Heat register
I just finished room-by-room manual J for my house., which is many decades old and will soon get roll-on wrb + continuous exterior insulation (we also bought new windows and doors but they have not been installed yet). House is > 3k sq ft and has many small rooms, most of which are closed off from each other. Some rooms require less btus to heat than smallest ductless head. Therefore, we are likely gonna heat with Mitsubishi “Hyper Heat” *ducted* heat pumps (we are at VT-NH-MA interstate; many mitsubishi dealers near us). Based on whole house heating load, we will need 2 outdoor units and 2 air handlers. Most days, we spend lots of time in attached garage making small wood items and tinkering with small gadgets. This is for both personal and business-related reasons. If garage ONLY stores these items, plus vehicles that are fully electric (no solvents, no combustion engines), is it safe to have heating supply and return registers in garage? From dec to march the space heater we have been using does not warm us enough to comfortably be in garage for long. We are planning continuous exterior insulation on house and attached garage but probably will not swap out the garage’s existing 70 year-old rolling door nor insulate its existing concrete slab. I know it’s unsafe to connect garage to heating system if there are combustion engines or solvents, but what if garage has neither of these—then is it safe? Thanks
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Replies
AU,
There are two issues.
Practically, if the work you do there doesn't generate any more particulate that you would in a basement workshop, it might be fine.
However all the codes I know of preclude it because they don't base their requirements on what one particular occupant might decide use a space for, but rather what activities generically can be expected to occur. North Americans move on an average every five to seven years. The next occupant may well revert to using the garage to store vehicles or solvents.
Thank you, Malcolm, for this helpful info
Note, the fans in the ducted minis tend to be much smaller than the fans in the standard ducted units.
The standard fans are higher horsepower and intended to work against more back pressure. They are so big that they all but idiot proof in that zero thought is put into the design of the ductwork and the system simply works.
The smaller fans in the minis, demand shorter and larger duct work with fewer bends with larger radiuses and larger filters designed on a computer not the back of a napkin.
Walta
If you have a fuel burner water heater you can put a hydronic fan coil on it and use it for heat. If the tank is not too far, this can be an open system as long as the bits you get are all copper or stainless.
The other option is a slim ducted mini split simply hung from the garage ceiling like a shop heater. No need for any ducting, just install a large filter on the intake. Best is always for this to be on its own outdoor unit as that would let you oversize it a bit so you can heat up the place quickly.
If you don't make a lot of dust, you can also go with wall mount mini split.
Thank you for these helpful responses