returns in bathrooms??

[thecarpenter]

I know one doesn't usually put a return in a bath, but....I have 3 bathrooms (only toilets and lavatories) and one office in a large workshop with a common west exterior wall. The bathrooms are all lined up adjacent with no common hall. Two baths and the office share the workshop space( unconditioned) while the first bath is an adjacent workshop(also unconditioned) with no common area except the outside. One fella tech said no returns in baths, 14" flex return with filter grill in ceiling of office with 8" supply and 7" supplies to each bath. Basically just pumping cold air into baths and office.
Each is about 9x10 or total ~400sq ft. Putting 1 1/2 tons(smallest unit available) instead of individual window units.
Will this work? I know not very efficent, but...

[NCHeat]

No returns in bathrooms or kitchens. Why would you want to circulate those smells? If you are using an AH at 600 to 800 cfm, the 14 in. flex return should work just fine.

[thecarpenter]

I know one doesn't want the smells... but how to get air back to the unit, remember, 3 rooms are only connected by closed doors through unconditioned space and the first bath is not connected at all?

[NCHeat]

Maybe you could explain the space to us better. An illustration could help. Are we air conditioning an out house?

[surenuff]

IT sounds like you will have to dump air in those bathrooms, and maybe let a exhaust fan remove the air to keep the bathroom from pressurizing. Then cut in a fresh air vent into your office to make up for the lost air from the bathroom vents that are not returning. This sounds similar to a job a had to do a while back. Keep in mind that the makeup air you are going to bring into your unit is from unconditioned space and will possibly add a large heat load to the unit. Just something to think about. I believe the 14" flex is going to be small for the return. And I will let you know what size return air filter grill you should look at. Also let us know about the length of the runs and the layout if you can. We will try to give the best advice we can.