Heat Not Working in House? How To Fix [With Pictures]

You feel a chill run down your spine...this isn’t a horror movie; it’s worse: your heat not working in house!! When the temperature drops, you must act fast – and you came to the right place. We've got you covered for all the information you need on troubleshooting six types of heating systems.

If your furnace, boiler, heat pump, or space heater is not working, you’re at the right place. You can figure out what kind of heating system you have and the common furnace repairs you might run into. What's more, if you need the expertise of a certified HVAC technician, give SuperTech a call! We'll send you a reliable HVAC professional who knows they must get your heat on fast.

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What Heating System Do I Have?

Have you ever wondered what kind of heating system you have and how it functions? Let’s take a look at the basics and get you started!

What Kind of Fuel Does My Heating System Use?

There are four common types of power for heating systems: 1) oil, 2) propane, 3) natural gas, and 4) electric. 

How is your HVAC system distributed?

How to tell which HVAC system you have in the home

Oil and propane systems will have large tanks that get refilled now and again. The pipe connecting the system to your outside gas meter can identify natural gas heating systems. Finally, your system may be wholly electric and not have any fuel.

Main Types of Heating Systems

Furnaces are centralized heating systems using forced air to push hot air to every corner of your house. Even though new furnace installations are typically natural gas, some systems use propane, or your system may use oil. 

Heat pumps produce heat without burning fuel. Instead, they collect it from outside the house, pump it inside, and distribute the heat using forced air through an air handler. Then again, the air handler is not to be confused with an electric furnace.

You may have a boiler or a hydronic (i.e., water) heating system. Boilers use either natural gas or oil to heat water. Pipes bring the hot water to radiators throughout the house and back to the furnace system.

Uniquely, to heat just one room or small area, your residence might have a mini-split. These are just small heat pumps in the room they heat. That means they can use direct heat for that small area and don’t need forced air. 

Gas Furnace Installation

Hydronic baseboards are an alternative to radiators to distribute heat from a central boiler. The baseboards are long and run along the bottoms of a wall, typically under windows. Inside the baseboard, you’ll see a copper pipe covered in a long row of metal fins. 

Electric baseboards generate heat just using electricity; on the outside, they look similar to hydronic baseboards. They also sport a long row of metal fins to distribute heat but no copper pipe since they don’t use water.  

Small spaces - often a garage - might have a gas space heater as an extra heating source. These mini-furnaces heat one room directly or a ductless system.

Why My Gas Furnace Isn't Working

Gas furnaces heat simply: Gas is ignited and burned to heat a “heat exchanger.” Fans blow air over the heat exchanger, and you have hot air to heat your house! Finally, the heated air is blown through ducts to every part of your house.

Pretty simple....but there are a lot of parts in the process that can break down! So let's look at the common causes of heat not working in house.

Always double-check your furnace filter as an initial troubleshooting process; a dirty air filter can cause some central heating systems to malfunction.
Gas Furnace Burners

Gas Furnace Not Turning On

If your furnace isn’t turning on at all, check to see that your thermostat is working and the settings haven’t been accidentally changed or reset. Also, make sure your furnace is getting power: which means the power switch isn’t off (it happens!), and take a quick look at the electrical panel for tripped breakers. Sometimes, essential safety mechanisms prevent the furnace from starting: overheating will activate the high-limit switch, while unburned natural gas will activate the flame rollout switch. Check out this blog for more details:  Why My Furnace Won’t Turn On? How to Fix? [With Pictures] (supertechhvac.com)

Gas Furnace Not Igniting

You might have an igniter problem if you hear your furnace system start up only to have it stop without firing. Sometimes the problem is a defective or broken igniter. Open the front panel and look for signs of damage or blackening on the igniter. Maybe the igniter is fine but fails to ignite because the circuit control board isn’t working correctly. Also, check that the inducer fan and its motor are running normally because they vent dangerous gasses from combustion. The gasses collect if the fan isn’t working, and the furnace stops igniting as a safety precaution.

Blower motor pulled out of furnace

Gas Furnace Blowing Cold Air

Is your gas furnace blowing cold air? We mentioned that ignition stops if the furnace thinks that combustion gasses are collecting. This isn’t always the inducer fan; it may be that the flue pipe conveying those gasses to the outside is damaged or blocked. The pressure switch is responsible for measuring the level of those combustion gasses: if it’s defective, then the heat not working in house. But maybe…it’s more straightforward: check for damaged wires or signs of a bad connection between the pressure switch and the furnace. 

