Green heat for garage/workshop

[ikessky]

In the next year or two I will be building a new garage/workshop. I'm probably looking at somewhere around 1200 square feet. Does anyone have any thoughts on heating this? When not in use, I would like to keep the temps around 40 degrees and then be able to bring it up to temp when I'm working out there. Ideally, I would install a wood boiler and run in-floor heat, but my insurance company will not let me run a wood stove/boiler in a garage or out-building. The town that I live in also will not let me install an OWB.

 

[EatenByLimestone]

Are you going to insulate it? What other fuels do you have available? NG, Propane?
Matt

 

[ikessky]

It will be well insulated. Backup heat would probably consist of NG, but I would maybe think of using propane due to the added cost of having the gas line run from the house to the garage.

 

[EatenByLimestone]

Might want to look into what electricity would cost too. You will probably be running electric out so dropping the appropriate line and running it to a sub panel may be worth it. Electric heat may make sense.

Matt

 

[Hansson]

Air to air heat pump maybe?

 

[ikessky]

Part of me thinks that the best thing to do might be just install an indoor wood boiler and run PEX from the install in my basement to a heat exchanger and fan in the new garage. It's not that much different from what an OWB system is and it would achieve what I need it to. Plus, I can control the heat with a simple turn of the therostat.

 

[begreen]

Electric for backup may be the simplest if you have reasonable utility rates. The best things to do are to insulate well and if possible, solar orient the building and windows to maximize winter solar gain. Maybe add a couple large opening Velux skylights on the south side roof. If the space is well insulated, I think a basic woodstove with a fan on it would do the job of raising the temp. It's not that big a space.

 

[Hansson]

I have one of this in a guest house.
http://www.solarventi.com/

Not hard to build one.it will give you some heat and ventilation

 

[ikessky]

Well, I think for now I'll probably plan to run in-floor heat off of a hot water heater and use a Reznor or Modine NG to bring things up to temp quickly. Last year I heated the house with the NG furnace and it cost maybe $200 per month on the coldest monthes. Keeping a garage that is probably better insulated at 40 degrees will probably cost a lot less than that, and the initial investment in equipment will be a lot cheaper. I'm going to keep researching solar power though. It would be nice to use it to heat the water for the in-floor or at least suppliment the energy the heater takes.

 

[Highbeam]

Your desired use of the garage screams for an instant heater. Something that will provide heat right away so that you can do your job in the garage and then leave. No sense in wasting a bunch of eneergy heating the slab for this purpose since your slab will take many hours to make a garage go from the low setting of 40 to a comfortable temperature of say 70. You need a quick heater like a furnace or radiant heater that burns gas or electric. If I had NG I would install a cheap gas furnace to blast heat into the garage when I want it and then shut the furnace off when you're done with the job.

 

[semipro]

I'm also in the process of building a garage and have some of the same concerns you do. My current plan is to insulate well, put some foam insulation under the slab, some loops in the slab and then use solar and/or electric heated water to heat the shop. I also may use propane heat of some sort for inside air heating for quick warm ups.

 

[Wet1]

Your desired use of the garage screams for an instant heater. Something that will provide heat right away so that you can do your job in the garage and then leave. No sense in wasting a bunch of eneergy heating the slab for this purpose since your slab will take many hours to make a garage go from the low setting of 40 to a comfortable temperature of say 70. You need a quick heater like a furnace or radiant heater that burns gas or electric. If I had NG I would install a cheap gas furnace to blast heat into the garage when I want it and then shut the furnace off when you're done with the job.

I really have to agree. The only thing an infloor system would do well is maintain the shop at the desired 40° base temp. Although, I agree with BeGreen that a well thought out passive solar plan would go a long way towards maintaining reasonable temps when the shop is not needed or heated.

I'd use NG rather than propane. Propane is much more expensive and you already have a hassle-free NG line on the property. As far as running the gas line to garage, yes they will hit you pretty good for this, but you can do some or all of this work yourself. Rent a Ditch Witch for a day, make the trench, and run the line... it's not that hard.

Running a indoor wood boiler might not be a bad idea, but it would be fairly expensive and would take a long time to get that area up to temp. I suspect you'd be much happier with passive solar and instant NG heat.

 

[ikessky]

Did a little searching on the net last night and found numerous people using hydronic radiant heat from the slab to keep their garages/shops warm. Even found a guy in my area who heats his tractor rebuilding shop solely on this type of system. Here is probably what I'm going to end up doing.

1) In floor radiant, but undecided on the method of heating. It will either be a hot water tank or boiler depending on what kind of pricing I can get at the time.

