When choosing a new heating system, you have two main options: a furnace or an HVAC system. A furnace generates heat, which is then distributed around the house. An HVAC system, often including a furnace as its heating component, is a comprehensive heating, cooling, and air quality system. Which is the right choice for your residence?

In this article, we explore the types of furnaces and HVAC systems suitable for home installation and the factors you should consider before picking one. 

What Is a Furnace?

Furnaces generate heat by burning a fuel like natural gas or through electric heating. The heat is transferred to air, water, or steam and circulated throughout the residence. Some homes have a standalone furnace to power the heating system, but they are often one component of a complete HVAC system.

Types of Furnaces

Furnaces are categorized based on their fuel source. The most common types include:

• Natural gas furnaces: Natural gas furnaces are the most widely installed residential heating option; they are efficient and cost-effective. They use natural gas piped from municipal lines, making them a convenient option for homes with existing gas connections. Gas furnaces have a high heat output and can warm up spaces quickly.
• Electric furnaces: Ideal for areas where natural gas is not available, electric furnaces convert electrical energy into heat. They are generally more expensive to operate because of higher average electricity costs, but they are cheaper to install and require less maintenance.
• Oil furnaces: In regions where natural gas and propane are less accessible, oil furnaces are a suitable alternative. They use heating oil stored in a tank that is regularly refilled. Oil furnaces can produce high heat output but are generally less efficient than gas furnaces.
• Propane furnaces: Often used in homes without natural gas service, particularly in rural areas. Like oil furnaces, they require a storage tank and regular deliveries. They offer clean-burning, efficient heating.

Each furnace type has advantages, depending on the location, availability of fuel sources, and specific heating needs.

How Long Do Furnaces Last?

On average, furnaces require replacement every 15 to 30 years, although a particular furnace's lifespan depends on its fuel type, quality, location, the building's heating needs, and proper maintenance. Regular maintenance—including inspections, tune-ups, and frequent air filter changes—can significantly extend a furnace's lifespan.

It's impossible to say how long a specific furnace will last, but there are general trends for each type of furnace.

• Natural gas furnaces can last 20 to 30 years because natural gas is clean burning.
• Electric furnaces have the longest lifespan, often exceeding 30 years, because they have fewer moving parts and no combustion.
• Oil furnaces have a shorter lifespan of 15 to 25 years because they are prone to soot accumulation.
• Propane furnaces also last around 20 to 30 years.

How Often Should You Change Your Furnace Filter?

Replacing your furnace filters is essential for maintaining air quality and furnace efficiency. A general guideline is to change furnace filters at least every three months (90 days). However, the ideal replacement frequency depends on the thickness and type of filter. Below are general guidelines under normal operation conditions. 

Note: High smoke or high dust environments such as desert areas may require more frequent changes. A visual inspection of the filter can show you when a filter is loaded.  If you are unsure whether you should change a filter, it is best to consult an HVAC professional or have your HVAC service company check your  filters when doing a seasonal cleaning of your system.

• Standard 1-inch pleated filters: Changing the filter every 90 days is usually sufficient for average homes without pets. If you have pets, allergies, or additional dust from construction, consider changing it every 30 to 60 days.
• Medium-thickness pleated filters (2 inches): These filters balance efficiency and longevity. In homes without specific air quality issues, change them every 90 days.
• Higher-thickness pleated filters (4 inches): Designed for superior air filtration, these filters can last 6 to 12 months before needing a change. However, the exact timing can depend on your home's specific conditions.

Inexpensive fiberglass air filters should be changed on a monthly schedule.

Adhering to these guidelines ensures your furnace operates efficiently, prolonging its life and maintaining healthy indoor air quality. Remember, these are general guidelines; you should check the manufacturer's recommendations for your specific filter type and consider your household's unique needs to determine the best maintenance schedule.

What Is an HVAC?

HVAC stands for Heating, Ventilation, and Air Conditioning. An HVAC system is a comprehensive installation for temperature control and air quality management. Unlike standalone heating units like furnaces, HVAC systems offer heating, cooling, and air purification.

The main components of an HVAC system include:

• Thermostat: This is the system's control unit, allowing users to set the desired temperature and operating mode.
• Furnace: The furnace component provides heating to warm the air distributed throughout the space.
• Air conditioner: The air conditioner cools indoor air by removing heat and moisture.
• Ductwork: The network of tubes heated or cooled air moves through from the furnace and air conditioner.
• Vents: Air from the ductwork is released into rooms through vents. Return vents draw air back into the HVAC system for re-heating or cooling.
• Air filters: Positioned within the ductwork or air handler, filters trap dust, pollen, and other airborne particles to maintain air quality.

Types of HVACs

HVAC systems come in various configurations to suit different building sizes, layouts, and climate control needs. The main types include split systems, ductless split systems, hybrid split systems, and packaged systems. Each system has its advantages and is popular in different contexts.

