Heated Garage Floor
02-21-2006, 08:49 PM
#1
Instructor
Thread Starter
Join Date: Oct 2004
Location: Southeast
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
Heated Garage Floor
I would appreciate some input from anyone who has a Heated Garage Floor. What type of system do you have? Is it cost efficient? Do you leave it on 24/7 during the winter? Recommended websites?
Now AC is a different story...
02-21-2006, 11:31 PM
#4
Track Day
Join Date: Nov 2005
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
I have radiant in my home and my garage. It has its ups and downs just like everything. The ups if you live in a WINTERY climate, The garage stays warm even if the door is left open for 20 or 30 minutes in sub zero temps. The snow melts off of the floor when it falls off of your vehicle and runs out of the garage instead of freezing the garage door to the concrete slab and of course it is so nice to lay down on the floor and have it all nice and toasty. The down sides, when the snow does melt off of your vehicle all of your windows get condensation or ice on them because there is no fan moving air around the garage. Temperature changes take about 24 hours, I just keep mine at 68 year round.
As far as efficiency goes everyone will tell you radiant is more efficient but that has not been my experience. Everyone I know who has force air and similar or larger house's has a lower heating bill than I do.
Hope this helps.
As far as efficiency goes everyone will tell you radiant is more efficient but that has not been my experience. Everyone I know who has force air and similar or larger house's has a lower heating bill than I do.
Hope this helps.
02-21-2006, 11:47 PM
#5
Addict
Rennlist Member
Rennlist Member
Join Date: Aug 2003
Location: Salt Lake City
Posts: 258
Likes: 0
Received 0 Likes
on
0 Posts
Radiant heat in garage
Hi Toby,
I assume you have a boiler/radiant heating system in your home and wish to add a branch to heat a new garage, is that right? If you have an existing garage, don't bother jackhammering the floor simply to put in heat. I have some experience in radiant heat, including in a garage. I have installed two boilers myself in past homes (plumbers wanted $8-$10k just for the installation labor: a couple of weekends for work an amateur willing to read manuals and try plumbing. The hard part is finding a "professional" willing to actually sell you, a consumer, the parts.)
The problem/advantage of a radiant floor system is that you have a huge concrete heat sink that takes a long time to heat up and cool down. Just as in a house, this is great if you intend to keep the temperature constantly comfortable. In a garage, however, I'd think you want to keep the temperature typically 45-55 F in winter and then occasionally raise it to 65-70 for weekend work sessions. In that case, you might prefer a (much cheaper) radiant baseboard setup. In my experience that can raise the temp to a comfortable working level in an hour or so. If you must raise the temperature faster (i.e., no time for coffee or breakfast before beginning work), then you can install a heat exchanger and powered fan unit in the corner instead of baseboard. That's a bit more expensive than baseboard, but still cheap.
Costs for a radiant floor system are about $1.00/sf for the tubing only (get only cross-linked PEX with oxygen barrier capabilities, unless you want to rust out your cast iron boiler core). Tubing has come down in price in past years. Then you've got to prepare the bed for the new garage floor by grading, etc. You must then install a layer of rigid foam insulation on top of the gravel, then run the tubing above that (according to a pattern planned based on heating loads expected) and finally pour the concrete. It is a big job. You have to guage the density of the tubing loops (i.e., closer together near cold exterior walls). There are specs and manuals that can help you do that, based on heat loss calculations, etc.
If you have cast iron radiators (e.g., old house) or baseboard (newer house), remember that the heat capacitance of the house radiant system and the concrete garage floor will be much different. This has two implications: First, you'll need separate "zones" with thermostatic controls for the garage and house. That means an extra pump for the garage circuit and running the thermostat wires, and so forth. But you'll also need a mixing valve to reduce the temperature of the garage floor supply. Your cast iron radiators in the house may require 180 F water on a very cold day to keep a 70 F inside air temp, but you don't want 180 F floors in your garage. You want ot supply those with, say, 100 to 110 F. A mixing valve allows cool "return" water to mix with the garage's radiant "supply" so your garage stays comfortable, and you don't burn your bare feet one morning when you get the newspaper.
