A Guide to HVAC Unit Types & Sizes

If you’re a homeowner, especially a new one, it’s important to know what kind of HVAC system you have and what the right sized unit is for your home. If the time comes that your unit needs to be repaired or replaced, it would be helpful to have an idea of your home’s specific needs. As a responsible homeowner, you should always do your homework. The team at A/C Masters is here to help with this guide for HVAC systems. 

There are four general categories that most HVAC systems fit into: 

  • Split System 
  • Ductless System 
  • Heat Pump 
  • Packaged System 

Split System 
The Split System is exactly that, a system that is split between an outdoor and indoor unit.  The outdoor unit contains the condenser and compressor whereas the indoor unit contains the evaporator coil and blower. The indoor unit is often connected to a furnace or heat pump.  Split-system central air conditioning is the most common type of heating and air-conditioning for residences, it also happens to be the least expensive to install. 

Ductless System 
The Ductless System is one of the easiest to install and one of the most reliable systems.  This system type consists of an indoor unit with a fan, a coil and an outdoor compressor; there is a mini-sized version of this type, which provides superior heating and cooling with the added benefits of energy efficiency. This comes at the cost of being able to cool only one specific zone (room). This system type is often operated via remote control. There is also the multi-split indoor unit, which offers the same amenities, the difference is that the multi-split indoor system can be expanded to cover five zones. Another variation, the multi-split outdoor unit, is very much the same as the multi-split indoor unit, with the single exception of control of each zone individually. These systems are a great solution for spaces where conventional duct-systems aren’t compatible. 

Heat Pump 
Despite the name, Heat Pump systems aren’t only for heating; they’re for cooling, too. This is enabled by the design of the pump, which allows the system to cool via a special valve. It keeps the indoor air temperature cool during warmer months; and when reversed, will keep the indoor air temperature warm during the colder months. To do this, the system draws air from the outside or the ground; the drawback is that, when temperatures dip too low, the heat pump isn’t as efficient. This is where the Hybrid Heat Pump System comes in handy, it consists of an electric heat pump that works in tandem with a furnace that runs on burning fuel. When it gets too cold for the heat pump to work as efficiently, the furnace takes over.  These are reliable systems and are generally very efficient. 

Packaged System 
The Packaged System is an all-in-one unit that provides heating and cooling, utilizing q compressor, condenser and evaporator.  These units are usually located on a roof or near the foundation and are ideal for homes or offices that don’t have the space to house the split system. Packaged systems have four system sub-types: heat pump, gas and electric, duel fuel and air conditioning. 

Size Matters 
HVAC units are sized to the amount of cubic feet that they need to heat and cool in a space. If your unit is sized properly, it can have a big impact on energy consumption and heating and cooling costs. If your system is rated for a smaller space than your home, then it will struggle to meet the heating and cooling demands; causing it to work too hard, which will make it wear out faster. If a system is over-sized, it could short-cycle. 

The proper sizing of a residential system depends on factors such as heat loss and gain, ductwork and sunlight. The use of tonnage to floor area ratios is common practice, but tends to be inaccurate in determining sizing needs. The use of the “Manual J” is more accurate, with room-by-room load calculations and air-flow requirement estimates for each area of the house.  The following is an estimation chart for tonnage based on square footage. 

  • 1.5 tons – 600 to 1100 square feet
  • 2-tons – 901 to 1400 square feet
  • 2.5-tons – 1201 to 1650 square feet
  • 3 tons – 1501 to 2100 square feet
  • 3.5 tons – 1801-2300 square feet
  • 4 tons – 2101 to 2700 square feet
  • 5 tons – 2401 to 3300 square feet 

If you think your system may not be the correct size for your space, you are looking to get a new system or you have any questions, contact A/C Masters at 757-898-2894. Our certified technicians are available for emergency service 24/7.