Forced Hot Air Heating
- Forced hot air heat is one of the most common types of heating used. The two main types used are gas fired and oil fired. These furnaces have an average lifespan of 20 – 30 years. The best thing you can do to maintain healthy household air during the heating season is to use a high efficient filter and to change it regularly (every 2 – 3 months). Most people use the blue fiberglass filters (7 – 8 % efficient). These filters stop only the largest of airborne particles and hair. They let everything else pass through to recirculate around your house making them essentially useless. The best type of filter to use is the highest efficiency disposable filter you can find. We recommend the 3M Filtrete disposable furnace filter. The top version of this filter is 90 – 95% efficient for dust and allergens and does a good job of keeping your house air clean. Filters must be the proper size. A filter that is smaller than the opening it is designed for allows dust particles to recirculate. Filters have a directional arrow on the side to indicate which direction the filter must be installed.
- It’s a good idea to set up some type of service contract with the gas company, oil supplier, or an HVAC professional to service your furnace regularly. Oil fired furnaces and boilers require yearly service to keep them working properly. An improperly maintained oil fired furnace or boiler can experience problems with oily soot buildup on the burners and result in incomplete combustion or possible carbon monoxide buildup in the house. Another possible result of an improperly maintained oil fired system is a puff back. A puff back occurs when there is a buildup of oil soot in the burner chamber from lack of maintenance. During the next call for heat, the system fires and blows the oily soot buildup out of the furnace and into your house.
Boilers / Radiator & Baseboard Hot Water Heating
- Radiator or baseboard hot water heating coupled with a hot water boiler is another common type of heat source. The concept for this heating is actually quite simple. Think of a hot water boiler (either gas or oil fired) as a big pot of water. When the burner compartment in the boiler turns on, it heats the water and moves it through the piping system and to the radiators. The radiators absorb the heat from the water in the pipes and heat the rooms in your house. There is no air filter with these types of systems. These systems should also be maintained with some type of service contract.
- There are a few things you can monitor on your boiler to be sure it is operating properly. One is the pressure gauge. Boilers have pressure gauges to measure the operating pressure of the system. A house with two floors should have a standing pressure in the boiler of 12 at least psi (pounds per square inch). Standing pressure refers to the pressure in the boiler when the system is idle or not running. A house with three floors should have a standing pressure of 17 psi. If the standing pressure is too low, it could mean the pressure gauge is defective or the system needs to have water added. When the system is operating and the boiler is firing, the pressure gauge should rise slightly, maybe one pound or so. If the pressure increases too much, it may mean that the expansion tank for the boiler is waterlogged and needs to be partially drained. If the pressure drops, it means there is a leak somewhere in the system and service is required.
- If you notice uneven heating on the surface of the radiators (hot and cold spots), it may mean there is not enough water in the system or there is air in the pipes. Individual radiators can be “bled” to release air in the pipes through a valve stem on each radiator. The valve is opened to release air and closed once water comes out. Bleeding the radiators should be done at the beginning of each heating season. Start at the radiators on the lowest floor of the house and work up to the highest floor.
- If leaks are noticed anywhere in the system (radiators, piping system, or boiler) contact an HVAC professional to service the boiler.
- Boilers also have what is known as a temperature & pressure relief valve (TPR). Its purpose is to discharge water from the boiler if the internal water temperature of the boiler exceeds 210 degrees F or 30 PSI. If water temperatures or pressures were allowed to exceed these points, the boiler could become damaged or worse, the boiler could explode. The TPR valve should have a directional pipe installed that points towards the floor and ends about six (6) inches above the floor. This helps prevent anybody standing nearby from getting burned with scalding water if the TPR valve were to open. This exhaust pipe should never be capped or plugged shut.
- Heat pumps are either split or single package systems that both heat and cool a house. In heat mode, the compressor, which sits outside the house, circulates liquid refrigerant through the piping system and absorbs heat from the outside air. Liquid refrigerant boils at extremely low temperatures (-40 degrees F) and therefore can absorb heat from air that seems cold. The heated refrigerant then runs to a coil inside the indoor air handler and has air blown over it from the air handler fan. The heat picked up from the heated refrigerant blows through the duct work and heats the house. Heat pumps are very efficient systems but draw some complaints from people not used to them. Standard gas and oil fired furnaces produce output air of 130 degrees. Heat pumps produce output air of approximately 90 degrees which feels cool to the skin but is high enough to raise the temperature in your house. When outdoor weather conditions get extremely cold, the heat pump loses efficiency and produces cooler air. It will still hat your house but it will do it more slowly. Heat pumps have an emergency backup mode to provide heat in case the heat pump system fails. The emergency heat is typically electric and is located within the supply plenum of the air handler and is very expensive to run full time. Some systems may have oil or gas heat installed and used as the emergency backup heat source. Do not run a heat pump in heat mode when the outside temperature is above 80 degrees F. Doing so can damage the unit. Likewise, do not run a heat pump in cooling mode when the outside temperature is below 60 degrees F. Doing so can damage the unit.
Summer/Winter Hook-Up Systems
- Summer/winter hook-up systems employ a gas or oil fired boiler to heat hot water for radiator or baseboard heating. They also provide the hot water for your house and eliminate the need for water heater tank. Since this type of system is in use year round, even when there is no need for heat, it is called a summer/winter hookup. The hot water supplied by the boiler for personal use is the same temperature as the water used to provide heat. Therefore, the output temperature of hot water at sinks, faucets, and bathtubs in the house can exceed 150 degrees. This is a very dangerous temperature that can result in instant scalding and burning of exposed skin. To prevent accidental scalds, a tempering or mixing valve should be attached to the main hot water supply line. The tempering valve mixes cooler water with the hot water from the boiler to reduce the temperature of personal use hot water to a safe level.
