subject: A Comparison Of Ducted Heating And Hydronic Heating [print this page] A heating system is a long term investment from which one should expect many years of trouble free use. Installing a system is a costly affair and one must weigh the options available and the pros and cons before making a decision to avoid costly rework or disappointment at a later time. Here we compare two popular and time tested systems, ducted and hydronic heating.
The main difference between these two systems is the physical principle by which they heat the rooms. Heat can be transferred by two methods, by convection or radiation. Convection is a process of transferring heat through a medium, for example, air. Radiation is the method by which we receive heat from the sun. It does not need a medium to carry it. Ducted systems use warm air as a medium for heating a room and hydronic systems rely mostly on radiation to transfer heat.
Principle of Ducted Heating
Ducted heating system circulates the air in the room through a heater where it is warmed. The warm air is then released back into the room via outlets. This is similar to how an air conditioner cools the room.
Heat is generated in a central heating unit which is installed either on the roof, under the floor, or outside. There is a network of concealed ducts which runs from the heating unit to strategically positioned air outlets inside the building. Warm air is circulated through the ducts and released through the outlets into the rooms which require heating. Natural gas is the preferred heating fuel for this system.
Advantages:
* Cheaper to install, initial investment is lower.
* Heats the rooms quickly.
Disadvantages:
* It is less energy efficient than hydronic.
* It alters the air pressure and air flow in the room which affects the return path of air back to the heating unit. Hot air is also lost thorough unsealed cracks and openings thus reducing heating efficiency.
* Room temperature is not even. The areas near the outlet are warmer than areas further away from the outlet, thus reducing the comfort level.
Principle of Hydronic Heating
This system heats the room by using radiant heat. This heat radiation transfers heat evenly throughout the room. It warms not only the air, but also the objects placed in the room as well as its occupants. This keeps the room warm for a long time.
The heat is generated in a heating unit which can be powered by electricity, solar energy, wood, natural gas, or LPG. The heating unit generates hot water which is then circulated to radiator panels, under floor heating coils, or a combination of both using pipes. The heating unit can be located inside or outside the building and its operation is regulated by using a thermostat. The water is circulated through the pipes and the heating unit operates till the desired room temperature is reached.
Advantages:
* Warms the room and its occupants.
* The focus of heating is on the room and not just the air, so it reduces what is known as air temperature stratification, the natural tendency of hot air to rise and getting cooled at the ceiling, resulting in loss of heat through the ceiling.
* Heats the room evenly.
* Due to the even heating, the system can provide sufficient warmth while operating at a lower temperature thus saving fuel costs.
* Lower operational costs, thus saving costs in the long run.
* No air flow dependence means less dust blowing about and thus it is safe for people with allergies.
* It can be installed in stages.
Disadvantages:
* Higher initial cost.
As is apparent from the above discussion of ducted heating vs hydronic heating, both these central heating systems have their pros and cons. Choosing one over the other depends upon the budget and whether one is taking a long term or a short term view.
