We are rebuilding our garage in the near future and as part of the design I am going to have an 8’x12’ room framed out for a shaping/glassing/sanding room. I am in NJ so we have a temp range from 0-100F and I want to heat/ac the space for year-round use. I have been advised NOT to bring in the duct work from the current central HVAC system so I avoid circulating shaping/sanding dust throughout the house system.
Any suggestions on the best systems to handle appropriate heat/AC and ventilation/collection of dust? Don’t want to go crazy $ wise (I only make 10-15 boards a year), but I would like a reliable/effective system.
I'll take a crack at this.. I'm not an HVAC tech. but have run ducting into garages off of the central house unit for home offices etc. You have to be sure your unit can handle the extra space otherwise it won't keep up It will run all the time or at least more than usual. This will result in the early demise of your unit. It would be better to to have a separate air conditioner and a separate heater for your shaping room. On Maui most shapers had a widow air conditoner. Make sure you buy one that is more BTU than you need for the square footage. At least two times what you need. Whatever you use for heat; duct it in thru the wall or ceiling. No pilot or open flame in the room. Dust collection is easy. Fit your planer with a vac system. You'll have to blow out any and all filters every other day. Every day is better. There are ways to blow dust out with a fan sytem, but they are pretty inefficent.
Thank you, McDing. I definitely want the shaping room to have a completely independent HVAC unit from the rest of the house. This is because I want independent control over the room temp for specific situations that don’t apply to the house. For example, when I’m not using it, in the winter, I’d keep the room in the 55F degree range. Not too cold to mess with epoxy or other liquids, but not nearly as warm as the inside of the house. Another example, when I’m glassing, I’d want to keep the room 75-80F+ for a quick epoxy cure (substantially higher than house temp)
So far my inquiries have led me to a “mini-split” type system. This is a single unit heat/ac that can be installed/controlled in a single room. These are normally pretty expensive, but I have found a reasonably priced one here:
I know these mini-split systems are standard-issue in most of the world but they are relatively novel in the US. Anybody have any opinions if these are appropriate for shaping/glassing room use? I would have to clean/change the filter alot, which is par for the course.
As for dust-control. I was thinking of a basic wall-mounted shop vac for general cleanup and possible hook-up to my Clark/Hitatchi.
My final question would be regarding Ventilation. How do I get fresh air in and stale/dirty air out without bringing in a bunch of cold air in the winter? Is this handled automatically by the mini-split system? Or will I need some sort of separate exhaust/intake in the wall?
That's a good price for one of those split systems, but a bigass window AC with heat strips will have about twice the btu and only cost (at most) $600. I run an 18,000 btu in my ~300sqft shaping room, so you'd be able to freeze or sweat in an 8 x12.
Do your rough sanding outside if you can, because an exhaust fan is needed if you stay in your room. Resin/glass dust is bad news for any HVAC filter.
Howzit jamie, Funny but the way those units work is they exhaust cold air outside where the fan is when using it as a heater and warm air when using the A/C. Just yesterday we had to defrost the cooling fans and pipes because it was so cold they froze up and the unit stopped working. Those systems aremeant for houses not shops and I would look into a different system. You say they are novel in the US so I had better check them out because here in Az almost everybody has A/C and heater 2 in 1 systems. Just checked the system and they are not like the ones we use. Aloha,Kokua
a mini-split heat pump like the one you provided a link to would probably work ok for your shaping room, but in that environment, it is going to crap out way before its time no matter how clean you try to keep it. a 2nd hand window a/c and a space heater may be all you need. Both disposable if they conch out and both cheap (or possibly you already have them). Or as Mike suggested, a window a/c unit with electric heat (the electric heat will keep the meter spinning!) Before you buy a heat pump, make sure that it has the ability to do its job in the below freezing weather you get in jersey - most heat pumps do not and require additional electric heat to keep the air temp up.
you need a lot of fresh air circulation for glassing and sanding. a unit that could condition those kind of volumes of outside air would be large and expensive.
i know a lot of backyard board builders glass in a closed space (i have done it myself) but it is not the best thing for you to do. Theres not really a choice if its too cold to open up the doors and turn on the fan and you want to get your board done. I guess if its not too often, we should be fine…thats the rationalization anyways…
Don’t tie into the house system to heat the Garage.
By pumping air out of the closed system of the house, you will create negative pressure inside the house. Kind of like a vaccuum bag system that the composite guys use. The end result of the negative pressure inside the house is that exhaust fans will draft backwards, as well as a fireplace if you have one. Smoke will blow down the chimney. Also on a rainy day, water will get pulled inside the joints between the window sash and the window frame.
OK. Thanks for all of the tips. A couple of things I know:
I will definitely use a “closed” system in the room and not tie it into the house.
Heat is more important to me than cooling. I just don’t want the room to freeze up. I want to store epoxy and other temp-sensitive stuff so I want to at least keep the room at 55 in the winter when not in use, then crank it up to 70+ when I’m glassing.
All of the walls/ceiling will be well insulated. I have that benefit since I will be building from scratch.
I’m still a little undecided on:
Most economical/functional way to heat. Another thing I discovered was floor-based radiant heating. Anyone use this?
Ventilation. Should I have a separate fan/vent or will the AC/Heat unit handle this?
1. electric heat will be your best bet. as stated before - a heat pump doesnt work well below freezing temps. you can get a wall mounted electric heater that runs off a thermostat or you can get an air handler/window unit/ (and maybe a mini split?) with an electric heat strip that will cool and heat. A radiant heating system could work well to heat the space but could maybe be a problem will all the dust on the floor from shaping.....
2. you will need a seperate fan (and intake opening) to ventilate your space. most backyarders just open the door and put a box fan by the door....check out yorkys factory thread in the industry section to see how to do it professionally.