Issues that come up during a home inspection about HVAC systems.


Damaged a/c junction box and evidence of condensation forming around duct air leaking into attic space observed at a Houston tx home inspection

Your HVAC system consist of some expensive equipment. So providing accurate information about the homes HVAC system to a home buyer is imperative. The are many parts working together to provide a comfortable environment. Most home buyers are very concerned and want information about how the air conditioning system is functioning. I'd say here in Houston home buyers are very interested in how the homes a/c system is functioning. I can't say I blame them. our climate is very hot for the majority of the year. So your homes a/c system is of course one of the biggest concerns of Houstonians.


What's the function of the a/c unit?


Picture of condensing unit

The main functions of the a/c unit is to cool the home and to remove the humidity out of your homes environment. It's not a good ideal to turn the air conditioning system off when you go out of town or when your homes vacant and on the real estate market. This is the worst thing you can do and can cause moisture issues in the home.


What does the HVAC systems consist of ?


Well for the cooling part of your HVAC system consist of a condensing unit which will be located at the exterior and an evaporating coil which is usually located in the attic space. There will be drain lines a drain pan, refrigerant lines. thermostat, wiring, service disconnect(s) emergency shut off, fan to carrier the air, ducts to distribute the air to desired areas, Plenum/ A/C junction boxes to connect ducts, Filters to clean the air, registers at room areas. Heating unit(s) to heat the air during the winter if needed, flue to carry carbon monoxide safety out of the home. So with so many parts and things can go wrong. Having a experienced home inspector is a great advantage for a home buyer.

HVAC duct system
Houston tx Heating unit
Old condensing unit

What type of issues can be found during a home inspection with the HVAC systems ?


There are many issues that can be found below I have listed a few of the problems found during home inspections that I've preformed. Remember a home inspector does a visual inspection and takes temperatures, but doesn't use pressure gages or take units apart.


  1. The temperature difference doesn't fall in between 14 degrees and 21 degrees so the a/c unit doesn't cool properly.

  2. Unlevel condensing unit(s) is not good for your condensing unit refrigerant needs to flow through the coils evenly if it's not the unit will not run efficiently and unlevel units could put additional stress on the refrigerant lines.

  3. Thermostat doesn't respond to the a/c system or heating unit.

  4. Condensation dripping from ducts, condensation dripping from refrigerant lines, condensation dripping from the evaporating coil, Condensation ponding on top on evaporating coil, A/C junction boxes or plenum, condensation dripping from registers and various areas.

  5. Thermostats not functioning properly.

  6. Air leaking into attic space at ducts, evaporating coil.

  7. No air flow at registers or low air flow.

  8. Water in the drain pan indicating that the primary drain line is clogged.

  9. Significate rust at drain pan. A lot of rust can cause the drain at the drain pan to clog and if there is not a emergency a/c shut device present at the drain pan. This can allow the drain pan to over flow into the attic area.

  10. Improperly sloped drain pans where the pan doesn't slope towards the drain line which also could cause the drain pan to over flow into the attic space.

  11. Missing emergency shut off at drain pan.

  12. Rust present inside the heater cabinet.

  13. Smell of gas in attic space.

  14. Evidence of flame roll out serious back drafting issue.

  15. Flue not properly connected at heating unit leaking carbon monoxide into the interior attic space.

  16. Mold like or mildew stains at registers.

  17. Dirty filters.

  18. Bent fins at condensing unit.

  19. Venting improperly.

  20. Venting not properly secured.

  21. Old heating and a/c units.

  22. A/C units that use R-22 the unit may cool properly, but at the beginning of 2020 it wont be legal to purchase R-22 refrigerant

  23. Heating units and a/c units missing service disconnects.

  24. Over or undersized breakers for condensing units


Best practices for getting the most life out of your a/c unit.


Keep the vegetation trimmed away from the condensing unit.

Getting the most out of your air conditioning and heating system is important to home owners due to replacement cost. What are some things you can do to prolong the life on your air conditioning system.

  • Having your yearly maintenance it's a good ideal and will help keeping your unit operating at an efficient and optimal level.

  • Everyone knowns this one ,but it is really important change your filters on schedule. Changing your filters will keep your unit operating at an efficient level. Dirty filters will cause your unit to have to work harder causing more wear and tear on the unit. It will cost more to cool your home when your unit is not working efficiently not to mention costly repairs. Following this advice can help your unit last longer and protect against premature failure.

  • Air leaking into the attic space can also make your a/c unit work harder so make sure to do #1 each year.

I see this one all the time during Home inspection services . Over grown vegetation at condensing unit. The condensing unit needs to be able to breath to cool properly and vegetation can restrict air flow and cause over heating issues. Be sure to keep areas around the condensing unit free of vegetation. Also clear any debris from unit such as leaves, pine needles, tree limbs and any other type of debris.

As you can see if you take care of your HVAC system it will take care of you. It will also help you go through the home selling process with far less defects reported. As a seller having your a/c in top working order can help you net a bigger pay day without having to negotiate for expensive repairs or replacement. The HVAC system is important to home buyers and not maintaining will cause you to lose money or worst you could lose the buyer do to buying fears. Spending the money to maintain your HVAC systems will save you money in the long run. It also limits break downs that seam to always happen at inopportune. So don't forget to call your trusted HVAC technician out at least once a year.