Furnace questions

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Right now our house has recirculating hot water, and we're contemplating (again) replacing our house with a modular. It too would have recirculating hot water. At the moment, my system is plumbed to the water supply, and uses plain old water. Works just fine.

In tossing around ideas for the house possibilities, it appears there is enough space to put a garage under the house. So my thoughts naturally turn to, how the heck would I heat it in winter, for the few times I need to do something and don't want to work in the freezing cold? Just putting in another zone seems kinda simple to me. But if the garage is unheated the vast majority of the time, then coolant would be needed.

So the question is, what's the drawback to using coolant instead of water? I'm guessing the coolant ain't free, but I'm not sure if it needs periodic replacement. Or if the lower heat capacity means it works less well, or some other factor that I just don't know about.

[I realize I could heat with electricity, that might be easiest/best for such light usage. Not really interested in wood or pellets.]

Question #2: if I were to insulate my basement, and seal it up, wouldn't it make sense for the furnace to have some sort of intake from the outside world? I realize my contractor & heating installer would probably have the answer, but I'm not sure how to view this--seems like, when the furnace kicks on, it just draws air through every crack and crevice in the house. Which could be good (air exchange) or bad (well, it's still heat loss--that incoming air could be in the living area).
 
Id run a modulating-condensing boiler with indirect hot water tank. That would handle your house and domestic water needs.

If you put a garage on a slab under the house, the question becomes how tightly sealed will it be?

I have an unheated, detached garage, and even in the coldest of weather it's nice to be out of the wind. Unless you let yourself get soft, it's good enough down to, say 20F.

If I wanted to have such a space, I'd likely use a separate dedicated space heater. Economics of it are fairly irrelevant because the percentage of time running it should be minuscule. If you decide to seal it up enough to heat it like the home, IMO you're asking for other issues.
 
Yeah, I don't want to seal up the garage and heat it all the time--lots of issues with heat/cool cycles on the cars themselves. I'm not even sure I want to regularly park the cars inside (but wife might have other plans!). However, the house would have a huge walkout basement, and it seems like cheap money & a good boost in value to put in a garage door if I could. Rather than build an outbuilding a hundred feet away, installing an electric drop, etc.

I realize that the garage would need to be sealed from the house (using whatever fire retardant sheetrock is required), whatever is required for code. I'm no good with hammers, so ultimately it's whatever the contractor thinks is a good idea too, for the record.

Modulating-condensing furnace, thanks, will keep that in mind. Many things to investigate.
 
I would look at putting in an electric heater with a fan. You'll need access to 220 volts, but you won't have to run any pipe or vent it. You could have it on a thermostat, or just a on/off switch if you don't want it on all the time.,,
 
I heat my garage with a small blue-flame gas heater. 30,000 BTU with an adjustable thermostat, and it's vent-less so only gas supply piping to deal with. Works great!
 
Don’t add a zone for limited use as it adds complexity issues to your system. Antifreeze adds further complexity as it is poison and if you check valve /
Pressure valve fails you poison your domestic water supply. No thanks!

My $25 used Delonghi radiant oil filled electric heater melted ice out of wheels and snow blower on a -5f outside night in our insulated garage. Garage was 45f.
 
You can pump in CryoTek antifreeze. It's not free and is not as good heat transfer as water and it's said to be slightly corrosive to valves. It needs to be saved when you open up the system for work.

I would add an air handler zone (hydronic coil with a fan). You can set the thermostat to 40 and without the fan running, not much heat will be lost. When you want heat, turn up the thermostat and turn on the fan. This type of heater will heat up the garage faster than plain baseboard.
 
Originally Posted By: madRiver
Don’t add a zone for limited use as it adds complexity issues to your system. Antifreeze adds further complexity as it is poison and if you check valve /
Pressure valve fails you poison your domestic water supply. No thanks!

My $25 used Delonghi radiant oil filled electric heater melted ice out of wheels and snow blower on a -5f outside night in our insulated garage. Garage was 45f.



CryoTek is non toxic and made for boilers assuming something in the boiler will fail allowing boiler water and domestic water to mix.
 
Sounds like electric is probably best. Since it'd be all new construction I should get a new drop from the power company too, so electric heat should be a minor issue.

As to what I'd heat with, not sure at this stage. Gas or oil, flip a coin. Might be nice to go gas and not have an oil tank in the basement.
 
Originally Posted By: dnewton3
I heat my garage with a small blue-flame gas heater. 30,000 BTU with an adjustable thermostat, and it's vent-less so only gas supply piping to deal with. Works great!
I use a 20000 BTU vent less blue flame heater for my whole house. It works great as long as you have some dedicated exhaust ventilation going while it's running. My propane cost for heating a 1000 sq ft house in Central Illinois is less than $250 a year.

For a garage they also have infrared ventless heaters.
 
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