What to heat garage with?

[Jon_E]

What do you guys in cold climates do to heat a detached garage? I am building mine right now, the plan is to spray-foam the shell and put radiant tubing in the slab, but that's as far as I have gotten. I would like to keep the system very small and simple, to save space and cost. I also don't need a great deal of heat. 58-62 degrees in the winter would be plenty warm enough. Garage is 24x36 w/ loft but the loft area does not need heat. It will just be the slab.

I have electricity, propane and wood options available. I definitely want to utilize the radiant flooring, I have it in my house and I think it's a necessity. I already have the materials. I am just not sure of the cheapest or easiest way to make hot water for running through the tubing. I could do an electric or gas water heater, either a tank-style or an on-demand style. I could put in a heat pump or a hybrid unit. I could even run PEX from my outdoor wood boiler, although I think that will actually be my most expensive option. I also do not have a water supply in the garage, so any filling or topping off of the system will have to be from a hose stretched from the house. Not a big deal but that's what I have.

 

[theoldwizard1]

I have electricity, propane and wood options available. I definitely want to utilize the radiant flooring, ...

Wood is probably the cheapest fuel, but it requires a fair amount of work and it is not "compact", unless you do an outside boiler.

The "out of the box" solution is a mini-split heat pump with a refrigerant to water heat exchanger. This is NOT a common solution in the US, but IT IS POPULAR in other parts pf the world. Mitsubishi and other heat pump supplier sell these type of systems outside the US.

Bonus - you can easily add A/C to your garage and heat and A/C to the second floor. Both of those can be added later if not in the budget during the inital build.


There are some down sides.

• You need to find an HVAC installer willing to install and support the system.
• There is a high initial cost, but that is offset by (much) lower operational costs compared to electricity or propane.
• Even the best min-splits start losing efficiency around 5F

View media item 43975
You will need some kind auxiliary heat source for those really cold VT nights !

 

[Jon_E]

Any ballpark on initial cost for that type of system?

 

[Highbeam]

Any ballpark on initial cost for that type of system?

I would love it if the heat pump water heater technology was available to America as it is in other countries, but it is not. It's such a disgrace. Those folks even get CO2 systems that blow our minisplits out of the water. I almost wonder if it isn't some sort of conspiracy. I can tell you right now that you won't be using a heat pump water heater so don't waste your time.

I am in a similar spot but a few years ahead of you. The slab has the tubes installed but I have not pumped hot water through it yet. We have no NG and the propane is just as expensive as electricity. So you may as well use a cheap, no maintenance, no venting, safe, electric wall kettle.

I have found that with no heat in the insulated barn that it stays well above freezing even when temps are in the teens. Pretty amazing what insulation will do. I have a woodstove in the shop that I burn on the weekends and it does okay but that huge slab of cold concrete is tough to heat up.

 

[theoldwizard1]

Any ballpark on initial cost for that type of system?

It should not cost any more than a typical 2-4 ton mini-split system, unless you plan on adding the air handler for garage A/C at the beginning. WAG $2,500-$3,500. I'm sure you would recover that cost in less than 10 years compared to an electric or propane boiler.

You have to make sure that the outdoor unit can generate heat at 100% efficiency down to close to ZERO ! This type cost more than others.

This would include the heat exchanger (not that much $$$) but not any of the radiant heat plumbing.

 

[pseudorealityx]

Wood is probably the cheapest fuel, but it requires a fair amount of work and it is not "compact", unless you do an outside boiler.

The "out of the box" solution is a mini-split heat pump with a refrigerant to water heat exchanger. This is NOT a common solution in the US, but IT IS POPULAR in other parts pf the world. Mitsubishi and other heat pump supplier sell these type of systems outside the US.

It's used here as well on the commercial side. My concern is that it doesn't fix the problem. You still need a heat source to keep the water loop at a reasonable temperature. And it requires additional energy for pumping, and losses associated with the heat exchangers. Typically you just add a boiler to the water loop... but that boiler still needs to use fuel of some sort.

 

[HoosierBuddy]

Today, propane is going to be FAR CHEAPER than power. I'm hearing people who were paying $4/gallon a couple of years ago getting locked in around a buck a gallon right now.

If I was in the same situation, and I wanted heat 24X7, I'd probably go with a high efficiency tankless boiler as my heat source and plan to tie into the wood burner in the future to give you at least the option to fall back on wood during future price spikes.

