inside tub installation guidance

[hair]

hi, the wife and i are putting our tub inside a 28'x16' room with 2 ,  8 ft. sliders, 4, 3'x6' double hung windows, and 1, 6 ft. slider, all vinyl.  room will be pine bead board which will be sealed with a quality exterior sealer/stain.  do i need a humidistat?  or can i just use my new dehumidifier, which i barely use anyway.  or can i put some kind of vent above the spa, one that does not take out the heat in the room?  also the room will have a gas fireplace for heat.  i'm just worried about the moisture issue, some people say it won't be a problem as long as the cover is on, and some people say it will be a problem.  anybody with an inside spa have any opinions on this matter, it would be appreciated.  thanks.

[Gair]

We live in central IL and have a Bullfrog 451 in a 10’X25’ room that was built on a patio. One 10’ wall to the North has no widows.  The 25’ wall to the East has three sets of double hung windows that are long to let the outdoors in.  The wall to the South has the door and a large double hung window.  The 25’ wall to the West is covered with aluminum siding and has the door to the house in the south end.  The others are T-111 on 4” centers that was sanded to a smooth finish.  All was painted with exterior paint with anti mold agent.  The ceiling is covered with a white vinyl bead board porch ceiling that follows the pitch of the roof. There is a 52” outdoor ceiling fan in the middle of the room.  The Spa is in the North West corner of the room. There is a 1350 cfm. fan vented to the outside in the South West corner of the ceiling.  I also have a small window fan that seals against the window frame to use when I need to supplement the one in the ceiling.  We have had no problems with this setup. We only use the fans when the Spa is open.   We are using Nature 2 and ozone for the Spa.  The room has its own heat. We keep the door to the house open almost all the time and with the Spa covered we have no smell from it in the house even in the kitchen which just inside the door. There is a large table with six chairs in the Spa room and we eat out there quite often in the evenings with no smell from the Spa.  All the windows have top down bottom up shades so we can drop the top of the windows down and also the shades so we have our privacy from the neighbors and their kids prying eyes. We live in an old neighborhood with close large two story houses so a Spa outside was not an option for us. It is winter here and we can enjoy our Spa anytime we want and we can leave the shades up and enjoy snow (when we have some) and also the birds.  

[johnvb]

We live in central IL and have a Bullfrog 451 in a 10’X25’ room that was built on a patio.

I'm also putting a spa inside, shoehorning into a 12 x 12 room. I like the idea of the top down bottom up shades, as we are installing double hung windows with outside screens. My idea is if the wind is strong, we can open the top sections and still be sheltered sitting in the spa.

What kind of floor covering treatment did you use? We have a concrete base, debating on tile, acid staining, or some type of commercial rubber coating. In a 12 x 12 room with a 7.5 x 7.5 tub, not much floor will be showing. Since it's part of the main house slab, I can't have any moisture transfer thru the floor.

I also planned using white vinyl bead board for the ceiling (actually what I'm looking at is AZEK, which I think is pvc). Haven't decided on the walls yet, maybe more AZEK boards, but the windows are Pella vinyls.

Speaking from no real experiences, I would think the spa room wouldn't need any more ventilation than a large master bathroom. For now, our room won't be conditioned, so I plan on installing a ventilator with a variable speed control, and set it for the lowest (quietest) setting that is sufficient.

One of our wet test was in a small private room, not much bigger than ours will be.  After 30 minutes of use, I didn't notice any major humidity buildup.

I also have a spare Aprilaire HRV unit laying around. This is a fresh air recovery ventilator that only moves 120 cfm worth of air, but recovers up to 77% of the heating or cooling energy from the exhaust air out of the room. It would help when the outside makeup air is too hot or cold.

Around here, the summers get real humid, so I may be adding some kind of conditioning HVAC equipment later. I have been told that it is better not to include the spa room in the main HVAC system, as the chemicals will eventually affect the equipment. (I'm a former HVAC tech, and this makes sense to me).

[hair]

quick question for gair, any reason you put your ventilator in the opposite corner of your room?  why wouldn't you put it right above your spa?  i just bought a 140 cfm venilator from lowes for $125.  it's a broan elite, whisper quiet, 2.5 sones, when it's turned on you can barely hear it.  i hope that'll handle my big room.  i'm also gonna have 2 ceiling fans.

[Gair]

My fan is 1350cfm I wanted it away from the Spa so when we sit in the Spa and don't have the jets on it will be quieter.  One thing that is very very important is that the room has it's own heating and cooling system.  When the Spa is open the extra moisture can cause problems with the whole house system.  You would be pumping that moisture thru your whole house also. This can cause mold. We close the door to the house when the Spa is open and run the fan or fans for about thirty min.  after we close it.
 Also the floor is concrete.  We are going to tile it this year with clay tiles, but not under the Spa.  The Spa will be setting a half inch deeper than the rest of the floor with a drain.