Thanks Cab - good info!

I didnt read all the replies, so I may be repeating some advice.

If your system is old and you plan on replacing anyway, consider one with variable or multi stage compressors. They have excellent turn down and only provide the cooling/heating necessary. So instead of cycling on/off all day, they just ramp up/down as required. Inrush or starting current is the largest energy drain on a motor.

https://www.goodmanmfg.com/resources/hvac-learning-center/operation/a-great-reason-why-your-air-conditioner-might-be-running-all-day

Then once you get a nice split system, install some automatic zone dampers with local tstat control. The zone dampers will modulate the airflow into each zone as needed. Manual dampers work to a point, but as seasons change, or the suns declination changes, airflow requirements also change. A zone damper keeps up with current demands.

Duct work size is important, as is grille placement. Most systems I see with issues is because of air distribution, not capacity. You can even have a high/low return system with zone dampers programmed for heating/cooling season.

Lots of options. None are really cheap.

Air balance is the cheapest fix, but as previously stated, air quantity requirements change with season and time of day. But it may help you limp along until you figure out the real issue(s).

Lots of different mini splits out there too.
Multi head (evaporator) mini splits utilizing VRF (variable refrigerant flow).
They do have (typically) their own compressor/condensing unit.
Here is the LG unit I had mentioned.
Think it is available as a single or multi head system for multiple zones.
https://www.lgdfs.ca/en/art-cool-gallery.aspx/LMAN097HVP

Nice looking place, David.

I have the same Saltillo tile in my entire house - but on a diagonal. Love it!

Good luck with your HVAC project - some good advice given already!

Years ago I installed a few zone systems. Didn't like them much back then but the newer systems are more refined.

You wouldn't happen to have an old Carrier "comfort zone" system would you?

Or Trane Comfort Managers... They were pretty crude by today's standards. Dump box technology with a voting system. Most votes wins in heating or cooling mode...

Oh, and badazz house David!

We don't have A/C and I thought of doing split systems but for the extra $$ on our little two bedroom one bath I just hung a couple window units.

Thanks Scott. I was happy where I was at - we had taken one of the lesser homes in the neighborhood and remodeled it 100% and added an office etc, but I made the mistake of telling my wife there weren’t any projects left.

And she really wanted to wanted move... I said I’d move if we could find something interesting/something different. So we got it and then some, but once again it’s the house in the neighborhood that “needs” everything. We knew it needed a new roof and that HVAC stuff was old, but I didn’t expect it to be “built” wrong. I also think it scared normal (non contractor or non motivated) buyers off - one of the first things I and some of my guys did did here was remove about 30 tons of debris leftover from the prior owner’s pool business! It wasn’t pretty.

And right away I began to think the HVAC looks way undersized, and that it also couldn’t breathe. We were still running the A/C then and the big unit kept freezing up. What we found is that someone had placed plywood shear-panel over one of the return pathways between the floors. And I could see how someone had hacked about a 4” X 4” hole in it to try and fix it. That particular return is about 14” in diameter at the air handler....

Anyways, I’m very happy here, but _everythjng_ needs attention.

There are some cool parts to it though. Like how careful they were to copy the 1910 house. I’d like to know how they managed to taper all the walls for example.

http://forums.pelicanparts.com/uploa...1550882602.jpg

In order to open up the return pathway we added a wall grate/return below the blocked area.

When we got here both return ducts tied into this “box I’m the ceiling - one on one end and one on the other. (And as I mentioned, the larger of the two return cavities was mostly blocked.)

In the 1st photo below you can see that “box” plenum where the two returns met, and there was one small grill (with no filter) collecting the air. For the time being I just enlarged the opening in the box/ceiling, then added the wall opening (2nd photo below):

http://forums.pelicanparts.com/uploa...1550883310.jpg


New opening in wall to let larger unit breathe:

http://forums.pelicanparts.com/uploa...1550883359.jpg

These, of course, are just bandaids...

Dave, not all return grills has a filter instead, it is at the unit itself. I have built special returns as part of the lower section of the cabinets for aesthetic reasons. Fake doors in front but grills on both sides. Sounds like like you have a bit of a mess or creative HVAC going on there? I see this a lot when with additions, those damn contractors just add to the duct work taxing the system to death and having not enough air flow to the new section, so the owners turn down the temp. trying to cool the hot part of the house. Hot in the Inland Empire. Thankfully Claremont isn't as hot as Rancho or Fontucky or any of those places east of you. Nasty hot out there.

I have a love hate relation with those mini split systems. I started to installed them right before they became popular, but hated the look of having a big old box on top of the wall, but they work well and cheap to install. Did I say they look like CRAP? There has to be a balance and in your case, aesthetic is the most important in this house. I suggest against it base on just that. You may be able to hide that on top of a tall cabinet where it isn't visible from the ground unless you go looking real hard. I've installed them near the top of the closet and built a chase to a grill above the closet door for bedrooms. All you see is the grill. Pain in the ass to turn on because the signals from the remote is blocked but the owners wanted it out of the way out of sight.

If you need to talk house, call me. I am more then happy to come out and give you my two cents over a cup of coffee. I can't do the actual work for you because I am committed for 2019 and 2020 but you don't need me for that. You know a bunch of guys that will do all that.

It’s a Trane Comfort Zone. Max temperature differential is 4 degrees. We like to sleep in a cool 62 degree room, but keep the house at 68 during the day. To change the bedroom from 68 to 62 we have to go up and down stairs to all three floors and reset all three thermostats to 62.

Wd: I’m not familiar with that particular setup, but at my last home I installed the Nest thermostats for both zones/floors. They tie into the Internet (and by extension, your smart phone) and you can both heat or cool or turn off your system while away (or before arrival home), AND it’s also handy while you’re home when you just want to change the other thermostats. Just a thought.

I have considered that. I don’t know if my system is compatible with a generic thermostat. I have also considered locking the dampers open and bypassing the whole zone system “brain” by installing a single programmable thermostat in the main floor master bedroom. The existing thermostats only have 3 wires going to them.

Got it!

I will say that the Nest (and probably all the others) are widely adaptable. And the Nest customer service was outstanding. When I called to discuss setting them up on my zoned system, they asked if I wanted a custom wiring diagram. I told them the colors of the wires I had and what they'd been attached to, and they emailed me a diagram that matched my wires to the back of their product. Very slick!

The app on my phone claims to be able to control multiple T-stats (Sensi) however I was not impressed with their customer service.

Looked up Trane Comfort Zone and as WD described it uses dampers to control temps in different zones.

I did see that Trane sells a WIFI stat.