Central air vs. mini split ?

In my case, it was without the air handler. But you can get whole AC only system eqpt, including the air handler for $2500 or less. Here's some examples:

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I know some will say you shouldn't buy Goodman because it's cheap. Others say they've had them and they are fine. When I was shopping for mine, the Rheem prices were only a few hundred more than Goodman. My old system was Ruud, which is made by same company as Rheem. Since it was still working after 25+ years, I chose Rheem. Been very happy with it. I bought it from the above website, but looks like they no longer sell Rheem.

Reply to
trader4
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Then the question becomes SEER, is that a variable speed A/H? Probably not. In a place with a 7 month A/C season, SEER will quickly eat up that thousand bucks you saved.

I also think there is a quality difference but that may just be me.

Although the complexity may be a factor, it is almost as cheap to get single head mini splits and have a bunch of them. That also gets you very high SEERs, up in the 20s. The one we put in the bedroom is 26 SEER. It also makes zoning an absolute thing. Each one is 100% separate.

The thing that is holding me back on the 3 head minisplit right now is the placement of the ceiling cassette and how I will deal with the condensate. I would like to avoid a pump.

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Reply to
gfretwell

I know of two geothermal installations. One was done because he could, not because of any money savings. The other was for economy, but I don't know the detail, but it is a very long payback. From what little I know, the well cost is the one big deterrent.

Wish I could get gas. I did upgrade my oil boiler and save a bunch, but gas would be better yet.

Reply to
Ed Pawlowski

I was thinking about a mini-split for the attic in our previous house. It had an air handler in the space I wanted to heat/AC but it would have been more work to use it than add a mini-split. OTOH, the solution ended up being to move. ;-) I my put a mini-split in our basement here. Like you said, installation would be a snap.

Reply to
krw

It's quite common. My previous house had two, 2T for the second floor (in the unheated attic space) and 3-1/2T on the main floor (no basement). This house has 4-1/2T for the main and a 1-1/2 for the second floor. Both are in the attic. No heat or AC in the basement.

Reply to
krw

about 6 years ago I got a new 90+ furnace with AC installed in my 1950 2 story home. Goodman cost under 4 grand and its worked great. used all existing ductwork except the plenemum to the furnace. central air is wonderful

Reply to
bob haller

What's quite common? Three zones on a single system, like the poster is talking about? Or a two story house that has two entirely separate systems. The latter is common here too, but not zoning within a system.

My previous house had two, 2T for the second floor

Reply to
trader4

Two independent systems. One for the upstairs, another for the main floor. In fact, I think it's the norm, here in the SE (don't know of any 2-story houses with a single system).

Zoning is not common.

Reply to
krw

A square evaporator that can go in the ceiling or even drop into a 2x2 T bar ceiling hole. Air comes out all 4 sides and the return is up the middle.

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Reply to
gfretwell

Good point about the freezing. I would think dehumidification would be better with a colder coil, though (until it froze).

The biggest problem with our current system is dehumidification. If it did a better job I'm sure I could bump up the temperature a few degrees. I'll probably have to replace the system(s) in a couple of years, though. I replaced one of the coils last year and the guy said the system wasn't long for the world (it's only six years old now).

I assume it's a matter of how many are closed. One or two bedrooms and closets(!) shouldn't cause much of a problem.

Reply to
krw

If you zone a conventional system you have less air over the evaporator. Less heat will be transferred to the evaporator. The evaporator can get too cold and freeze up. I assume this can be prevented by a 'freeze stat' on the evaporator to shut down the compressor, but it is added complexity and short-cycling also has to be avoided. I suspect dehumidification may not be as effective.

I haven't seen a zoned conventional system. One major company that adds air conditioning to existing forced air houses wanted existing zoning defeated for air conditioning so all zones were open and only one thermostat controlled the system. Do they make 2-stage compressors?

My understanding is that room outlets may have to be rebalanced between heating and cooling, particularly 2 floor. Outlets could be closed in rooms that are not used, but freeze-up may be a problem.

Reply to
bud--

Yep, humidity is a big factor in comfort. Had anyone look at the system, and try to improve the humidity?

. Christ>

Reply to
Stormin Mormon

We had someone in last year, when we first moved into the house. He changed the (leaking) coil and added a 24" return in parallel with one of the others (getting too cold - condensate rusting out the unit). that probably made the humidity higher but he said there wasn't nearly enough return size. It works a lot better, anyway. Of course it didn't work very well at all without coolant. ;-)

Reply to
krw

Yes, lack of return air is a really common problem.

I'm trying to remember what helps lower humidity. Lower fan speed, perhaps. More time in the air handler.

Ah, well. Your man at the scene is best person to figure it out.

. Christ>

Reply to
Stormin Mormon

He doesn't seem to be the brightest bulb in the pack but I think he can handle the handlers. ;-) We signed a service contract with him. $200/yr which includes maintenance twice a year, (6) filters included. He threw in the service calls for outages, the additional return line, and grille, with the contract, but not the coil. ;-)

Reply to
krw

We have a 2 zone two stage system with a single compressor (dual stage) and air handler (dual speed). There are dampers to open/close each zone, and a central control box to take the inputs from the 2 thermostats, decide when to turn on the common system (and which stage, as the thermostats can call for stage 1 or 2) and which damper to close (if any).

This was profesionnaly installed, by the book; they did have to carefully balance the zones -- our upstairs zone is significantly smaller, so they enlarged a couple of upstairs vents and set the downstairs damper to not fully close. I think the controller we have can theoretically handle 3 zones, but balancing the minimum airflow would be a bigger challenge of course.

It works pretty well; upstairs and downstairs are able to be kept roughly at the same temperature (or different per the thermostat settings -- we are never upstairs during the day, and it's just the master bedroom, so we let that zone go higher then).

Josh

Reply to
Josh

I already have a condensate line going out of that closet in the hall where the existing air handler is but you need a pump in the cassette no matter what.

I am really coming around to just swapping out the existing central system here. Mine is still running (knock wood) so this will be a fall project when we can live with the windows open and the attic is not so hot.

Reply to
gfretwell

The biggest factor in humidity is properly sizing the system in the first lace. Bigger is not better. It won't run long enough and you will be "cave clammy", cold but still with lots of humidity

Reply to
gfretwell

Yes, from what I've read, that is one problem. Some zoned systems apparently dump the unneeded cool air to the basement or other unused areas where the temp doesn't matter much to avoid the above problems. However, it's obviously a very inefficient strategy. I guess if you had plenty of ducting so that the system had sufficient air flow regardless of the zoning, then it would work. But that has it's own problems, like where to run all of them, cost, etc. Two stage system would seem to be better idea.

Yes they do and I would think they would be ideal for a zoned single system.

I do that at my house.

Reply to
trader4

The problem is it freezes quickly. It's similar to having a system that is oversized for a house. The house gets cooled off so fast that if it's a more moderate day with high humidity there isn't enough run time to get the humidity out. Two stage systems are good at that.

Might it be oversized?

Yes, I close a few depending on the season. You just have to have some common sense and not close off a lot of them. I think it's probably hard to get in to trouble if you're just balancing. But very easy if you're trying to close them off to avoid heating/cooling large areas of the house to save some money because they aren't used.

Reply to
trader4

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