Shop woodstove

[Ashful]

To not hijack BrowningBAR's thread, where this conversation started, how do those of you using a woodstove to heat the shop handle rust and condensation? Me? I always kept my shop at the last house heated 24/7 with electric. This past winter, my first in the new place, I watched rust appear on everything I owned, sitting in my new (unheated) shop. Just as with the old place, I'm finding that if I don't always keep the inside warmer than the outside, the relative humidity creeps up. This is not due to humidity generated by any heating appliance / stove, but just due to the interior of the shop sometimes being colder than the outside air.

Jags keeps his metal shop heated solely (?) with a wood stove. Question is... what happens when the fire goes out, and interior temperatures plunge? I can almost hear the metal rusting...

I know, I know... I should be running an outside wood-fired boiler, plumbed to both the shop and the house. It's just not something we have the energy to install right now.

 

[DanCorcoran]

It'd be helpful if you add your location under your avatar. Humidity problems (along with many other issues) vary from location to location.

Update: thanks!

 

[Highbeam]

The dewpoint is the number you're after, keep the shop temp above the dewpoint and you won't get condensation. I plan to have a low temp automatic heater and then a woodstove for when I'm in the shop.

Have you insulated your shop? Good insulation and airsealing can almost accomplish the base heating alone.

 

[fossil]

I live in the High Desert country of Central Oregon...that's how I handle rust and condensation...I don't have any.

 

[Ashful]

Thanks, guys. My old shop was insulated crazy-tight. The new one is just an empty carriage barn, ca. 1800. No insulation yet, but that's a project for this winter.

 

[Jags]

I don't seem to have any problem until the first few warm days of spring. Beyond that, if in winter and I heat the shop up to 60-65F (my preferred shop temp), it takes MANY hours to bring the shop "material" up to temp. Cement floor, 4ft cement walls (transitioning to studs) and literally TONS of metal are in the shop. As soon as I quit fueling the heat, the temps will start to drop right back down (unless I am on several hours of heating). I also keep pretty active air motion. A wall fan and ceiling fan are in use when the stove is lit. 12 ft ceilings.

But yes, I have found some rust on a few of my finer machine tools. That does not make me happy. Those are now located in drawers instead of on shelves. Keeping them under cover seems to eliminate the condensation on them - at least to a degree. I have also gotten surface rust on my wedge bed Rockwell planer. That ticks me off. I have tried everything including waxing it, but the moisture will build underneath it - and I don't know how.

Edit: Joful - I did not ignore your conversation you sent to me. It had an issue that was sent over to Craig - It did not have a "response" box for me to respond.

 

[SKIN052]

I have a small shop, 16 x 24 with a concreat floor, insulated stud walls and ceilings. I was having a issue with condensation as well. I bought a small fan heater, similar to the one pictured below. it cost me $15 bucks on sale and has lasted 2 winters now. I keep it going on the lowest setting possible and it keeps my shop around 8 deg celcius. It also has a built in overheat sensor and will shut off it something were to go wrong. Mostly only run it at night since the sunlight is typically enough to keep the place above zero. Plus I am in there often and always have my old wood stove going.

 

[Ashful]

I was planning to install a mini-split system with two wall units (one first floor, one second floor) in this new shop. Would cost me approximately $4000 installed, for two floors of 600 sq.ft. each. If I go with a propane backup, install cost goes up, but operating cost would be lower in the coldest weather.

I have much more trouble keeping this building cool than I do keeping it warm. It gets good solar heating, given it's location and construction. Plan was to leave the thermostat at 50'F (or as low as it will let me go) in winter and 85'F - 90'F in summer, likely turning down the summer AC to 70'F when I'm actually using the shop, weekends and occasional evenings. Would be fun to put an NC-30 or some other good utility stove out there, but wondering where the cost trade-off would happen, since I only heat the shop above 50'F when I'm spraying paint. Not sure I want to deal with a wood stove going when I'm spraying paint, and not sure how much the heat will even run with the thermostat set at or below 50'F.

 

[Highbeam]

I was planning to install a mini-split system with two wall units (one first floor, one second floor) in this new shop. Would cost me approximately $4000 installed, for two floors of 600 sq.ft. each. If I go with a propane backup, install cost goes up, but operating cost would be lower in the coldest weather.

I have much more trouble keeping this building cool than I do keeping it warm. It gets good solar heating, given it's location and construction. Plan was to leave the thermostat at 50'F (or as low as it will let me go) in winter and 85'F - 90'F in summer, likely turning down the summer AC to 70'F when I'm actually using the shop, weekends and occasional evenings. Would be fun to put an NC-30 or some other good utility stove out there, but wondering where the cost trade-off would happen, since I only heat the shop above 50'F when I'm spraying paint. Not sure I want to deal with a wood stove going when I'm spraying paint, and not sure how much the heat will even run with the thermostat set at or below 50'F.

