HVAC DIY

I will soon have my addition construction drawing from an architect. The architect does not do HVAC drawings, he mentioned I need to find (he has some he can recommend) HVAC contractors who can do HVAC drawings based on his plan. These HVAC drawing and then =93fed=92 into his construction drawings which then become integral completed blueprints.

Once I have HVAC drawings I need to decide how to install all HVAC stuff (forced air furnace, A/C, condenser, ducts). I expect it will be quite expensive. I am trying to stretch my small budget and see if any of HVAC work I can do myself and if it makes sense and can save me money at the end. Does anyone have any suggestion regarding what I can reasonably do to cut the addition HVAC work? I am handy, have extensive remodeling experience but no HVAC experience. I probably won=92t be able to install furnace and A/C but can I install ducts? Will I be able to save money this way? Any advise would be appreciated.

Reply to
ls02
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Ask some friends if you can poke around in their houses to see what their HVAC system looks like. Then you will know if it looks like something you could do.

Reply to
salty

Yeah, easy to do. It's the system design that seems the hard part (something I'm looking into myself right now and it's not as simple as just slapping a few bits of metal together)

By 'addition' is this construction onto an existing property that already has ductwork, furnace etc.? Or is it a separate building which will have its own heating?

If it's got its own heating (so you're going to have to invest in some sort of heat source anyway) I'd go with water-filled radiators (as Existential Angst says), gas-fired combi boiler, and heat your hot water using the same boiler. Pipes take up a lot less space than ducts do, and you'll have a lot more control over where you want the heat.

cheers

Jules

Reply to
Jules

Mini splits are expensive to install but the ability to zone the cooling may make your payback period pretty short. If you only run the rooms you use. I have a central system but we only run the mini in the bedroom when we go to bed. That way my wife can have the 70 she likes to sleep without cooling the whole house. I also have a mini in a new addition we only cool when people are sleeping over. It is open to the screen cage most of the time.

Reply to
gfretwell

Depending on the length of the cooling season. But indeed, the zoning is Da Bomb. I don't know how much heat pumps save over oil or gas, but whatever savings there are would help as well during the heating season..

They are also easier on the wiring than a central air compressor, and would lower demand charges, if such exist for residences.

What brand/type did you install? Did you measure the power consumption?

I was going to do two 12K btu units, but the mitsubishi/fujitsu price came in at $5K for the pair, and it turned out that installation in these two particular locations was not quite the slam-dunk I thought it would be. So I passed on it for this year, will look at cheaper units, maybe that Amcoraire unit. I'm wary of internet stuff, tho.

Reply to
Existential Angst

I am not saying it is easy or hard. Just to me installing ducts and registers appears to be more feasible for me to do then any other part of installing forced air equipment. It is possible though that even ducts are out of my reach or it won't save much $$$ at the end so it is best to hire pro to do all work. That's why I wonder what if any I can resonable do myself to save on HVAC work.

Reply to
ls02

One is an LG the other a no name clone of the LG (labeled Allstyle). They look pretty much the same to me. They are both 1 ton and seem to draw about 10-12a @ 120v. The thing I like is they will run on a garden variety 120v circuit so if your panel is getting filled up you only need one slot and that could be a piggyback breaker, so really zero new slots.

We are pretty much A/C only here so I didn't buy the heat pump option.

One I bought installed. I put in the other, no big deal but I have done some HVAC before. The bedroom machine is on the christmas light circuit, since they both ended up in the same place and are usually non-coincidental loads.. If I really see the need I can run another circuit out there pretty easily.,

Reply to
gfretwell

A lot depends on what kind of ducts you run. When I lived up north I installed metal myself but I did have a fishing buddy that hooked me up with the fabricator so it was just putting them in. All of the drops were run with round pipe and that just snaps together. The ducts themselves needed the lips bent over and the S Slips and drive flanges driven in. It was really pretty easy. A wrap of silver tape sealed everything up. The trick is getting a decent price from a fabricator. They are a pretty closed community. A lot won't even talk to you if you are not in the trade. Ever been to alt.HVAC? ;-) If you use duct board and flex duct, you need the tool to cut the angles in the duct board without breaking the foil. use silver tape, (not "duct tape") and get a plastic wiper doodad to seal the tape down. The HVAC supplier usually gives them away. Keep your flex straight and pulled pretty tight so it doesn't have a lot of ridges to slow the air flow. Some say it is best to run it on

1x running boards where it crosses truss chords to give yourself a flat surface. Seal all the joints with mastic when you are done.
Reply to
gfretwell

I am not going to use flex ducts, only straight metal ducts. I believe all ducts components (round ducts, elbows, registers, etc.) are available from big home centers. I have experience snapping them together and I nkow how to seal joints with aluminum tape and furnice cement.

