I'm remodeling a 1500' ranch house. Interior already gutted. Doing all work myself. Plan to install heat pump and ductwork myself as well. Seasoned DIY'er, but minimal experience with HVAC or ducting. Preliminary research leads me to believe that I should probably go with a 2.5 ton split system with a minimum 14 SEER. If I go with a split system, I'd prefer to use an upflow evaporator and route the ducts through the attic area using ceiling registers. Don't need the attic for storage and I like keeping the crawlspace open for routine maintenance, inspection, etc..

Some info about the house:
Built 1969
1500 sq. ft.
26'W x 57'L
Brick veneer siding - Wood windows to be replaced with Low-E vinyl windows
5/12 gable roof - ridge vent, soffit vents, gable vents (no powered vents)
Black architectural shingles (attic gets very hot during summer months)
No basement - Graded crawlspace slopes from 30" at one end to 18" at the other
Floor and ceiling joists 16"oc. Will be thoroughly insulated as part of remodel
Stick built roof with knee bolsters. No trusses.
No obstacles around exterior perimeter. Several options for placement of outdoor unit.
8' interior ceilings. Walls and ceilings to be finished with drywall.

Ok, now for the questions:

Split system or package system?
2.5 or 3 ton?
Brand recommendations?
Any serious drawbacks to using attic ducts and/or ceiling registers?

Thanks in advance for all responses. Will be happy to provide additional info if needed.

Michael
Darlington, SC

I would put the air handler, coil, and ducts in the crawl space. Condensate drains are notorious for plugging up. Big hassle in the attic. The crawl space is also much closer to the conditioned air temperature. I have mine sealed and insulated. It stays dry and about 60 degrees year around. Even with tightly sealed, insulated ducts, you are still going to have losses.

Yeah, they can be in the way. I ended up taking the last 8 feet of the supply duct off last summer when I moved my water heater to gain access to the piping. What was put together can always be take apart.

Thanks for the feedback, Labman. Sounds like you've had a lot of experience in the trades. It's always good to have a friend who can offer some sage advice.

Have you considered putting the Furnace and evap coil in a closet in the garage. The water heater could also be placed there. With the work you are going to do on the windows and I am sure you will insulate the attic space well, I feel like 2 1/2 ton 14 S.E.E.R will be adequate for the house.
As for as brands I would check around in your area and see what is the most popular brand of equipment, and also a distributor that has been there for many years. Sometimes if it is not a popular brand for that area you will be having to order parts for you equipment. Also if it is a brand that changes distributors often you may have trouble getting warranty work done. Carrier is a good brand and I have had very good luck with them for over thirty years in the business.

Thanks, letmetellu. I'm leaning towards a split system with the interior unit in a centrally located closet. Maybe run a trunk line the length of the attic with supply ducts branching off to each room as needed. However, I have concerns about the summer heat in the attic placing a heavy burden on the A/C. I Also want make sure that the ducts don't sweat on the ceiling below.

Carrier certainly has a lot of experience with HVAC technology. Trane and Goodman seem to have most of the market share in this area. I had a Trance once. It was a good unit, but they have become very expensive with a lot of proprietary technology from what I've heard. On the other hand, I have a Goodman package unit in my current house that has served us well. It doesn't have all the bells and whistles (fancy filtration and such), but they are competitvely priced.

Since this will be a DIY installation, I have to make sure I use a brand that won't void my warranty just because I'm not a professional contractor.

Thanks,

Michael
Darlington, SC

My old furnace and A coil was in the garage, and the hot water heater still is. Poor set up. The hot water heater has to be up on a stand. The furnace took up space otherwise better used. When I put in a new furnace 10 years ago, I put it in the crawl space. That may violate code now, but it works very well. The system is a Bryant, and the contractor worked with me on me doing most of the work, but him doing the Freon and start up.

