Radiant vs. All Others

[Adesn]

Hi all! First time poster, long-time lurker on this very informative forum.

I am in the process of building a new 36' x 24' shop to house my "part-time" sign and graphics business. We are demoing the old building in a few weeks, and pouring a new slab with frost walls. The building will have 12' walls with a loft area for storage. We will also have two large garage doors and the entire building will be an open space under the truss system.

I have been going back and forth on the heating options.

For starters, we are located in Vermont. The winter nights can get down to 0 but mostly we are in the 20-30 degree average throughout the cold season. My time in the shop is pretty limited to 1-2 days a week (and some nights) as I work full-time for another company. I would mostly like the ability to turn the temp down to 45 and then up another 10 degrees to work comfortably and/or dry some paint as needed.

Everyone I talk to in various building trades says to go with radiant if you can afford it, since we're starting from scratch. My original idea was to hang a Modine in the corner and run it low, then crank up a bit as needed.

Just looking for another opinion and maybe options I'm not thinking of from the garage experts here, thanks!

 

[Kaizen]

It’s the cost of insulation that makes pex crazy. Pex itself is cheap.
If you can afford install it even if you are not using it.

Radiant in a slab does not change fast as you describe. You are feeding it water at a low temp to maintain or move it up. Thicker the slab the more it retains. If you lost power it would maintain temp for days.
Of course the insulation in the rest is vital. If you can seal off attic storage I would.
I have radiant in some parts of house and it is awesome. Wish I had the money to put in garage.


Sent from my iPhone using Tapatalk

 

[yeldogt]

Do you have natural gas? ..... if so with 900sf of space and proper insulation and doors the cost to heat that building will be low.

You can't do what you want to do with radiant -- too slow to respond and when you do want it to raise the temp quickly -- you have to pump hot water into the slab. Defeats the whole reason.

Radiant is the best comfort wise and no odd air currents .... but, it costs more to install (often much more) vs other system and it does not save huge amounts of fuel.

Radiant is about comfort .... you heat the slab and keep it that way.

Also -- you must insulate the slab with radiant ... use enough tube (PEX)

 

[Dagny]

Put the modine I prefer reznor but both should be set above 50 to avoid condensing.

 

[Ralf11]

Heat rises, so putting the source in the floor is a good idea.

Radiant is slow to change but a timer to turn it up a day in advance is not hard to do.

Radiant + a mini-split makes sense to me.

 

[Adesn]

No natural gas, will be going with propane as fuel.

The old shop had propane through a hot air furnace with a plenum on top, routed through ductwork into two areas separated by a wall; a garage and office space. When working full-time in the shop it was fine, but after switching to part-time, we had plenty of issues with the furnace keeping the heat down to 50 trying not to burn through so much gas.

This building will be stick framed (2' x 6') but we are going to side the whole thing in 1" foam insulation, strap it, then finish with metal siding. This seems better for long term maintenance and saves on sheathing the outside given current lumber prices.

Going with radiant will probably boost the budget around $3,500 - $4,000 vs. forced air, so I guess my main concern is what kind of issues might we run into with a radiant slab, especially if we keep the heat down to conserve fuel.

Is it just as efficient to keep it around 60 vs. 50?

 

[kj_mustang]

To be efficient, you would need to add more insulation than just the 1" foam board. And you will spend plenty on the metal and trim pieces. I just spent $900 for roof and siding metal for a 8 x 10 shed.

 

[kTHREE]

Split the difference.
Go with an IR tube, quick to bring up to temp, efficient.

 

[Adesn]

Should've mentioned we will be blowing in insulation as well, just not sure if we're going to get to it this year.

Placing an IR tube over the work bench area would make sense to warm things up quickly, and they don't seem too crazy on the price.

 

[Jackfre]

900 sq ft in VT? Install a Rinnai Energysaver. Depending upon the lay-out possibly two smaller units. When I left the New England market we figured that 5% of all the apt and homes in VT had them. Your other option is to check the rebates on mini-splits. VT Energy is a good source of info on them. Your propane company will know the Rinnai’s really well. If you have the resources on a small business, yes, radiant is great, but cost, cost, cost is the order of the day. Hanging a unit heater will be the lowest cost probably, but also the least comfortable.

