looking for a new AC/HP unit

[Russianwolf]

Looking around to see what I should do.

We currently have baseboard heat and a attic installed AC unit that's 20 years old and needs a new blower motor (assuming the guys can find it I may have it rewound for this summer).

I figure its time for a new system and thought a HP unit would be most cost effective. The house is 2000 square foot finished and my shop is 900 square foot in the basement. The one issue is the space that has the Kitchen,Living room, dining room and loft are all connected one large space with only the three bedrooms separate.

Right now, we are running window units in the master, one of the lower bedrooms and the livingroom, but 36k btu won't keep it cool in the heat of the summer so now is the time look at a change.

So what should I do? I don't like having the unit in the attic as its a pain to get to to service and if the condensate drain clogs the leak damages the ceiling. The ducting is the worst possible (flex tubing) and at least one of the guys said he thinks there is some mold in it.

I've been looking at either getting a new traditional system installed in the basement with some new ducting, but how to get it to the upstairs poses a problem. The other idea is the mini split systems that use no ducting. I may even be able to do most of the install myself and just have them come out and do the final hookups.

What do you guys think?

[LCHIEN]

i would think one central unit would be more reliable and more efficient and quieter than a collection of smaller window units (not to mention more attractive).

whether these are of sufficient advantage to offset the inconvenience and cost of installing ductwork is for you to determine.

[tommyt654]

One possibility would be to keep the attic unit and use it only for the upstairs and have another unit for the lower half. This would alleviate the burden of heating and cooling the whole house on 1 unit and allow a seperate unit to be installed in the basement for heating and cooling the lower half. I have noticed that most of the larger sq. ft. homes in the south that have recently been built have these type of systems anyhow.I believe its more efficient to simply cool and heat the area being used rather than the whole house and you would have seperate thermostats for each. Might be something to think about.

[Russianwolf]

Loring, Our experiences with DC systems should give you a good bit of info on AC systems.

Anything with ducting is less efficient. Especially the flex tubing ducting they built my home with. Also, with the mini splits (not window units) if one blower goes out, the other rooms are still being cooled. So LOML won't kill me, just be annoyed.

these are the systems I'm looking at for the mini-splits. You can use either the wall units or ceiling vent units so looks isn't a big concern.

http://www.fujitsugeneral.com/wallmounted.htm

[Russianwolf]

One possibility would be to keep the attic unit and use it only for the upstairs and have another unit for the lower half. This would alleviate the burden of heating and cooling the whole house on 1 unit and allow a seperate unit to be installed in the basement for heating and cooling the lower half. I have noticed that most of the larger sq. ft. homes in the south that have recently been built have these type of systems anyhow.I believe its more efficient to simply cool and heat the area being used rather than the whole house and you would have seperate thermostats for each. Might be something to think about.

but I want the unit out of the attic to prevent damage (already am going to have to replace the bedroom ceiling up stairs due to a leak a couple years ago.

[jziegler]

Mini-split system for the upstairs, and ducted unit for the 1st floor in the basement? That's what my house will eventually have. Right now, the 1st floor has window units and the 2nd has the mini-splits. We have 3 bedrooms and a bath on the second floor, and had 2 Mitsubishi mini-split systems each with 2 indoor units installed last year. They are heat pumps (although we have hot-water heat that we mostly use), are very quiet in operation, and have very good efficiency ratings (enough to qualify for last year's energy efficiency tax credit). Installation on them is pretty fast and straightforward.

[capncarl]

The mini-split units are a bit pricey. You can get good efficency units that will drive up to 4 evaporators (wall units). They are heat pumps, but can also be purchased with heat strips. Drawbacks are no make up air, and heat or cool. That means if you put in a multiple evaporator unit grandma can not turn on the heat if the other units are cooling.
capncarl

[Russianwolf]

The mini-split units are a bit pricey. You can get good efficency units that will drive up to 4 evaporators (wall units). They are heat pumps, but can also be purchased with heat strips. Drawbacks are no make up air, and heat or cool. That means if you put in a multiple evaporator unit grandma can not turn on the heat if the other units are cooling.
capncarl

grandma don't live here.

[tommyt654]

Couldn't you put a larger pan under the drain line to offset any clogging of the line say something that would hold a few gallons or more and then put a sensor of some sort to let you know if it was getting to full. Thats what I have seen down here.

[jackellis]

An attic is about the worst place possible for an AC unit. Attic temps are usually in the 130-140 degree range. Not where you want the machinery.

The cost of moving air around is small compared with the cost of cooling it, so as long as the ductwork is carefully installed and carefully sealed, the cost of additional fan power is small potatoes. Besides, sheet metal ductwork is relatively large and very smooth unlike DC hose, and air velocities are lower so losses are lower.

I don't know anything about split vs. single units but get the highest SEER rating you can afford. I think the minimum allowable in California is 16 and there are 18 SEER units available.

[Russianwolf]

Update

Well, after calling a couple guys and having them over to check out what we have and do the measuring they needed I have the following.....

2 quotes for 3 ton 14-16 SEER traditional AC units that I got when the system died last year.

Sears made an appointment to come by but canceled and I wouldn't let them reschedule on my time. I took a day off and they canceled less than 24 hours before.

I had a guy come out specifically to talk about the Mini-splits and he promised quotes on both the mini-split and traditional. I've called numerous times and haven't heard a word back.

Lillian got the guys from Costco to come out. They gave me quotes on a mini-split and traditional. Their prices were double that of any other quote.

Got a local recommendation, he gave me a quote for a traditional unit on the spot, but hasn't been able to get info on the mini-splits.

So, we called the 2 guys from last year to see if they would honor the old prices or if they needed to make any adjustments to keep them in the mix.

Now I have scheduled one of the ones from last year to come out next Friday and install a 16 SEER American Standard traditional AC for the same price he quoted me last year. $5400. Not the cheapest, but far from the most expensive we had.

I'm disappointed that I couldn't get any real quotes on the Mini-splits. But I have to get this done. The one guy that did quote (from Costco) was $11k for a traditional 14 SEER and $12k for a mini-split 19 SEER.