maintenance for this HVAC system look like? 
  • Do you have a service plan in place to help maintain my system? 
  • What is and isn’t covered in the quote, and what does your guarantee cover?
  • Does the system I’m looking at apply for a tax credit? (This is a thing!) 

For more questions to ask, follow these tips for smart hiring on Thumbtack

Compare prices from HVAC specialists near you.

How much does air conditioning installation cost? 

air conditioning units in apartments

The cost to install central air  ranges from $1,100 to $9,500. A heating, ventilation and air conditioning (HVAC) expert can troubleshoot or repair your home’s heating and air conditioning systems. The cost of air conditioning maintenance and repair is $50 to $100 on average nationally, though it’s rare for a site visit to cost less than $100 in parts and labor. Most companies charge a flat rate to cover the repairs needed after inspecting a system in person — and as a rule, the older the unit, the more expensive a repair is likely to be. 

The average lifespan of an AC unit is 15 years, and most HVAC specialists can perform a routine system check and tuneup for $125 to $200 on average. The best way to keep your AC and heating system working efficiently is to change the air filter once a month (the manufacturer will suggest the same thing). Keeping your air filter and condenser coils clean and free of debris can help lower utility bills.

For more on costs, see “How much does air conditioning installation cost?

Who to hire to replace your AC unit. 

Here’s who to hire when your air conditioner needs replacing and your whole house breaks into a sweat. 

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