single room hvac unit

[new_boater]

Hope you guys can help me with some ideals for this.

I have a 3 season room that we are going to convert to a family room.
it is 15 x 24 with a sloped ceiling high side being 14 feet and connected to main house by one wall.

I do not want to tie into main house heating/cooling for many different reasons.

what i am looking for is a single room unit that i can mount in the wall or something to handle heating and cooling and be economical to operate.

I have no problem running gas or electric for the unit.

Wall depth will be either 2x8 or 2x10 to help make it a energy efficient room.

Thanks for any help and advise

 

[captmello]

Re: single room hvac unit

You don't have a lot of options, "Practically speaking."

Have you seen those units in the Hotel/motels? Expensive and noisy.

If you can't hook into the exising house furnace, electric baseboard for heat, Leave the door open to the rest of the house for A/C.

Add a couple ceiling fans.

Those thick walls are not going to help that much. 2x6 is plenty, Good windows and doors are more important, IMHO.

Good Luck!

 

[new_boater]

Re: single room hvac unit

i was thinking of something like that or what hospitals use(quieter)

i am not opposed to 2 separate units either meaning baseboard heat and a small window ac unit.
i was mostly hoping for a nice clean look and efficient to run

 

[mthieme]

Re: single room hvac unit

NB,
My living room is of similar size, 15x27 with a 12 1/2' high cathedral ceiling. It's located in the center of the house. It's an old summer house which I have spent a couple decades (so far) reconstructing. I have efntrak heat which is inefficient due to the duct work. A friend gave me some old 220v baseboard heaters, tehy draw 3A max and are the oil filled kind. These are mainly for backup. A fireplace with an insert is in this room which is the main heat source.
The house does not have central air so I resort to window rattlers which I hate. Having said all that, I have been looking at ductless split HVAC units. We have these here and there at work and work well and are not noisy although they are plenum units which I could not use. There are many manufacturers of these. I'm looking at Sanyo because tehy are the only ones that offer four zones. The system runs about $5K (no labor). I expect you could go this route and have it installed for one room for under $2K.

 

[Beefer]

Re: single room hvac unit

Beefing up the thickness of the walls to 8" or 10" will help dramatically IF you insulate properly. The additional 2-4" makes a huge difference. If you've ever been in an older manufactured home in the dead of summer or winter with 4" walls, you can tell what I mean about the difference a couple of inches make.

There are units out there that are window/wall mounted that provide both cooling and heating, similar to what hotels have, but I've heard they aren't as noisy. Just be sure that whatever you get, it's rated for that sized room (3,960+/- cu ft). A unit like that from what I've heard is around $600. Don't quote me on the price though.

 

[new_boater]

Re: single room hvac unit

i figured with that size room i would just go with super thick walls and use a r30 or so insulation to get every bit of help with energy savings

a wall mount unit or something that could go in between the studs is what i was thinking about
do you have a link to something like what you are talking about

 

[SS MAYFLOAT]

Re: single room hvac unit

Check out Mrslim.com

These are split units made by Mitsibishi (sp) They handle both heat/cooling. Bit expensive, but are considered the best of the bunch of these type units.

 

[captmello]

Re: single room hvac unit

i figured with that size room i would just go with super thick walls and use a r30 or so insulation to get every bit of help with energy savings

If your room has no windows or doors this may help. a double pane insulated new window gives you around R4 insulation, triple pane can get you close to R10 depending on the quality. Insuate your ceiling to R39-44.
that is where the heat loss is along with drafty windows and doors.

As you may have noticed, its the A/C that is really the difficulty here. If your in Michigan you need A/C only a couple months out of the year.

I would get sick of listening to these other combo units running all winter even if its a low hum.

If you want to spend 4 - 5K then hook up to the rest of the house.

Not knowing what you have now for HVAC limits suggestions.

