The applicable Codes require that “habitable spaces” have permanently-installed heating that can maintain a room at 68° F. 3′ above the floor and 2′ from exterior walls. Note that air conditioning is not required, and that bathrooms are not considered habitable space. This is where a difference between Home Inspectors and Code officials comes into focus. While there are complicated loopholes that may (or may not) make bathroom heat a necessity, we should be reporting to our clients when a bathroom is not heated, or when AC is poorly distributed.
In this component we will be looking at the distribution systems for conditioned air (ducts) and for hot water/steam (pipes). While there has been some evolution in distribution materials and methods, hydronic and steam heating remains fairly straightforward. However, the Code’s increased emphasis on energy concerns has affected forced air systems significantly, and for the better. In the past, the nominal leakage of conditioned air from the ducts was 25-30%. Now we expect properly sealed, correctly sized, insulated distribution. Overall system balance is needed. In colder climates, leaking ducts and over-pressurized rooms can lead to serious condensation and mold problems.
Inspect the visible ductwork for damage, separations, inadequate support, and missing or deteriorated insulation. All supply outlets should have adjustable registers, and returns have grills. When you are closing a room’s door with the system running, there should not be a strong breeze that pulls the door shut; this indicates an unbalanced distribution and over-pressurized spaces. Always take an opportunity to look into ducts when possible, especially floor ducts and returns. A large amount of dirt, including construction debris, toys, and water damage can be found. Remember: supply and returns are not permitted in garages, and returns must not be close to the combustion heating plant.
There is a finished area which is missing a permanent heat source. All finished and habitable spaces require a permanent heat source. Hire an HVAC contractor to evaluate the system and to make required repairs.
There are distribution registers in the garage. This is safety hazard that permits automobile exhaust fumes to be drawn into the system and enter the living area. Remove or permanently seal the registers.
There is flexible (non fire rated) ductwork in the garage. In the case of a fire, there is no protection for the ducts entering the ceiling; fire could get into the living space above. This is a safety hazard. Hire an HVAC contractor to evaluate the system and to make required repairs.
There are fuel lines or plumbing pipes installed through ductwork. This is unsafe in the event of a leak. Hire a plumber or HVAC contractor to make the required repairs.
There is a return opening which is improperly located. A return cannot be too close to open combustion appliances due to the risk of back-drafting or causing combustion gases to enter the living area. Hire an HVAC contractor to relocate the return opening.
The ductwork is damaged This causes the loss of conditioned air. Hire an HVAC contractor to make the required repairs.
The ductwork is separated. This affects proper distribution and permits loss of conditioned air. Hire an HVAC contractor to make the required repairs.
The ductwork insulation is missing or damaged. This reduces system efficiency and causes condensation problems. Hire an HVAC contractor to make the required repairs.
The ductwork is inadequately supported. This allows damage to the ducts and reduces airflow. Hire an HVAC contractor to make the required repairs.
The ductwork system is very dirty. This affects efficiency and can be a health hazard. Hire an HVAC contractor to make the required repairs.
There are damaged or missing supply registers. The airflow cannot be properly controlled. Replace the registers.
The HVAC air filter is dirty and is restricting the air flow. Replace the filter.
The HVAC system air filter is missing. This allows dirt to circulate through the house. It will also collect in the HVAC system and affect performance. Replace the filter.
The HVAC air filter is collapsed. This allows unfiltered air to circulate through the system and may cause damage to the blower fan. Replace the filter.
The HVAC air filter is the wrong size for the system. Some of the conditioned air is not being filtered. Install a properly-sized filter.
The HVAC air filter has been installed backwards. Air filters are designed to filter air in one direction only. A reversed filter will not filter the air correctly. Reverse the filter.
The HVAC air filter enclosure is not properly secured or sealed. This can affect efficiency, as well as filtering performance. Repair and seal the enclosure.
Many original hot water/steam distribution systems, often 100+ years old, are still in reliable service. The cast iron and threaded steel pipes do not deteriorate as do potable water lines. In a hydronic system, the water becomes “dead” after being in the pipes a while: it has very little free oxygen in it to contribute to the oxidation process. This is why it’s bad practice to drain down and refill the piping unless absolutely necessary. It just introduces fresh oxygen. The reliability exception is radiant floor heat using copper pipes in a concrete slab. These should be considered at or past the EUL. Modern hot water radiant distribution uses special PEX tubing with an oxygen barrier. These are installed under the wooden floors with reflective pans and insulation, or in lightweight gypsum or concrete.
Most of the inspection here is visual: looking for signs of leakage. Of course, we want to know that the radiators, baseboards, or floors are warming up satisfactorily. Use your Infrared camera! Nothing beats it for seeing radiant distribution.
There is evidence of leaking in the boiler system’s distribution pipes. The affects proper heating and can cause water damage. Hire an HVAC contractor for repairs as needed.
There is a radiator or baseboard which is not heating. This creates an unconditioned finished area. Hire an HVAC contractor to evaluate the system and to make required repairs.
There is a leaking radiator. This will cause water damage. Hire an HVAC contractor to repair or replace the radiator.
There are unstable radiators. This is a safety hazard and can cause leaks. Hire an HVAC contractor to secure the radiator.
