Zoning is complicated and inefficient, especially if you have a single stage heat source (heat pump or furnace), made worse if you do not have a multi-speed air handler/furnace.

When a single zone calls for heat, the furnace blasts its full output into an area that can't handle that much heat/cooling, often through ducts that can't handle all the air. To compensate, the system is usually designed with a bypass, which routes excess heated/cooled air back to the intake side of the system, or a dump zone, which is an area that gets heat/cold whether it needs it or not. Neither is ideal, and the bypass can cause equipment problems if not set up properly.

The added complexity of a zoned system adds to the sophistication required of the servicing techs. Not all HVAC techs are well versed in zoning.

Just as a guess, the problems you are experiencing are probably the result of poor duct design and installation in the first place, possibly aggravated by less than ideal insulation and/or air leaks in your house's envelope.

Get somebody different out there to evaluate your entire HVAC system before you invest in zoning. It may be the right approach, but it may also be good money chasing bad.

Now, if you don't mind, I have to ask a question. Why in the world do you have propane heat in central Texas instead of a heat pump?

Honestly because I don't like a heat pump. I had a heat pump at my old house thinking that it would be great and I really wish I hadn't done that afterwards. I don't like that the heat isn't really hot and never really felt that comfortable after doing that system so didn't want to do that again and DH felt the same way - actually more so than me, but I tried to like it since I'd spent the money and convinced him it was the way to go. Honestly I didn't really see much savings from it either. My electrical bills weren't that much lower and in that house I had only electric heat.

I'm going to get out with the caulk gun and see what I can find if the temp is ever in a good range around here. I know it is well insulated so air leaks would be the only thing.

The problem is the ducts and the placement of the unit. One issue is the flex duct used is also smushed together going over there. Only way to fix that one is to re-route it and thus making it longer. One of the companies that have experience with zoning gave us other options, but no matter what the bedrooms on the other side of the house still will be less in temperature or higher depending on outside temp due to the long run of the ducts.

Any suggestions on what you think could be done to improve this then without zoning?

Can I just change to a variable speed fan or does it mean the whole unit?

I miss having two units as I did with the old house. I also don't like heating/cooling the main parts of the house while sleeping and although in the winter I use a really warm cover and am not bothered by the cold in the master - only the baby's room is bothering me here, in the summer it just feels too warm at night even with ceiling fan on and no covers.

The master is very close to the unit so duct length etc. is not the issue there and airleaks doesn't seem to be the issue as I've not detected any drafts in there, but using a candle. Did this when we first moved in due to temp diff. After that they did some air balancing.

Do I have any other options in getting the house to be more comfortable and not having to heat/cool areas we don't use? In my old house the main areas weren't heated/cooled during the night as much and the bedrooms weren't during the day.

Here we do need to heat/cool the baby's room during the day, but not the master.

In the end though I'd just like something that feels comfortable and to not have the main part of the house at 73 so the baby's room and master can be 67.

Sorry for the ramblings and the book I wrote. Just getting really frustrated by this and we have moved on to other companies than the one the builder used as we are tired of dealing with the builder and the hvac company and not getting anywhere after 2 years.

Long ducts aren't a problem if they are done correctly, and it doesn't matter where the HVAC equipment is as long as the ducting is designed and installed correctly. It may be cost less to design and install the HVAC system if the equipment is centrally located, but it isn't an absolute requirement.

Flex ducts should be minimized. If the entire house is served by poorly installed flex ducts, you are almost guaranteed to have major problems.

You need to get a really good contractor out there to evaluate you current HVAC system and give you some recommendations.

Propane must be dirt cheap in Texas. Here, it costs three times as much to heat with propane as it does to run a heat pump.

I want to back up the opinions you've already received about bypass ducts. DON'T DO IT.

You're much better off buying multiple pieces of equipment and achieving your zoning goals that way.

Bypass ducts are a nightmare. They don't work. They destroy your equipment. Then the air shuts off and you end up without any A/C anyway.

I had a furnace & A/C set-up put in my last house with a bypass duct that was so bad it filled the equipment with water and created a 12' diameter pool of mud in my basement.

When I told the contractor I wanted to hold his last payment until he fixed the system, he sued me, figuring it'd be easier to bully the money out of me than fix such a bad system.

What I learned from other HVAC contractors, Internet forums, and any HVAC textbook I could get my hands on after that was that bypass ducts are bad and should be avoided at all costs.

Zoning is complicated and inefficient, especially if you have a single stage heat source (heat pump or furnace), made worse if you do not have a multi-speed air handler/furnace.
That's simply not true. Zone systems that are set up right will work well. Also there is nothing wrong with a bypass if installed corrrectly. A good tech will know what to do. To OP: A two story home will most usually have problem with temp. difference. A zone system will work nicely.

This is for a one story home.

So how do I make sure the companies are qualified. I have asked how many zoned installations they do and if I can get references to someone with a similar setup. Not sure what else I can do to make sure they know what they are doing if I do go ahead with the zoning.

We have to do something. I'm tired of having to have the thermostat at 73 so the baby's room can be at 67. Ideally we'd like it at 68 or above. We'll see how it goes with a freeze tonight and what we'll have to crank it up to.

What are my other options. Replace the ducts with metal ones and hope that solves the issue? What are things we could look at?

"That's simply not true. Zone systems that are set up right will work well. Also there is nothing wrong with a bypass if installed corrrectly. A good tech will know what to do. To OP: A two story home will most usually have problem with temp. difference. A zone system will work nicely."
-- ckr74

Please read the article linked below, especially part 23.

BTW, when my contractor and I had a sit down visit with his normal HVAC sub, I broached the subject of zoning our build, a passive solar ranch over a walk-out basement. I got to listen to a 15 minute diatribe over the evils of zoning from a guy who owns an operates a heating and air conditioning company. His comments pretty much mirrored the information in the linked article.

We ended up using someone else, but there were other reasons for that.

Lyfia, how many returns do you have in the house? Do the too cool rooms have their own returns, and do you keep the doors to the too cool rooms closed at night?

Sometimes rooms don't heat properly because the air can't get out of them properly. If the air can't get out easily enough, the room becomes slightly pressurized making it harder for the air to get into the room. When that happens, sometimes other rooms get the air destined for the cool rooms, exacerbating the problem.

Here is a link that might be useful: Keys to High Performance Heating and Air Conditioning

Well...fixing your ducts would be a start. How about relocating the stat closer to that bedroom...yes other parts might become warmer (tto warm even) but maybe you can rebalance those areas(close off the dampers). I'd think this would be very inexpenive to try...

The return air is fine and there are no pressurizing issues. Everybody that has been out has started with that one and then said never mind.

We don't have an issue of other areas getting too warm.

I don't fixing the ducts will be inexpensive as it would mean re-doing them all the way they are now.

We feel the air blowing in this area, just not as warm as the ones closer to the unit. Actually feels more like we have a heatpump than a propane unit in that part of the house.

Did someone measure the temp of the air coming out of the various registers? If they did and there is a significant variance, I don't see how it could be anything but duct problems.

If you hire someone, grill them about how they do ducts. Use that link I posted to educated yourself first.

Yes, but the majority of it was done when the difference in inside vs. outside temp wasn't as significant. They even put a thing that measures and records the temp in the room and by the thermostat for a week. Of course this week happened to be so the system hardly ran due to similar inside/outside temps.

I will read it and see what we can get done.