Mini Split in Wisconsin

[bedn0009]

I'm thinking of installing a mini split in the cold climate of Wisconsin for a 1000 sq ft shop. This will be primarily woodworking/storage. I'd like to keep the temp around 40 most of the time... but I understand that that may not be a huge savings vs 50+ with a heat pump, correct?

I've received some helpful PM's on this, but is anyone else using a mini split in the north? MN/WI, etc?

Also, what's the cost of these systems? They would seem somewhat simple to install?

 

[sublime68charger]

How good is your insulation in the shop?

I can't help on the mini split question but knowing how much insulation you have will help with what your asking the mini split to heat or cool.

Good luck and a bump for you back to the top of the list!

 

[bedn0009]

Thanks for your reply. I am building this new, so walls will be R21, R30 in the ceiling. Garage doors are R18.

 

[Showkey]

Nat Gas not available ?

I would insulate r40-60 in the ceiling. Not matter the heater choice.
Most Mini splits will not work well in the extreme cold we experience for months on end.
Even the best high end MS are not going to work at -10 to -30*.

 

[bedn0009]

Thanks for the replies...

I DO have natural gas available....

My question (for someone who knows): Does the efficiency and low operational cost for a mini split offset the fact that I'd need some type of auxiliary heat source for those times when it gets ridiculously cold? Or, would the building retain enough heat that even in those rare times the mini split shuts itself off due to extreme cold, I'd still maintain an "above freezing" temp? I'm shooting for 40 degrees most of the time, not 72.

 

[cowboyjosh]

If you have natural gas available install a REZNOR type unit heater. Electric heat is always more expensive and a mini split will likely be more then a natural gas unit heater. With a mini split it cuts off at like 10 degrees or something; I had some folks here in Colorado want one in their garage a few years ago but went with a Reznor after they investigated the mini split more. I think after the first winter you might be disappointed with the mini split and I doubt if you have temps below 0 for days on end that the building will stay 40 degrees when its too cold for the MS to operate, no matter how well its insulated.

 

[Dagny]

What Josh says.^

 

[James-W]

If it were me, since natural gas is available, I would definitely go with a vented natural gas furnace for heat. The price for natural gas is reasonable and when you want to crank up the heat you can get the temperature up to where you want it very quickly.

 

[bedn0009]

Thank you all. So a follow up question and a curveball... the garage will have a second floor which at some point will likely be finished space (14x32). What if I bought a used forced air NG house furnace and set that in the upper level with a couple of ducts down into my garage. This would be in lieu of the unit heater.

 

[James-W]

Thank you all. So a follow up question and a curveball... the garage will have a second floor which at some point will likely be finished space (14x32). What if I bought a used forced air NG house furnace and set that in the upper level with a couple of ducts down into my garage. This would be in lieu of the unit heater.

You can do that, but you would need to put in return (cold air) ducts as well as heat ducts.

 

[Showkey]

NAT GAS is dirt cheap, the furnace or garage heaters call be found for $500-700.
NAT GAS will also allow quick recovery from 40-50* to 70* in minutes.
I keep my shop at 40-45* all winter with great insulation it costs very little and it can be 60-65 in minutes.

Instead of used ..........I would look at a new 90% plus furnace at a place like Alpine Air.

https://www.alpinehomeair.com

I purchased two Goodman furnaces from them, free FEDEX shipping, no Tax. They were less than some used units and they have a warranty.

There are several other places that are selling heat and air units to the general public. Then you install or have heat air guy install for you. The Internet is changing the HVAC business just like tools, car parts, electronics etc etc........

Often there are problems mixing garage space and living space with a shared heating unit. CO from the garage making it through the cold air returns is always a concern and often against code.

 

[cowboyjosh]

You can do that, but you would need to put in return (cold air) ducts as well as heat ducts.

Legally no, garage and living space above cannot share a furnace.

Do a REZNOR for the garage and a small furnace and ac unit for the living space over the garage.

 

[James-W]

Legally no, garage and living space above cannot share a furnace.

Do a REZNOR for the garage and a small furnace and ac unit for the living space over the garage.

I realize that, but he doesn't really have a garage. He said it was a woodworking shop and a storage place. I was under the impression the reason for not having a furnace that heats both a house and a garage is so that exhaust fumes don't get into the house via the duct-work. But in this case there would not be any exhaust fumes since no vehicles are parked inside.

If the same rules apply regardless of whether it is a woodworking shop or a garage, then I stand corrected. I thought it only applied to a garage.

 

[Ken Greene]

if the woodshop has a door large enough for a car, to the building dept it is or can be a garage at some point. Therefore they will not allow the second floor to have the same air source for HVAC

 

[bedn0009]

if the woodshop has a door large enough for a car, to the building dept it is or can be a garage at some point. Therefore they will not allow the second floor to have the same air source for HVAC

Based on the feedback this morning from my building inspector, your post above about not allowing a common heat/air source for the two floors appears to be incorrect. Will have confirmation tomorrow.

 

[Sokoloff]

Regardless of whether the building inspector will allow it, if you're creating finished living space, I wouldn't share air exchange with a garage. Too much chance of it going badly, and not worth the risk, IMO. Radiant heat or radiators? Sure, share away, but nothing with shared ductwork for my money and family.

 

[Ironhorse74]

Heat pumps work best when the ambient air temperature is close to the target heating or cooling temperature. There is a good chart here: http://www.bdmdialog.com/?p=1164

 

[DEnd]

If the same rules apply regardless of whether it is a woodworking shop or a garage, then I stand corrected. I thought it only applied to a garage.

The same rules should apply. Think of it as an industrial/residential split. If you are doing industrial type work in an area then it needs to be separated from where you do residential/office type things. Woodworking, Metalworking, automotive repair, etc... all have the potential to offput large amounts of VOCs and other hazardous gasses. With that you need to not only ventilate the space correctly, but you also need to ensure that you have a negative pressure in those spaces in relation to the air pressure of any adjoining residential/office space.