# HVAC



## showcattleguy (Jun 30, 2011)

Putting the final pieces together and was about to pull the trigger on a mini split but had a thought and figured better safe than sorry. How should I exchange air to/from my room? I have it sealed up very tightly as I went to the nines soundproofing and don't want to have trouble with stale air. I figured any solution someone else has used that I could steal or configure for my own needs would help immensely. Or would it not really be a problem. Need help please told the hit I would get back to him by Saturday


----------



## ALMFamily (Oct 19, 2011)

The mini split is probably your best bet for maintaining your soundproofing - the fan unit only has the feed and return coolant lines running to it from the outside unit. They are 3/8" IIRC and you can drill a hole through then seal around the line with accoustic sealant. 

The mini split do have drain lines IIRC so you will have to plan for that as well. Is your room in the basement?


----------



## showcattleguy (Jun 30, 2011)

Yes it is in the basement and I have the required refrigeration lines and the line for the required condensate pump in place I just don't want to invest in a mini split and have really stale air in my theater room because it is not getting exchanged, just cooled if that makes any sense


----------



## cdguy (Sep 5, 2012)

What do you use to heat/cool the rest of the house?
IMO I dont like mini splits, I have sold many, but for residential aps, they are not the best choise, often the cheapest, but most times not by much..


----------



## showcattleguy (Jun 30, 2011)

I have a furnace/central air but am trying isolate the room from the ductwork that runs throughout the house


----------



## cdguy (Sep 5, 2012)

How many sq feet is the room, is the furnace gas?
I would just throw an inexpensive 90+ furnace with an inexpensive A/C unit , Ducane or Kelvinator ect...
50K btu 90+ $840
1 ton case coil $190
1 ton compressor $690
Then depending on the room, you use flex duct and a plenum kit you will spend $500 on Duct work, then the gas line can be flexible and the exhaust vent will be PVC... If you do it yourself you will be under $3000 but have a real system... Stand alone with its own tstat...


----------



## ALMFamily (Oct 19, 2011)

cdguy said:


> How many sq feet is the room, is the furnace gas?
> I would just throw an inexpensive 90+ furnace with an inexpensive A/C unit , Ducane or Kelvinator ect...
> 50K btu 90+ $840
> 1 ton case coil $190
> ...


So, if I understand correctly, you are suggesting adding a second furnace and A/C unit that would supply the HT room?


----------



## showcattleguy (Jun 30, 2011)

The room is only 300sq ft and I have no where near enough room to put another furnace in my basement but that would probably be a viable option if I only had more space


----------



## ALMFamily (Oct 19, 2011)

That is what I was thinking as well - the footprint for the mini-split is probably one of it's plusses.


----------



## cdguy (Sep 5, 2012)

With a 0 clearance 90+ you only need about 24"X24" of a foot print, I put them in existing closets or build a small closet for them with 2x3's... Im not sure where you are located but with our climate, a heat pump with our winter temps isnt always the best option... I was thinking the room was larger than 300sq also, I was thinking 500... A ductless system will be fine, just not what I try to sell, they are loud, unsightly, not as reliable, and hard to find parts for {sometimes}...


----------



## showcattleguy (Jun 30, 2011)

Sorry house is small only 2100sq ft so this is all I have to work with. Back to my original question does anyone think there will be a problem with stale air since I will be just cooling and not really exchanging the air


----------



## ALMFamily (Oct 19, 2011)

I think you will be fine - the only chance I could see for the air to get stale enough to notice would be if you did a marathon viewing and never left the room.


----------



## showcattleguy (Jun 30, 2011)

Well I will also point out that our room has the capacity for 10 people though I'm not sure how often it will get filled I don't want anything but perfection as I'm sure everyone does considering how much time and effort goes into building these rooms. But if that happens we could always leave the door open I guess


----------



## ALMFamily (Oct 19, 2011)

Just thought of a test to put your mind at ease - take a ride in your car with the family. Turn on the A/C - make sure to use the setting of recycling the air. If you do not notice a change in air quality, I would think you should be fine.


----------



## ironglen (Mar 4, 2009)

A car is far from sealed, so infiltration will cause significant air exchange, though it seems otherwise.

300 ft² is pretty small for a system. I agree with cdguy to avoid a mini-split, if possible, so you probably have few options, including using a mini, install a 1-1.5 ton split as cdguy suggested, or using your whole house system.

Mini: stale air problem, install stand-alone erv to bring fresh air into the space

1-1.5 ton split: noisy/space issue, if acceptable, use an air-circulator featured thermostat to circulate/filter air along with a compressor lockout to prevent short cycling. If you have numerous people and equipment, you will have quite a bit of btu's in that room, so it may be more useful than you first think and is probably comparable to a mini in cost

Whole house system: run returns and supplies to the basement using flex duct and large grills and registers, which shouldn't pass much sound and will be the best sound quality for the ht room by far of the three choices


----------



## cdguy (Sep 5, 2012)

I was thinking about a fresh air intake {w/makeup air} or a low loss fresh air exchanger, the problem is they all take up room and are loud.. I dont think a mini split is giong to make you happy, its going to feel stuffy and impinge on the theater with noise and they tend to have much higher static pressure to make up for their low CFM register size... 
I know these decisions are hard, but making them twice is even harder..


----------



## showcattleguy (Jun 30, 2011)

Mini splits are loud? The one I was quoted is 26/28/31 for low/med/high. I thought that was rather acceptable but I am not sure. Could I place it in a soffit in my adjoining room and sort of flex duct it in so it could pull air from the game room and circulate that way? Not sure how far I would have to take the isolation of the soffit.


----------



## cdguy (Sep 5, 2012)

showcattleguy said:


> Mini splits are loud? The one I was quoted is 26/28/31 for low/med/high. I thought that was rather acceptable but I am not sure. Could I place it in a soffit in my adjoining room and sort of flex duct it in so it could pull air from the game room and circulate that way? Not sure how far I would have to take the isolation of the soffit.


Yes they are a lot more noticeable than a FWA unit, Im not sure which units you are looking at, but most do not show the sound level when they are out of their quiet modes, and most of them arent very effective in said mode...

It may be the only way you can go, so try it out, if its stuffy in the room after, than fix the problem when it arrises... Maybe some oxygen lines at each of the theater seats...


----------