- Summer/winter hook-up systems also have a temperature & pressure relief valve (TPR). Its purpose is to discharge water from the boiler if the internal water temperature of the boiler exceeds 210 degrees F or 30 PSI. If water temperatures or pressures were allowed to exceed these points, the boiler could become damaged or worse, the boiler could explode. The TPR valve should have a directional pipe installed that points towards the floor and ends about six (6) inches above the floor. This helps prevent anybody standing nearby from getting burned with scalding water if the TPR valve were to open. This exhaust pipe should never be capped or plugged shut.
- Either an electric furnace or electric baseboards generate electric heat. Both systems are considered to be efficient because the electricity you pay for with them is converted 100% into heat and none of the heat is lost up a chimney. However, electric heat is expensive to run as a primary heat source and can result in high electric bills. Electric furnaces use a coil with electric toaster-type elements that heat up. Hot air is then blown over them to be circulated around the house. Electric baseboard heaters use an electric element that heats up and delivers heat to the rooms by means of natural convection. No gas or oil is needed for either of these systems as electricity is the heat source. Electric baseboard heaters must be installed properly in order to provide adequate heat. These heaters provide heat through convection (cold air falls and warm air rises) and therefore, need to be installed with the opening at the bottom of the baseboard unobstructed. Combustible materials, papers, curtains, and furniture should be placed an adequate distance away from electric baseboard heaters to prevent a fire hazard. Wall-to-wall pile carpeting with padding underneath can block the opening at the bottom of baseboards and prevent the proper flow of air around the baseboard heating fins. This applies to hot water hear baseboards as well.
Duct Work / Pipes & Circulators
- Duct work is a system of air vents that are piped throughout the house to deliver heated air to different rooms in a house with a forced hot air furnace. Some duct systems have dampers built into the ducts to allow you to balance the system and reduce the amount of heat flowing into a certain room. It is a good idea for people with allergies or sensitive respiratory systems to have their duct work professionally cleaned and vacuumed. Ducts accumulate dust concentrations over years of use and if a central A/C system is in place, mold spores could be present from the moisture.
- Heating systems that use boilers to provide hot water heating use pipes and a circulator pump instead of duct work. The circulator pump moves the heated water through the piping system and the pipes carry the heated water to the radiators or baseboards.
- The heating thermostat is typically located in the main living area of the house and should be visibly mounted on a wall. The thermostat should not be located in an area that is particularly drafty, hot, or in direct contact with sunlight coming through a window. Installations in these areas can result in an overheated or underheated house due to false readings of the actual temperature of the house. Some houses that have more than one heating zone have more than one thermostat. A good idea for any household is to replace a single mode thermostat with a programmable setback thermostat. These thermostats allow you to program the heat cycles to fit your lifestyle. You can program it to automatically drop down to 62 at bedtime, rise to 68 when you get up for work, drop to 62 when you leave for work, and rise to 68 when you return home. Setback thermostats used in this manner can save 10 – 15% or more on your annual heating bill. Heat pump thermostats are different from thermostats for boilers or forced air furnaces. They are designed to only allow temperature increases of 1 – 2 degrees at a time in heat pump mode. Moving the thermostat setting for a heat pump any higher than this at one time will trigger the emergency heat mode to activate. Emergency heat mode on the thermostat is indicated by a red light. To prevent this from happening and paying for expensive electric heat, move the thermostat up only one (1) degree at a time or remove the thermostat cover to expose the mercury bubbles. The heat lever will have two (2) mercury bubbles. The bottom bubble controls the heat pump and the top bubble controls the emergency backup. Move the heat lever just enough to activate the heat pump without activating the backup. Heat pumps are at their most efficient when their thermostat is set at your desired temperature and left alone. Special setback staging thermostats are available for heat pumps. They are programmable and increase your house temperature 1 – 2 degrees at a time before cycling up and raising the temperature again. This allows for large temperature increases without activating the emergency backup heat.
- All fossil fuel fired furnaces and boilers require an adequate combustion air source in order to burn their fuels properly and efficiently. Examples of fossil fuels are any type of gas, oil, or coal.
- Standard mid efficiency furnaces and boilers draw their combustion air from the square footage of your house. If one of these furnaces is installed in a utility closet or an enclosed area with a door, the door or wall to the enclosed area must have at least two vents in place to allow the furnace to draw combustion air. If a furnace cannot draw adequate combustion air due to lack of ventilation, it will draw its combustion air by pulling air out of the chimney flue. When this happens, combustion gases that contain carbon monoxide are drawn back into the living area and recirculated throughout the house. An easy solution to provide adequate combustion air to a furnace or boiler in an enclosed area is to change the door for the enclosed area to a louvered door.
- High efficiency furnaces and boilers are equipped with provisions to draw their combustion air from outside the house. This is accomplished by running PVC pipe through a hole in the house wall to the outside. The pipe attaches to a receiver on the furnace cabinet that runs to the furnace’s sealed combustion chamber. No house air is used for combustion air in this type of set up. This allows high efficiency furnaces and boilers to be installed in enclosed areas without ventilation.