 

[Sumboodie]

It'd be just fine keeping at 45* and kicking up to 65* for the day or two a week he's working in there.
Or even better, put in a hanging hot water radiator as well. Use it for a quick warm up and the slab to maintain.
That's how I have my garage setup.

Do you have natural gas? ..... if so with 900sf of space and proper insulation and doors the cost to heat that building will be low.

You can't do what you want to do with radiant -- too slow to respond and when you do want it to raise the temp quickly -- you have to pump hot water into the slab. Defeats the whole reason.

Radiant is the best comfort wise and no odd air currents .... but, it costs more to install (often much more) vs other system and it does not save huge amounts of fuel.

Radiant is about comfort .... you heat the slab and keep it that way.

Also -- you must insulate the slab with radiant ... use enough tube (PEX)

 

[Sumboodie]

What will handle the shear loads of the wall without sheathing? Is this a pole barn or timber framed?

No natural gas, will be going with propane as fuel.

The old shop had propane through a hot air furnace with a plenum on top, routed through ductwork into two areas separated by a wall; a garage and office space. When working full-time in the shop it was fine, but after switching to part-time, we had plenty of issues with the furnace keeping the heat down to 50 trying not to burn through so much gas.

This building will be stick framed (2' x 6') but we are going to side the whole thing in 1" foam insulation, strap it, then finish with metal siding. This seems better for long term maintenance and saves on sheathing the outside given current lumber prices.

Going with radiant will probably boost the budget around $3,500 - $4,000 vs. forced air, so I guess my main concern is what kind of issues might we run into with a radiant slab, especially if we keep the heat down to conserve fuel.

Is it just as efficient to keep it around 60 vs. 50?

 

[Adesn]

What will handle the shear loads of the wall without sheathing? Is this a pole barn or timber framed?

The idea is to wire, insulate inside the bays, and then sheath the inside walls with plywood.

Not 100% sold on this idea, but I have seen it done on a couple of other new buildings in the area.

We are also not sheathing the roof, but just strapping the truss system and then screwing down the metal roof. The roof will then be spray foamed inside.

 

[kj_mustang]

I hope all strapping planned is with 2x4's.

 

[jacks2000]

You say you're doing graphics. If that includes cut vinyl the unit heater will be blowing your materials away. I have radiant in my 3200 sq ft shop set at 56 deg. Since I wanted AC I also installed a furnace since it's not much more than an air handler. I bump up the T-stat when I'm ready to go out there and it 65 in less than 10 minutes.

 

[Randy in Maine]

Back 10 years ago when I built my 40x28x12 shop, it was about the same money to use structurally insulated panels vs the cost of time, labor, waste, insulation, and a lot more wood. I used these https://murus.com/product/polyurethane/ Much tighter and better insulated than most things that are stick built.

2" of rigid foam under the slab is about $1 a square foot. The local concrete supply people delivered it to me at no extra cost. I insulated my stem walls also. I used 1/2" pex 1 linear foot per square foot of foundation. My shop is only about 20' from my house so I just ran 3/4" pex to/from the new shop under the foundation from my house propane condensing boiler to the new shop. The shop is its own zone. I keep it 50º all winter. Very comfy. No dust or fire out there either.

 

[finn]

My shop is 48x75’, with radiant in the floor. I don’t use the shop every day, so I ended up adding a 75k hanging heater to bring the temperature up when I am working in there.

I get a lot of pushback, but in my opinion, and based on my experience, radiant in floor heat is the wrong system for a building that doesn’t require full time heating.

My house also has radiant in the floor, and it works well there.

 

[theoldwizard1]

Everyone I talk to in various building trades says to go with radiant if you can afford it, since we're starting from scratch. My original idea was to hang a Modine in the corner and run it low, then crank up a bit as needed.

Radiant in-floor heat is the MOST COMFORTABLE heat you will ever experience ! If your feet are warm, you are warm.

The big downfall of in-floor radiant heat is "recovery". If the temperature of your slab is 45F it is going to take some time to get it up to 65F.

