Home Inspections - HVAC

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HVAC is what keeps your house comfortable throughout the year. Having a sufficient as well as efficient system will save you hundreds of dollars annually. I would recommend that people, especially investors that hold property as part of their retirement, learn more about the HVAC system. This article is not written to teach you about SEER’s, BTU’s, Brands etc…….this article will touch upon some of the problems we find while inspecting homes. There are several types of systems out there, but for this article I am talking about electric and / or gas systems.

The problems are in no specific order.

1.) Failing to change air filters

This can easily be remedied by spending approximately $2.00 a month for a filter.

Failing to change your filter could damage your system, costing thousands of dollars. If you do come across a house where the filters are dirty, this is a clue to evaluate the system closer; a professional may be needed for this job. While we are on topic of Air Returns, they should not be covered / blocked. All grilles and returns should have at least 3 inches of clearance from any object that could restrict the free flow of air. Doors should be left open when possible. When doors are closed there should be at least ¾ inch gap between the doors and floor.

2.) Poor system design

Recently, while inspecting a fairly new home, I was reading substantial temperature difference from one side of the house to the other, in particular one of the bedrooms. Using a Raytek MiniTemp (you Trekie fans will see this instrument being used frequently on Star Trek – Enterprise) measuring room temperature and checking for insulation problems, I noted a 10 degree difference between a couple rooms. The damper was open but the air flow was some what weak.

This house had a single system which was located in the attic. Upon further investigation we found the flex duct feeding this room was unusually long and distant from the main trunk. Since this system was located in the attic and taking into account the long line that fed this room, it was easy to figure out why there was such a difference in room temperature…………..poor design by the HVAC contractor.

In the county I am currently building in, this would not have happened. The county inspectors are looking at HVAC designs at rough in, checking them for efficiency. This is seldom done but my hat is off to those inspectors that do such. While plans with cathedral ceilings can be problematic for the HVAC contractor, they should advise their client the need to do a split system (separate system in and of itself) when needed, in order to efficiently control the temperature of the house. I know that tightwad builders are the primary reason for this happening in the first place however it is not advantageous for the builder to try to save a few dollars if they are going to get complaints when Harriet Homeowner becomes educated in HVAC systems and finds out why one side of the house is warmer / cooler then the other.

3.) Freon low or leaking

One is required to have a license in order to install Freon in the system. When your whole house is not cooling then majority of the time, this is the problem. Call a licensed professional to correct this problem.

4.) Overflow line clogged

This is not to be confused with the condensation line, the overflow line typically come from a tray that the AC sits on. This usually gets clogged when insulation or other debris gets into the tray clogging the tube. If the overflow line has water coming out of it, then you need to call your HVAC contractor, there is a problem with the system. Ask your contractor to install “float switch,” this switch will automatically cut off your unit when the overflow tray gets clogged / full.

5.) Ductwork problems

Ductwork problems can be anything from unsealed or un-insulated ductwork to even standing water inside same. Just the other day I was assisting another inspector on a foreclosure inspection. Other then the fact that the previous owners decided to take out their frustration on trying to destroy the house before they left…….the company that was hired to “winterize” the home, after the occupants were removed, ended up flooding the house causing numerous gallons of water to enter into the floor ductwork. You could tell by the sagging ductwork which ones were filled with water and needed to be replaced. Quite frankly I would replace all the ductwork.

6.) Outside unit (Compressor / Condenser)

This unit should be free of grass, seeds and shrubbery. Nothing that could restrict the free flow of air should be within two feet of the outside coils.

7.) Under or over sized unit

The old rule of thumb is 1 ton will take care of 600 square feet, however with higher ceilings and more open plans, it is essential that your house is correctly measured and sized. I have heard of homeowners, builders and even HVAC contractors advise that it is ok to oversize a unit…….putting a 3 ton system into a 1200 square foot home. Over sizing a unit will cause it to “short cycle”…..the unit will constantly turn on and off, it also puts more moisture / humidity in the air during the summer, which can lead to other problems such as mold and mildew etc. Your hvac system should be correctly sized, if you could go either way then go under – not over.

Other things to be aware of

Do not run any air conditioning system when the outside air is below 60 degrees, this may damage your unit. Do not shut off registers in order to satisfy other parts of the house, consult with a HVAC contractor about installing dampers at the trunk instead. Using the register as a means of controlling the air in various rooms can also put back pressure on you system. For those with gas furnaces, it is advisable to install a carbon monoxide detector in the house. If there is a crack in the heat exchanger, this permits carbon monoxide to enter into your distribution system (ductwork) and into the house.

There are more things that one could go over but again, these articles are to educate the owner / investor for inspection purposes, visit various sites on the web to learn more about your HVAC system.


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