A tricky question about the economics of heating a garage

sreja

Ok my wall friends, unlike my usual steam heating questions, I come to today with a less technical and more hand-wavey financial guestimation question.



Here's the scenario:



We have a 4 car garage on the bottom floor of our condo building.  It's probably about 40 feet by 15 feet, with no possibility of insulation -- old wooden doors and four big single pane windows.  We are in central illinois by the way.



There are steam radiators in this garage (on the ceiling) which we keep running in order to keep the garage above freezing (there are TRVs on these radiators).



The reason we have to (minimally) heat the garage is because there are a bunch of water pipes on the ceiling (which is about 10-12 feet high).  Some of the water pipes are insulated, some are not; these water pipes are feeding the apartment(s) above the garage.



As a side note, in case it's relevant, a substantial number of end of main steam pipes also traverse the garage ceiling on their way back to the boiler room.



OK so to my question:



Does it make sense to think about putting a drop ceiling in the garage, and insulating on top of it?  And when I say does it make sense what I mean is -- is it economically a good tradeoff -- will it pay for itself relatively quickly?



My thinking is that it must be so wasteful to heat the entire garage -- it would surely save money if we drop the ceiling and then either insulate enough that we can just turn the ceiling radiators off -- or even if we leave them on with the TRVs,  it will surely be much easier for them to keep just the upper couple of insulated feet of ceiling space above freezing, rather than wasting all of the heat in the entire leaky garage.



So it seems clear to me it would save heating costs -- BUT i have no conception at all about how much it would save and how long it would take to pay back the costs of putting in an insulated drop ceiling -- and whether it's worth the drawback of making it harder to see and access the pipes on the ceiling of the garage if we ever need to access them.



Anyone have any thoughts?

STEVEusaPA

I definately think....

It would help.  Drop ceiling with insulation above them are done all the time in commercial buildings, and you have the height.  It's hard to fully answer your question about cost/payback without being to calculate how many btu's your wasting in the garages, vs. how much it's going to cost to have a drop ceiling installed.  I guess, get a bid or 2 for the insulated drop ceiling.  Once fully insulated you should need very little heat in that space to protect from freezing.  You could even put a remote thermostat up there to monitor the temps, as your fine tuning your trv's.  It's possible your end of main steam pipes might be all the heat you need.  And of course mark the tiles that you're gonna have to remove for inspections.

sreja

re: A tricky question about the economics of heating a garage

Thanks Steve,



Yeah i suspect if its insulated it would be warm enough to not need any heat at all.



The problem is that without some kind of really rough estimate of the cost savings, it's hard to know whether it's worth the effort -- and hard to suggest that the building move forward on it.

Steve Whitbeck

fire rating

fire rated construction might be a problem in a comercial bld.

nicholas bonham-carter

Cost of heating difference

Why not put it to the board that the volume of garage being heated will be only 1x40x15 (feet), instead of 12x15x40, with less temperature exposure when the outside air comes through the door. Perhaps in addition to having become a steam enthusiast/expert, you will now have to learn about suspended ceilings!

I don't know how the fire rating comes into this as there must already be some fire rating in the ceiling of the garage.--NBC

Kevin_in_Denver_2

Insulate and heat trace for the pipes?

Have you considered just wrapping heat tape on the pipes and insulating them?

sreja

re: A tricky question about the economics of heating a garage

It's an interesting idea about just insulating the pipes and then turning off the heat.



I have to admit though that i'm a bit wary about it.



The insulated drop ceiling has the benefit that the radiators will still be up there and with the TRVs, they will kick on if needed to keep above freezing, so there is no danger of frozen pipes.



But if we wrap the pipes and turn off the heat, and something goes wrong one winter and pipes freeze and burst, i'll get blamed for creating a major headache.



Nicholas, I've already raised this project with the board, which is what prompted my post -- since the reply was basically: "yeah but would it really save us money? and how long before it pays for itself?"

sreja

re: A tricky question about the economics of heating a garage

Can someone illuminate me a bit about what kind of fire rating concerns I should have?  It's a 14 unit (5 story) brick building.

Patrick_North

Never say never

Why the certaintly that there is "no possibility of insulation "? This space doesn't sound all that big. Reframing the doorway to accomodate a weathertight, insulated door and adding some interior storms could have a huge impact. Insulating the walls would be an improvement, too.

Of the insulated drop ceilings I've seen, none were done well, all complicated the access to mechanicals, and most (eventualy) hid larger problems.