Regardless of your choice of heat, solid foam insulation (at least 2") and a vapor barrier under the concrete will help a lot.

 

[65ranchero]

I see you are in Vermont: I don't know if its going to be classified as commercial or residential but there are rebates for both heating and insulation.

https://www.efficiencyvermont.com/r...lation&hvacfilter=Heat+Pumps&type=Residential
https://www.efficiencyvermont.com/r...oling+&+Ventilation&hvacfilter=&type=Business

https://www.efficiencyvermont.com/r...on+&+Air+Sealing&hvacfilter=&type=Residential

https://www.efficiencyvermont.com/r...ation+&+Air+Sealing&hvacfilter=&type=Business

 

[65ranchero]

Back 10 years ago when I built my 40x28x12 shop, it was about the same money to use structurally insulated panels vs the cost of time, labor, waste, insulation, and a lot more wood. I used these https://murus.com/product/polyurethane/ Much tighter and better insulated than most things that are stick built.

2" of rigid foam under the slab is about $1 a square foot. The local concrete supply people delivered it to me at no extra cost. I insulated my stem walls also. I used 1/2" pex 1 linear foot per square foot of foundation. My shop is only about 20' from my house so I just ran 3/4" pex to/from the new shop under the foundation from my house propane condensing boiler to the new shop. The shop is its own zone. I keep it 50º all winter. Very comfy. No dust or fire out there either.

I have a similar set up works for me. I insulated my 4' stem walls with https://www.insofast.com/
cut in half and covered with FRP
Oil hot water boiler ( on it's own zone) set at 68F all the time and it really does not strain it at all

 

[haugy]

For what it's worth there is a lot of good info in here. And one of the points was, full time vs occasional heat. I'm going with radiant in floor in mine. But I will be working out there (office build in it) and my boat storage will be in there. That will mean I'm keeping my floors at 55° or more during winter. I'll be spray foaming and insulating as well so my shop will hold temp well. With a good size heater in the system I'll be roasty toasty. The infloor for me is to ensure that days I'm not working in there, the shop maintains that temperature. Otherwise, while nice, it would be an expensive waste.

 

[stingry]

Based on my experience with radiant floor heat, I believe it to be the most comfortable heat you can have. No cold spots, no noise and no moving air. Yes, the upfront costs are higher but I consider that to be the cost for the comfort it provides. I keep my shop 65 degrees all the time. It is so nice to have it constantly warm, if I’m going out for a few minutes or a few hours. My system is very economical to run. I’m in western Nebraska where we have below zero temps but not to often. Most winter days are in the thirties and forties with overnight lows in the single digits and teens. My natural gas and electric bills are around $100 on the coldest months. My shop is 3600 sq ft with 10 ft walls. Very economical!!

 

[finn]

Based on my experience with radiant floor heat, I believe it to be the most comfortable heat you can have. No cold spots, no noise and no moving air. Yes, the upfront costs are higher but I consider that to be the cost for the comfort it provides. I keep my shop 65 degrees all the time. It is so nice to have it constantly warm, if I’m going out for a few minutes or a few hours. My system is very economical to run. I’m in western Nebraska where we have below zero temps but not to often. Most winter days are in the thirties and forties with overnight lows in the single digits and teens. My natural gas and electric bills are around $100 on the coldest months. My shop is 3600 sq ft with 10 ft walls. Very economical!!

Your low gas /electric bills are the result of the attention to detail you made when insulating, not because of the radiant.

A btu is a btu, and heat loss is to the atmosphere, up the stack, or into the ground, and is the same regardless of heat distribution method..

 

[Improved700]

Make sure you take into account the sign and display equipment being used currently, but more importantly in the future. Eco solvent and UV/LED machines need to be kept at a "office like" temperature, and do not like to be cooled down overnight or over the weekend, and then brought back up to temp on Monday mornings. Additionally you are going to want to maintain a fair amount of humidity to combat static issues, that cause problems with equipment.

