Boiler heat - what type A/C?

John R. Hall

Although I can put together the answer based on what I know as a journalist, I'd like some Wallies' opinions. My brother is looking to get estimates on putting a/c in his home (tri-level) that already has boiler/baseboard heating. Since he has no ducting and is mainly concerned about cooling the upper level, I thought a high-velocity Unico-type system migh be best for him. Comments? Suggestions?

kframe

A minisplit system may be something worth looking into as well.

Big Ed

I like them

They do make a nice neat system......But as you already know they are a tad more expensive.By the time you buy all of their fittings your paying about 50% more. I find high velocity units usefull in moden attic free homes and old homes with the lack of large closets ,plaster walls and ballon construction . They come in handy because they stir the air good blowing out of the floor....I was always tempted to set up a Marilyn Monroe skirt blower in a hall way , Do you think they will sell .......Most Split levels have enough room for a Low velocity system . If not a high velocity is the way to go.

John Mills_3

HV drawbacks

$$$$
$$$$
and $$$$

Everything is expensive. If you MUST run the little ducts, it's great. If you have room for conventional ducting, you can get so much more equipment for the buck. The Unico or SpacePak air handler is very pricey, with conventional, a top of the line variable speed probably would be less money. The HV air handler drops the SEER 1-2 points and the capacity 1/2 to sometimes a ton where the variable speed air handler boosts the SEER. Most Unicos are rated at 10 SEER with a "12 SEER" outdoor unit. SpacePaks seem to do better but the Unico boys say SpacePak is fudging

Ductwork is pricy with HV too. Zoning is very easy with conventional ducting and with a multi-level, might be nice to do. Most multi-levels don't need much cooling, if any, on the lower level so if you concenate your ducts on the upper levels, cold air is nice enough to fall.

Might even look into a heat pump to use in mild weather so he doesn't have to fire the boiler just to run a few minutes to take the nip out of an early season or late season morning.

Mark J Strawcutter

my experience

I've owned two homes with separate cooling systems totally independent of the heating systems. One conventional, the other hi-velocity.

Both did the job equally well. The hi-V system was much more expensive but necessary due to space (or lack thereof) considerations.

If a conventional system will fit, I'd say go with that.

Mark

Dan M

Hv

I am about one week away from the having a high velocity unico system installed in my two story farmhouse. The system will also cool my finished attic, I was glad to see the contractor brought out the Unico guys to work out design details. The unico people seemed like they new what they were doing. At this point the only drawback is extreme cost $9500.When you look at a pile of tin pipe and plastic fittings and a couple of days laber you wonder. I understand how cost envolve engineering and research as well as materials and laber but still find it hard to beleive what is charged for some of this stuff.

Mike T., Swampeast MO

Hi-Velocity Efficiency

Is highly related to humidity. As opposed to conventional systems they actually gain efficiency as the dewpoint rises. All I know of (in this area at least) are absolutely lauded by the owners for efficiency of operation.

In less swamp environments (and particularly where conventional ductwork can be run) the cost factor makes their benefits much less straight-forward.

One benefit not mentioned too often: Hi-Velocity systems MUST be VERY well-sealed to even function--there is MUCH less leakage than in the vast majority of conventional ductwork.

Irene

cost of unico

Count yourself lucky, my current estimate for installing unico of just two floors. Place the unit on the roof with beams and drop down through the closet to get to the lower level ceiling is $17,000. I would gladly pay $9,500.
Irene

Dan M

OUCH !
I had some quotes of $12500 and some less and decided to go with this one in the middle because I liked the contrators detailed approach.

Irene

I love New York

The only thing really detailed was the payment plan.

Tom Anderson

Look at the fan energy it takes to drive that air through those itty bity ducts. Ouch!

And that energy hit probably does not show up in the ARI SEER efficiency ratings, because the ARI standard makes basic universal assumptions (not applicable to hi velocity) about fan energy when the SEER values are calculated....

Hi velocity systems certainly have a place, especially in difficult retro installations.

"Good" efficiency, just like car gas mileage, is a relative term. Electric prices will not be dropping, only increasing.

My $ .02 cents...

Mark J Strawcutter

low volume

high static, high velocity but low volume

my 2.5 ton SpacePak only does about 450cfm

Mark

Mark J Strawcutter

location, location, location

and physical construction of the building can have a lot to do with cost.

Doing anything in NYC adds a premium - why just the parking fines for trucks during a project have got to be a killer.
:-)

Mark

GW

you're killing me

You make it sound like the contractor is going to retire off the surplus of dollars he charged you... give me a break! You could but a window unit for a couple of hundred dollars you know. Golly, you have buyer's remorse and you haven't even paid yet...

Gary

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

flange

if there is enough room and a decent budget, you might want to consider a properly zoned system. in this type of application, you will get better overall control, while saving some energy. ducts must be sized correctly though.

Irene

Not a foolish New Yorker

I said my estimate for installing the unico system was $17,000. I am not nearly foolish enough to actually pay that. I have three window units that completely cool the entire house with no problems and I can turn them off the downstairs one when I just need the up stairs cool.I was told you can not zone with Unico. So I will save my $17,000 to give to the lucky plumber who comes to over haul my one pipe steam system. I can probably buy a couple od new window units with the leftovers... See you on friday (I hope) John.
Irene

Mark J Strawcutter

a/c equivalent of \"double-hung zone valve\"?

I'd never want to go back to the noise and uneven cooling of window-shakers.

We were able to cool our entire house with central A/C for less operating cost $ than just the downstairs with a window unit.

Mark

Mark J Strawcutter

proper zoning?

The only proper zoning I can see for forced air A/C would be separate systems for each zone. My understanding is that even some of the mini-splits with multiple inside units off a single outside unit have multiple compressors in the outside unit.

Dampers, bypass ducting, "dump" zones, freeze-stats on coils don't seem like good solutions. Maybe using ice as a "buffer tank"?

Mark