Heating and Cooling Systems - Furnace and Heat Pump Replacement Tips

Sooner or later you will replace your heating andsecured flexible air ducts may leak and may work
cooling system. Furnace and heat pump airloose from the plenum.
handlers have a useful life of about twenty years.6. Do not bend a flexible air duct so that it
Air conditioning condenser useful life variesreduces the diameter of the duct. An air duct is
between five and fifteen years. The condenser islike a garden hose. If you kink a garden hose, the
the outdoor unit. If you need to replace yourwater flow is reduced. If you kink a flexible air
heating and cooling system, here are some tips toduct, the air flow is reduced. Reduced air flow can
ensure that your system provides safe, energycause the system to work longer to heat and
efficient, and green operation. These tips apply tocool your home. Reduced air flow can also cause
gas and electric forced-air systems.comfort problems in rooms. Improperly installed
flexible ducts are a common problem.
1. Comply with all local building codes and7. Install an overflow pan or condensate cutoff
manufacturer's instructions when installing yourswitch under air handlers with evaporator coils
new equipment. You should obtain a building permitlocated in attics and anywhere else inside the
and have the new installation inspected, but this ishome where leaking water could cause damage.
seldom done. A qualified and licensed contractorExtend a ¾ inch diameter pipe from this
should know and comply with local building codespan to a visible location outdoors. If you see
and with manufacturer's instructions.water coming from this overflow pipe, there is a
2. Install new equipment that has the highestproblem. Call a qualified contractor to locate the
energy efficiency rating that you can afford. Theproblem.
energy savings from a high efficiency system will8. Install a 3/4 inch diameter drain pipe from the
often save you more over the system's life thanevaporator coil to the outside or to a plumbing
the additional cost. Higher efficiency systemsdrain. Slope the pipe down toward the discharge
qualify as green and add value to your home.point over its entire run. Insulate this pipe if you
They may also qualify for government and utilitylive in a warm and humid climate. Water that
rebates.flows in this pipe is cold and can cause
3. Replace both the furnace or air handler and thecondensation on the pipe's exterior. This
condenser, even if the furnace or air handler stillcondensation can damage materials and provide
works. An air conditioner condenser andmoisture for mold.
evaporator coil (the inside and outside units) are9. Replace the circuit breakers for the condenser
designed to work best as a system. You mayand air handler if the recommended circuit breaker
not receive the full energy efficiency of the newrating for the new equipment is different from
condenser if it is connected to an old evaporatorthat of the old equipment. It is common that new
coil. An improperly matched condenser andequipment is more energy efficient than the old
evaporator coil may be highly inefficient and resultequipment and needs less power to operate. More
in higher than necessary energy use.energy efficient equipment usually needs a circuit
4. Use mastic to seal all joints. Do not use ductbreaker with a smaller rating.
tape. You may use foil tape at joints, but mastic10. Confirm that the air ducts are the proper size
is better. These joints include where: theto work with the new system if you are adding
evaporator coil connects to the air handler, theair conditioning to a home without air conditioning
supply plenum connects to the evaporator coil,or if you are changing from one type of system
the return plenum connects to the air handler, andto another. For example, air ducts sized for an old
the air ducts connect to the plenum. Supply andoil-fired furnace may not be properly sized for a
return plenums are rectangular metal boxeshigh efficiency gas-fired furnace. Improper air duct
where the ducts connect to the air handler. Jointssizes may affect system energy efficiency and
and ducts that leak air can significantly reduce themay cause comfort problems.
energy efficiency of your system and increaseA new furnace or heat pump can provide many
operating costs.years of safe and energy efficient service when
5. Connect flexible air ducts to the plenums usingproperly installed. By using these tips you can
both foil tape and plastic straps. Improperlyensure proper installation of your new system.