Need Help Finding Suppliers for My New Garage - Radiant Heating

[Frank R]

That doesn't really change anything, it just reduces the heating load.

Let me ask this: what benefit do you see from the heated floor as opposed to just leaving the furnace you're already paying for on a low thermostat setting and turning it up when you're there?

The forced air furnace heats the shop quickly but the floor area remains cold.

I had a friend do my drywall finishing in my old garage. Even though he ran the heater he said it was noticeably colder when he was mudding near the floor.

 

[Frank R]

Yes - I was referring to AC using Mini Splits - in fact, you could use the Mini Splits in the summer and bridge seasons when its 40-50 degrees for heat, then the radiant for the deeper cold winter months.

I will have to look into Mini Splits to see if they are suited for our area. I know that heat pumps are not ideal.

 

[Carl_NH]

Frank - they work down to -5 F easily - below that fossil fuels are more efficient - is Dearborn Michigan your location ? - it would help get better responses for your local climate.

 

[quicksandfarmer]

The forced air furnace heats the shop quickly but the floor area remains cold.

I had a friend do my drywall finishing in my old garage. Even though he ran the heater he said it was noticeably colder when he was mudding near the floor.

Cold floors are caused by the floor being uninsulated and the building being leaky.

I like to say that an ounce of insulation is worth a pound of hydronics. You'll do more to make the building comfortable by insulating and sealing it than with anything you can do with a heating system.

A heated floor is most noticeable in a leaky and poorly insulated building. A lot of the favorable reports come from that sort of installation. Buildings built to modern standards are comfortable with almost any heat.

I realize a lot of shops will have garage doors that are tough to seal. But if you're considering heating the floor it should be well-insulated anyway.

 

[Frank R]

Updated my location.

 

[Frank R]

Cold floors are caused by the floor being uninsulated and the building being leaky.

I like to say that an ounce of insulation is worth a pound of hydronics. You'll do more to make the building comfortable by insulating and sealing it than with anything you can do with a heating system.

A heated floor is most noticeable in a leaky and poorly insulated building. A lot of the favorable reports come from that sort of installation. Buildings built to modern standards are comfortable with almost any heat.

I realize a lot of shops will have garage doors that are tough to seal. But if you're considering heating the floor it should be well-insulated anyway.

Michigan adopted the new building codes a few years ago. I have to build my walls with 2x6s to account for the extra insulation. I am planning on using rockwool, or cellulose.

BTW: I am thinking that I will only heat one third of the floor space, the part I use for my shop. I will have a wall separating the shop from the rest. That way I would only heat the floor in the garage part when I really needed it.

 

[Carl_NH]

Rock wool is excellent for walls and does a better job of insulating than fiberglas in and around electrical boxes and filling in the gaps. I would imagine they will also require ceilings or roof of R40 too - so depending on your stucture thats batts or blown in etc.

You could do radiant heat, but for occasional use a modine or similar wall mount LP system is quick to heat 2-300 SF, or a 9K mini split too will heat that size area in 30 minutes or less. The radiant is not instant - it takes a while..

As quicksandfarmner says, if its well insulated thats the key and under the slab too.

 

[jigs_n_fixtures]

That doesn't really change anything, it just reduces the heating load.

Let me ask this: what benefit do you see from the heated floor as opposed to just leaving the furnace you're already paying for on a low thermostat setting and turning it up when you're there?

We it is lots more comfortable to work on an insulated and heated concrete floor, than and uninsulated and unheated floor.

 

[jigs_n_fixtures]

I will have to look into Mini Splits to see if they are suited for our area. I know that heat pumps are not ideal.

Frank - they work down to -5 F easily - below that fossil fuels are more efficient - is Dearborn Michigan your location ? - it would help get better responses for your local climate.

I installed an air-to-air heat pump in a Forest Service office in Salmon, Idaho about a decade ago. It works down to -20F. I installed a smart, fuzzy logic thermostat with the system, which learned the buildings heat properties, so I knows how long before start time it needs to start heating to have the office at 70-degrees, at 0700.

In the five years I monitored the systems use data, the only time the emergency strips came on was when someone came in early or on a weekend and bumped up the thermostat. Otherwise, the system used the temperature sensor in the compressor housing, and the anemometer, to calculate the lead time needed to get the building up to temp before people started work. After five years the system had paid for itself in increased efficiency versus the old oil burner with separate air conditioning.

The efficiency of air-to-air heat pumps is rapidly getting better, and you could also look at water to air, or a ground loop to increase efficiency.

 

[quicksandfarmer]

How are you planning on heating the water for the floor?

If it's with an electric water heater, you'd get the same efficiency with a heated mat.

I'm not necessarily trying to talk you out of hydronics, but it's not necessarily going to deliver much comfort and everything about it is going to be expensive. Even if you can install the tubing on the cheap.

 

[jonsstihl]

If you are going to tile like Kenny D I wonder how the costs would compare to using the heated wires you lay down before you tile.

 

[not2old]

Don't forget that if you open the overhead door in the winter with hot air, you will lose all the heat. With hot water in the floor, the room temperature will recover quickly.

 

[quicksandfarmer]

Don't forget that if you open the overhead door in the winter with hot air, you will lose all the heat. With hot water in the floor, the room temperature will recover quickly.

You lose the same amount of heat either way. A furnace can pump heat into a space a lot faster than a heated floor can.

 

[Frank R]

We it is lots more comfortable to work on an insulated and heated concrete floor, than and uninsulated and unheated floor.

But what about an insulated but unheated floor?

Quicksandfarmer has a point.

I already have a Modine Hotdawg ceiling furnace that heats a one-car space in hurry. If I left it on at 50 degrees it would bring the slab up to temperature, where it would not be so uncomfortable.

I got an estimate back from Creatherm. For 100 panels, it would cost me about $1700 for the foam panels, which includes shipping. This is for a three-car garage. Plus the PEX, manifold, piping, water heater, exhaust, and wiring. I am starting to hesitate on this.

 

[Frank R]

Did some more thinking.

I am going to install foam under the concrete anyway. I will need to put down mesh as well. So all that is left is to install the PEX before the concrete gets poured. Whether I use it later or not is a separate issue. Now I need to decide if I go with something like Creatherm panels or just Foamular XPS 250 and attach the PEX to the mesh with zip ties. The Creatherm is about $500 more expensive but is easier to install the PEX.