ac and insulation advice

[gtcs]

I have most of the other parts of the build planned out, but I have no idea what to do for ac and insulation.

The building is a 30x40x10 'glorified carport' with a 4:12 pitch.

What I am thinking right now is DIY sprayfoam on ceiling, and r13 in the walls, which are 2.5" tubing that I'll put a 1" hat channel on. For heating and cooling I really don't know. Mini split? Maybe 2 window units framed in? Maybe a used heat pump system?

I really have no idea, my old shop had a swamp cooler, not doing that again, currently an old window unit in a 2car garage... if I open the door its over, unless you're right by the unit.

Surely theres better ideas out there than these. Help.

 

[markietas]

In any sort of quantity DIY spray foam is almost always more expensive than a pro.

 

[AndyCBR]

I have most of the other parts of the build planned out, but I have no idea what to do for ac and insulation.

The building is a 30x40x10 'glorified carport' with a 4:12 pitch.

What I am thinking right now is DIY sprayfoam on ceiling, and r13 in the walls, which are 2.5" tubing that I'll put a 1" hat channel on. For heating and cooling I really don't know. Mini split? Maybe 2 window units framed in? Maybe a used heat pump system?

I really have no idea, my old shop had a swamp cooler, not doing that again, currently an old window unit in a 2car garage... if I open the door its over, unless you're right by the unit.

Surely theres better ideas out there than these. Help.

Whatever insulation you do is going to be better than none for sure. Concentrate on sealing the envelope as most losses are due to infiltration. R value is great but sealing is important also.

A mini split would work but with that area many (myself included) would suggest one outside unit that can drive 2 heads on the inside. The heads need to be on an exterior wall so they can drain condensate so plan for that.

Another simple option is one or two smaller packaged units (the opposite of a "spit" system) that sit on the ground outside and have minimal ductwork. You see these on commercial buildings (like warehouses) from time to time.

The cheapest option would be 2 window units framed in but they don't dehumidify quite as well and can be a little noisy. Can't beat the price point though and they are basically disposable.

 

[gtcs]

I can't find an insulation company locally, but if that is the case I will look in the neighboring areas for one.

I think I will go for the window units then, if dehumidifying is their weakness I'm good, I live in the desert so theres not much to start with.

Do you think those window units with heat would be sufficient for winter? it gets below freezing here, but not often.

 

[AndyCBR]

I can't find an insulation company locally, but if that is the case I will look in the neighboring areas for one.

I think I will go for the window units then, if dehumidifying is their weakness I'm good, I live in the desert so theres not much to start with.

Do you think those window units with heat would be sufficient for winter? it gets below freezing here, but not often.

They have window units with electric heat also but you will have to rough in 220v (you will anyway for larger A/C units anyway).

Not very efficient but since you won't need it very often it would work for your application.

Put one each on the opposite sides of the building to help with mixing and air distribution.

Not sure when you will be done but keep an eye out for sales at your local home center. If you can wait until fall you can usually score some deals on old stock before winter. There are also some online places (Amazon, AJ madison, etc.) that will open up your choices and be competitive.

 

[gtcs]

Yeah, those 220 ones are what I was thinking. I'm an electrician so running circuits is the easy part for me, much cheaper than an HVAC tech anyway. As far as the heat I just want something to keep it above freezing, I don't do much more than the necessities when its cold, I also have the propane tank top heater from my old shop if I need to warm it up quick.

Thanks for the replies.

 

[James-W]

In any sort of quantity DIY spray foam is almost always more expensive than a pro.

I agree, if you want spray foam then have it done professionally.

 

[theoldwizard1]

The building is a 30x40x10 'glorified carport' with a 4:12 pitch.

What I am thinking right now is DIY sprayfoam on ceiling, and r13 in the walls,

By ceiling, I assume you mean the underside of the roof deck. Install as much insulation as is practical and that you can afford.

DIY spray foam can be a real hassle. Make sure the DIY part is worth the cost savings. Double check the fire rating and if your insurance company has any issues. Fire rated drywall on the inside will not only look good, but might be required by code/insurance.

For heating and cooling I really don't know. Mini split? Maybe 2 window units framed in? Maybe a used heat pump system?

It depends somewhat how many hours a day you are going to use your shop and if you need to maintain a "reasonable" temperature. A few hours per day, go with window A/C. Try to wire them so they can be turned on 20-30 minutes ahead of time.

A mini split would work but with that area many (myself included) would suggest one outside unit that can drive 2 heads on the inside.

The cheapest "cost of operation" would be a mini-split. With a building your size, I strongly recommend 2 air handlers. A lot more money initially, but it you plan on using the building a lot or need to maintain a temperature, it will pay back.

 

[theoldwizard1]

Do you think those window units with heat would be sufficient for winter? it gets below freezing here, but not often.

If they are resistance heat strip, the operational cost will kill you if you want to "maintain" temperature.

As far as the heat I just want something to keep it above freezing, I don't do much more than the necessities when its cold, I also have the propane tank top heater from my old shop if I need to warm it up quick.

There a better (more efficient) ones out there now a days so you might want to go shopping before winter.

 

[gtcs]

Thanks for the replies. I think I found a company the next town over to do the spray foam, and you guys are right. I was looking to spend about 1500 on a DIY kit for the ceiling, he says he'll do it ALL for 3000 if I wait till he has another job in the area.

Question though, the foam I'm looking at is white, and fire rated. My hope is to NOT need to cover it with another material, but have that as my finished ceiling. Anyone see a problem with it? I may paint it with a high gloss paint for better lighting, would that be ok?

I also think I may hit up an HVAC guy we use for work about maybe buying an used ac unit, but I still need some kind of heat. I do have Nat gas on the property, but had not intended on piping it to the shop.

 

[DC73]

Question though, the foam I'm looking at is white, and fire rated. My hope is to NOT need to cover it with another material, but have that as my finished ceiling. Anyone see a problem with it? I may paint it with a high gloss paint for better lighting, would that be ok?

If the foam is really fire rated you might be okay but local codes will dictate. I do remember reading that there is a white coating that can be applied over exposed spray foam to meet codes. Sorry but I don't remember any more than that.

If you don't want to pipe natural gas to the shop, your best bet might very well be a ductless mini-split system.

DC