Reply to
ls02

That were me with the Amcoraire. When I bought it, I roughly figured 3 years to amorize it. Now, it's gonna pay for itself in less than 2 years. I have a 12K microprocessor controlled version with a seer of 18. Central unit (old (for around here)) has a seer of 8 or 9. I plugged the Amcoraire into my Kill-a-watt for a couple of days (summer time). In 55 hours it used

6.8KWH!!!!! My honey and I like it cold in the bedroom. I have the "setback thermostat" set the house to 79 at 2300. I set the bedroom a/c (gotta love those zones) to 69 degrees. If I build another house, it will have several of these mini-splits (they are heats pumps also). Also one outside unit can run two inside units. The only wart I have found so far is this: the fan does't run all the time during the heat phase.

I am not going to use flex ducts, only straight metal ducts. I believe all ducts components (round ducts, elbows, registers, etc.) are available from big home centers. I have experience snapping them together and I nkow how to seal joints with aluminum tape and furnice cement.

Reply to
lost

Hey, good you popped up! Yeah, I often cite your older post in the useless alt.hvac.

6.8 kWhrs for 55 running hours? Or cycling on and off for 55 hours?

Is your unit 120 or 220V?

You cited 500 W at full load. Another poster here cited 10-12 amps at 120 V. If yours is running at 220-240 V, both would be in the same ballpark. If yours is running at 120, then there is a big big diff!

What does your killawatt read when you first turn it on, and how does it ramp down, current wise?

Reply to
Existential Angst

Yeah, they are - but I bought a couple of runs of 6" duct from HD once (the rest I needed came from my local Restore place) and of the whole pile there I got the only good two that weren't badly damaged (and even then one of those was a real pain in the butt to snap together)

I think I prefer rectangular duct - it's a lot easier to work with, particularly if doing anything custom, and takes up less space (because for a given cross-sectional area a round duct takes up more useful space)

cheers

Jules

Reply to
Jules

Please be sure to consult with the HVAC installer. Some of them get very upset with home owners who are trying to save a buck. They like to do the whole package. Yours may not be as easily upsettable.

Reply to
Stormin Mormon

If you look at a portrait of the Mona Lisa, will you know if you can paint?

I'm not sure looking at finished ducts tells if you can install duct.

Reply to
Stormin Mormon

Well, I know it wouldn't help you. But, that's okay, because I'm not talking to you. The guy my advice was directed towards is smart. He probably has a rough idea of what his skill level is, and seeing what the stuff looks like may be a big help.

Reply to
salty

Insulated metal ducts are not available at any big box store I've been to. Just ends. Just about all installations these days use flexduct. It is far faster to install, lighter, and because you do not have as many junctions you have less risk of leaks.

You ask an installer to use all rectagular metal duct instead of flex and your quote will be thousands higher.

Reply to
jamesgangnc

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Do flex duct have more resitance to air flow? I remember they are not recommended even for bath exhaust fan.

Also if metal ducts are not insulated, can I insulate them myself? Do I wrap ducts with special duct insulation wrap?

Reply to
ls02

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I think you will be hard pressed to find a bath exhaust fan in a typical house built in the last 20 years that does not have a piece of

4" flex connecting it unless it is already at the exterior wall.

You need to size the flex appropriately. For short to medium runs use

6", for long runs use 8". If you have a lot of long runs in one direction then you use 12" or larger to a square hub and then run your multiple 6s from it. If you are doing it yourself you can fabricate boxes from ductboard. They make flex takeoffs for ductboard.

Metal duct work is insulated on the inside, not the outside. I believe there are condensation issues with insulating it on the outside. Metal duct work is galvanized but long term exposure to water will eventualy cause damage.

Reply to
jamesgangnc

I think you will be hard pressed to find a bath exhaust fan in a typical house built in the last 20 years that does not have a piece of

4" flex connecting it unless it is already at the exterior wall.

You need to size the flex appropriately. For short to medium runs use

6", for long runs use 8". If you have a lot of long runs in one direction then you use 12" or larger to a square hub and then run your multiple 6s from it. If you are doing it yourself you can fabricate boxes from ductboard. They make flex takeoffs for ductboard.

Metal duct work is insulated on the inside, not the outside. I believe there are condensation issues with insulating it on the outside. Metal duct work is galvanized but long term exposure to water will eventualy cause damage.

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Heh, makes sweating copper pipe for a hot water system seem more and more attractive, eh?

Reply to
Existential Angst

When Stormin looks at the Mona Lisa, he's proly wonderin how it would look pasted on his shower curtain, next to the Elvis print.

Reply to
Existential Angst

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