Multiplication factor for no insulation and porous structure

[rslaback]

My wife has a cheap amish built playhouse in the woods behind our house that she uses as a kitschy writing cabin for her sermons.



It will soon be getting a power line run to it so that she can have lights and also a mini-split to serve as heat and cooling to extend its use a bit in different seasons. It also means that I get to reclaim my battery powered shop vac.

The structure is wood frame with pine board and batten and gaps in the floor with a rug covering it. It is in no means air tight. I know at 7'x10' the charts are going to tell me I need 5000btu but realistically how much capacity should I add based on the structure being so airy? I know it is a waste and I am sure some guy is going to come along and tell me to seal it all up and insulate it but that isn't going to happen. It ruins the simplistic vibe that she loves.

The only experience I have with something like this is our 12 foot pop up camper with a slide out which has a 15,000 btu air conditioner on the roof. It does ok when we camp in summer. I imagine this wouldn't need something quite that big as the wood will be a bit better insulator than canvas but I'm not sure.

Thoughts?

 

[danski0224]

It's 70 square feet.

How hot/cold do you want it to get in there? Door open or closed?

You could cut a hole in the wall and stick a small window unit in there.

In heating season, the operating limits of the equipment will become a problem before not being able to heat the space.

I would get the smallest mini split and go that route if you don't want to put a window unit in the wall.

 

[jack stand]

Id put it to her this way, it's insulation and some type of rustic wood on the walls or an electric blanket and a box fan.
Any M/S that I've seen need a 30 amp supply to the outside unit, it might get to be a pretty long run from your panel to the shed.
For what you're proposing (spending) the first thing I'd do would be to jack up the building to gain 6" more clearance from the ground. It'll help this little building survive possibly doubling its lifespan.
You are a loving husband!

 

[pcmeiners]

How hot/cold do you want it to get in there? Door open or closed?

In this case does it matter if the door is open or closed.

 

[strength_and_power]

Does she spend 40 hours a week there or 4? As small as it is, I’d think the smallest MS will turn it into a near meat locker.

 

[danski0224]

In this case does it matter if the door is open or closed.

Of course it does.

 

[American Locomotive]

It's 70 square feet. Even a plug-in space heater would likely keep it warm enough.

I would think any 6,000 BTU class minisplit would be more than adequate enough. There are even some 120v options in this capacity range.

 

[WildBill]

I know you said no on this but If it was possible I would put some 2-3" rigid foam insulation under it. Really easy to do and wouldn't mess with the rustic feel but would make a big difference when its cold. I did that to my wife's little writing shed and it made a huge difference in the winter. Now she heats it with a tiny space heater, think its 500 watts. Cold floors ****.

As for mini-split I would just go with the smallest one one you could get, I would be worried about humidity control going bigger.

 

[Firebrick43]

Id put it to her this way, it's insulation and some type of rustic wood on the walls or an electric blanket and a box fan.
Any M/S that I've seen need a 30 amp supply to the outside unit, it might get to be a pretty long run from your panel to the shed.

??? I cant find a small mini split 18k or under that requires a 30 amp breaker?

 

[Lassen Forge]

I would insulate that roof, then if you want the rustic look, sheet it with wood... seriously, that's going to be an oven/refrigerator otherwise.

 

[Firebrick43]

I know you said no on this but If it was possible I would put some 2-3" rigid foam insulation under it. Really easy to do and wouldn't mess with the rustic feel but would make a big difference when its cold. I did that to my wife's little writing shed and it made a huge difference in the winter. Now she heats it with a tiny space heater, think its 500 watts. Cold floors ****.

As for mini-split I would just go with the smallest one one you could get, I would be worried about humidity control going bigger.

It would be really easy to do. A building that size can be easily pushed all most all the way over onto a saw horse by just two or three people and a sheet and two sheets of 2" foil faced poly iso put in between the joist with foil face down. Another two sheets in the rafters and some pine boards for a ceiling installed.

With an trim nailer and a miter saw available I couldn't see it taking more than a few hours.

If one waits and installs AC and such it becomes much harder to insulate under the floor after the fact.

 

[rslaback]

The biggest reason we are hoping to go with a mini split instead of a window or wall unit is noise. I absolutely hate the fan and compressor noise that those units introduce into your house.

 

[NUTTSGT]

Will a mini split even run properly in that small a space ?

 

[The Cobbler]

I'm just thinking out loud here, but the cost of a mini split ,plus the fact it will be very inefficient... I'd spend a few hundred and a dozen hours ( or whatever) to seal it up a bit at least .

 

[Stuart in MN]

My wife has a cheap amish built playhouse in the woods behind our house that she uses as a kitschy writing cabin for her sermons.



It will soon be getting a power line run to it so that she can have lights and also a mini-split to serve as heat and cooling to extend its use a bit in different seasons. It also means that I get to reclaim my battery powered shop vac.

The structure is wood frame with pine board and batten and gaps in the floor with a rug covering it. It is in no means air tight. I know at 7'x10' the charts are going to tell me I need 5000btu but realistically how much capacity should I add based on the structure being so airy? I know it is a waste and I am sure some guy is going to come along and tell me to seal it all up and insulate it but that isn't going to happen. It ruins the simplistic vibe that she loves.

The only experience I have with something like this is our 12 foot pop up camper with a slide out which has sa 15,000 btu air conditioner on the roof. It does ok when we camp in summer. I imagine this wouldn't need something quite that big as the wood will be a bit better insulator than canvas but I'm not sure.

Thoughts?

You're in Wisconsin where it can go from +100F to -30F. Without sealing up the building and insulating I think you're fighting a losing battle. Having said that, try a couple of the online heat loss calculators to see what they recommend. I'm not sure if they have have settings for zero insulation, though.

 

[rslaback]

You're in Wisconsin where it can go from +100F to -30F. Without sealing up the building and insulating I think you're fighting a losing battle. Having said that, try a couple of the online heat loss calculators to see what they recommend. I'm not sure if they have have settings for zero insulation, though.

Of course it is a losing battle. But it isn't a system that is going to try to maintain a temperature for days. It shouldn't be much different than a camper with canvas walls I wouldn't think. We figure out ways to heat and cool those things.

 

[American Locomotive]

Will a mini split even run properly in that small a space ?

They have small minisplits. I can't speak for all brands, but Mitsubishi's 6,000 BTU unit will run as low as ~1500 BTU heating/cooling