AllanJ

No one system is the "best" for everyone. You need to match up the requirements with the specific heater type.

JDSStudios

I didn't say best, I said most efficient.

9 lives

So would it be the same to dig in a little hole or trough and just have the family pee in it....now that would be efficient !

Mark Lue

Ya everyone's requirements will be different. if you only wish to heat up the garage to work on the car sometimes, then the solution and $ spent in all probablity will be different from someone who wants his "Man Cave" to be 20 degrees all the time. The only reason that I haven't heated my garage is because people say that it promotes rust.

.... next you'll be recommending farts as a source of fuel.

Imo000

But of course high wattage light bulbs are the most efficient. If gives you light when working on the car and the remainder is turned into heat. Now I’m gonna go and hide!

AllanJ

Pretend I said "efficient" then.

The heaters work in different ways and you need to match them to your needs.

As mentioned above, if you want to keep your garage at 20C all the time, then heating a 4" thick slab of concrete with in-floor heating makes sense. The concrete will store and radiate heat for a long time. In-floor heating can be very efficient in a case like this because it can maintain a temperature well.

However, if your garage is kept cold until you go out there Thursday night after the kids go to bed so you can spend an hour installing a new driver's seat, in-floor heating is one of the worst choices you can make from an efficiency point of view. It will take a long time to bring a giant slab of concrete up to temp from near freezing. You'll be in bed before it really kicks in.

In that case, best to turn on a simple $30 electric heater from Rona or Canadian Tire and point it at you so the warm air is blowing in your direction. Run that for an hour and then turn it off when you go back inside. 1500W x $0.08 kW/h = $0.12 Yes, 12 cents. (adjust for your own electric rate, but I bet you have the change under your couch cushions)

Figure out your garage heating needs and then look at heater types that can do that specific job. Then you can compare the efficiency of one vs another for that specific task.

Mark, watch out for those farts. Keep them away from an open flame.

Shemmer

Mark I can't see how a car kept in a (constant) warm climate, by that i mean not hot one minute then cold the next, will promote rust. If the air and all the items within it maintain a constant temperature then condensation will not form, the same as if it were in your living room, warm and dry. Now bring your car in from the cold then you have a different story like a can of pop just taken out of the fridge.

Forced air can create a condensation issue if the differential between the heat and cool cycle are too great. The heater blows really hot for a short time heating up the room and everything in it then shuts down. Cold air drafts in a poorly insulated garage may form small amounts of condensation on the surface of a warm car which is in the form of water and water forms rust but let me tell you I'll take that minute chance of rust over having my 20 and 30 year old cars sit in Arctic temperatures running more risk of things cracking and drying up due to extreme cold temperatures. If that was the case the why not throw a cover on the car and leave it in the driveway?

As for efficiency, it's a fact that hot water heating is the most efficient source of heat and by placing it within the floors you now have consistent even heat distribution rising up wards virtually eliminating cold air drafts. According to one manufacturer the average household uses 20 BTUs per square foot less with in-floor heating. Combine that with a concrete slab and you benefit more so due to the fact that concrete has the ability to retain heat a lot longer and more importantly for a garage the one main source of moisture in the winter is through the floor which is why some will even go as far as placing a plastic vapor barrier down on the ground before parking your car on it.

Unfortunately, most of us have budgets and we need to work within them so unless you are building from scratch the costs to retro-fit in floor heating may make it prohibitive.

Shemmer

Um..................ya........ok. Tell us how that works out for you.

Shemmer

Right, the slab does take a few minutes to warm up if installed properly but it's really not intended for a switch on and off heat. It's more of what you said in keeping the space heated constantly.
Before my gas heater I had a portable propane heater but it realy took forever to bring the temperture up where it was comfortable enough to take your jacket off and the venting was always an issue. I believe electric will be even worst and take even longer to heat the space comfortably
I guess if all you need is localized short term heat then a space heater is definately the cheapest route but my guess is that all you'll be able to warm is your hands unless your garage is R2000.

Mark Lue

I park my DD in the garage as well so temp is not constant.

AllanJ

Not sure when building codes changed here or in your area, but for a while now you must have a vapour barrier below the concrete so you shouldn't get any moisture coming through the concrete. It will all come from your car that just came in from the rain or snow. Easy way to check if you have a moisture problem under your concrete. Take a 12"x12" piece of poly and tape it to the concrete floor, sealing all 4 edges. Let it sit a week and see if any condensation forms between the poly and the concrete. If you get condensation, then you have a moisture problem under the concrete.

Never trust manufacturers claims about "20 btus less per sq ft", blah, blah, blah. That's when things are fully skewed in their favour. In a few months I'll be gutting my ensuite and I'm looking to replace the electric convection heater with an in-floor radiant system to help keep the stone tiles warm for tender toes. I checked a big manufacturer of an electric mat version of this product and even they say not to bother using set-back thermometers with it. It'll take too long to adjust the temperature for the few hours at night and/or daytime when the house is empty. Do you think manufacturers are really comparing their system (which really must be running all the time) to a regular system like we have that uses a setback thermometer to run cooler at night and during the day? Our heating demand will be far lower most of the time - even though we might be using a less efficient system. I'm sure the difference in "btu per sq ft" will be much less than 20.

Anyhow, I just felt like doing a mini-rant. I really dislike most marketing methods when they don't represent reality.

Cheers,

AllanJ

You probably don't need to worry about the condensation issue so much. You're playing it safe which is fine, but I have several woodworking power tools in my garage and have a forced air heater running during the daytime. All those cast iron tabletops will rust in a nanosecond if given a chance and I clean & wax them once every two years. It just isn't a problem.

However, letting R-comps freeze is a problem. Hopefully if you have some track tires they are kept in a safe place where they won't freeze.

Cheers,

JDSStudios

What can I say, you got nice rolling eyes in your message, here are some back to you too

It goes without saying or pretending, that all else being equal, one system will be more efficient.
Of course size, materials (concrete slab), time, and usage defines what is best for a particular person.

From what I read here, it looks like in floor water radiant is the most efficient.
All else being equal, of course. Let's pretend we want a constant 10 to 12 degrees, so our pcars never freeze
in the garage.

Now, here is a nice, non-sarcastic, very efficient warm smile for you

IXLR8

Although warm air can hold more moisture than cold air, for any of what you mention (condensation) to happen, you need moisture in the air to start off with.

There are days when I have pulled my motorcycle out of the cooler garage on a very warm warm and humid day; it was covered with water droplets instantly...just as a pop can taken out of the fridge into warmer air would be.

Storing a winter driven car in a heated garaged...now that will cause it to rust far quicker. Washing a salt covered car down with water will cause it to rust quicker (use cold water) than leaving the rust on provided it is extremely cold outside.

AllanJ

Thx for the warm, efficient smile.

I don't know that I'd agree with the in-floor water setup as being the most efficient. Natural gas forced air systems can be 95% efficient - efficiency being defined as how well the system converts energy (natural gas) into usable heat. I think in-floor hot water radiant setups are less than that. They need to heat the water (definitely not 100% efficient and will vary based on how the water is heated) and then the water runs through lines in the slab. Heat is lost along the way in addition to heating up a portion of the slab that leaches outside the desired heating zone.