Weird Sounds Come from Gas Furnace

Weird sounds and smells coming from your furnace are a red flag. If you smell burnt wiring, turn off your furnace system to hopefully head off any significant damage. Try to find the location of the electrical short and call an experienced technician for furnace repair. If you smell a metallic/chemical/sour odor, this could be a crack in the heat exchanger. Turn off the furnace, air out the room, and call an HVAC professional. Loud sounds from the ducts may be just a loose duct piece somewhere, but if you hear humming, buzzing, or clicking from the furnace, you likely have a problem with a motor that a technician should look at.

The problem with your furnace isn't here? We have this detailed article just for Gas Furnaces: Common Furnace Repair and Problems [With Pictures How to Fix] (supertechhvac.com) 

Why My Boiler Isn't Working

A central boiler heats water with natural gas, oil, or propane. The hot water or steam circulates through pipes to radiators or baseboard radiators in the rooms of your home. The cooler water loops back to the boiler again. 

Let’s take a look at common causes of boiler heat not working in house:

Boiler Isn't Turning On

If your boiler isn’t turning on at all, first check the thermostat is working normally and the settings haven’t been changed or reset. Your problem might be a malfunctioning aquastat that controls the water temperature. A defective aquastat won’t signal the burners to start heating. Finally, check your boiler switch to not only make sure it’s on but that it is undamaged and is functioning normally. 

Boiler Isn't Igniting

Maybe your boiler isn’t igniting correctly. Check your pilot light first: a nice, steady flame should be seen. Look closely at the pilot assembly for signs of damage, blackening, or debris indicating problems. Also, is your pilot getting gas properly? The gas valve controls the flow of gas, so if it breaks down or has internal debris, you’ll need the help of an HVAC professional. Your boiler has several safety switches, such as the high limit switch (prevents overheating) and flame sensor (ensures a proper pilot light), that can break down and keep the boiler from igniting. They need to be replaced.

Boiler Leaking Water

Is your boiler leaking water? That’s a bad sign. Especially if you have an older boiler, the problem could be a crack in the heat exchanger where the water is heated. Since the exchanger is expensive, investing in a new, reliable boiler is often better. Also, check the fill valve: fill valves control the pressure inside the pipes, and a defective valve can allow high pressures that force a leak in another part of the system. You can also get high-pressure leaks if the pressure relief valve doesn’t function properly since it usually protects against high pressure.

Boiler Insufficient Heat

If you notice your boiler isn’t producing enough heat, you might have a defective limit switch. The limit switch monitors temperature, pressure, and water flow in the system, and if it malfunctions, it can turn your boiler off too soon. Don’t forget to check the aquastat and its settings: wrong settings for the high and low temperatures can lead to poor heating. Finally, how long has it been since the combustion chamber of your boiler was cleaned? Soot buildup here makes the combustion inefficient, and its insulating effect can keep the heat exchanger from thoroughly heating the water.

Boiler Producing Sounds and Smells

Weird sounds and smells from your boiler need to be addressed quickly. If air is trapped in your pipes, the water circulation pump can experience noisy airlocks. Bleeding trapped air from your radiators will usually remedy this. Other noises in your pump can indicate internal blockage or seizing. Your boiler can make noise if it struggles to exchange air for combustion. Look outside where the flue pipe damper takes in the air; this sometimes gets blocked with debris. Finally, maybe you are getting delayed or rough ignitions because of irregular gas flow: it’s time to check the gas pressure control. If the gas pressure control is not functioning correctly, rough ignitions will vibrate and rumble in your boiler.

Why My Heat Pump Isn't Working

How does a heat pump collect heat for your house when the temperature outside is below freezing? It seems impossible, but it's true. 

Heat pumps collect extra heat from the outside air, ground, or a nearby water source. How? They lower the pressure of the refrigerant so much that the outside air is warm in comparison…and collects that extra heat. The refrigerant moves inside, and the extra heat is concentrated to heat your home. Pretty neat! Forced air moves the heat through the house.

Heat Pump Isn't Turning On

If your heat pump isn’t turning on, check that your thermostat usually functions and the settings haven’t been changed or reset. A quick look at your circuit box might reveal a flipped breaker. Was there a power surge, or maybe you have a bad breaker? If you have fuses, you may have to replace a blown fuse.