I loathe units in the crawlspace, nothing will get a service man in a worse mood than a crawlspace at midnight or an attic at noon. I would put it in a utility room or garage. Since a heat pump runs all the time (almost) and flex duct has a poor R value and because heat rises I would put the ductwork in the floor with return cut in high on the walls. This will give you better efficiency warmer flors and better comfort. Don't use flex in the crawlspace though, Use metal and insulate it yourself with foilbacked insulation. Living in SC as lond as you do foam board insulation, house wrap, and good windows, I would go with a 2.5 or even 2 ton system for better dehumidification. If the unit is oversized it will cool the air to rapidly and not get the humidity worked out of the house. Duct design will be important also. Make sure the ductwork will carry 1000-1200 CFM. Look into buying a Manual D and J book, this is the only sure way to know if the system will handle the workload. Manual J Eighth Edition - ACCA 33-8 (http://www.books4hvac.com/index.asp?PageAction=VIEWPROD&ProdID=443)

Thanks for the helpful suggestions, NorthernHeat. I was planning to use a split system with an upflow evaporator. One of the bedroom closets has a wall against the hallway in a central area of the house. My plan is to use part of that closet by positioning the inside unit in there and facing it out to the hall. I was also going to elevate the unit enough to provide one central return directly below it with a decorative grill. I've owned three houses in the past that had total electric heat pumps and none of them had returns in multiple rooms -- just one central retrun wherever the filter was located. Is that something unique to southern regions of the country? This heat pump will also be total electric.

Thanks,

Michael
Darlington, SC

I don't like to use a central return for multiple reasons. Noise, bedrooms will suffer comfort levels if doors are closed, negative pressure will usually occure around that part of the house causing appliance to draft poorly or pull untreated air from the outside through any crevice it can find usually causing dark lines around carpet, walls and even seen it so bad you can see dirty air has been pulled through every floor board joint.

Hmm... never considered all those things. Thanks for the insight. So, are you suggesting that I run a supply network to eah room in the crawlspace and a return network to each room through the attic? Seems like an awful lot of ductwork. Note: I'm assuming it would be easier to place high mounted wall returns by making short drops from above. Am I misuderstanding all this?

Michael

It is a small house, I would use a downflow furnace, coils are coils if they are virtical only the horizontal coils are different. Put the coil under the air handler, some manufactureres want the coil on top, making it a pull through coil on top of the air handler, doesn't relly matter though. Return ductwork in the attic, supplies in the crawl. Returns in at least the master bedroom, who cares about the kids? Just kidding. And I would like to see a floor plan to tell you how many more you should add, but 3 or 4 if sized right will work very well. Attic ductwork I would do in flex. Returns can use the wall cavity for the ductwork and are easy to pan-off in the attic.

Great info. Remind me to send you a Christmas card - a nice one!

I'll see if I can generate a floor plan and attach it to a post so you can see what kind of area I'm working with. What about the filter? Would I need to rig up something to accommodate it?

Michael

No you don't need a return in each room, 3 or 4 properly sized returns will be better than 1 central return. And yes you will probably want at least one supply ran to each room sized according to the heat loss/gain of each room.

I've attached the floorplan. Hope it's formatted correctly.

Michael

One thought about placing the unit in the hallway, some areas do not let you put a furnace or water heater in a hallway where a fire could block exit from the bedrooms on the end of the hall. Goodman is use quite a bit in my area and seems to be very good equipment. The question about sweating should be solved by using a good two inch insulation with a good vapor barrier. About the warranty being voided because it is a do it yourself installation. I don't think that would be a problem is you are doing it in your own home and get the permit in your name and have a licensed installer do the actual freon work and then sign off on it.

"One thought about placing the unit in the hallway, some areas do not let you put a furnace or water heater in a hallway where a fire could block exit from the bedrooms on the end of the hall."

This will be a total electric split heat pump system. No Gas. Going with a tankless electric water heater also.

Michael

How is the eletric power for heatpro heat pump hp13023772 rev: b