You can buy low temperature thermostats for conventional heaters and you can also run a mini split in very cold temperatures. Modern minisplits are making heat well into the single digits. Low temp stats for the mini split are a bit tougher since they have a stat built into them.

 

[Jags]

What is this "mini-split" system you folks are referring to?

 

[lukem]

What is this "mini-split" system you folks are referring to?

Ductless HVAC.

 

[Jags]

Ductless HVAC.

Electric or LP/NG

 

[fossil]

Like the heat pump through the wall of a motel room. Heater/cooler. Except the mini-splits are in two pieces...one mounted inside and the other outside. No ductwork, hence it's a one-room unit.

 

[Jags]

Like the heat pump through the wall of a motel room. Heater/cooler. Except the mini-splits are in two pieces...one mounted inside and the other outside. No ductwork, hence it's a one-room unit.

Cool - now I got it.

 

[Ashful]

You've no doubt seen them before, Jags. They often look like a baseboard radiator, mounted on the wall above a window or door. It's an evaporator and air handler in one unit. Condensor still sits outside, but typically these condensors are much smaller than conventional, and are configurable to run up to four independent evaporators.

Aside from some remarkable efficiencies, the big advantage is no ductwork to run. Just run some wiring and your cooling lines thru an exterior wall, straight into the back of the indoor unit.

 

[Jags]

Yep, I got it now. I would guess for someone that wants to condition the shop 24/7 it sounds like a reasonable approach.

 

[Highbeam]

Unfortunately, the inside unit looks like ass. Otherwise you would see these things in every home. The efficiencies are extraordinary.

 

[fossil]

Relatively new on the scene, still relatively unknown to the man on the street. Lots and lots of players in the game. Many units from which to choose. Some folks make systems where one outside unit can service a number of inside units...so you spend your money conditioning the space you care about rather than the whole danged house. Sure makes sense to me. I've looked at a lot of them and I didn't think I was forced into the "ugly corner". Many of them look just fine to me. I'm starting to think seriously about it, as I don't have central AC as a part of my heating system, and there are lots of days every summer when my house really gets uncomfortably hot. If I could cool one room of my choice, that would be a very "cool" thing. Rick

 

[billb3]

We got one with two heads. Evaporator is quite thin and super quiet.
Only "ugly" part I don't particularly care for is the lines running up the wall outside.
The mastiff gets heat stress and then sick with too much weather above 80 and it was either spend big bucks on meds and diet and vet bills or an air conditioner. Plus over about 78 / 79 she starts panting like crazy and drinking way too much water to compensate. Not really something you want a dog taking PPA for incontinence doing.

 

[fossil]

Yes, there is a refrigerant line set...just like with a conventional central AC system. The evaporator and the condenser have to be connected by tubing for the working fluid to cycle. And both inside & outside units require electric power. Rick

 

[Ashful]

I've installed two of these systems in the past, as well as conventional systems. The only mini-splits I've used (or would use in the near future) are Mitsubishi. The installers love them. I love them. The outside unit is so damn quite, you almost can't tell it's running from more than a few feet away. The inside units are not something I'd want above the TV in my living room, but I've found discrete places to tuck them over closets, etc. They're the perfect solution for my workshop... I think.

 

[Highbeam]

And both inside & outside units require electric power. Rick

True, but you only need to run wire to the outside unit, the lineset between the inside and outside units includes the small wire needed to power the inside unit as well as the condensate line if needed. Drawbacks to this system are that there are no backup heating coils so when it is too cold for them to make enough heat, the room cools off. A nice benefit of the minisplits is that they don't need a lot of power. A dedicated 20 amp, 220 circuit is enough for most of them. You could repurpose a baseboard heater circuit to provide the same power to the minisplit and get way more heat.

 

[pen]

True, but you only need to run wire to the outside unit, the lineset between the inside and outside units includes the small wire needed to power the inside unit as well as the condensate line if needed. Drawbacks to this system are that there are no backup heating coils so when it is too cold for them to make enough heat, the room cools off. A nice benefit of the minisplits is that they don't need a lot of power. A dedicated 20 amp, 220 circuit is enough for most of them. You could repurpose a baseboard heater circuit to provide the same power to the minisplit and get way more heat.

The Mitsu unit I just purchased this summer claims to maintain 100% of its heating potential at 5 and 80% of his heat down to -13. Time will tell, but for the cooling system, I've been extremely impressed with it's operation and cost efficiency.
I didn't buy from here, but this gives you an idea.
http://www.younits.com/mitsubishi-m...nit-air-handler-18000-btu-1.5-ton-p-4871.html

pen

 

[begreen]

Unfortunately, the inside unit looks like ass. Otherwise you would see these things in every home. The efficiencies are extraordinary.

One man's opinion. I have seen several of these installations in various homes and they look fine to me.

 

[fossil]

I'm beginning to seriously consider this (mini-split system) as a solution to the summer heat in both my house and my guest apartment. Should really start my own thread in the DIY forum...think I will. See ya over there. Over & out. Rick