Hello! I am new to the inspection community and have been asked to complete a home inspection on a new construction home. The reason I am reaching out is the realtor and potential home buyer is questioning the size of the heating/cooling unit in the house to be appropriately sized within the home.
I understand the Standards of Practice for HVAC systems which do not fall under this specific question, but do not want to walk into the inspection and pushed into answering. I know as a home builder, we ensure new constructions are up to code and adequate/sufficient for the home.
Does anyone have any thoughts on this subject or ways to circumvent answering this question putting myself in a tougher situation with the clients.
Meaning, I can reference who installed the HVAC unit and attach that to the home inspection report? I believe this is the largest reason they are having a home inspection. The realtor stated the HVAC is the biggest concern that i is big enough to efficiently service the size of the home.
Sizing HVAC equipment is probably the most argued about thing in the HVAC world. There is A LOT that goes into it - sqft, building type, insulation, sun exposure, location and probably a bunch of other things not at the top of my mind. The buyer sounds like the type that wants someone to hold their hand and tell them everything is perfect and that’s just not what HIs are educated or able to do. I know it’s slow and we like to get every job but I’d be very careful around people like this and be sure to manage their expectations of what service you provide.
Stay in your lane. You should have nothing to do with the warranties or load calculation. The agent needs to go directly to the seller or seller’s rep. If the sizing on the HVAC system is what is driving their decision to have the inspection, let them know that they can get the information for free.
On a side note, a slightly undersized AC is more efficient and dehumidifies the home better than an oversized one.
I can’t speak for your area, but as for new construction in my area, the HVAC system would fall under the mechanical permit section of the build, and the unit should be sized to the cubic feet of the structure that it needs to heat and cool, and that is what I would tell my client if they were to ask.
In saying that, I do test the systems to make sure they function as intended.
Maybe it’s square feet, regardless it should be part of the HVAC installation.
As a home inspector it really doesn’t matter how it’s measured as it’s beyond the scope and best not to go down that rabbit hole unless you’re qualified to do so.
My wife and I can’t even agree what temperature to set the thermostat. One of us is typically too hot or cold. The hvac system operation is mainly subjective to the home owner. Ductwork configuration alone has a big impact on efficiency. I can list several variables that goes into hvac design, but the human factor trumps them all.
Zoned ductwork, ceiling fans and thermostat placement can have an impact on comfort. Here in south central Missouri two story houses 1800sf and larger typically need separate units for the main floor and upstairs. I have seen several houses where the master bedroom was on the 2nd floor and the thermostat was in the master bedroom, everyone else on the 2nd floor were on their own. I have seen thermostats in the living room exposed to direct sunlight for a few hours each day. Dirty air filters have a big impact on hvac efficiency. Back when my wife was going through menopause she kept the house so cold at night I slept with a sock hat on my bald head a few times. If it wasn’t for an electric blanket I wouldn’t be alive today.
Don’t forget mini-split systems can be used to tweak hot and cold spots in large homes at a fairly low cost.
New homes are required to meet energy efficiency standards. There are multiple ways they calculate this and we won’t get into it here. However part of that configuration/calculation is the size and efficiency of the HVAC unit and that is a required recorded item on the energy efficiency configuration/calculation.
The answer to your client’s question is simple. Have them obtain the energy efficiency configuration/calculation documents which should describe a properly sized unit.
Just another consideration. You will need to become comfortable with saying things like “That is outside the scope of this inspection and I will not be making that determination.” And then tell them what you will do.
Heads up…there are folks who think AC tonnage is everything. Tell them that it is 3.5 ton unit on a 3000sq ft home and they say “Great”. As others have said here, it ain’t that simple. Manual J calculations take into account many factors and are way, way beyond our responsibility to do.
There might be less than half a dozen home inspectors who measure split or do Delta T assessments correctly.
“Tell me what your concerns about the AC sizing are. Why are you wondering if it is sized properly? Determining correct size for each home and measuring split is beyond what home inspectors do. I can tell you if the AC is blowing cold air at the registers and if the system appears installed properly. In general, new homes are built to be very energy efficient and typically do not require the same size of AC systems needed on homes built even 20 years ago. If you have concerns about correct sizing, I recommend having a HVAC tech evaluate the system.”
I just tell them that it’s beyond the scope of a home inspection. Then I tell them why. Things like the volume of the building, insulation, amount of windows, where the home is located, type of system, etc. is best done by a HVAC contractor or building designer.
