Have a garage in backyard yard. I live in Michigan and this last week it has been 9 & 10 degrees (Dec).....half of building..(24x24)...is for storage and other is small workshop. Do not have a heater yet...just want to know if it worth it to insulatehalf of building and garage door.

 

Insulation doesn't generate heat so if you have an un-conditioned space then insulation wont do much!

 

That's difficult to say from afar. Do you want to insulate the half used for storage or the half used as a workshop? And, to what extent? For example, providing heat to a workshop you use for a few hours on weekends is much different from heating a storage area. For an occasional use workshop, a space heater and minimal insulation may be all you need. A heated storage area could be a more difficult and expensive proposition. Insulating yourself can be a fairly simple (and low cost) project provided you're willing to seal it properly. Likewise, Find out what it would cost to insulate and heat, then decide if that amount is worth it for what you want to do.

 

Using only half of garage 12x24...other half for storage mowers and such....garage door not insulated...don't use it much in winter due to weather

 

is the garage actually laid out with 2 rooms or is it just 1 big space really can't see the point of insulating half if it's just one big space would need to do the whole thing.
a couple of oil filled space heaters would likely bring the temp up some and may make it at least more comfortable to work in for a few hours obviously insulation would help also.

 

Insulation does not provide heat, it only slows changes in temperature. Without a heat source, there is no point in insulating.

 

A common heating solution for an uninsulated garage / workshop is a kerosene space heater = 'salamander' or a gas-grill propane tank mounted infrared heater - both heat a space quickly; the infrared has a benefit that it warms YOU without having to warm the cold air around you.

Our farmhouse had an uninsulated 1-story barn/garage which I used as a winter workshop / rec room in high school & college. An old 'salamander' kerosene heater kept the 30' x 30' space comfortable in winter.

One thing I HIGHLY recommend is that you find a way to contain the heated air. Example, my barn/garage had 2 large collar-tie beams 8' above the floor running horizontally which were spaced about 10' apart. That made it easy to drape some heavy plastic sheeting / tarps over the beams to create a small semi-enclosed space that was MUCH easier to heat - useful for working on a car in the winter.

While I mostly agree with Marq1 & stickshift that insulation doesn't provide heat, in SOME situations it can-
Example is my rebuilt & insulated 2 story barn/garage which retains / incorporates the south facing overhanging porch. In winter when there is no wind, that semi-enclosed (floor, roof, 2 walls) southern exposure stays a good 20F°-30° warmer than ambient air temperature- so I just open the screen door and let the warm air rise into the barn as 'passive solar heat'. With just sunshine, a windbreak, and insulation, the upper floor is usually in the comfortable range around 50°F without any heat at all.

 

But the insulation didn't generate the heat, it just helped contain it like it would do with any heat source!