New build, no gas

[Conrad]

I’m prepping to build a new garage/workshop, located in Colorado, where winters get down to single digits frequently and sub-zero a few times a year. Natural gas isn’t an option so I’m considering a few options to keep temps high and costs low.

- Structure: detached 1400sqft steel building, I plan to blow in insulation to seal it up immediately after it’s erected, after that I’ll frame it, put in bats of fiberglass and finish with drywall and paint

- Slab: I’m considering laying down electric radiant mat in the concrete slab, I plan to pour 6”. The HVAC guy I spoke to said it would be very costly to run; I agree and I’m not trying to use it to provide heat, rather just take the chill off the slab and prevent the floor from being a huge heat sink

- Heat: I’m considering using two options for heat, a 220v powered electric blower for quick heat up, and a pellet stove for sustained heat

Feedback on this setup appreciated,

I’m curious how effective radiant flooring is, does having different zones affect anything

 

[3rdgen]

How easy is it to get propane, Electric slab heat will be murder on the hydro bill.We have plenty of shops here with a propane boiler and infloor or just a propane fan forced heater too.

 

[Jagmandave]

You should be looking at passive solar options in your build, there are lots of ways to bring heat into the building that don't require electricity at all....especially in Colorado where you get so much sun.

Other than that, I would invest in insulation under the slab, then instead of warming the slab with electricity, put solar panels on the roof and use the electricity to heat the building?

 

[Showkey]

I have multiple bath rooms with in floor electric radiant. Those were not trying to warm a 6”slab.

Have you done the numbers on electric radiant in concrete ?

One supplier as Quick ball park estimate:
150 sqft. is 18 amps 2256 watts at $660..........so in theory you would be 10 times those numbers to do 1700 sqft ?????

Even 10,000 watts is about 34121 BTU/hr

If your forced to use electricity maybe a high quality low temperature rated mini split ?????


Second 3rds comment in post #2:
Propane boiler with in floor PEX would be good choice, not inexpensive. Propane hanging furnace 80k btu would by far the least cost and very effective.

 

[nadogail]

Passive Solar "Heat Grabbers", IMHO, might be very effective.

 

[Conrad]

There's no infrastructure here for LPG/NG, so I have to consider other options.

You should be looking at passive solar options in your build, there are lots of ways to bring heat into the building that don't require electricity at all....especially in Colorado where you get so much sun.

Other than that, I would invest in insulation under the slab, then instead of warming the slab with electricity, put solar panels on the roof and use the electricity to heat the building?

The way the building is situated, it doesn't get much direct sunlight, especially during winter hours, so until solar tech becomes very efficient, I don't think its really feasible. Will definitely be laying foam insulation under the slab.

Have you done the numbers on electric radiant in concrete ?

Materials yes, usage no, I'm trying to get some input around how effective is heating the floor when it comes to making a place comfortable. I have radiant in my kitchen which is nice in the morning when I'm barefoot making breakfast but its not the primary heat source, and other than being nice to the touch, its hard to say how much it matters.

 

[Jim greengo]

No way to get a big propane tank filled?
How about a couple of mini splits/heat pumps?
I'd definitely insulate the floor either way.

 

[u3b3rg33k]

plenty of air-water heat pump options to run your slab. electric backup for the few days it's so cold it can't function.

 

[jlv03]

plenty of air-water heat pump options to run your slab.

Any examples?

I wouldn't go with electric resistance in/under a slab - too expensive to run, and nearly the same amount of work as putting in PEX. If you want to heat your slab, put the PEX in and make a decision on a heat source later.

 

[Randy in Maine]

When I lived in SW Colorado I had LP gas readily available. I would just buy a 1000 gallon tank and just have it filled when needed.

 

[toyotadriver]

I’d be surprised if propane isn’t available in your area. What do other people use?

 

[theoldwizard1]

- Structure: detached 1400sqft steel building, I plan to blow in insulation to seal it up immediately after it’s erected, after that I’ll frame it, put in bats of fiberglass and finish with drywall and paint

- Slab: I’m considering laying down electric radiant mat in the concrete slab, I plan to pour 6”. The HVAC guy I spoke to said it would be very costly to run; I agree and I’m not trying to use it to provide heat, rather just take the chill off the slab and prevent the floor from being a huge heat sink

For the slab, you need at least 2" of rigid foam and a vapor barrier. If there is a surrounding foundation wall, it needs to be insulated also.

You will go broke with ANY kind of direct electric heat. Propane is your simplest solution, either in floor hydronic or hot air.

Pellet stoves are only cost effective if you can purchase and haul the pellets directly from the factory. Any middle man will kill the cost.

Mini split heat pumps can be cost effective if you have a lot of insulation and you purchase a high efficiency unit. Good ones will produce heat out even down to about -10F.

In floor heat is extremely comfortable because if your feet are warm, you feel warm. Zoning helps reduce the cost, but only if the zones are separated by walls.

 

[TractorJeff]

Where in Colorado in the Rockies?
Nearest Town?

 

[Conrad]

Where in Colorado in the Rockies?
Nearest Town?

Conifer


I'm leaning toward the heat pump, seems I can get a pretty high efficiency 48k unit for under $4k; installing a 1000lbs tank would logistically be a PITA since it would require excavating and maybe some tricky pipe work (I'm on a steep hillside), so my upfront cost would be pretty high.

 

[toyotadriver]

I searched the area of your town and found several propane suppliers. Prices seem pretty good per gallon. If your shop is fairly well insulated you won’t need a 1000 gallon tank. I live in a slightly warmer climate (still gets cold) and I heat my 1200 sq foot on a 120 gallon tank. I bet a 250 gallon tank would be the right size for your needs.

 

[kj_mustang]

Yeah, an above ground 250 or 500 gallon would be plenty. I heat my pole barn, house radiant, hot water, and kitchen range with one yearly fill of a 1,000 gallon tank.

 

[ericm]

This calculator below is useful for estimating costs to heat your building using different energy sources. Someone here posted the link. Unfortunately the calculator fixes the target interior temp to 70 degrees but it's still useful for comparison.

https://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

 

[u3b3rg33k]

Any examples?

I wouldn't go with electric resistance in/under a slab - too expensive to run, and nearly the same amount of work as putting in PEX. If you want to heat your slab, put the PEX in and make a decision on a heat source later.

Chilltrix has them, arctic heat pumps, nordicGHP. plenty out there. it's just a heat pump with a water HX not an air HX.

 

[jlv03]

Chilltrix has them, arctic heat pumps, nordicGHP. plenty out there. it's just a heat pump with a water HX not an air HX.

I had heard of Chilltrix and Nordic GHP before, but not Arctic Heat Pump. Unfortunately still pricey, no matter what brand you start exploring.

If you want to find yourself going down a deep Internet rabbit hole, start exploring CO2 air-to-water heat pumps. Seems to be much more popular outside of North America.

 

[u3b3rg33k]

I had heard of Chilltrix and Nordic GHP before, but not Arctic Heat Pump. Unfortunately still pricey, no matter what brand you start exploring.

If you want to find yourself going down a deep Internet rabbit hole, start exploring CO2 air-to-water heat pumps. Seems to be much more popular outside of North America.

I believe SandenCO2 is 4.5kW/15kBTU/hr, about $3500 (IIRC), 80gal tank. will do 150F+