Small Room Climate Control

[Pack Rat]

I need to house electronic equipment (Radios) in an insulated 8X10 ft. shed.
Any suggestions on heating and cooling this small of an area?
I would like to use a thermostat for around the clock year around temperature control.
I'm looking for an efficient way of doing this. The smallest mini-split is still too large.
Unoccupied temperature around 50* occupied 72 to 76*. This will be a ham shack.

 

[justinjoyal]

Is humidity an important factor ?

If not, oversizing is not an issue. If it is, you could use a dehumidifier.

A 9kbtu mini-split would throttle down in A/C mode and would not have a problem heating the area when needed, all while costing pretty much nothing to run.

 

[BillK]

dd,
What kind of power do you have out there ? I have my Ham setup in my attached 2 car garage and I have a 5000W heater that does just fine keeping it warm even on the coldest days around here. I am sure a detached shed will be a little different. Mine has a thermostat but I usually dont leave it on if I am not in the garage.

Maybe a 2KW amp would do the trick

 

[Pack Rat]

It would be a new build so power would not be a problem. The walls will be framed with 2X6
for more insulation. I thought about using overhead electric infrared heat panels for heating.
I don't know about cooling. Yes humidity would be a consideration.

 

[Climatecreator]

How about something like this? 7kbtu heating and cooling?

https://www.amana-ptac.com/products/ptac/ptc073g-air-conditioner

 

[u3b3rg33k]

How about something like this? 7kbtu heating and cooling?

https://www.amana-ptac.com/products/ptac/ptc073g-air-conditioner

A minisplit would work better than a single stage 7k PTAC. that'll probably short cycle to an early death.

Perhaps a desiccant dehumidifier if humidity is an issue? those don't have a compressor to worry about.

 

[493mike]

How about something like this? 7kbtu heating and cooling?

https://www.amana-ptac.com/products/ptac/ptc073g-air-conditioner

And fresh air to boot!
Mike

 

[Falcon67]

Mini split would be my choice - more $$$$ but very efficient and very effective. You could not give me a PTAC.

 

[Pack Rat]

I'm going to **** can the whole idea. It's just too small to heat and cool effectively.
The smallest mini split is still too big. I would have a bigger shop building built but
green space rules won't allow it.

 

[u3b3rg33k]

I'm going to **** can the whole idea. It's just too small to heat and cool effectively.
The smallest mini split is still too big. I would have a bigger shop building built but
green space rules won't allow it.

build it tight and spray foam it. you probably won't need heat if the gear is on. if the gear is on you won't have condensation on the gear - a little desiccant dehumidifier will also add a little heat and can keep up with small moisture infiltration. a cooling fan/shutter should do for keeping temps down.

 

[Falcon67]

I'm going to **** can the whole idea. It's just too small to heat and cool effectively.
The smallest mini split is still too big. I would have a bigger shop building built but
green space rules won't allow it.

I see 9K ductless heat pumps that should do it, 17 SEER under $900. It may cycle a bot more, but whatever.

 

[Climatecreator]

I hate PTAC units too, but they're small enough for what the OP wants. I use mini splits a lot as well, however they're not the answer to everything. I even have them in my own house as well as a building I take care of that has 125 units that we took the PTACS out of and installed ductless.

Maybe check out Magic-Pak

They install in a stud bay and would do the trick if you could get a small enough one.

I agree though that with enough electrical equipment running and good insulation you may not need anything additional aside from a small space heater depending where you're located.

They also have through the wall units like windows AC but as heat pump even additional electric heater internal, AND they go down to like 5kbtu.

So many options....

Good luck

 

[u3b3rg33k]

9k minisplit is smaller than a 7k ptac, because the ptac is on/off and the minisplit is variable. even with a horrible 3:1 turndown, that still gets you a 3kBTU/hr AC at minimum. much better than a 7k ptac.

Magic-Pak looks cool, but the problem is their smallest unit is 1 ton, and they don't appear to be variable speed. just too big.

 

[Pack Rat]

I thought about extra insulation so that the HVAC unit wouldn't cycle so often. Am I wrong in my thinking?

 

[terabitdan]

The better the insulation the more short cycling since the system has such a small load.

Mitsubishi has a 6k mini split with 9k of heating, but even that is 2-3x oversized if you insulate really well.

