My Heater is Running but My System is Set to Cold

Thermostat set on cool

You open your electric bill and you get a surprise.

It’s not a good one. Your bill is unexpectedly high.

Or maybe not that unexpectedly. When you think back, you realize there were times when your air conditioner was running but your home somehow felt warmer, not cooler.

This is a good indication that it’s time to contact your local air conditioning repair service. Not only is your system malfunctioning, your heater is for some reason kicking on even though the system is set to cool. Here are three reasons why that might be happening.

1. A fault in your thermostat

Honeywell Smart thermostat

Most thermostat fixes will need the skills only an air conditioning repair service can bring. But you can still at least look at your thermostat.

Maybe it’s something simple: the thermostat has only lost power. Check your circuit breaker or – in the case of battery-operated thermostats – pop in a new battery. The worst case scenario is that the thermostat is defective and needs to be replaced.

2. A bad thermostat connection

It might be that the thermostat’s connection to your HVAC system has come loose, or that there’s a short in the wiring connecting your thermostat to the heater and air conditioner. These shorts can result from any number of things, from water damage to mice chewing on the wires.

In any event, your thermostat might be in cooling mode but have no way of communicating this to your system, which can cause the heat to come on. Again, an air conditioning repair service can help you fix this connection.

3. Electrical issues with your furnace

HVAC installer stripping wires for new residential system

Although they perform different jobs, your air conditioner and heater work together closely. It’s the blower inside your furnace that circulates cool air through your home.

And inside your furnace, you have a complicated system of wires and circuitry. Wear and tear and water damage can cause these systems to malfunction, a common cause of the “heating in cooling mode” issue.

The furnace’s motherboard is like its brain, sending signals for what to do. When it stops functioning properly, the cooling signals it gets from the air conditioner and thermostat get misunderstood, which causes the heater to come on.

What if my air just isn’t cold enough?

Even if your heater isn’t running, you might find that your air conditioner just isn’t generating cool air. If that’s the case, there are a few things you can do to remedy the issue:

Cleaning AC filter
  • Remove the AC’s condenser unit and make sure it’s clear of debris. In many cases, a clogged condenser is all that’s necessary to prevent the flow of cool air.
  • Clean the air conditioner’s filters, as dirty filters make your system work much harder to produce cold air.
  • Clean the compressor unit. The fan inside can become dirty. Use a damp cloth without touching the electronics and avoid using a hose or any other running water.

If this seems like too much to tackle on your own, All Seasons Comfort Control can help. Our air conditioning repair service experts have spent years working with Bucks County area homeowners to make sure their heating and cooling systems do their jobs.

Contact us today to find out how we can make your home a more comfortable place.

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