2) An overhead Modine-type NG unit with a thermostat for back up and to bring things up to temp quickly.

3) Passive solar to help decrease engergy usage whenever possible.

I'm really interested in the in-floor heat beause I would like to use this shop to expand the part time auto detailing that I do. I will have a drain, but I think the in-floor heat will help dry my slab a lot quicker. I'm not really thinking about an indoor wood boiler any more, because the cost just doesn't really justify the install.

 

[mayhem]

Oversized solar hot water system feeding a large storage tank (like a super insulated 275gal oil tank) that then runs into the floor...properly insulated and passive solar you might get well over the 40 degree base you're looking for if you have the solar exposure on the panels. This is a system thats been stuck in my head ever since I started heating my basement floor with my oil boiler and realized the floor PEX tubes would probably work jsut as well off a solar DHW setup. Just need to have enough hot water storage to get through the nights and cloudy days.

Electric or maybe pellet backup, though the insurance company may feel the same about pellet as they do wood.

My wife's uncle uses a couple ceiling mounted infrared heaters in his otherwise unheated 3 bay garage...I've worked on my car there in teh dead of winter with jsut a heavy shirt and no gloves. They do a great job of heating up whatever you point them at...not the air.

 

[JustWood]

How far from the house will the garage be?

 

[ikessky]

The current house is a ranch style running from north the south. The north end is the current garage. The plan is to remodel the garage into a large family room and build a new garage just north of that with a breeze way connecting the two structures. So, the new garage will only be a few feet from the house, but no where near the duct runs from the house furnace.

 

[potter]

I have in floor w/ high eff LP boiler in my shop. As others have said in floor is great for consistent temps, but would be inefficient and expensive and slow to ramp up for occasional use. You have to heat the entire cement mass before heating the space. It is a smart and economical solution (in the long run), but doesn't sound right for the use you described. I'm thinking about adding a wood stove in my shop as part is not used all winter. I would set a base temp 58? and then heat only the space I'm using to comfort.

 

[jebatty]

Hansson, the solar vent idea is very good. We have a local company with solar hot air collectors which perform very well. RREAL Why fail to take advantage of free solar light and heat and instead pay for fossil fuels to provide the same?

 

[ikessky]

Talked with the guy across the road who runs a little Modine NG in his garage. He said that to keep the garage at 40 degrees all winter maybe cost him an extra $10. I think I might just go that route. Instant on and off which will be nice for most of the time that I'm in there. I'll start checking with my insurance also, because it would be nice to have a wood stove in there for those times that I will be in there for longer periods.

 

[Dune]

Get a different insurance company, put indoor boiler in outbuilding, heat home with wood and outbuilding with waste heat, and do the passive and active solar as well.

 

[semipro]

Talked with the guy across the road who runs a little Modine NG in his garage. He said that to keep the garage at 40 degrees all winter maybe cost him an extra $10. I think I might just go that route. Instant on and off which will be nice for most of the time that I'm in there. I'll start checking with my insurance also, because it would be nice to have a wood stove in there for those times that I will be in there for longer periods.

I don't think there's much that could beat forced air NG for occasional use in a garage. IF you wanted to go further maybe you could do some passive solar (windows, overhangs, etc.), hydronics in the slab, and forced air NG. I'd consider insulating the slab and putting the hydronic tubing in it either way. It won't cost much to do that and you can heat the circulating water whatever way you chose to later (solar, NG, ?). if ever.

 

[jebatty]

Based on your proposed bldg alignment, it appears that roof slope will be N/S - this is good, as you have the ability to put solar collectors on the roof, for hot water or air and for electricity, and you can put in the skylights. I also would recommend considering the solar tube lights (Solatube is one brand which we have; works amazing well). Exterior wall space facing south also is good, again for solar collectors. In my mind a new building which is not oriented to take advantage of solar is throwing away megabucks over the bldg's lifetime. Energy cost is one of those famous "sucking sounds" as you dole out dollars to the smart and rich guys. Become one of them by maintaining your solar options.

I've got a new shop being built right now. Roof alignment with slope to the south and sidewall facing south were the MAJOR factors in locating the building. Our house already is aligned for passive solar, and we get just about 100% of our space heating from solar during sunny late fall/winter/early spring days.

 

[ikessky]

I'm not switching insurance companies. Lot of other options. We are still debating what we want to do with construction and remodeling and what not. It will give me a little time to think about everything. Personally, I'm leaning towards setting up a NG forced air system and then tinkering with solar a little.