Realistically, your best bet is to super-insulate the shed and use electric baseboard and a window A/C.

Using R25 in the walls, R48 ceiling and R-10 around the perimeter of the shed you only need about 3000 BTU/hr at 6 deg outside. The estimated annual heating cost is $250 and that’s assuming 70 deg inside.

You’ll never get payback on the mini-split cost for this small an area. Put that $2k into spray foam insulation.



Sent from my iPhone using Tapatalk

 

[Voi]

even with a horrible 3:1 turndown, that still gets you a 3kBTU/hr AC at minimum.

Sounds like the OP has decided to go a different direction but thought I'd mention there is at least one mini-split that modulates down to 1500 BTU/hour. Pretty sure it's a Mitsubishi.

I don't have it bookmarked on this computer but as I recall it was a 1 ton unit and actually modulated lower than their 6k and 9k units.

 

[Pack Rat]

The better the insulation the more short cycling since the system has such a small load.

Mitsubishi has a 6k mini split with 9k of heating, but even that is 2-3x oversized if you insulate really well.

Realistically, your best bet is to super-insulate the shed and use electric baseboard and a window A/C.

Using R25 in the walls, R48 ceiling and R-10 around the perimeter of the shed you only need about 3000 BTU/hr at 6 deg outside. The estimated annual heating cost is $250 and that’s assuming 70 deg inside.

You’ll never get payback on the mini-split cost for this small an area. Put that $2k into spray foam insulation.

That's exactly my thinking except for the foam. I'm concerned with toxic fumes
from the foam in the event of even a small fire. A neighbor girl died from toxic fumes.
She was sleeping on a couch in her basement when an outlet caused a small fire.
The fire burned itself out in a very small area but the fumes from the foam killed her.

 

[aunsafe2015]

Sounds like the OP has decided to go a different direction but thought I'd mention there is at least one mini-split that modulates down to 1500 BTU/hour. Pretty sure it's a Mitsubishi.

I don't have it bookmarked on this computer but as I recall it was a 1 ton unit and actually modulated lower than their 6k and 9k units.

Pretty sure that LG makes one that modulates all the way down to 1,000 btu.

 

[Pack Rat]

Pretty sure that LG makes one that modulates all the way down to 1,000 btu.

Thanks for the info. I will look into it. Sounds like a workable solution.
I don't care about short cycles, it's the number of times it cycles that concerns me.
Is that an LG mini split, or wall unit?

 

[aunsafe2015]

Thanks for the info. I will look into it. Sounds like a workable solution.
I don't care about short cycles, it's the number of times it cycles that concerns me.
Is that an LG mini split, or wall unit?

Mini split. I'll see if I can find it.

 

[Voi]

Mini split. I'll see if I can find it.

I was curious as well so I spent some time searching. The LA090HSV5 modulates down to 1023 BTU/hour.

 

[aunsafe2015]

I was curious as well so I spent some time searching. The LA090HSV5 modulates down to 1023 BTU/hour.

Yep so does LA090HYV1 according to the engineering manual. 1,023 BTU for both heating and cooling.

 

[Voi]

Yep so does LA090HYV1 according to the engineering manual. 1,023 BTU for both heating and cooling.

Thanks. I was looking up the specs on the HYV1 but the submittal page was formatted differently and I couldn't find it. I figured since the square footage size and number of fan speeds was comparable it must modulate down the same.

 

[Pack Rat]

There may be some interest in this thread. I'm sure many people want to build a small footprint
workshop or hobby hut with heating and cooling.

 

[mpire]

Get a heat pump water heater and plumb it into the house water heater as a pre-heater. It will do a good job cooling down the room and save you money down the line. I'm pretty impressed at how well it does de-humidification in my garage. It can fill a 5 gallon bucket on some days. It definitely pumps out cold air.

Only negative is you don't want it too far from the master shower. So you would have to get creative there.

Also, lots of power companies are giving big rebates on them. Mine gave me $650 and it was only $750 brand new on sale.

 

[rburke65]

PackRat....explain Green Space Rules please. Is this a local sq. ft. build space ss Ue?

 

[Pack Rat]

PackRat....explain Green Space Rules please. Is this a local sq. ft. build space ss Ue?

