Rooftop AC in place of escape hatches?

[BBTC2K]

I was wondering if anyone has ever used their roof hatches as a spot for either roof ac or fantastik fans?

If so, how did you get them to fit?

thanks

shawn

 

[oldog12]

I often wondered about the same thing... Just eye-balling it, it looks as though they're made to order for a roof mounted AC unit

 

[eggman-SKO]

The way it looks to me, is that the emergency roof top opening is around 18-20 inches, where the roof top is meant for 14 inches.

 

[frank-id]

Roof vents

Most buses roof hatches are larger than size required for a AC unit. The hole needed for a fan or AC unit is 14 1/8 inch. Covering an existing hole usually requires some roof work and some method of reducing the hatch hole. Most roof AC units use long bolts to clamp unit to the roof with no fasteners connected to roof. Carrier units are the most expensive but seem to me to be the best of the AC units. Frank

 

[oldog12]

Wow, it sure seems a waste not to use those holes...

 

[Steve-SKO]

Better that the holes are too big, if I had escape hatches I would definetly make some adapters to use them for A/C. With all that space around it you could make some really nice trim.

 

[oldog12]

I was thinking along the same line... its there, might as well use it...

 

[frank-id]

Roof vent hole

I think the most important consideration for roof AC is placement. My Crown bus has 2 roof AC units and a center fantastic vent. One AC is at thr very front of the bus to allow some creature comfort while traveling down the hiway. I think I'm also gonna make a curtain to restrict the cooling air to be a the most value to the driver. I mostly travel alone. My bus is not yet insulated so heat and cooling are not great. My plan is to drill many 1/2 inch holes and inject insta foam with care. After foam has stopped expanding, carpet will be glued to ceiling, and with wood strips screwed in place. Frank

 

[oldog12]

I was also wondering about carpeting my ceiling in hopes of increasing the R value, I'm just a little concerned about the glue not being able to handle however hot the roof/ceiling may get

 

[Steve-SKO]

I think the best benefit of the carpeting is the sound deadening you will get from it.

 

[oldog12]

Santa's Reindeer?

 

[GoneCamping-SKO]

What you're going to find is, the gaskets they sell to seal them with are only 14" and it's pretty likely anything larger is just not going to fit the under side of the roof top unit.

You probably could formulate some kind of fan system and a screen without too much trouble though. I like having just an opening hatch up there....with screen of course...

 

[oldog12]

What would happen if you cut a hole into the hatch cover itself and mounted the AC on the hatch cover?

 

[eggman-SKO]

I dont see the plastic hatch cover holding up to the vibration nor the weight that a roof top unit has. I would be keeping the escape hatches for just that, as they are designed for. And cutting a couple of 14" holes in the roof to accept the AC units.

 

[oldog12]

I see your point, I was sure hoping to try avoiding cutting another hole in the roof...

 

[the_experience03]

Good idea with the drill a hole and fill with foam idea, Frank. Are you concerned at all about trapping water or anything? That seems like something I might want to try.

 

[GoneCamping-SKO]

Well, if you wind up laying that bus over on it's side somehow, climbing out the roof hatch might be handy!!

I think in the long run, you'll be better off cutting a hole the correct size rather than trying to retro a hole that is too big.

 

[oldog12]

Well, if you wind up laying that bus over

You see a lot of roll-overs?

 

[the_experience03]

It would have to be a pretty spectacular rollover to block the side door, rear door, and kick-out front windows.

 

[Ryan Grimm]

I see a couple obvious things:
The hatch cover is too weak to support the AC unit. Simply make a cover or adapter (sheet ply with aluminum covering, self-adhesive foam tape to seal off), place that in the opening, and use longer screws or threaded rod to replace the now-too-short ones.

Next, if you use/build the adapter, maybe set it up so that a couple hold-down latches can be built in....SOMEONE out there makes them, I've seen similar latches in hardware stores (National Hardware brand?). Then if you need the roof exit in case of a rollover, you unlatch the AC, drop it off, and bail out.