Heat Pump Freezing Over

Sometimes the outdoor unit of your heat pump freezes up, but usually, the unit should defrost itself. What’s gone wrong? The defrost control board might have taken damage through overheating, a short, or a failed component. Or, you might have low refrigerant levels because of a leak. This makes the heat pump work extra hard, and defrosting becomes difficult. Finally, is the condenser fan and its motor functioning normally? If it breaks down, the outside unit won’t exchange heat efficiently or defrost properly.

heat pump condenser frozen

Heat Pump Emergency Heat

Have you looked at your thermostat and realized your auxiliary or emergency heat is running? Check your thermostat setting first to ensure it's in heat mode. Sometimes the relay control that tells your auxiliary heat to turn on/off is malfunctioning, and the ‘off’ signal isn’t being sent. A qualified HVAC technician will be your best bet in this case. Don’t forget that your auxiliary heat is supposed to kick in if the heat pump isn’t up to the task. Your outdoor condenser can start to struggle to collect heat over time or just fail, and we have a lot more details to help you in this blog post: What To Do If Auxiliary Heat Shown On Thermostat? [With Pictures] (supertechhvac.com)

Heat Pump Producing Cool Air

When your heat pump produces cool air, you can check around your units and pipes for any signs of a refrigerant leak. Without enough refrigerant, the system must work harder to collect heat…and, at some point, can’t keep up. A broken or struggling condenser motor in your outdoor unit will make collecting heat difficult or even impossible. You just won’t get enough heat inside. But don’t forget to check your auxiliary heat kit: your system relies on the heat kit on the coldest days, so if it isn’t working, the house won’t be warm enough. 

Heat Pump Burning Smell

You should react quickly if you smell burning from your heat pump: turn off the power to the system to prevent a minor burn from spreading. The problem may be an electrical short and burnt wire; a quick fix for a qualified HVAC technician. Sometimes the blower motor seizes and will smell. Since the heat pump needs it to drive warm air through the heat exchanger and ducts, it must be replaced. If you are lucky, this is a false alarm (yay!): the first time your auxiliary heat turns on, it can have a strong smell, so you just need to air out until the smell goes away.

heat pump burned control board

Why My Mini-Split Isn't Working

A mini-split is a small heat pump that heats only one room. Mini-splits pump refrigerant to the outdoor unit to collect heat and back inside to the indoor unit in the room to be heated. The indoor unit can look quite different depending on the brand, but they are a ductless system as they heat the room directly. 

Mini-Split Isn't Turning On

If your mini-split isn’t turning on, you might want to check that your remote control is working and has good batteries. A quick look at the circuit box might also reveal a blown fuse that needs to be replaced or a circuit breaker to flip. It can also happen that a breaker hasn’t flipped but has an internal defect, so your mini-split isn’t getting any power.

mini split heat pump repair

Mini-Split Heat Not Working in House

A mini-split that isn’t producing enough heat might be low on refrigerant, making your system work extra hard to produce any heat. Check your units and pipes for signs of leaks. Sometimes the outdoor compressor and its motor struggle and fail, and the amount of heat collected is reduced. Then again, have you checked the coils in the outdoor unit? They should be relatively free of debris and grime; otherwise, they act like insulation, and the system can’t collect enough heat. 

Mini-Split Blowing Cool Air

Your mini-split is blowing cool air, and the heat isn’t getting evenly to the rest of the room? First, look at the mini-split’s blower motor that pushes and blows the heat into the rest of the room. If the blower motor seems fine, maybe it’s just not getting the proper signal to turn on. It’s time to look at the control board: a faulty one won’t properly send those signals. Does the control board also look good? Now check the ‘control wire’ that connects the indoor and outdoor units and lets them communicate. Look for damage or loose connections that would stop signals from reaching your mini-split components.

Mini-Split Has Weird Smell

Does your mini-split have a weird smell? Sometimes, the blower wheel should be checked if you're smelling a light moldy smell. Together with the blower motor, it moves air for the indoor unit, sometimes needing cleaning. Another place mold can collect is the evaporator coil of the indoor unit. This can be cleaned, but don’t forget that regular HVAC maintenance will prevent this buildup. If you smell burnt wire or burning, turn off the unit immediately. Look - and sniff - at the blower motor and its wire connections for any signs of shorts or damage.

indoor mini split wall mount

Mini-Split Leaking Water

Is your mini-split frozen up or leaking water? The problem might be a dirty air filter. A dirty air filter makes heat exchange difficult, and the system over-compensates with colder refrigerant…so ensure your air filter gets cleaned regularly; indoor air quality is just as crucial as air flow. Then again, maybe the defrost control has a problem, and the system has stopped defrosting your outdoor unit. Finally, if your problem is dripping water, look for cracks in the drain pan (indoor unit) that catch condensation from your evaporator. Also, check the attached drain line to see if it is clogged. 

Why My Baseboard Heater Not Working 

Baseboard heaters are long units that run along the bottoms of walls and come in two types: 1) electric baseboards use electricity to generate heat, and 2) hydronic baseboards - a water system - get heated water through pipes connected to a central boiler.  

Looking inside either type of baseboard will reveal a long row of metal fins to distribute the heat. No forced air here; they rely on convection and heat rising. Electric baseboards are usually hardwired into the house electricity. Hydronic baseboards can be recognized by the copper pipe that runs through the metal fins and heats them with hot water or steam from a central boiler.