Personally, a forced air furnace system would be fine, but need to make sure, as someone else pointed out that dust blowing around may cause an issue. However there are many, many sign and display shops using forced air heat/cooling than there are with radiant in floor heat.

Also, if you ever move up in equipment, there may be the need to cut out and repour a pad for large equipment, which would be an issue with in floor heat.

Natural Gas forced air, would be my vote.

kevin

 

[Adesn]

Make sure you take into account the sign and display equipment being used currently, but more importantly in the future. Eco solvent and UV/LED machines need to be kept at a "office like" temperature, and do not like to be cooled down overnight or over the weekend, and then brought back up to temp on Monday mornings.

A few years ago I moved printers/cutters and computer equipment into an office in my house on the same property. The garage was in pretty bad shape when we purchased the property and we knew that it would need to be demo'd and rebuilt someday.

Thanks to everyone for the helpful replies! I'm still going back and forth on the best heating system for this new shop, but have plenty of work with a demo and site work ahead of me, so I will continue to browse this forum for info.

 

[slowtwitch73]

Your low gas /electric bills are the result of the attention to detail you made when insulating, not because of the radiant.

A btu is a btu, and heat loss is to the atmosphere, up the stack, or into the ground, and is the same regardless of heat distribution method..

Eh.. I disagree. You end up ******* away heat with other systems because it's not efficiently distributed. Heater on a ceiling warms up the top foot real nice.. meanwhile you can freeze water on the floor, so you crank the heater up to try and make up for it, etc.

You get a more uniform column of heat, so use less gas etc.

 

[WisJim]

No matter the type of heating system, insulate properly (minimum 2" foam) under and around the slab, or your cold floors will be regretted for the life of the building. Even without infloor radiant heating, insulation will keep the floors warmer.

 

[finn]

Eh.. I disagree. You end up ******* away heat with other systems because it's not efficiently distributed. Heater on a ceiling warms up the top foot real nice.. meanwhile you can freeze water on the floor, so you crank the heater up to try and make up for it, etc.

You get a more uniform column of heat, so use less gas etc.

Warm air is less dense than cold air, so warm air always rises towards the ceiling.

Your feet stay warmer with radiant, since the floor is always above the thermostat set point in heating season. This may let you run a lower thermostat setting. I have lived with radiant floor heat for thirty years, and don’t really understand why some people can’t look at it objectively. It has some advantages for sure, but it’s not a system for low cost of installation or an intermittently used shop.

 

[yeldogt]

Based on my experience with radiant floor heat, I believe it to be the most comfortable heat you can have. No cold spots, no noise and no moving air. Yes, the upfront costs are higher but I consider that to be the cost for the comfort it provides. I keep my shop 65 degrees all the time. It is so nice to have it constantly warm, if I’m going out for a few minutes or a few hours. My system is very economical to run. I’m in western Nebraska where we have below zero temps but not to often. Most winter days are in the thirties and forties with overnight lows in the single digits and teens. My natural gas and electric bills are around $100 on the coldest months. My shop is 3600 sq ft with 10 ft walls. Very economical!!

Natural gas is the key to affordable running cost ... with propane you have to give a bit more thought. Also -- with cheap electric in some parts of the country a good heat pump can be the answer.

Nothing is like radiant ... it's the best. Will say again -- you don't do radiant to save money.

When NG is available ..even a poorly designed system with less than perfect insulation will not cost a lot to heat 900sf. Propane can be 4x the price .. resistance electric even more.

Someone doing 12" spacing w/ poor insulation is not going to be happy trying to bring the slab up and down all the time -- especially if it's a thick 6" slab. Again -- 12" spacing w/ thick slab ..maintaining temp w/ natural gas ... will work for most.

The only way to heat a slab quickly is more tubing ... but, it has limits. It's all about BTU's ..... IN.

Another factor is the water temp -- depending on the insulation. My building require a slab of around 75 ..... With radiant you are pumping low temp water. To bring a slab up to temp quickly -- you need higher temp water. Even with 6" Tube spacing. This will be less efficient.

You can always devise various ways to lower overall temp -- but getting under mid to high 50's is often not possible. Some people do shoot for 57 with the idea of another heat source to bring it up.