HVAC-Package units, are they any good? In the deep south, trying to keep the unit from out of the crawl space. My HVAC man has prosposed a package unit with condenser and furnace all in one unit. Anyone have any knowledge about this, or the pro’s and con’s. Thanks
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
This centuries-old paint offers vapor-permeabiity, maintainability, and longevity with zero VOCs, but know its limitations before you get to work.
Featured Video
Video: Build a Fireplace, Brick by BrickHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
I've used them in the past. They work fine, but I prefer a split system. Locating the evaporator in the central interior of the structure (like a split system typically does) lends itself to greater efficiency. If aesthetics is a concern, you should know that package unit installations generally don't have as neat an appearance on the exterior as a single condensing unit does.
New knowledge is priceless.
Used knowledge is even more valuable.
Lifespans of package units are *typically* shorter than split systems, especially heat exchangers.
Easier to replace a separate furnace or air conditioner than those subsystems in a package unit.
Efficiency choices of package units are not as good as a traditional split system- but that is changing.
Package units have options like economizers that allow "free" cooling if temperature and humidity are low enough with automatic control systems (unit draws 100% outside air for cooling).
An adjustable outside makeup air damper allows continuous mixing of outdoor air in package units.
Why not give up a few square feet of floor space and install a downflow unit in a closet?
Well, I'm open to suggestions. The problem with the downflow unit is I don't have a lot of places I could put one. Could put the downflow in the corner of a closet and fur around, though. I could use a split and place it under the house, though. I don't like the fact that with the package unit I have duct going from the outside unit through the brick. Not very neat for a high end house. Are package units cheaper and more problematic?
Either you make the changes to make a downflow unit work, or live with the alternatives.
Ugly duct going through the brick exterior is one negative you mentioned (then there are flashing details and waterproofing the duct itself), and poor access in a crawlspace is another.
I don't make big ticket decisions on what is "cheaper". I get what is needed to do the job right. Base model package units are no different than base (builder) model split systems- they are both engineered and manufactured to meet a price point (cheap).
You will pay for the energy used by your HVAC system for many years to come. Get efficient equipment- install it properly and install the ductwork right. I have made good money fixing low bid hack work on ductwork.
I would not install a package unit in my home because I think they are ugly- then there are those other details mentioned earler.
Given a choice between a downflow unit crammed in a corner of the house instead of a central location, I would install it in the crawl- but there would be easy access and a concrete floor. Best choice for me would be a utility closet and a downflow unit with real return ductwork- not a filter grille in the adjacent wall.
Ok, so the package unit isnt very desirable. You said you;d rather have a downflow if you could put it in the center of the house. If you couldn't youd place it in the crawl. This brings me back to the reason I was looking into package units. Locating one in the crawl space means I am adding to the moisture underneath the house, so I could run into severeal problems there, not to mention the probable shorter life span. The only place I could place the down flow would be in a closet towards the back of the house. This makes the downflow not very good, according to what you're saying. So if I place the unit under the house (in the crawlspace), what suggestions/things to watch do you recommend? Thanks
You can also place it in the attic, of course.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Second story's unit will be in the attic. First floor would be hard to put in attic with all the beams and etc. Dont want to fur ceiling.
Just use one unit and zone it.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Committed to one unit for up and another unit for downstairs.
You are not adding any moisture to the crawlspace by locating the unit there. The only moisture is from the condensate created by the AC and furnace, which should be run to a dedicated sump pit tied to the sewer.
If the ducting is done right, the unit can be located at one end of the house. Problem is that most ducting is *not* done right, therefore the customer complains about poor airflow and/or hot/cold rooms. ACCA Manual D should be used to design ductwork, not the lowest HVAC contractor price.
In my home, the second floor unit would also be located in a closet, with only the ductwork in the attic.
It is absolutely imperative that *all* attic ductwork is sealed for best performance. As little as 10% leakage on the return side will cause performance issues on the cooling side. A media filter with a gasketed door should be used. You will get 10%+ leakage on the return just around the air handler doors if they fit poorly and the typical 1" filter rack if it is done poorly. The air conditioner does not cool 130*F attic air well at all.
I would also seal and insulate ductwork in a basement/crawl. Yes, it leaks to the "conditioned space", but you lose the ability to control the air in the ductwork through leakage.
Flex ducting should be kept to a minimum and there would never be any ductboard in my house.
I have had a package unit for almost 10 years in my home. Before that, I had one in South Carolina for 4 years before moving here.
We used the hole for the floor furnace as the return air I had one problem with the unit in FL . Replaced the thermostat, it was bad.
In the deep south, trying to keep the unit from out of the crawl space
Probably a good idea, since too many southern c/s are functionally "outside."
However, there's South and there's South. Not a bad idea to check the buildingscience recommendations for your climate region.
If you are in an area that has 8-12 weeks of heating "season" (like mine), tacking on a heating unit to the a/c airhnadler makes a certain amount of sense. Ok, so that means the ductwork for forced air is "backwards"--but that's only for the very brief heating season.
Now, I'll admit a bias, I like a stand-up mechanical unit in a central closet for houses in my area. This can be tough, as far too many of the locally-sold units are cheaper-than-bargain-basement apartment-use units. But, getting the filters where there's a tiny possibility that the residents will change them is far better than having them in overheated attics or in dank, humid, cramped crawlspaces.
But, that's me; others differ.
My only other "gripe" with combination units has to do with when only part of the unit "dies" on you. Crack the heat exchanger on the heater, and you need a new one. Guess how many fit the existing air handler? Pain in the rear all around.