Metal pole barn w spay foam- heating costs

[Al Burton]

This has been discussed a little here but I am curious of the heating/cooling costs associated with heating a metal sided building with closed cell foam vs other insulation tyes, i.e foil or vinyl sided fiberglass. I decided againsted open cell insulation. The price diffence between the closed cell foam and fiberglass as we all know is substantial.

I have a 30x40 with 12ft walls I built ten years ago to store farm equipment and a long since gone boat. At the time I built it I decided not to insulate or put in a concrete floor. Now I am considering putting in a floor and turning the building into a shop. I have quotes of putting in 1 to 2 inches of close cell foam but I'm curious what it would actually cost me to heat the building. Ideally I would keep it between 50-60 most of the time. I haven't decided on the heating/cooling system yet either. It would not take much for me to dig a line for natural gas or I could go with electric unit.

Any thoughts?

[Ray Newman]

Question: what is the R-value of the insualting material that you intend to use?

I think once you know this, a call to your electric/natural gas supplier might provide the answer you are looking for as rates vary depending upon location, average temperature, usage, etc.

[Brian Ross]

Al.. I have a 28 x 48 shop that is insulated with R 13 in the walls and R 23 in the sloped ceiling sloped to 17 ft in the middle. I heat it with a 135,000 btu radiant tube made by Schwank. My heating bill is costing about $80 a month during the winter and I heat with natural gas. I work in the shop full time and keep it at about 60 degrees. I live in Ontario and our climate is probably about the same as you will find in the Detroit or Chicago area. For the first winter I used propane to fire the radiant tube and it was costing about $300 a month. Didn't make that mistake again.
I built my own home in this area and the whole house was insulated with sprayed in Polyurethane foam. My heating bill for that house was about 40% of what my neighbors with similiar homes were paying. I had 2 inches in the walls and I think 3 in the ceiling. It is expensive to get it installed but I believe it is worth every penny. It is totally air tight.
Good luck with your journey

Brian

[Al Burton]

That is one of the reason I asked here, most of the HVAC guys I've talked to do not have alot of experience with it yet and I have a little bit of a hard time just taking the foam industry's word for it.

[Brett Baldwin]

Hey Al. So you know up front, the company I work for makes open- and closed-cell sprayfoam so I am biased. I've worked in the industry for about 13 years now. I started in the field and moved into manufacturing. I'm far from an expert but I'm confident in what I know.

Your choice of closed-cell versus open-cell is a good one in my opinion. Open is great but it needs more space to provide the best benefit so if you don't have 2x6 walls, you'll be losing out on R-value. The closed-cell will give you approximately R-7 per inch. Like Brian said, it's greatest benefit is a total air seal. The thing you'll have to evaluate is how well the penetrations (windows, doors, skylights, etc.) are sealed since those are always the biggest areas for heat gain or loss. An R-1000 insulated building with an open door isn't going to save you much in heating costs. Your return on investment isn't short with foam, many years in most cases, but it is the best insulation out right now for most situations, in my biased opinion.

If you're not sealing it behind drywall, you should also consider how to protect it from fire.

[NICK BARBOZA]

If you're not sealing it behind drywall, you should also consider how to protect it from fire.

That is a VERY important point Brett brings up! that stuff is very flamable!!!


I like the idea of spray foam, as I think it will pay for itself in the long term.

Good luck,
NWB

[Bruce Volden]

I put up a 36 X 60 pole shed with 10' walls. Foamed half of it (closed cell) and also have a "office" about 17 X 10 included in the foamed side. I keep the office @65 degrees, heated with a non-vented propane wall mount furnace---that cost me about $250 / yr. The working side for the woodstuff is heated with a pellet / corn stove and is in use infrequently so I can't give you a cost on that, also the price of corn is so high now that corn stoves are a WASTE of money! I would not hesitate in using foam in the future, sure it costs more, but last winter the coldest it ever got in my woodshop was 30 degrees---that was after a week or more of not firing up the pellet stove. In the summer the warmest I have ever seen it was 72 degrees. I should also mention that I have R 49 fiberglass in the ceiling. HTH

Bruce

[Thomas Bank]

From my experience as well as research into the issues, the large benefit of a sprayed foam system is not as much the R-value that it imparts as the sealing quality of the sprayed foam.

