Heating Systems The average homeowner often improperly uses the term furnace when discussing their boiler. This same confusion happens with heat pumps. The difference between a Furnace, Boiler and Heat Pump:  | A furnace has a burner that heats the air and then blows it out of vents, sometimes called registers. You won't find any radiators if a furnace heats the house. Both a furnace and a heat pump use vents to discharge warm air in the house. | | A boiler heats by boiling water and making steam in a steam system. In a hot water system, a boiler heats water without reaching the boiling temperature, and circulates it through the pipes. The heated water or steam is sent through radiators to heat the house. | | A heat pump is a central air-conditioning system that works in reverse in the winter time. No matter how cold it is outside, there's always some heat in the air. The Freon in the heat pump can absorb this heat. The air is then blown over the Freon coils and the house is heated with warm air through the vents. |
The basic operation of a heating system is this: 1. The temperature in the house falls below the setting on the wall thermostat. The thermostat then engages the burner or heating coils to turn on. 2. The air or water is then heated in an area called a heat exchanger. Picture the heat exchanger as a box where the burner or heating coils are located and the air or water passes around this area and the heat dissipates. 3. From the heat exchanger the water or steam in a boiler system goes through pipes to the radiators to heat the house. In a forced hot air system, (FHA), the air is heated as it passes over the heat exchanger. The heated air then moves through the plenum, which is the area just above the heat exchanger, and it goes through the vents to heat the house. 4. When the temperature in the house gets high enough to satisfy the thermostat setting, the thermostat tells the heating system burner or coils to shut off. Advantages of different heating systems: | Forced Hot Air Systems: FHA systems have the benefit of being used for central air-conditioning with the same ducts. If the furnace fails in the winter, there are no heating pipes to freeze. However, the house water pipes will freeze unless they've been drained. You can remove dust from the air and humidify it with a FHA system. | | Steam Systems: Steam systems don't have water in the pipes that can freeze or leak. It doesn't dry out the air in the house. It takes a little longer to heat the house since the water must reach boiling temperatures of 212 degrees Fahrenheit first to make steam. | | Forced Hot Water Systems: Forced hot water systems heat faster than steam systems. You don't need to monitor the water level since the system is always filled with water. | | Heat Pump Systems: Heat pumps are central air-conditioning systems that work in reverse. They can remove dust and humidify the air. Heat pumps can be used as an A/C system in the warmer months. |
| | Disadvantages of different heat systems: | Forced Hot Air Systems: Forced hot air systems have one main drawback. That is, if the heat exchanger leaks, there will be lethal carbon monoxide and products of combustion coming out of the vents in the rooms. | | Steam Systems: Steam systems do not always have an automatic water feed on the system. When this is the case, the homeowner will have to monitor the water level in the boiler to make sure it doesn't get too high or too low. | | Forced Hot Water Systems: Forced hot water systems heating pipes can freeze if the heating system fails in the winter. Also, the pipes can leak over time due to rust and corrosion from constantly being filled with water. | | Heat Pump Systems: Heat pumps usually need a backup electric coil heater to assist them in very cold weather. This is because they may not be able to heat the house adequately in very cold weather. Heat pumps are mostly found in warmer climate areas and condo units. |
The three most common ways to fuel a heating system are: Oil, Gas and Electric. Heating systems generally have a life expectancy of 20-25 years. Heat pump compressors last about 7-10 years. Often heating systems will last longer, especially the old cast iron boilers. However, it's like an old used car, you never know when it can die. There will be many times that you'll find a heating system that is operating past its normal life expectancy. Just budget your funds to plan for a replacement in case the system dies in the near future. Take a quick look at the heating system just to get a feel for it before turning it on for the test. Check for a service card showing the last date of maintenance service for the heating system. The ceiling over the heating system should have a covering of sheet metal or 5/8 inch fireproof sheetrock to help prevent the spread of fires in this area. See if there's a data plate on the heating system stating how many BTU's it is. The total heating capacity of a furnace or boiler system is usually measured in BTU's (British thermal units) or tonnage. One BTU is the amount of heat that's required to raise the temperature of one pound of water by one degree Fahrenheit. One BTU is about the amount of heat given off by an old-fashioned wood match. An average single family house that's about 2,500 square feet in size should have at least a 125,000 BTU heating system to heat the house adequately. This number will fluctuate up and down based upon many factors. Some of the factors are: how many windows the house has, what type of insulation, if it's a condominium that has a heated condo attached to it on each side, the efficiency rating of that particular heating system, etc. The biggest factors generally are the square footage, the amount and types of windows and insulation in the house. These calculations must be carefully figured out by the heating contractor before they install the system. There will be times when you find a house with a heating system that's too small to adequately heat in cold weather. Also, if the house has a lower level then you may want to finish the basement to make a playroom. Another possibility is that you may be planning to put an addition on the house. Make sure you remember that if you plan to heat additional areas of the house, then you need to speak to a heating contractor. Have the heating contractor figure out if the existing heating system is large enough to heat the expanded areas. You'll also find houses with air-conditioning compressors that are too small to cool the house adequately. These types of problems are caused by an inexperienced contractor who didn't know what he was doing. It could also be caused by a homeowner who wanted to save a few dollars by installing a smaller heating or air-conditioning system. |
