Hello. I was wondering what is/would be, the most economical way to heat a garage during the Winter. I have a 2 3/4 car garage. It's a very generous 2.5 car size. I used a torpedo-style heater last year, but the bottles of propane don't seem to last all that long and they are pricey. I have an "attic" area above the cars that is open, with several areas used as storage with 3/4 inch floors. I'll include the square footage in a little while. It's something like 650 square feet, I believe.
I installed the mitsubishi heat system (heat and ac) (slimline) very economical to run, with rebates, I think it was less than 2 k, saved most of that in the first few years. garage is 3 car apx 1000 sq ft. phred
I am just completing the construction of my garage and am planning the same unit papa scoops mentioned. These Mitsubishi units seem like the perfect way to go for both heating in the winter and cooling in the summer. Again I have not used one yet but a buddy has and loves it.
The question I am trying to answer is can I install it myself or do I need to pay someone? I had my electrician wire for it so I am good there.
Most mini-split, slimline units are very easy to install. Some carpentry work to support the indoor and the outdoor units, an electrical power hookup and the refrigerant hoses are pre charged so just screw or snap on to the connectors. The temperature control is normally via a handheld remote so no wiring.
I've used these mini-split units in two garages with success. I would mount the indoor unit above head height since it blows the heated or cooled air fairly intensely.
I think that those torpedo-style heaters are not very good for your air quality as well as being thirsty?
Amount of heat needed depends a lot on the insulation, etc.. also maybe the desired indoor temperature? Are you thinking about A/C as well?
the wall-mounted gas (or propane) units look pretty nice.
Good luck.
If you are only worried about heat, you may want to consider a waste oil heater. Don't have any personal experience, but I hate dragging my used oil away. If you have a few friends with waste oil, you might get free heat.
There are quite a few small portable heat & A/C units on the market now, which might serve your purpose and are very affordable. Here is one example that heats or cools up to 700 sq.foot. These are easy DIY installs and make for just another consideration.
https://www.compactappliance.com/honeywell-portable-air-conditioners/HL14CHESW.html
I installed a Hot Dawg heater from Home Depot. Great unit and very efficient.
https://www.homedepot.com/p/Modine-Hot-Dawg-45-000-BTU-Natural-Gas-Garage-Ceiling-Heater-HD45A/202812648
Thank you everyone for your ideas and input. I was thinking about Mitsubishi. That one heater from Home Depot sounds like a decent idea, but I will need to find a way to route nat gas to the garage. It is well equipped with outlets, as it has about 14 of them! I might insulate the ceiling. The garage is constructed of cinder block. It generally stays about 10-12 degrees or so warmer than the outside. Also, my door is off the floor a little bit on one end, forming a narrow wedge shape. Can my door be shuffled around after loosening some bolts, to make it sit flat all the way across the opening? I replaced the rubber gasket on the bottom of the 2-car door 2 years ago.
Took the used gas furnace out of the house during its replacement. And put it out in the garage. No cost other than another thermostat and some piping.
Quote from: SNAKEBIT on October 25, 2018, 10:18:15 PM
Thank you everyone for your ideas and input. I was thinking about Mitsubishi. That one heater from Home Depot sounds like a decent idea, but I will need to find a way to route nat gas to the garage. It is well equipped with outlets, as it has about 14 of them! I might insulate the ceiling. The garage is constructed of cinder block. It generally stays about 10-12 degrees or so warmer than the outside. Also, my door is off the floor a little bit on one end, forming a narrow wedge shape. Can my door be shuffled around after loosening some bolts, to make it sit flat all the way across the opening? I replaced the rubber gasket on the bottom of the 2-car door 2 years ago.
If your door seal is screwed in you should be able to remove the screws and adjust the seal to fill in the gap. No need to try adjusting the door.
Salamander ;D
Salamander? The rubber gasket has a channel you push it through from one side to the other. The house heater doesn't sound too bad, it just might take up too much room in my garage. I think the ductless heater system may be the way to go for now.
