AC condenser undersized - HI said nothing - to blame?

[James H. Bushart]

Originally Posted by tspargo

Wrong? Maybe, maybe not? I can assure you that I let it be known that an inspection is not to determine the size/adequacy of appliances like this.

After all, this was at a HI I was performing, I had a vested interest in explaining such things.

But, just as I would comment about a 30 gal water heater in a 5 bedroom 3.5 bath home, if I noticed that a 2 ton unit was serving a 3200sf home, I'd probably make mention of it, especially if there were alterations/additions to the property. Do I have to? Nope.

If you, as an HI, are going to be foolish enough to remark on the adequacy of the capacity of the HVAC....you had better be prepared to look foolish.

Understand, first, that the majority of systems that are installed are over sized. Why? First, most computer programs that calculate the Manual J requirements will add a 25% fudge factor. If the AC contractor adds his own 25%, we are up to a 50% oversized unit.

Using square footage of the building and climate is NOT the formula for calculating required capacity. The characteristics of the building shell and climate, along with the quality of air=conditioner installation, determine how many square feet of floor space can be cooled with each ton of capacity.

You have no idea of the adequacy of the capacity of the unit if you have not measured the airflow, the duct leakage and/or refrigerant charge.

So....if you want to play "Barney Phyfe - Home Inspector"....feel free to advise your clients, after comparing the capacity on the label to the realtor's estimation of square footage, that their capacity is (or is not) insufficient, but be prepared to be just as shakey, wide-eyed and sweaty as Don Knotts when a qualified contractor calls you on it and insists you compare your analysis to his.

[Tim Spargo]

Jim,

Do you read what I say before you reply???

Barney Phyfe... too funny.

I had actually "replied" to this and thought "why?" and deleted... no point.

Same tactics, different day.

Go ahead and co-sign a 3200 sf 3 story house with a 2 ton AC, having poor cooling upstairs and see where your thinking leaves you. If that wan't your point, what was?

[James H. Bushart]

Originally Posted by tspargo

Jim,

Do you read what I say before you reply???

Barney Phyfe... too funny.

I had actually "replied" to this and thought "why?" and deleted... no point.

Same tactics, different day.

Go ahead and co-sign a 3200 sf 3 story house with a 2 ton AC, having poor cooling upstairs and see where your thinking leaves you. If that wan't your point, what was?

My point is simple....

To describe the situation as you just did - "...a 3200 sf 3 story house with a 2 ton AC having poor cooling upstairs..." is the job of a home inspector. To advise that the 2 ton AC is undersized is not.

[David A. Andersen]

All right, you guys are starting to piss in my cornflakes!

To start with that house is not 3200 ft.². It is something like 2133 ft.² without the basement. The basement doesn't have a cooling load because it's below grade. It possibly has a dehumidification load, but not a sensible heat load. Depending on construction.

Last Friday I did a 4,124 square foot home that had 2 tons up and 2 tons down. That's just about equivalent to your 2,133 ft.² per square foot of house.

Refrigeration pressures on the low side were excessively high, but the house was vacant and the thermostat set at 85°. High humidity. I was in and out of the house letting crappy air come in during my inspection.

The client didn't want all kinds of neat diagnostic tests done that I frequently do...

So I had to break out all the tools and do it anyway because 2 tons per 2133 ft.²?!

The NACHI guys say it can't work!

I did a thermal scan and a blower door test for free!
Guess what? The house was extremely insulated, extremely air sealed and the equipment was performing to maximum capacity in accordance with ambient conditions. I have seen very few houses this energy-efficient (even energy Star homes)! The west facing wall was solar loaded and I couldn't even see the radiant energy affecting the wall from the interior! Outdoor air temperature 92°, relative humidity 72%. It was literally raining in the crawl space! Outdoor air ventilating the crawlspace deposited rain drops all across the vapor barrier. Fiberglass bat insulation in the floor trusses were completely dry! No moisture intrusion from anywhere into the crawl space. Just precipitating from the air!

Don't say it ain't so, until you take the readings people!

[Tim Spargo]

Whatever your points are James, they can be easily made and discussed in a far more professional manner. Which is generally simple to do, yet something you choose not to do.

Why, I don't know.

[James H. Bushart]

Throughout our message board, you will find advice from former HVAC techs who are now inspecting homes for a living that have included a service call as part of their SOP and who want to claim that to do less constitutes fraud against a client.

I disagree with the concept that for the small fee of $350 to $500, a home inspector is to assume total liability for the client's comfort, health, affordability and enjoyment of their new home. We simply do a relatively quick (3 hr) visual inspection in a standard way, and report what we are able to see.

For you to assume that the original inspector did not do his job and to report this to a real estate agent....strictly in my opinion.....makes you a part of the problem that we face as inspectors. Your response should have been something on the order of "Inadequate capacity is one possible reason for the problem you describe. There are many others as well....none of which fall under the scope of a home inspection."

My "Barney Phyfe" comparison is directed at the home inspector who attempts to use what little he knows as a means to impress others as a marketing tool. "Look at how dumb this guy is. Makes me look pretty smart, don't it?" Then, as the "stupid" guy proves to be right....Barney inhales deeply through his nose, shakes his head vigorously with his wide eyes bugging out....walks away as the gathering crowd laughs at him.

I didn't direct this particularly at you, but only you would know if it applies or not. Barneys get themselves in trouble with knowledgeable contractors and builders and make us all look stupid. They eventually leave the business and we continue to bear their legacy of stupidity.

We are home inspectors. We perform home inspections. To understand what a home inspection is, one must read and understand the standard of practice for a home inspection. That is its definition.

A Barney Phyfe inspector calls out a contractor and previous inspector for installing and missing an inadequate tonnage, and is laughed out of his job when the Manual J calculations show the right tonnage and the warm third floor was from a leaking duct system.

A professional home inspector points out the warm third floor and recommends that it be professionally evaluated.

I hope this is kind and gentle enough to be taken in the proper context.

[John Gromkoski]

If it's hot upstairs, whether or not I think the Condenser is undersized or not, I'm going to report that fact in my report and will likely suggest a further evaluation by a qualified HVAC contractor. And you can be damn sure if I do believe the AC is undersized, I will recommend a further evaluation. I may mention that a possible reason for this is the size of the condenser, but will not commit that I know the exact reason for it. I think it's our duty to tell our client what they REALLY want to know, and in this case, the fact that it's 80 plus degrees upstairs is something I think they would want to know.

Does anyone take temperature readings at the supply and return vents when inspecting the AC system?

[Bruce A. King]

Lots of threads on here about taking splits, just had one the other day where the split was within a reasonable range but it had problems. The filters were clogged and the occupied house temp would not drop, it actually went up one degree during the inspection even during a cloudy period with window shades . The suction line was not as cold as I typically find either so it needs work even though the split was ok. Inspectors need to get a feel for what the house temps and the hvac system is doing during the whole time they are there. That is the best we can do without having pressure gauges installed.

[David A. Andersen]

Does anyone take temperature readings at the supply and return vents when inspecting the AC system?

Yes, way too many of us do!

I recommend that everyone take temp splits on every inspection!



But use a hygrometer instead of a thermometer.