My point being, electricity is expensive now and will get pricier in the U.S. as we wind down the coal fleet and replace it with sun/wind/natural gas powered generation. At least there's a chance propane will stay inexpensive.

To the posters who would like to see advanced heat pump technology in the u.s., It's just a matter of time. The power prices need to rise to make these units payoff better. Once it does, they will be more common.

Phil

p.s. The much more economical solution would be to rethink the 24X7/radiant heat requirement. If you only want to heat it when you are working out there...a gas unit heater that only runs a few hours a week would save you maybe 80% in operational costs.

 

[Flivver250]

As a former Vermonter myself, I know it gets crippling cold. Any heating system with water is subject to freezing and splitting unless it is fueled for 6 months and kept running. In Vermont that is expensive, especially in a shop. Wood would be my first choice. Pleasant heat and an easy renewable resource there. NG is not usually available as I recall so I might have LP back up, and a kerosene salamander to rapidly take the chill off is a must. I have seen -59 in Canaan while ice fishing and -40 to -50 is common. Gas or electricity as primary constant heat might cost mas much as heating the house. In my northern Idaho shop I had a big LP heater suspended from the ceiling in a 42x40 shop and it was was hellaciously expensive to keep it a constant 50 degree in an area that rarely got colder than +20. I cranked it up when I played in it. My next shop I used a salamander and let it get cold when I didn't use it.

 

[bcoke]

Jon I too am in SW VT. and did a radient system in the floor, 36x40 monitor style barn with 36x20 loft...........I use propane with a condensing boiler, certainly not the cheapest way to go but well worth it IMHO. The main thing is insulation, more insulation, than add more .....get the point! I leave it set at 55 degrees and the garage is great even at the extreme weather we had last year!!! With the warm feet, tools,benches etc it will feel great [had to take off sweatshirt as too hot].....no heat upstairs but the loft has an open stairway so het rises and stayed comfortable, I have a sheet of foam insulation to close the opening off if necessary but have not used it.......double digits below zero maybe raise it to 58 degrees. Now my only problem is being at the end of the line [electric] so when power goes out next to the last one to get turned on.......6 days last winter I have two dwellings and the barn ran generators to keep the heat in all buildings [2 generators-3 buildings meant I had to share one back and forth between two of them]..... Now - not a paid commercial, but I use HighTech Plumbing in manchester to install and highly recomend him for work/information.....Rich is a decent guy and knows his business, quality work, will give you all options and is fair in his prices [remember you do pay for quality]. Good luck Bcoke

 

[NUTTSGT]

I have electricity, propane and wood options available. I definitely want to utilize the radiant flooring, I have it in my house and I think it's a necessity. I already have the materials. I am just not sure of the cheapest or easiest way to make hot water for running through the tubing. I could do an electric or gas water heater, either a tank-style or an on-demand style. I could put in a heat pump or a hybrid unit. I could even run PEX from my outdoor wood boiler, although I think that will actually be my most expensive option. I also do not have a water supply in the garage, so any filling or topping off of the system will have to be from a hose stretched from the house. Not a big deal but that's what I have.

If you want radidant floor heating, already have the materials and the wood boiler, why would it be your most expensive option ?

 

[Renfrick1]

How about a propane boiler heating a storage tank. Then use the storage tank for your radiant loop. Cheap and cost effective

 

[Renfrick1]

Then you add a modine heater for fast heat if you open the door and let the cld air out

 

[pseudorealityx]

How about a propane boiler heating a storage tank. Then use the storage tank for your radiant loop. Cheap and cost effective

That's not helpful... if you attempt to isolate the concrete, the water in the loops will freeze. You need to keep it flowing or use high concentrations of glycol (~50%), but that has it's own host of problems.

 

[Outback2013]

I thought I would add this post as it seems to fit into this discussion. I am building a garage 26 x 40. Will be heating with a radiant floor system. I will have to heat with electricity, at 10.25/kw. There is no gas in this area. I have read about heat pump style hot water tanks, boilers, standard hot water tanks and quite frankly a bit lost as to which one is the best fit, generally speaking.

Presently our home has an 800 sq ft addition which I heat the basement with radiant floor heating. This system has 2 zones heated by a 40 gal hot water tank. It has worked seamlessly for 24 years. I also have a 40 gal domestic HWT. I am wondering if I install an 'indirect heating system' using an electric boiler or heat pump hybrid heater to heat our domestic water and then by use of a heat exchanger run two circuits to the in floor systems, via pumps to their tanks or directly to the floor.