Good luck,

Patrick

STEVEusaPA

I can't imagine you....

Need to have the ceiling fire rated. The existing ceiling there now is, or should be, fire-rated by code. What happens below that doesn't need to be. But if someone insists, the ceiling tiles can be fire rated.

Mark Eatherton

What Kevin said...

I protect my water lines in the mountains with self regulating heat tape, and I've nver had a problem. I do back it up with a control device that lets me know if there are any issues (heat tape failure), but I find it very cost effective. (adds about $1/day to my electric costs during peak cold season).



If its above 45 F, the tape is off.



ME

Zman

Heat Tape

Mark,

Could you describe the heat tapecontrols and monitoring you are doing. I have seen many "self regulating" products that are too hot to touch in the summer and consuming significant energy when by design they should be off.

Thanks

Mark Eatherton

Zman...

I don't even remember who's line it is, maybe Frostex?



In any case, it is a self limiting heat tape, that has a sensor that disables the tape if the ambient is above 40 to 45 degrees F. The alarm system is my ENV control logic with a sensor connected to a pipe that is susceptible to freeze potential.



One has to be careful about the application of insulation over certain heat tapes. Check with the manufacturer to make sure it is OK.



ME

Paul48

Hard to say

What your concerns regarding the codes in your area may require.They vary from one city to the next, and are subject to inspectors interpretation, and or whim.I'd find out what is required in your area before further consideration.

Zman

Thanks ME

I think the sensor is the key. I have been very suspect of the raychem type used for roofs and gutters. They are advertised as internally self regulating. My hand and ampmeter think otherwise. I think in this application the insulation and heat tape is viable.

Rod

Fire Codes/Inspection

I agree with Paul's suggestion. This type of situation is VERY arbitrary.

- Rod

bld999

Insulated drop ceilings

I would guess if you can frostproof the system without putting in a ceiling, future maintenance, leak tracing, etc, will be much easier. Lots of times, suspended ceilings are constructed with insulation batts layed on top, which is fine when new, but after several people open it up in a few places to do work, the stuff gets put aside out of the way and not put back, so the thermal protection begins to degrade. With an 2' x 4' conventional lay-in grid, you also have suspension wires everywhere, and usu. they are right in your way. Major pita for working.  As for fire rating, there should be a one hour rating in place from when the building was constructed. 

rusty pipes_2

convection????

I hate to be a nay sayer, but to get the heat thru a 1 foot (even a 2 foot) deep space you are going to need some air circulation also.  A thermostatically controlled small fan that moves the air around above the batting may be necessary.   If the heat is all to one side, and some of the pipes are on the other side of the garage, then no way will the heat get across to the far pipes.   Radiators need space for air movement, and enclosining them into a ceiling "crawl space" seems problematic.  Good luck with this.  Rusty Pipes

sreja

re: A tricky question about the economics of heating a garage

interesting point rusty -- i suppose we could always put a fan up there.



but to tell the truth -- i suspect that if we had an insulated dropped ceiling, the heat from the apartment above the garage would be enough to keep the pipes above freezing, without needing any radiator heat at all.

Paul48

Curious

What is the ceiling of the garage now?

sreja

A tricky question about the economics of heating a garage

The floors/ceilings are actually 8 inch thick poured concrete, with a kind of clay/ceramic/brick tile (maybe 1/4 inch thick).

sreja

A tricky question about the economics of heating a garage

The floors/ceilings are actually 8 inch thick poured concrete, with a kind of clay/ceramic/brick tile (maybe 1/4 inch thick).

Paul48

Then

I would not bet on them not freezing.

rusty pipes_2

Murphy's Daughter

Murphy will always do what he can to make pipes freeze.  My daughter left our garage door open over night ... 5+ degrees out that night.  We woke up to water making our garage look like an ice rink.   Took me most of that morning to get all of the splits in the pipes leading to our washer and dryer patched back together.  I think the drop ceiling is a great idea, just make sure that the air is moving over to the coldest point.  And, keep those doors closed. Rusty Pipes

rusty pipes_2

Murphy's Daughter

Murphy will always do what he can to make pipes freeze.  My daughter left our garage door open over night ... 5+ degrees out that night.  We woke up to water making our garage look like an ice rink.   Took me most of that morning to get all of the splits in the pipes leading to our washer and dryer patched back together.  I think the drop ceiling is a great idea, just make sure that the air is moving over to the coldest point.  And, keep those doors closed. Rusty Pipes