Depends on where you live (lowest temp and amount you are raising lowest temp), amount of insulation you have and square feet, along with ceiling height.
Also, what fuel is available and how much is electricity in your area? Do also need a/c?
All factor into required btus and type of unit.
You're getting all sorts of answers because everyone has differing answers to the questions above.
Do a btu calc first.
My wife surprised me with a garage heater several years ago for Christmas. It's a Modine ceiling-mount 60K BTU natural-gas heater. Heats my insulated 1200 sq-ft / 9' ceiling garage from 40F to 70F in about 20 minutes. Mine needed a horizontal exhaust with a helper fan which added to the price. Installed price was about $1400.
(http://www.saacforum.com/gallery/245-061118231114.jpeg)
Quote from: Bossbill on November 06, 2018, 08:14:14 PM
Depends on where you live (lowest temp and amount you are raising lowest temp), amount of insulation you have and square feet, along with ceiling height.
Also, what fuel is available and how much is electricity in your area? Do also need a/c?
All factor into required btus and type of unit.
You're getting all sorts of answers because everyone has differing answers to the questions above.
Do a btu calc first.
^^^ This is the only real advice in this thread.
Insulation is measured by its R-value. The R-value lets you calculate how much heat will move through a certain wall area depending on the temperature difference between the indoor and the outdoor air.
So let's say you have a wall that contains R-10 insulation in the United States. Let's say the wall measures 8 feet high by 10 feet long, or 80 square feet. Let's say it is 70 degrees F indoors and 30 degrees F outdoors, or a 40 degree F temperature difference. The calculation looks like this:
80 square feet * 40 degree F difference / 10 = 320 BTUs
In other words, you would need a heater producing 320 BTUs to compensate for the heat loss through that wall, and that heater would be running continuously.
If you are not in the United States, you do the same kind of calculation but you do it in SI units, using degrees C, meters, square meters and SI R-values. What you get out is watts. So if you have a wall that is 2.4 meters high and 3 meters wide (7.2 square meters), and the outside temperature is -1 degrees C while the inside temperature is 21 degrees C (22 degrees C temperature difference), and the insulation is SI R-1.8, you get:
7.2 square meters * 22 degrees C difference / 1.8 = 88 watts
If you multiply watts by 3.4 you get approximate BTUs and vice-versa.
So now let's look at a house. Let's imagine an idealized 2,500 square foot single-story house. It is a square that has 4 walls that are each 50 feet long and 8 feet high. The ceiling and floor are 50 x 50 foot squares. The ceiling has R-30 insulation. The floor has R-15. The walls have R-10. It is 70 degrees F inside and 30 degrees outside. How much heat is escaping through the insulation?
Each wall is 50 x 8 = 400 square feet for a total of 1,600 square feet. With a 40 degree F temperature difference and R-10 insulation you get:
1,600 * 40 / 10 = 6,400 BTUs
The ceiling has 2,500 square feet at R-30, so:
2,500 * 40 / 30 = 3,330 BTUs
The floor has 2,500 square feet at R-15, so:
2,500 * 40 / 15 = 6,660 BTUs
So the whole house needs about 16,400 BTUs (or 4,820 watts) to maintain its temperature.
No real house is ideal like this, however. A real house has windows that might be at R-2. And doors that might be R-4. And there are little leaks that allow cold air infiltration, plus less insulation around outlets, etc. All in all, a real 2,500 square foot house might need 20,000 to 25,000 BTUs (depending on how many windows/doors and how "tight" it is) to maintain its temperature.
