Your NAHIPA Member Home Inspector will apprise you of the age of your
heating and cooling systems whenever possible.
Components of most heating and air conditioning systems have a design
life from 10 to 20 years, however poor maintenance practices may
significantly decrease that life expectancy.
Like most other components of a home, there are many ways to provide heat
to a house, both in means of fuel and delivery system, and some homes
even employ multiple systems.
In our area, most homes are heated by some type of furnace that converts
fuel to heat and distributes it throughout the home as warm air through
duct work, or as warm water through a hydronic delivery system.
But it is not uncommon to find heat pumps, wood burning or pellet stoves,
electric-resistance heaters or other methods being used to augment the
primary heating system, or sometimes as the primary heating system
Because even the most modern heating systems can pose health risks if
carbon monoxide backs up into the home,
it is essential that any recommendations your NAHIPA Member Home Inspector
makes regarding service or obtaining the opinion of a specialist be acted
Warm Air Systems -
Sometimes called forced air furnaces, warm air furnaces heat the home by
distributing warm air through duct work.
They are popular because the same ducts that are used to circulate air
for the heating system can also be used for air conditioning.
In addition, some modern gas fired units are designed to fit in closet
space or attics.
In most warm air furnaces, fuel is burned in a combustion chamber below a
The by-products of the combustion warm the heat exchanger before being
discharged outside of the home.
The system recirculates air within the home by drawing air through the
supply grills and filter.
A fan located near the heat exchanger then forces the air through the heat
exchanger and out into the home.
Warm air furnaces can be fueled by natural gas, oil, or propane, although
some have an electric-resistance heating element.
In addition, some may be configured to add outside air or humidity to the
air circulated through the home.
Warm Water Systems -
Hydronic systems use warm water distributed through pipes to various
Older systems may use cast iron radiators where many modern installations
use baseboard convector elements or pipes embedded in floors or walls.
Some installations also employ fans to blow air across pipes or coils to
help distribute the heat.
In most modern systems of this type, the fuel is burned below a cast iron
container or coil that holds water.
Although this is a closed system and the water is recirculated, most
hydronic systems have expansion tanks and automatic fill valves to maintain
proper water pressure.
A circulating pump distributes the warm water to the heating devices
through a network of pipes, forcing cooler water back through the return
Systems employing a tank keep warm water ready, within a specific
range of temperatures.
As cooler water returns to the furnace, the temperature in the tank drops
to the point where an internal thermostat signals the furnace to warm the
There are many variations to this type of system.
In addition to burning oil, natural gas, or propane, there may be multiple
sets of distribution and return pipes to allow for multiple heating zones
within the home.
Heat Pumps -
Heat pumps are sometimes confused with warm air furnaces.
They both heat the home by circulating warm air through duct work, but
that is where the similarity ends.
To over simplify, your heat pump is basically your air conditioner running
Heat from the exterior coil is transferred to an interior coil within your
air circulation system.
Air is circulated across the coil and into the home.
Other Heating Sources -
Although most homes use one of the methods mentioned above, some homes use
other methods as either primary or secondary sources of heat.
Wood and pellet stoves, electric-resistance, and solar.
Central Air Conditioning -
When a home with air conditioning is heated using a warm air furnace or
heat pump, a significant portion of the heating and cooling system are
usually shared, including the fan, thermostat, filters and ducts.
If a home is heated using another type of system such as a hydronic system,
central air conditioning can be provided as a separate system.
A central air conditioning system includes equipment both inside and
outside the home.
When the system is running, the refrigeration compressor outside moves
refrigerant to produce a cool coil in the air circulation
unit inside the home.
A circulating fan moves air across the coil, cooling the air and
causing condensation to form on the coil, removing moisture from
The condensation is then removed through a hose to the outside.
We conscientiously test and evaluate the heating and cooling systems in
accordance with our
standards of practice.
However, we do not dismantle and inspect items such as the heat exchanger,
evaporator coil, condensing coil, and other items that require evaluation
by a specialist.
Our inspection is that of a generalist, and is designed to identify
adverse conditions and significant defects that would warrant evaluation by
Therefore, it is essential
that any recommendations your NAHIPA Member
Home Inspector makes regarding service or obtaining the opinion of a
specialist be acted upon appropriately.