The baseboard or fan coil solution saves money in several ways. First, the equipment is cheap and doesn't require pouring concrete. Then, you don't absolutely need a mixing valve (i.e. $$) for baseboard or fan-coil (forced air) units. You want full temperature boiler water in those systems, just like in the house cast iron or baseboard radiators. You also don't need a separate pump for that circuit (also $$). You can "tee off" the main house supply and install a "Sparco" type zone valve (small $) to simply shut off the branch when the garage thermostat is satisfied). So now you also save the expense of another pump and the thermostatically activated relay to turn that pump on and off as the garage calls for heat.
Mixing valves, additional zones (and the pumps they require), etc start to get into money. So I recommend you go with the simplest thing: add a baseboard (light, steel) circuit to your garage, running a supply and return line up the wall behind the sheetrock and through the ceiling or wherever (on the warm side of the insulation, next to the ceiling sheetrock!) to the house and boiler. Again, use cross-linked, oxygen impermeable tubing if you run plastic to the garage. If you undersize or oversize the baseboard a bit, it is easy to shorten or extend your baseboard with a soldering torch and a trip to a plumbing supply house. You can correct a too hot or cold (miscalculated) in-floor system a bit with the mixing valve adjustments, but if it is too far out of whack you'll need a jackhammer to add or subtract tubing!
I like Buderus boilers (www.heiztechnik.buderus.de in the original
German, http://www.buderus.net in the USA): German, unbreakable, efficient. Don't buy a pressurized combustion system or super-efficient condensing exhaust boiler (Viessman makes those). They're expensive and they have got too much to break. When something breaks in these complex systems the electronics shut down the boiler (no heat). There's no "limp home" mode. An atmospheric pressure boiler is enough (ca. 85% efficient). There's not much that can go wrong with a flame underneath of a tank of water that you can't fix.
Mike
Porsche 1995 C4
1987 Vanagon Syncro Camper
Buderus Heiztechnik G234X with self-built, 4 zone, mixing valve equipped hydronic system retrofitted to the space previously occupied by an asbestos-covered monster.
I assume you have a boiler/radiant heating system in your home and wish to add a branch to heat a new garage, is that right? If you have an existing garage, don't bother jackhammering the floor simply to put in heat. I have some experience in radiant heat, including in a garage. I have installed two boilers myself in past homes (plumbers wanted $8-$10k just for the installation labor: a couple of weekends for work an amateur willing to read manuals and try plumbing. The hard part is finding a "professional" willing to actually sell you, a consumer, the parts.)
The problem/advantage of a radiant floor system is that you have a huge concrete heat sink that takes a long time to heat up and cool down. Just as in a house, this is great if you intend to keep the temperature constantly comfortable. In a garage, however, I'd think you want to keep the temperature typically 45-55 F in winter and then occasionally raise it to 65-70 for weekend work sessions. In that case, you might prefer a (much cheaper) radiant baseboard setup. In my experience that can raise the temp to a comfortable working level in an hour or so. If you must raise the temperature faster (i.e., no time for coffee or breakfast before beginning work), then you can install a heat exchanger and powered fan unit in the corner instead of baseboard. That's a bit more expensive than baseboard, but still cheap.
Costs for a radiant floor system are about $1.00/sf for the tubing only (get only cross-linked PEX with oxygen barrier capabilities, unless you want to rust out your cast iron boiler core). Tubing has come down in price in past years. Then you've got to prepare the bed for the new garage floor by grading, etc. You must then install a layer of rigid foam insulation on top of the gravel, then run the tubing above that (according to a pattern planned based on heating loads expected) and finally pour the concrete. It is a big job. You have to guage the density of the tubing loops (i.e., closer together near cold exterior walls). There are specs and manuals that can help you do that, based on heat loss calculations, etc.
