HVAC Services

HVAC Systems and Components

HVAC systems regulate the temperature and humidity of homes, offices, and large industrial buildings. HVAC Lexington also offers ventilation that mechanically removes stale air and brings fresh air.

HVAC Services

Property owners should look for equipment that’s less likely to break down or malfunction and systems that are easy to repair. They should also consider if the equipment requires extensive maintenance to keep it functioning efficiently.

Heat pumps are efficient alternatives to traditional furnaces and electric-based systems. They don’t create heat – they simply redistribute the existing heat in your home, saving you money on energy bills and helping reduce carbon emissions. Using a reversing valve, they can switch between heating and cooling mode to cool or warm your home, depending on the season.

A heat pump system is composed of an outdoor unit, which looks similar to the unit in a typical split system air conditioner (though it’s slightly larger), and an indoor fan coil that functions as the air handler. The unit also contains a compressor, which moves refrigerant through a cycle that uses the air in your home to transfer the heat.

The process is simple based on thermodynamics, which states that heat naturally flows from high-temperature areas to low-temperature ones. Your heat pump takes advantage of that by transferring heat from the ground or air into your home, or vice versa.

In your home, the air is pulled into the ductwork by a fan and passed over an evaporator coil, where heat is transferred to the refrigerant. The refrigerant is then sent to the outdoor unit, where a fan blows outside air over the condenser coil to dump the heat and make the cycle start over again.

This allows your heat pump to run efficiently, cooling your space and providing supplemental warmth when it’s cold. In fact, it requires only about half the electricity as a traditional gas furnace. It’s important to note that heat pumps lose efficiency when it’s very cold, so they should be used with a backup fossil fuel heater if you live in an area where winter temperatures regularly drop below freezing.

If you’re considering a heat pump for your home, contact your local Carrier dealer to help you evaluate the size of your space and climate. They will be able to recommend the best system for you. If you’re already using a heat pump, they can also provide maintenance to keep it running at peak performance. Whether you have an air-source, water source or geothermal heat pump, your technician will be familiar with the system and will know how to identify any problems that may arise in piping, underground equipment or within a unit that’s not easily accessible.


Furnaces are the most common source of heating for homes in North America. They provide a clean, efficient, and economical way to heat your home. They operate using the combustion of solid, liquid or gaseous fuel and can also use electrical energy in the form of resistance heating (Joule heating) or direct current (DC) electricity.

The most common type of furnace is a natural gas or oil-fired unit that is connected to a forced air distribution system that distributes heated air throughout your home via ductwork. These systems are often paired with central air conditioning and in some cases with a heat pump to keep your home comfortable year-round.

Your furnace is a major part of your HVAC system and serves several important purposes including air temperature regulation, regulating humidity, and keeping the indoor environment clean. A carbon monoxide detector is also required for your safety and should be checked regularly to ensure that there are no leaks from the system.

When the thermostat signals that it is time to warm your home, gas valves open and the ignition switch is activated. The gas is drawn over the igniter and combusts to produce hot gases that heat the exchanger. The cooled exhaust gases are then vented outside through the flue or chimney.

A separate vent pushes colder ambient air into the furnace and is mixed with the heated air from the heat exchanger. A blower fan then spreads the conditioned air throughout your home through ductwork. The blower fan can run at multiple speeds to increase efficiency.

Most modern furnaces are designed to maximize efficiency and operate with minimal noise. They may be single or two-stage and rated for annual fuel utilization efficiency (AFUE) of up to 98%. AFUE is a measure of the efficiency of your furnace and includes both peak and part-load efficiency, taking into account start-up, cooldown, and operating losses. The more efficient your furnace is, the less fuel it will use to heat your home. The higher the AFUE rating, the more money you will save on your utility bills.

Air Handlers

Air handlers are a key component of your HVAC system. They work in tandem with your air conditioner condenser and heat pump to ensure you have consistent temperatures throughout your home. An air handler consists of an evaporator coil, blower motor and air filter. It also has various electrical and electronic components to improve your indoor comfort and overall efficiency.

Essentially, the air handler acts like a delivery truck for your heating and cooling system. The air conditioner condenser, located outside on a concrete slab, compresses refrigerant and delivers it to the evaporator coil inside the air handler. As warm indoor air passes over the evaporator coil, the refrigerant evaporates and cools the air in your home. The air handler then circulates this conditioned air through your home’s ductwork.

In addition to distributing cooled air, an air handler may have a heater coil for supplemental heating in the winter. This is why an air handler is sometimes referred to as an “air furnace.”

Your evaporator coil inside your air handler is often covered in a layer of water or glycol to prevent it from freezing. As the evaporator coil absorbs refrigerant, it also removes humidity and cools the air. This is then delivered to your ducts and homes, delivering comfortable temperatures in all rooms.

The air handler contains a blower motor to drive the air through your home’s supply and return ducts. It also houses an air filter to trap particulates such as dust, mold and bacteria. These contaminants can cause breathing difficulties and affect your heating and cooling system’s performance.

Other features of an air handler include dampers to control the ratio of return and outside air to mix with the conditioned air. In some cases, an air handler can be equipped with a multi-stage or variable speed motor for enhanced energy efficiency and comfort.

While some HVAC systems use an air handler to condition and circulate cool air, other systems don’t require them at all. This depends on your system type and the dynamics of your house’s ductwork. Our Hoveln technicians can assess your system and help you determine whether an air handler is required.


Thermostats are the familiar devices we use to control the temperature in our homes and buildings. They are designed to maintain the preferred (or set) air temperature in a room by sending an electrical signal to the heater when the thermostat senses that the air temperature has fallen below the desired setting. The heating system then fires up to bring the room back to the set temperature. Most commonly, we use them to control electric baseboard heaters, but they can also be used to control gas, oil, or forced hot water heaters. These thermostats may also contain a mechanism called a heat anticipator, which prevents the heater from switching off too soon.

While bimetallic thermostats are still in some use, most newer systems utilize a digital display and microcontroller to measure the temperature. Some of these systems, such as the XR724 offered by Trane, are energy-efficient smart thermostats that provide up to 30% savings on your energy bill when left at their default programs.

In these digital systems, the thermistor or semiconductor device measures the temperature, and the microcontroller then converts this information to a digital value. The display screen shows the current room temperature, and some also show time-of-day or day-of-week settings for the temperature. Some digital systems can also detect when your home is occupied or unoccupied, and can adjust the set point accordingly to save energy.

When you select a new thermostat, make sure it is the right size for the space where it will be installed. Then, carefully follow the installation instructions and photos in the user manual to wire it up. Make sure you follow industry standards for color codes, and double check that the connections are secure. After completing your installation, turn the HVAC power back on at the main breaker.

Some homeowners are reluctant to make the switch to programmable thermostats and system zoning because of the initial cost. But RetroZone has developed an affordable alternative to a traditional zoned system that uses the existing ductwork and combines it with a programmable thermostat and air pumping system.