Heat pump or wall unit?? for the garage

[*89x2*]

Still weighing options here...

roughly 880 sq. ft w/ 10 ft ceilings - what would be the better choice? A heat pump (gas is not an option at this point... ) or a wall unit Heat / AC unit

Looking for pro's and cons.

*Also, what size breaker / circuit would be needed to run each repective unit?

Thanks

 

[DkBG]

Mostly it depends on where you live . I have a heat pump for my house and it runs very cheaply , but when it gets below freezeing the back up heat kicks in . Also , if your planning to keep it a constant temperture the heat pump is fine , but if you let your garage be cold most of the time and just want to heat it up occasionally , you should know that the heat pump will take alot longer to bring it up to temp. Thats because they don't put out hot air . Just warm air . They are very efficiant air conditioners too . Cliff

 

[Mr.Cool]

Your location and intention of use for your conditioned garage will determine exactly what you need. Assuming minimal insulation and the sg ft you gave I would not go any larger than 2 ton heat pump with 10kw auxillary heat. That will give you approx. 60,000 btu's of heat for a quick warm up and 24,000 of cooling. You will need 30 amp service to the outdoor section and 50 amp service for the indoor.

 

[*89x2*]

Thanks guys

I am trying to recall - Maybe it is R17 in the walls between the 2x4's - it is whatever the better r value is, while being able to fit - the next best r value was for 2x6 const.

The attic is blown insul.

I don't think I need to keep the garage warmer than say... 55-60 degrees at most

I am in the Mid Atl. if that helps (currently under snow )

I have a 60 amp breaker in the house feeding to a sub panel in the garage - detached

It is divided up now for the lights and plugs...

I imagine I would need something a bit more w/ the heat pump...

Thanks - Ohh, can a dehumidifier be part fo the heat pump itself?? Do yo know of any makes / models??

 

[Mr.Cool]

Sounds like you have a decent amount of insulation. You could always add more in the ceiling if you need it. And glue some foil backed insulation board to your garage door. The cheapest way to go would be to install a package terminal heat pump (pthp) like you would see in a motel room. The largest one you will find is approx 14,500 cooling with a 5kw backup heat. 30 amp service should suffice. Don't expect alot of heat out of it when the temp starts droping below 35. As for dehumidifying the cooling mode will take care of this. If you go this route mount it high enough to keep the snow away from it. GE, Carrier, Amana are some of the makers of these units.

 

[*89x2*]

As for dehumidifying the cooling mode will take care of this. If you go this route mount it high enough to keep the snow away from it. GE, Carrier, Amana are some of the makers of these units.

Do you think it would dehumidify enough by itself??

Also, The Mfr's. mentioned above, are any better than another?

Looking for + / - on them...

I guess for the money, in a detached structure the size I have, that probably would be the most efficient way to go...

 

[Mr.Cool]

If dehumidifying is your biggest concern you want the unit to run alot when it is cooling so you don't want to oversize the cooling unit. Since the biggest size they make in a pthp is around 14000 or 15000 btu for the area you are trying to cool dehumidifying should not be a problem. However if it is cold and damp where you are in the winter you will need more heating capacity to keep the humidity down. So you will have to look at another source for heat.
They are all good units, GE does have good nationwide service. See what you can find locally.

 

[SurfnSun]

Chris Im not fan of heat pumps b/c like stated the don't put out very much hot air.

A very cost efficent method could be a propane heater on a timer. A decent sized propane heater could heat your garage in less than 5 minutes. Set a timer on your outlet to run every 15-20 minutes for a 5 minute cycle. You could keep your garage warmer than your house for a few bucks a month.

 

[RLE80L48]

What brand or type of propane heater can be used on a timer like that. Sounds interesting. I have hot water in the floor and use electric heater on a timer . Its a bit expensive and takes forever to raise or lower the temp. Don't6 want to go through the hassle of a boiler and all.I do want to keep the shop heated around the clock.Fill me in on any particlars involved.Thanks,Ron

 

[SurfnSun]

Sorry I was thinking of kerosene heaters, not propane.

Basically you plug them in and they fire up. My dad used these in the construction industry and I stole one from him to heat the garage when I worked on my car in the winter. We had a 1000sqft garage, in a few minutes you'd be peeling off clothes b/c it was so warm.