If you have cast iron radiators (e.g., old house) or baseboard (newer house), remember that the heat capacitance of the house radiant system and the concrete garage floor will be much different. This has two implications: First, you'll need separate "zones" with thermostatic controls for the garage and house. That means an extra pump for the garage circuit and running the thermostat wires, and so forth. But you'll also need a mixing valve to reduce the temperature of the garage floor supply. Your cast iron radiators in the house may require 180 F water on a very cold day to keep a 70 F inside air temp, but you don't want 180 F floors in your garage. You want ot supply those with, say, 100 to 110 F. A mixing valve allows cool "return" water to mix with the garage's radiant "supply" so your garage stays comfortable, and you don't burn your bare feet one morning when you get the newspaper.
The baseboard or fan coil solution saves money in several ways. First, the equipment is cheap and doesn't require pouring concrete. Then, you don't absolutely need a mixing valve (i.e. $$) for baseboard or fan-coil (forced air) units. You want full temperature boiler water in those systems, just like in the house cast iron or baseboard radiators. You also don't need a separate pump for that circuit (also $$). You can "tee off" the main house supply and install a "Sparco" type zone valve (small $) to simply shut off the branch when the garage thermostat is satisfied). So now you also save the expense of another pump and the thermostatically activated relay to turn that pump on and off as the garage calls for heat.
Mixing valves, additional zones (and the pumps they require), etc start to get into money. So I recommend you go with the simplest thing: add a baseboard (light, steel) circuit to your garage, running a supply and return line up the wall behind the sheetrock and through the ceiling or wherever (on the warm side of the insulation, next to the ceiling sheetrock!) to the house and boiler. Again, use cross-linked, oxygen impermeable tubing if you run plastic to the garage. If you undersize or oversize the baseboard a bit, it is easy to shorten or extend your baseboard with a soldering torch and a trip to a plumbing supply house. You can correct a too hot or cold (miscalculated) in-floor system a bit with the mixing valve adjustments, but if it is too far out of whack you'll need a jackhammer to add or subtract tubing!
I like Buderus boilers (www.heiztechnik.buderus.de in the original
German, http://www.buderus.net in the USA): German, unbreakable, efficient. Don't buy a pressurized combustion system or super-efficient condensing exhaust boiler (Viessman makes those). They're expensive and they have got too much to break. When something breaks in these complex systems the electronics shut down the boiler (no heat). There's no "limp home" mode. An atmospheric pressure boiler is enough (ca. 85% efficient). There's not much that can go wrong with a flame underneath of a tank of water that you can't fix.
Mike
Porsche 1995 C4
1987 Vanagon Syncro Camper
Buderus Heiztechnik G234X with self-built, 4 zone, mixing valve equipped hydronic system retrofitted to the space previously occupied by an asbestos-covered monster.
02-22-2006, 12:09 AM
#6
Track Day
Join Date: Apr 2004
Location: Pittsburgh, PA
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
I have an infrared garage heater. The actual unit is an 'Erenco Infrared Garage Heater'. Its about 1' X 2.5', mounts on rear wall with a steel bracket, uses no electricity and runs on gas. The heater works by primarily heating the floor, cars and other objects using infrared heat. This small unit works wonderfully, and its pretty efficient. Hard to believe this heats a two car garage, but it does. One of the best 'home upgrade' decisions I've ever made.
One consideration is positioning vs. the ceiling -- it throws off a LOT of heat to the ceiling, so you need to be very careful about placement. Related, I keep a very clean garage but would be reluctant to use this unit if I had paper on the floor, gasoline or other flammables, etc. that might be near this unit -- its really an 'open flame' and, in my opinion, open to more 'risk' vs. fully contained furnaces.
One consideration is positioning vs. the ceiling -- it throws off a LOT of heat to the ceiling, so you need to be very careful about placement. Related, I keep a very clean garage but would be reluctant to use this unit if I had paper on the floor, gasoline or other flammables, etc. that might be near this unit -- its really an 'open flame' and, in my opinion, open to more 'risk' vs. fully contained furnaces.