So, bottom line, I have to heat my garage and may decide to consolidate the 3 hot water systems. Has anyone had any similar experience with the above?

 

[chuckcrj]

I would love it if the heat pump water heater technology was available to America as it is in other countries, but it is not. It's such a disgrace. Those folks even get CO2 systems that blow our minisplits out of the water. I almost wonder if it isn't some sort of conspiracy. I can tell you right now that you won't be using a heat pump water heater so don't waste your time.

I am in a similar spot but a few years ahead of you. The slab has the tubes installed but I have not pumped hot water through it yet. We have no NG and the propane is just as expensive as electricity. So you may as well use a cheap, no maintenance, no venting, safe, electric wall kettle.

I have found that with no heat in the insulated barn that it stays well above freezing even when temps are in the teens. Pretty amazing what insulation will do. I have a woodstove in the shop that I burn on the weekends and it does okay but that huge slab of cold concrete is tough to heat up.

Air to water heat pumps are definitely available in the US. This is only one example, there are many other brands available as well. http://www.daikin.com/products/ac/lineup/heat_pump/index.html

 

[Jackfre]

Chuck, it is my understanding that Daikin is in the process of dropping the air to water unit, so they will be orphans. To bad.

To the OP, You live in the biggest Rinnai Energysaver market in the US. Approx 5% of all the homes and acts in the State of VT have one. For your garage I would go with an EX38LP. Ask you propane company about them.

 

[theoldwizard1]

I am wondering if I install an 'indirect heating system' using an electric boiler or heat pump hybrid heater to heat our domestic water and then by use of a heat exchanger run two circuits to the in floor systems, via pumps to their tanks or directly to the floor.

Water heat by a high efficiency (outside) air sourced heat will ALWAYS be cheaper than an electric boiler. The best an electric boiler can do is 100% efficiency. A decent heat pump will beat that by a long margin.

The down side is, a heat pump can only make heat down to about 0F, so if you live in a very cold climate, you need a back up heat source.

 

[chuckcrj]

Chuck, it is my understanding that Daikin is in the process of dropping the air to water unit, so they will be orphans. To bad.

To the OP, You live in the biggest Rinnai Energysaver market in the US. Approx 5% of all the homes and acts in the State of VT have one. For your garage I would go with an EX38LP. Ask you propane company about them.

There are plenty other brands to take up the slack.

Not to mention, any half decent hvac guy could make one. Air source heat pump and lineset and instead of connecting to a conventional a coil, use a plate heat exchanger and expansion valve and you have an air to water heat pump.

 

[Showkey]

It's hard to beat a quality 90 plus NG or LP furnace for cost of operation or install.

The ultra high mini split are $$$$ and many lower cost units are not going to perform well at low temps.

 

[rfp5980]

What do you guys in cold climates do to heat a detached garage? I am building mine right now, the plan is to spray-foam the shell and put radiant tubing in the slab, but that's as far as I have gotten. I would like to keep the system very small and simple, to save space and cost. I also don't need a great deal of heat. 58-62 degrees in the winter would be plenty warm enough. Garage is 24x36 w/ loft but the loft area does not need heat. It will just be the slab.

I have electricity, propane and wood options available. I definitely want to utilize the radiant flooring, I have it in my house and I think it's a necessity. I already have the materials. I am just not sure of the cheapest or easiest way to make hot water for running through the tubing. I could do an electric or gas water heater, either a tank-style or an on-demand style. I could put in a heat pump or a hybrid unit. I could even run PEX from my outdoor wood boiler, although I think that will actually be my most expensive option. I also do not have a water supply in the garage, so any filling or topping off of the system will have to be from a hose stretched from the house. Not a big deal but that's what I have.

I built this a couple years ago. Burns wood. Works incredibly well.

Sent from my SM-G900V using Tapatalk

 

[theoldwizard1]

It's hard to beat a quality 90 plus NG or LP furnace for cost of operation or install.[/QUOTE]
LP might be cheap now, but it won't stay that way forever.

The ultra high mini split are $$$$ and many lower cost units are not going to perform well at low temps.

True, but compared to LP it is a big cost savings. I would guess you would make your money back in less than 10 years and you get the bonus of AC !

 

[Slowgsr]

What about a waste oil boiler?