Furnace, heat pump, ac, how confusing! How are they all connected?
Your HVAC system is responsible for heating and cooling your home by using a refrigeration system. Your furnace is only responsible for heating your home with fans and coils. Some furnaces rely on natural gas or propane while all HVAC systems are electric.
Below you can find a deep dive into furnaces and your air conditioning system so you can understand how they work independently and together.
Let’s get started.
Furnace VS Air Conditioning System
Forced air systems describe the air distribution system of the central air conditioning system. A central air conditioning system is what heats and cools the air in your home utilizing the refrigeration cycle.
A furnace is a forced-air system that uses the duct work inside of your home to send heat throughout your home. The central air conditioning system uses that same distribution system to send hot or cool air throughout your home.
Typically, your HVAC system has an outdoor unit that has a condenser, compressor, and fan. The indoor unit is the air handler that delivers hot or cold indoor air to your entire home.
While the central air conditioning system uses forced air ductwork, they are independent of each other.
The furnace doesn’t require the HVAC system to work, but the central air system relies on the forced air ductwork to disperse the hot or cold air.
How to Know if I have an AC or Heat Pump?
The easiest way to check if you have an AC or heat pump is by checking the outside and indoor units of your air conditioner. Look up the make and model and determine if your AC system is using a heat pump or not.
If you’re handy, you can also check within the condenser to see if there is a reversing valve that indicates you have a heat pump.
How an Air Conditioner Works With a Heat Pump
What’s great about heat pumps is that they’re able to heat and cool at the same time. They blow air over an evaporator coil which moves the heat from the air to the refrigerant.
The heat is then circulated within the refrigerant to the condenser coils, where the fans blow it along the coils. Heat is then moved in this process to the outside while the cold air is directed into the ductwork of your home.
The process also works in reverse, by taking in cold air from your house through the air handler or furnace and then passing through hot coils which heat the air.
Once the refrigerant condenses to a liquid, it passes through an expansion valve which helps release pressure.
The pressure helps to reduce the temperature of the refrigerant and allows for cold refrigerant to pass through the outside coil.
The cold refrigerant (which is now a gas) is then sent to a compressor where it raises the temperature and is brought back to heat the cold air it comes into contact with. The cycle continues until you’ve reached your desired temperature.
In central air systems, the evaporator coils are inside. With newer heat pumps, those coils require a lower atmosphere and are best operated outside.”
As Energyguide.org.uk mentions since heat pumps are constantly running during the colder weather, they tend to be less efficient in winter. This is due to the low coefficient of performance levels of the heat pumps, meaning that they need more energy to heat up rooms efficiently.”
Is a Heat Pump Better than a Furnace?
Heat pumps are a more efficient way to heat your home and they don’t require natural gas like a furnace does which makes them safer.
The disadvantages of a heat pump are that they can have a higher upfront cost and they have issues running in extremely cold weather.
Can a Furnace Work Without an Air Conditioning System?
You can use a furnace without an air conditioning system. A furnace, or forced air system, is independent of your HVAC system. HVAC systems do however need to use the ductwork that is normally provided by furnaces/forced air systems.
Some homes only have air conditioning as the winters are fairly mild and don’t require an extra heating system.
Other homes require both an air conditioning AND furnace system because the temperature drops so low that a heat pump won’t be able to work through the harsh winter.
Do you use the furnace for AC?
Both your furnace and AC system are connected, but you do not use the furnace for air conditioning. These systems are independent of each other, and during warmer weather, you want to turn your furnace off.
Does a furnace also cool?
A furnace does not cool, it only heats. Your HVAC system does use the ducting, vents, and plenum of your furnace, but they don’t rely on each other to work.
Do furnaces last longer than AC?
Furnaces last from 15-30 years while central air conditioners last from 15-20 years depending on usage and climates. This can force you to upgrade both your furnace and air conditioner because if you have both in your home, you’d want to replace both so their energy efficiency is greater.
Is a furnace or air conditioner more expensive?
To replace your air conditioner, it can cost anywhere from $4000 to $12,000 while replacing your furnace can cost $3000 to $7600.
These prices reflect installation, labor, and anything else that may be required to install your new furnace or air conditioner.
Should I replace my furnace and AC at the same time?
Your furnace normally lasts longer than your air conditioner which can make for an awkward situation if one gives out before the other. By having two equal systems, you’ll be able to enjoy better energy efficiency and overall better performance from both systems.
Final Thoughts
While it can be difficult to understand at first, the difference between your furnace and HVAC system is simple. Your furnace is used to heat your home while the HVAC system uses the forced air system of your furnace to distribute the hot and cold air around your house.
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