I just finished insulating my 24x24x9 detached shop Monday. It was in the 18 F to about 35 F. I'm using a 1500 watt quartz space heater that has a small fan in it. It heated the shop to 48-50 F and didn't run all the time. The temperature was fine for what I was doing with a long sleeve shirt and occasional jacket. It does seem to have a few cold dead spots. I have propane available at the shop but, Im just not comfortable having an open flame and the moisture they produce. Also, I'll be creating a lot of dust from grinding, cutting, sanding, painting etc. this winter. Yes, venting air while doing such.
If I stay with electric, watts are watts, whether I'm using 120 or 240 volt it isn't going to matter on the bill. I'm thinking about comfort and possible cost savings from run time or some other factor I haven't considered. I was wondering about the fan forced electric heaters sold at Northern Tool. Most have a higher BTU and wattage, so I'm thinking more air movement equates to quicker heat-up, more comfort. I do have a few shop fans I could run to get possible same effect. Thoughts please!
Am I thinking about this correctly?
Also, what about a heat-pump...I know a HVAC guy and can probably get a unit cheap from a disconnect or remodel.
Craig
Regarding using a heat pump, depends on where in the world you live. Heat pumps are one of the most efficient forms of heat because they 'move heat' like a pump rather than 'create heat' like a fire. They are an A/C that acts in reverse. An a/c uses the freon to steal the heat from your home and move it outside. It doesn't eliminate the heat or create cold (both of which are impossible), it just moves it outside or pumps it, if you will. A heat pump works exactly opposite and in fact, you could technically just flip a window unit around and it will heat your home (just take care of the condensate, which will now drain in your room).
The only issue with a heat pump is they lose effectiveness below about 30 to 35 degrees F. There is just not enough heat in air that cold for it to steal and pump into your shop. So most have emergency electric heaters that kick in and then you're right back to electric resistance heat, which is far more expensive than propane in most areas. Generally, in the US, anything above the Carolinas or Tenn, don't bother installing one, as the cold days are just too damn cold. Anything below that and you might find some savings.
Dont forget that with a split system heat pump, ductwork, copper and a freon costs might kill the cost of that job, whereas a wall/window unit is self contained. So maybe a wall unit is something to consider. Also, the benefit of the heat pump is it should have a reversing valve in it so summertime it is also an a/c.
Or, use that propane and install a vented space heater and that will take care of the heat and eject the flue gases outside (including the condensation). Really depends on what region you are in. Probably best to run this advice past your local hvac buddy, as he would likely know what is best.