posted March 16, 2005 02:01 PM            

I mean they are schooled and licensed on how to install these things...so there must be a reason.

The unit serving the upstairs gets its return from the downstairs. And the unit serving the downstairs gets its return from the upstairs.

And both thermostats are located downstairs - around the corner from each other on the other side of the house from the staircase that connects the floors.

There are no bedrooms upstairs...just a large open space and a bathroom and no doors, other than the bathroom door, separating the upstairs from the downstairs - air can flow up and down the stairwell.

My thought is that it will get hot as hell upstairs when the downstairs unit is set to a low temperature because the unit keeps blowing air upstairs without ever significantly raising the temperature downstairs - so the thermostat will never reach its set point.

posted March 16, 2005 06:12 PM            

Not I.

posted March 17, 2005 07:52 AM            

Did this design appear to be the direct intent?

posted March 17, 2005 08:47 AM            

The two units are both in the attic space but are on each side of the finished upstairs - one's on the left and ones on the right divided by about 25 feet of finished floor space and two walls.

And I'm positive that's the way they had them hooked up because I ran them one at a time...and then got my helper, who is also an inspector, to go check them too...he can back with the same puzzled look.

And there's no way that could have been an oversight - when you open the attic access door, the first thing you see is a duct running from the unit to the ceiling below and staring right at you, to the right, is the return on the upstairs wall.

The same goes on the other side - when you open the attic access door, the first thing you see is a duct running from the unit to a register in the upstairs room...and no return grill..cause it's downstairs.

And looking at the unit (the way its installed, the connections are made, etc..) it was done by an HVAC guy.

I looked into becoming an HVAC contractor a long time ago...it takes extensive education and on-the-job experience to get into the business...so I have to wonder if they had some type of reason for doing it this way.

But I can't figure it out. The Realtor grilled me good on it too: "How do YOU know if their installed backwards???"...like how dare I question a HVAC guy.

I said, "Because they LOOK like they are".

Then she asked me in a threatening tone, "Do you KNOW who OWNS this house???"

posted March 17, 2005 11:54 AM            

Reading your post makes me wonder about the age of the home, its history and the intent of the ductwork layout.

We’re all use to seeing a horizontal split in the home that divides two HVAC systems. This means one system serves the bottom floor and one serves the upper floor. The thermostats are assigned locations on each floor.

Sometimes, for reasons unknown, maybe a modification history we’re not privy to, some systems will have a vertical split. Now you have one system serving the lower and upper floors one side of the house while the other system is serving both floors on the other side of the house. In this case, the thermostats can be at the same level as long as they are in their respective area of responsibility.

posted March 19, 2005 07:07 PM            

Is there a logical reason why a system would be designed this way. If so why and how would it work any better than a normal upstairs/downstairs set up.

With many years in HVAC, I have never seen such a set up.

posted March 20, 2005 05:19 AM            

Many investors keep the original ductwork to save money when converting smaller two story duplexes into a single-family dwelling.

You’re right, they don’t work very well and an unknowing homebuyer usually pays a heavy price. I tell my clients that the concealed ductwork configurations in converted homes may be unusual and may not work properly. If they’re concerned, they can get an HVAC guy out there for further testing.

I got hung up on this in my infant years with a converted duplex. Now that I’m up to toddler, I won’t get bit again and always look out for this configuration, especially when I inspect any of the above type homes.

posted March 22, 2005 08:14 AM            

The electric unit serving the downstairs is a two ton unit - the upstairs enclosed attic space has the 4 ton gas unit.