Only so much of a lot can be covered by roofed structures.
Because of the size of my house and storage shed I only have
about 150 sq. ft. left that I can use following set back rules.

 

[75gmck25]

It seems like a window A/C unit with a heat pump function would also work. They are relatively cheap, and very easy to install. You could build a sleeve into the wall of the shed during construction.

If you use foam wall insulation, you will also need to have a heat/flame barrier on the walls (sheetrock, etc.). This is how current code deals with the possibility of risks from burning foam in a house. I'm sure a lot of folks ignore the code, but even in a house with foam insulation in the attic you are not supposed to use it for storage or any other use that requires frequent access unless there is a heat/flame barrier over the foam. The code also applies to basements with foam insulation.

My area also has Floor Area Ratio (FAR) limits. For example, since my lot is under 8000 sq ft, I am limited to a max garage size of 250 sq ft, unless there is a existing building already grandfathered. However, if I want to put a shed on my property (no foundation) there is no permit required, I can put the shed one foot from the lot line, and there seems to be no limit for the number of 100 sq ft sheds I can have. I can also install a simple deck of nearly any size, but if I add overhead cover it comes under size limits.

Bruce

 

[justinjoyal]

I don't care about short cycles, it's the number of times it cycles that concerns me.

Isnt that like saying i dont care if the sky is blue im just concerned that it’s blue? Lol.

Inverter systems modulate, they dont cycle on and off. You wouldn’t have to worry about that if you went the mini-split way.

 

[u3b3rg33k]

Isnt that like saying i dont care if the sky is blue im just concerned that it’s blue? Lol.

Inverter systems modulate, they dont cycle on and off. You wouldn’t have to worry about that if you went the mini-split way.

Thanks for the info. I will look into it. Sounds like a workable solution.
I don't care about short cycles, it's the number of times it cycles that concerns me.
Is that an LG mini split, or wall unit?

Generally speaking, they go hand in hand. demand is divided evenly into on/off cycles, so short cycling = early equipment death. if you can get your building insulation to play along with grouping demand periods, please tell us how

 

[Pack Rat]

When I upgraded the insulation and windows in my house the furnace and A/C ran for
a shorter length of time and they stayed off longer before turning back on. Bills went way down.

 

[u3b3rg33k]

When I upgraded the insulation and windows in my house the furnace and A/C ran for
a shorter length of time and they stayed off longer before turning back on. Bills went way down.

hence a "shorter cycle".
Ideally you'd replace the system with a smaller one that would run for a similar period of time. bills would stay way down, but the system would be quieter, draw less power (better for the grid), and control humidity better.

Once I clear up some massive holes in my envelope I'm planning on downsizing my 40/60k furnace to a 20/30k if possible.

 

[Pack Rat]

hence a "shorter cycle".
Ideally you'd replace the system with a smaller one that would run for a similar period of time. bills would stay way down, but the system would be quieter, draw less power (better for the grid), and control humidity better.

Once I clear up some massive holes in my envelope I'm planning on downsizing my 40/60k furnace to a 20/30k if possible.

OK I get what you're saying now. I have a service contract with an excellent HVAC company.
Their analysis shows that I'm right sized for now. I'll need to replace my HVAC in the house
in the near future, but I'll need to get the cold air return duct work re-done to balance
things out. I'll stop by their shop tomorrow to ask what they recommend for the shed.
The general consensus here is a mini- split, but that would cost more than the shed.
I'm leaning towards a thru wall AC unit with heating. I'll see what they say.

 

[u3b3rg33k]

Note that most through-wall that are cost efficient for heat (i.e. have a reversing valve) don't work below 40F, or use resistive strips below 40F. it can be tough to figure out from spec sheets what is what. sometimes they're not even advertised properly. I had to hunt for one that's got the features I want, and I will still have to hack it to get it to be what I want it to be.

operating costs can quickly eclipse first cost (purchase) of a significantly better unit (i.e. <1 year ROI on a better unit) if you don't apply some maths before purchase. In the end, you will usually spend more running the gear than you spend on buying the gear, so keep that in mind.

 

[Lightman]

http://www.iceqube.com/thermoelectric-heat-sinks/

have used something like thi sin electric substation electronic cabinets.

orginals had compressors, replacements all electronic.