Chris
Quote from: SNAKEBIT on November 06, 2018, 05:48:32 PM
Salamander? The rubber gasket has a channel you push it through from one side to the other. The house heater doesn't sound too bad, it just might take up too much room in my garage. I think the ductless heater system may be the way to go for now.
here you go snake.
https://www.globalindustrial.com/p/hvac/heaters/portable-electric/global-salamander-heater-portable-fan-forced-electric-240v-15-kw-1-phase-62-5-amps?infoParam.campaignId=T9F&gclid=CjwKCAiA_ZTfBRBjEiwAN6YG4cOO_ZKNJYYlQnZ1NBqFwTDA6r6y0VCyw-d-9K3p59gPDEjk9qupDhoCyV8QAvD_BwE
Boss, you are correct! Chris, thanks for the info you bothered to post. I/we appreciate that. My future Shelby thanks you one and all for the advice and conversation. Our Winters lately, have not been in the "normal" range, dang it. I'll figure a system out to use and go with it. I hope my next garage will be a 3 or 3+ size garage. I told my wife, I didn't want to go down in size with our next garage or we were not going to buy that particular house! Same goes for the basement. ;) :o
Rat Fink covered this a few years back ::) ;D
(https://i.imgur.com/H3QIZD8l.jpg)
I think I've tried every heating system known to garages.
Wood Stove -- By the time this thing gets going, it's bed time. The exhaust ducting is expensive and sourcing wood is a PIA. It's even a PIA if the wood is free.
Drip Oil stove -- Replaced my wood stove with a 50s drip oil stove. Used home heating oil. Painful sourcing oil, took forever to heat up.
Salamander (inline jet heater) -- comes in kerosene and propane. One of the better ways to kill yourself, if not vented right. At best it stinks (kerosene). At worst it catches things on fire. Painting around these things is a good way to have your fire insurance investigator visit you. If you survive.
Unit heater (Reznor, Modine, Hot Dawg, etc) -- Comes in natural gas or propane.
Look in any concrete floored store front, gas station, Jim Herrud's garage, or my shop and you'll see one (or more) of these. Usually uses B-vent or similar venting.
Turn on the thermostat and within 30 minutes you have warmth and a fairly even heat.
Infrared radiant tube heater
Usually used with ceilings 10' or better, these 10' long (and longer) gas or propane heaters radiate heat down like the sun and warm objects which in turn warms the air. As seen in some box stores near the checkout.
Radiant Heat Panels
My house came without regular ducting, so we opted for ceiling mount radiant heat panels, with an average size of 2'x8' per panel (2 per 15x15 room). Available in 120V and 240V. Very efficient, instant heat and like the tube heaters, they heat objects and not the air. Plus, they are zone heat.
Also note you can find electric infrared tube heaters in various sizes, just like the gas fed varieties.
Boiler-fed Hydronic heaters.
If you run a boiler for your house heat you may be able to use excess capacity to run a Reznor style hydronic unit heater(s).
In my 24Dx60Lx10H stick framed moderately insulated main shop I run an older propane Reznor XL125 (125KBTU). It will rise the temperature from 40 to 65 in about 30-40 minutes. I admit it's not that efficient.
The connected but L'ed off 24x24 cathedral shop has enough obstructions from the main shop that it requires a 60K Reznor.
The connected but walled off paint area has two ceiling mounted 240V 2500 watt electric infrareds to raise body panel temperature and to keep open flame away from painting.
There are many options, but overall a larger unit than required will raise the temperature very quickly. Get too big and they quick-cycle, reducing their lifespan.
Look at the energy costs in your area to determine which unit is cost effective.
If propane is your only or best choice, remember to factor in the cost of tank rental, ditches and running possibly hundreds of feet of line for large buildings. Some propane supply companies are vastly superior to others with respect to cost.
I thought I'd mention recovery time as well. Like how quickly you want to recover from heat loss events like opening one of the bay doors to let a car in or out, running a large exhaust fan, etc.
In my small shop which I try to work in when it's too hot or too cold in the big shop I have central heat blown in from up above.
However, if I have to work in the big shop and it's cold sometimes I run a propane tank with the 3 round circle burners mounted on top.
My big bld is 2000sqft and 16' ceilings. I assume it's important to keep one of the doors cracked with outside air and not paint
around the heater.
Any other safety tips?
Thanks
My "heat pump" mini split is a Fujitsu
my friend down the road, uses a old wood stove to heat his paint shop.....still there after all these years (not recommended, but works for him) phred