Electronic Baseboard Isn't Turning On

If your electric baseboard heater not working, check the thermostat setting first to see if it’s on heat mode and if the settings haven’t been reset. Next, take a look at the circuit box for tripped breakers. Don’t forget that a faulty breaker might not trip but can still stop power from reaching the baseboard. You might have a problem with the ‘electrical limit’: it’s the safety switch that prevents overheating. A faulty electrical limit will keep your baseboard from heat not working in house.

Hydronic Baseboard Isn't Producing Heat

A hydronic baseboard that isn’t producing enough heat might be struggling with trapped air in the system. Turn off the boiler and ‘bleed’ the system of air by releasing the air at every baseboard’s bleed valve. Sometimes minerals and sediment collect in the systems pipes, letting a fraction of the water through to heat. On the other hand, if you think the problem is with the central boiler, we have a whole section above just for Boilers.

Hydronic Baseboard Is Leaking Water

A hydronic baseboard that is leaking water is a bad sign. Cracks can develop in older units because of corrosion or metal fatigue from expanding and contracting, and sizeable cracks often require unit replacement. If the leak starts at the bleeder valve of a baseboard, it might need tightening or replacement. Another common area for leaks is pipe connections, so give these an extra look for signs of moisture, rust, or corrosion. Be careful working with your baseboards - the water is boiling and can cause severe burns.

Why My Space Heater Not Working

Do you have a garage or workshop that you heat with an extra space heater? It might just be an electric one from a local store, but we’ll focus here on natural gas space heaters that are popular for their cost-efficiency.

Gas Space Heater Won't Turn On

Check the thermostat setting first to troubleshoot a gas space heater not working. Look for signs the thermostat isn’t responding normally, and check the settings. Next, look at your circuit box for tripped breakers, and remember that a breaker with an internal fault might not trip but will prevent power from getting through. Finally, unplug the space heater and look at visible wiring for signs of loose or broken connections.

Gas Space Heater Isn't Igniting

A gas space heater not working might not get enough gas if the gas valve is malfunctioning and not allowing gas through. Gas flow can also be stopped if the thermocouple breaks down: a safety switch triggers when it senses gas build-up, and a faulty one will cut off gas flow. Of course, the problem is sometimes directly at the ignition point in the pilot light assembly. Look for signs of an uneven flame or if the pilot assembly has blackening or damage.

gas space heater

Gas Space Heater Blowing Cold Air

If your gas space heater is blowing cold air, the problem is often the blower motor for the fan. In particular, older models can seize or break down. However, the motor might not get the proper signals from the safety limit switch. The limit switch prevents overheating and fires; a defective one will stop the space heater from functioning normally. A faulty control board has the same effect, and the system stops working without the proper signals for operation. 

Gas Space Heater Make Noise

Is your space heater making noise? Try and pinpoint the location, if possible. Blower motors can rattle and screech if they have loose or broken parts. A cracked heat exchanger can also rattle and pop if it breaks. In this case, you should immediately turn off the unit and vent out your room since cracked heat exchangers can allow carbon monoxide buildup. However, noises from your space heater might come from a less dangerous source: it is the shaking of a loose part of the cabinet.

How to Prevent Breakdowns in the Future

Preventive Maintenance

It’s pretty simple if you want to save money in the long run: there’s no better way than annual check-ups and preventative HVAC maintenance. A qualified HVAC professional will clean, refill, tweak, and check your heating system. You’ll have an efficient HVAC system that saves you money on energy and has a long life.

Also, the HVAC technician will spot minor problems before they become big problems - and there is a BIG difference in the costs between the two. A small leak fixed before winter is better than a complete breakdown on a cold night two months later…and it can happen. The wear and tear from a little problem caused the breakdown three months later. If you want to keep your heating system running smoothly and have a long life, the furnace maintenance will pay themselves.

Trust SuperTech with those checkups and heat not working in house - it will pay dividends on your heating bill savings and keep your system running a long, long time. We’ll work till the system runs clean and smooth and nip any minor problems in the bud. We want you to keep your HVAC system for years and years, and SuperTech’s certified HVAC professionals will do you right! 

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It isn’t always easy figuring out what’s wrong with your heating system and why heater not working, but what you learn here will go a long way to help you understand your furnace, boiler, and heaters better. 

It’s great to get informed and make the best decisions possible to get your heat running smoothly and energy-efficient again. 

We want to help you save money and keep your heating system running smoothly. Don’t forget to call SuperTech for heating repair and HVAC maintenance because those check-ups will pay dividends on your power bill and help avoid future breakdowns on cold winter nights.

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