• Split systems: The most common type of HVAC, split systems have an outdoor air condenser and compressor and an indoor unit housing the furnace and evaporator coil.
• Ductless split systems: Ideal for homes without ductwork, ductless split systems, or mini-splits, are a flexible solution for heating and cooling individual rooms. These systems have an outdoor condenser and one or more indoor air-handling units. They are increasingly popular in renovations, extensions, and buildings where installing ductwork is impractical.
• Hybrid split systems: Hybrid systems combine a gas furnace with an electric air-source heat pump. They automatically switch between gas and electric power to reduce operating costs.
• Packaged systems: Packaged HVAC systems contain the evaporator, condenser, and compressor in a combined outdoor unit. While less common in residential settings than split systems, packaged systems are useful when indoor space is at a premium.

How Long Do HVACs Last?

HVAC systems have multiple components, each with a different lifespan. We've already discussed how long furnaces last: between 15 and 30 years, depending on the type. 

The other major component is the air conditioning unit. Air conditioners often need to be replaced more often than furnaces; they are located outside and exposed to extreme temperatures and weather conditions. On average,  air conditioning units last between 15 and 20 years.

If your HVAC system uses a heat pump, it will likely have an even shorter lifespan. Heat pumps are often used year-round, whereas air conditioners tend to be used seasonally. Greater wear-and-tear means heat pumps last around 10 to 15 years on average.

How Often Should You Change Your HVAC Filter?

As with furnace filters, the frequency of HVAC air filter replacement depends on the air filter type and efficiency, the environmental conditions, and specific household needs. For an in-depth exploration of when to change HVAC air filters, see How Often Should You Change Your Air Filter?

• MERV 1–4: These are often inexpensive fiberglass filters requiring monthly replacement.
• MERV 5–7: Change 1-inch pleated filters at least every three months; for non-pleated versions, more often.
• MERV 8–12: Change 1-inch pleated filters every 1–3 months and 4-inch pleated filters every 6-12 months.
• MERV 13+: 1-inch pleated filters may need changing every 2–3 months, and 4-inch pleated filters every 6-12 months.

To learn more about the differences between HVAC air filter types, see MERV 8 vs MERV 11 Air Filters and  MERV 11 vs MERV 13 Air Filters.

Do I Need a Furnace or an HVAC?

Deciding between a furnace and an HVAC system depends on your heating and cooling needs, your climate, and the features you want in your home's climate control system. Below, we outline who might need a furnace and who might benefit more from an HVAC system.

Who Needs a Furnace?

A furnace might be the ideal choice for homeowners or buildings in colder climates where heating is the primary concern for most of the year. Furnaces are designed to provide efficient and powerful heating solutions, making them suitable for places with harsh winters. They are particularly beneficial for:

• Homes in cold climates: If you live where winter temperatures regularly plummet below freezing, a high-efficiency furnace will keep you warm and comfortable.
• Budget-conscious homeowners: Those looking for a cost-effective heating solution might choose a furnace. While the initial installation and running costs can vary based on the fuel type, furnaces generally offer a reliable heating solution with a lower upfront cost than HVAC systems.

Who Needs an HVAC?

An HVAC system is suited for those who want a comprehensive solution to address both heating and cooling needs. It's ideal for:

• Homes in regions with varied climates: If you live in an area that experiences hot summers and cold winters, an HVAC system provides all-season comfort.
• New constructions or major renovations: Building a new home or undertaking a significant renovation presents an opportunity to install an integrated HVAC system. 
• Homeowners seeking improved air quality: HVAC systems include filtration and ventilation components that will enhance indoor air quality. They suit households concerned with allergens, dust, and air purity.

Ultimately, choosing between a furnace and an HVAC system hinges on individual needs, environmental conditions, and long-term comfort and cost considerations.

Frequently Asked Questions

What does HVAC stand for?

HVAC stands for Heating, Ventilation, and Air Conditioning.

How much is a new HVAC system?

The cost of a new HVAC system varies with the system's size, type, brand, and features. Homeowners should plan to spend between $5,000 and $10,000 for a complete installation. High-efficiency or systems with advanced technology features can increase the price, sometimes exceeding $10,000.

How much is a new furnace?

The price of a new furnace depends on the type (gas, electric, oil, etc.), size, efficiency rating, and brand. Generally, the cost ranges from $2,000 to $5,000, including installation. High-efficiency models and those with additional features may cost more.

How do you relight your furnace pilot light?

Relighting a gas furnace pilot light is straightforward, but it's essential to follow safety protocols:

• Locate the pilot light: The pilot light assembly and the gas valve are typically located at the bottom of the furnace.
• Turn off the gas valve: Rotate the gas valve to the "Off" position and wait at least 5 minutes for the accumulated gas to dissipate.
• Turn the valve to "Pilot": After ensuring no gas smell is present, turn the valve to the "Pilot" setting.
• If you have an automatic pilot light: Hold down the red pilot light button until it relights.
• If you have a manual pilot light: While holding down the reset button or the pilot control knob, use a long match or a barbecue lighter to ignite the pilot. Hold the button for 30 seconds to a minute after the pilot lights to ensure it stays lit.
• Check the flame: The pilot flame should be blue with a slight yellow tip. If it appears weak or goes out, you may need to clean the pilot orifice or consult a professional.
• Turn the gas valve to "on": Once the pilot light is steady, turn the gas valve to the "On" position to resume regular furnace operation.

If you encounter difficulties or the pilot light won't stay lit, it's safest to call a professional to inspect and repair your furnace.