 

[new_boater]

Re: single room hvac unit

the biggest reason for not hooking to the rest of the house is the furnace is at the other end of house and that is about 65 feet away, as it is right now it has a hard time with the long runs and keeping a uniform temperature throughout the house

the room currently has 7 door walls and these will go away to be replaced by a standard 36" thermo door and 4 thermo windows all will be triple pane for the r value

cooling is not as much of a issue as having a very comfortable room during the cold months. we like to play on the floor with the grandkids and it really needs to be warm

 

[captmello]

Re: single room hvac unit

Is this room on a slab? If so keeping the floor warm can be a challenge. I still believe baseboard is the most practical and an easy DIY. Be sure you've got a couple large ceiling fans to keep the air moving around.

I've done some heated floors in a few bathrooms with electic heat elements you can get at the "Depot". They also make elements to go under carpet and Laminate flooring. These are not ment to heat the room however just warm the floor. These are not practical for your whole floor but if you knew your final layout, you could create a warm spot on the floor for the kids. Those warm floors are great.

Someone mentioned a gas fireplace, good idea.

 

[new_boater]

Re: single room hvac unit

yes sits is on a slab but as it is about 12" lower than the main house i plan on putting in 2x8 joist for the floor and having a shallow step into this new room

base board heat is a option and maybe just put a window ac unit for the few months that it is needed

in floor radiant heat would be nice but entails a lot of extra equipment that
i would like to avoid

i have seen the "floor" heaters you are talking about and i am considering them for a "play area" on the floor

 

[cpubud]

Re: single room hvac unit

just get a window unit heat pump and mount in thru the wall.

 

[new_boater]

Re: single room hvac unit

What is the correct way to calculate the requirements of a given room size?

 

[SS MAYFLOAT]

Re: single room hvac unit

It may not be 100% correct, but I always figure 12,000btu of cooling to 400 square feet. There are more precise calculators out there for wall thickness, windows, doors, ceiling height, type of insulation, etc;

 

[new_boater]

Re: single room hvac unit

thanks ss mayfloat i will work with that

 

[captmello]

Re: single room hvac unit

sits is on a slab but as it is about 12" lower than the main house i plan on putting in 2x8 joist for the floor and having a shallow step into this new room

If this is the case, by adding the floor joists, you can now insulate between the joists and your floor temp should be ok. You'll want a vapor barrior between the insulation and subflooring.

just get a window unit heat pump and mount in thru the wall.

What's this?

 

[JamesCoste]

Re: single room hvac unit

We just added on a 24 x 16 addition. It is two-story. Our existing HVAC was pipped into the bottom floor and is "sufficient" during Florida summers.
We bought a Hotel Unit "through the wall" GE PTAC unit for my son's upstairs room and love it! It cost about $1250 though but has a pretty good SEER rating. It is quiet, meets the need, and should last a long, long time.

We'll see.

here is a picture of it from the inside:

.


http://home.jamescoste.com/AdditionPaintStain/images/dsc06066.jpg

 

[smclear]

Re: single room hvac unit

I design HVAC systems for a living. There are too many unspoken factors.

I have attached a very basic spreadsheet for determining how large a unit you will need. It will get you very close.

You will need to enter the square footage of each wall in the proper area. Do the same for the windows. The difference between sunlit and shaded is not as simple as saying all "East" walls are sunlit. Only you know your room. What side sees the most sunlight? Use that as the sunlit side.

It is important to determine the right size unit first. Get one too small and the thing will never cool to your satisfaction. Get one too large and you'll run the risk of burning up the compressor. It will cycle 'on' and 'off' far to frequently. Not to mention the added upfront costs.

The hotel units are called PTAC units.

Sorry about this but apparently an Excel file is a "invalid file" and can't be uploaded.

 

[new_boater]

Re: single room hvac unit

smclear,
you have pm mail

 

[new_boater]

Re: single room hvac unit

If this is the case, by adding the floor joists, you can now insulate between the joists and your floor temp should be ok. You'll want a vapor barrior between the insulation and subflooring.

my plan was to put the thickest plastic i could find right on the slab than build the joist and every thing above that
is that the correct way?