Done properly, fiberglass batts can be a very effective insulator. Unfortunately, proper installation is not always achieved. Gaps between batts and between batts and framing members allow air to circulate and lose heat through convection if not outright drafts.

[Herbert Mulqueen]

Have way over 100 post frame buildings under my belt.

I would plan to put some foam insulation under the slab. I used 1 1/2 inches of blue stuff. So we have 4 foot of insulation under the perimeter of the building.

This will cut down on drafts. When the hot air hits the cold slab.

Herb

[Ray Newman]

Re-reading this thread triggered a thought.

In a 30 x 40' building, with 12’ high walls, would a ceiling fan help move the warm around to keep the shop and the materials, tools, etc., warmer? With a ceiling that high, the warmer air will hover there and not circulate.

Could a fan be wired to come on when the heater operates? Or just wire it so you could turn it on when in the shop.

My shop is in a well insulated 30 x 36’ building, 10’ ceiling, with an insulated concrete floor. The wood shop area is 24 X 30’ and heater is a propane fired Hot Dawg heater (Modine), set to about 50 degrees, and I can feel the difference in the floor level temperature.

[Al Burton]

One of the reasons I posted this is claims made by installers. I've had two different spray installers tell me my building could virtually be kept at my desisred tempature with a 50k btu furnance easily, that seems a little low to me. One reccomended a small Mr Slim unit. That is without a ceiling, just the metal roof sprayed. My other issue not discussed is my sliding door but let's face it, there is not a good solution for sealing a double sliding door other that replacing it or living with it.

I do like the ceiling fam idea, it may help.

Trust me on the corn/pellet stove I learned my lesson the hard way sbout 5-6 years ago. I bought my pellet insert when pellets were $2 a bag, now they are $5 plus a bag and corn is not worth it either. I can heat with natural gas much cheaper.

[Thomas Bank]

In a 30 x 40' building, with 12’ high walls, would a ceiling fan help move the warm around to keep the shop and the materials, tools, etc., warmer? With a ceiling that high, the warmer air will hover there and not circulate.

From my experience, the issue becomes that moving the air basically brings the "wind chill" equation into the issue. The moving air ends up feeling cooler to you and you have to keep it warmer to compensate.

[Ryan Hellmer]

Hybrid? I have an acquaintence in Montana that built his own house, on the insulation he had closed cell foam sprayed 2" thick on all the ceilings and exterior walls (framed 2x6) and then used fiberglass batts to fill the rest of the voids. Seems like it gives you the best of both worlds, sealant from the foam and cost/effeciency of fiberglass. I think he's ending up with about r-30 in the walls with more in the ceiling. Has anyone else heard of this?

Ryan

[Bob Winkler]

The spray-foam company I went with here in CT offers the hybrid option. They spray foam between the studs to get a good airtight seal and thermal break and then uses fiberglass batts over it. I decided to go the full foam option because the savings was only about $500-700. Since my shop is realtively close to neighbors, I wanted the max sound isolation benefits the foam offers.

Bob

[Chris Friesen]

One of the reasons I posted this is claims made by installers. I've had two different spray installers tell me my building could virtually be kept at my desisred tempature with a 50k btu furnance easily, that seems a little low to me.

It depends on your weather and the amount of insulation, but it's certainly not impossible.

I live in the Canadian prairies, so we see -40 in winter. My house is 1200 sq ft, is 30 years old and my 80k btu high efficiency furnace is bigger than it needs to be. Done right, a shop could easily be better-sealed than a house.