What Does HVAC Stand For? Heating, Ventilation, Air Conditioning

HVAC stands for heating, ventilation, and air conditioning. It is the umbrella term for the systems that heat, ventilate, and cool a building. In southern New Hampshire, a home may have all three functions in one system or use separate equipment for heat, cooling, ventilation, and humidity control.

See the EPA approach to source control, ventilation, filtration, and moisture control.

H is for Heating

The heating side covers any equipment that produces or distributes warmth. Common NH heating systems include:

• Furnaces: burn natural gas, propane, or oil to heat air, distributed through ductwork. Most common in homes built after the 1950s.
• Boilers: heat water that circulates through baseboards, radiators, or radiant floor tubing. Common in older NH homes.
• Heat pumps: move heat from outside to inside, or reverse for cooling. Modern cold-climate units work efficiently down to well below zero.
• Electric baseboard and resistance heat: simple and reliable but expensive to run. Often used as backup with a primary heat pump.

V is for Ventilation

Ventilation gets overlooked, but it matters more as homes get tighter. Air sealing and modern insulation save energy while trapping pollutants, moisture, and odors inside. Ventilation equipment includes:

• Bathroom and kitchen exhaust fans: remove moisture and cooking odors at the source.
• HRVs and ERVs: exchange stale indoor air for outdoor air while transferring some heat, and with an ERV, some moisture, between the air streams. They are used in many tight or high-performance homes, but the ventilation design depends on the building and applicable code.
• Whole-house exhaust ventilation: a continuously running fan that pulls air out, with makeup air drawn in through controlled inlets.
• Air filtration and purification: often integrated with the duct system, including media filters, UV light, and electronic air cleaners.

AC is for Air Conditioning

Air conditioning removes heat and moisture from indoor air. While "AC" once meant a separate cooling system, modern equipment increasingly combines heating and cooling in one unit (a heat pump).

• Central air conditioners: an outdoor condenser paired with an indoor coil and air handler, distributing cooled air through ductwork.
• Ductless mini splits: an outdoor unit paired with one or more indoor heads, no ductwork required. Popular in older NH homes without ducts.
• Heat pumps: as noted above, provide both heating and cooling from a single system.
• Dehumidifiers: sometimes integrated to manage NH's humid summers, especially in finished basements.

How the pieces work together

A home's comfort system may include heating, cooling, distribution, controls, source exhaust, whole-home ventilation, filtration, and humidity control. The right combination depends on the building, occupants, existing equipment, and the concerns the homeowner wants to solve.

Need help with your HVAC system?

If your heating, cooling, or ventilation equipment is past its prime, or you are not sure what would fit your NH home, contact A.J. LeBlanc Heating or call 603-623-0412. Serving New Hampshire families since 1928.

Frequently Asked Questions

What is the difference between HVAC and AC?

HVAC covers heating, ventilation, AND air conditioning. AC refers specifically to the cooling portion. A central AC is part of an HVAC system; the HVAC system is the whole picture.

Is a furnace the same as a boiler?

No. A furnace heats air and distributes it through ducts. A boiler heats water and distributes it through pipes to baseboards, radiators, or radiant floors. Different distribution, different equipment.

Do all HVAC systems include ventilation?

In older NH homes, often no. Many rely on incidental air leakage, which is not ideal in tight modern homes. More new homes now include a dedicated HRV or ERV for controlled ventilation.

How long does an HVAC system last?

Service life varies by equipment, installation, runtime, environment, maintenance, condition, and parts support. We inspect the system and judge repair or replacement from its actual condition and performance.

How do I know if I need a new HVAC system?

Common signs include rising energy bills with no change in habits, uneven temperatures between rooms, more frequent repairs, equipment past its expected lifespan, and excessive noise. A licensed HVAC contractor can assess your system and give you honest options.