Technological advancement has brought us a fair choice of heating and cooling systems. Now we can choose among various fuels, heat delivery options, control devices and more. Here are the basics of heating and cooling systems every homeowner should know. Also learn about available heating fuels and their pros and cons.


All home heating and cooling systems consist of three basic components:

  • Heat source or the central unit – the device which turns fuel into thermal energy in form of highly heated air, water, steam or oil. In oil heated system, this part of the system is the burner or furnace. In cooling systems it is the central air conditioning unit which chills the air or other liquid with a cooling gas.
  • Means of delivering heat to rooms – this includes room heating or air conditioning outlets such as radiators or registers and pipelines which connect them to the central unit.
  • Controlling devices – they allow you to control your system or its parts to work in accordance with your preferences. This can be a thermostat, remote control or in the latest heating system designs – smartphones, tablets and other connected devices.

Additionally, some heating systems have fuel storage units, such as oil or propane tanks.

gas-oil-furnacesHome central heating systems are built around furnaces. A furnace consists of a burner unit which initiates the flame and combustion chamber where the process of turning fuel into heat takes place. The burner unit consists of a pump which draws the fuel from storage or pipeline and ignition spark which burns it. Combustion chamber may further heat air which is delivered to room registers via ducts, or water which is delivered by pipes to radiators. Furnaces which heat water for radiator systems are commonly called boilers.

Electric heating systems are somewhat different in construction as electricity does not need pumping nor ignition. In combustion chambers there are heat exchangers, which are usually slim and long pipes made of copper or alloy with similar heat exchanging properties. Heat exchangers are exposed to direct flame which heats the liquid which passes through them.

Burners and heat exchangers are the most important and most sensitive parts of your heating system. These deteriorate as you use them and become less energy efficient with time. Their deterioration may be slowed down with proper maintenance.

Furnaces and boilers can last around 10 years, with oil heated ones able to serve you up to 20 years or more if properly maintained.

Some large urban areas have district heating networks, where “furnaces” are real factories which deliver heat to buildings. District heating allows for greater energy efficiency than individual systems, and ease of use for residents. However, they are available only in limited areas which are densely populated. For example, New York City steam system covers only some parts of Manhattan, and a possibility to expand it to Long Island has never been considered.


The most common heating fuels include:

  • Heating oil – Diesel fuel made for heating purposes.
    PROS: Very safe and easy to maintain. Leakages can be found quickly once they occur. Oil burners are relatively easy for handling. Modern-day heating oil is very clean, as it has very low amounts of sulfur. Oil burners can last very long with a proper maintenance. Many oil suppliers to choose from.
    CONS: Equipment requires annual maintenance checks. Not the cheapest of fuels, but there are tricks to buy oil at a relatively low price, such as ordering it during warm months or using oil price comparison services.
  • Natural gas – Delivered through pipelines. Has no color and nor smell, but refineries add odorants to make it noticeable if leaks.
    PROS: easy to use and calculate consumption. Little environmental impact.
    CONS: Its prices are unstable and can abruptly grow. High suffocation hazard from leaks. Dependence on a pipeline and a single delivery method.
  • Electric systems – can be either central or you can have plug-in heaters only when you need warmth.
    PROS: Easy to manage. Very clean and silent source of heat.
    CONS: Very expensive as an energy source, though it can be somewhat cheaper if used with certain billing plans.
  • Gases – like propane and similar to natural gas, but stored in tanks like oil.
    PROS: Cheap and clean, easy to use.
    CONS: Explosion and leakage hazard. As is a bit heavier than air, the leakage will mean that leaked gas will go to the ceiling and increase risk of a highly devastating fire. Recently became very expensive.
  • Coal – one of the oldest way to heat houses.
    PROS: Very cheap when compared to other fuels.
    CONS: Extremely dirty and unhealthy. Hard to manage and use in furnaces and boilers. Most commonly used in fireplaces. Most devices that burn coal can also use wood, but it’s less efficient.
  • Pellets – They are compressed particles of waste from wood processing, agriculture, virgin lumber or high energy crops. Stored in tanks and drawn by a pump into an electronically controlled burner unit.
    PROS: Easy to manage and control, very safe and relatively cheap.
    CONS: It is bulky and a whole tank is burned up quickly, so needs frequent delivery. Pellet heaters also require very frequent cleaning and other maintenance. Not the cleanest source of heat.

There are also some other fuels such as corn kernels, kerosene, gasoline and mazut. These are, however, mainly obsolete or dirty and phased out or used only for heating certain facilities. To learn more about Heating and Cooling please visit


room-air-conditionerAir conditioners are devices that chill the indoors using refrigerant agents such as R-410A or cold water. Air conditioner’s principle of work is called refrigeration cycle.

Refrigerant is compressed and condensed to achieve high temperatures and then is cooled by air to become liquid. Due to difference between its natural state and the temperature, this liquid is able to absorb heat once put through expansion valves and becomes gaseous again and ready for the next cycle.

It is clear that this cycle requires an external source of power, this is why air conditioners are powered by electricity or gas.

Some air conditioners are capable of reversing that cycle and can thus be used for heating. This way they act as an electric stove or furnace (if the air conditioner is central). In a climate with very cold winters and equally long and hot summers such as that of Long Island, this property of an air conditioner can be highly beneficial.