Something like this.....
http://www.heatershop.com/forced_air_kerosene_heaters.html

You can even get a thermostat
http://www.heatershop.com/scheuco_spare_thermostat_6184.html

 

[SurfnSun]

After more surfing on that site they even have ducting that you can hook up and vent the heat to the garage.

http://www.heatershop.com/scheuco_ducting_8348_8351.html

 

[IH2LOSE]

My garage on plan on using a fujitsu split system for dehumidifying ,cooling and heating down to about 40 degrees

http://www.fujitsugeneral.com/wallmounted.htm

I am chossing this product because it has a dehydration setting So it will run all on its own to maintain a certain humidity level. It will also provide cooling and heating thru the heat pump side

I am also installing the hot dawg heater from modine to provide heat.But I will have the heater on a outside thermostat locking it out from running unless the tempitures are below 42 degrees in my area the heat pump will heat the area much more effecently then the hot dawg.above 42 degrees the heat pump does not have to defrost it self so there is no wasted energy with the heat pump.Again I am using the fujitsu unit more for its de-humidifing cababilities.

I am going to over size the hot dawg to allow for a quick reheat (if it was a home i would undersize it for long on cycles) and I will undersize the fujitsu for nice crisp dry air.

My proffetion is heating and cooling and hearth products so if you guys&gals ever need unbiased advice drop me an email I am more then happy to share my knowledge .

Lastley the last type of a heater you want to use are the ones called NON-VENTED or VENT-FREE there is actually no such thing as them they are just marketing terms the correct term should be ROOM-VENTED or BUILDING-VENTED the by products of burning fossil fuel is actually moisture laden and very corrosive.The last thing you want to breath or have your car stored in.

 

[*89x2*]

That is GOOD STUFF

What size shop are you talking about here??

what model are you looking at??


I am a shade under 900 sq in that one :confused

Thanks again!!!!!!!

 

[IH2LOSE]

The absolute biggest I can go is 600 square feet.

it will be a vaulted ceiling to allow for the lift to go back in.up to todays energy codes

on the cooling side normally if I was asked to cool this area I would chose a 1,5 ton unit to over come a hot car coming in the garage in summer.for my garage I will chose a 1 ton unit

on the heating side I would normally install a heater with an output of at least 33,000 btus so there unit 45 would do it.But because I want a real quick recovery in colder weather I am chosing there unit #60

Here is a link to there site

the company has been around forever



http://hot-dawg.modine.com/unleash.php?expand_index=0

Again you would not use my sizing recomendation for a home but I have noted why I am chosing to go this way

If there was a manufaturor who made heating unit like the hot dawg that used outside air for combustion I would use that one instead to avoid infiltration and and the unit would stay in better shape because it was using cleaner air then that found in a garage.

Probabley the best system I could install would be a condencing warm air furnace located in my wifes garage with a standard a/c system ( it would be safe because it uses out side air for combustion) I could also add a high eff air cleaner to clean the air.But I am chosing the fujitsu system strictley for its dehumidifing properties and because the outdoor unit is very small .a standard a/c sytem can dehumidify just as well as the fujitsu unit but I would have to add alot of controls to it to slow down the fan speed and another controller to allow the oudoor unit to remain running in colder tempitures.

I also have a boiler in my home that I could have used with a hot water hanging heater (hydro air)but for me its easeyer to run 1-gas line then to run the heating pipes over from the boiler.
When we did my partners home he chose to do his house with a hydro air set up and we do not run anti freeze in the heating pipes we just installed free-a-stats on the water lines so if the heating pipes ever get to 38 degrees they just turn on the boiler and the circulator till the tempiture of the pipe get 5 degrees warmer.this is to avoid them freezing if some one leaves the door open.

I DO NOT recomend using antifreeze in a heating system unless its isolated from the boiler with a plate type heat exchanger.

I could also install radent heat in the new garage slab but I always try and design a system as simple as possible.Allthough for my customer I do what they want my personal phillosophy is to keep things as simple as possible.

 

[IH2LOSE]

Also the worst way to heat a garage is from steeling a heating duct from your existing warm air frunance.I was just out at a home last week where they were compaining of dust and oders coming from the heating sytem we installed last year and not enought heat in the master bed room.

None of these problems the customer said were there untill we install there new heater and it was all my fault and I should fix it or they would hire a company to fix it and then sue me for the repairs

What I found was the bedroom was above there garage and the duct work ran across there garage and was sheetrocked over.the home owner cut a hole into the bedroom duct in the garage ceiling and installed 2 heating registers for his woood shop.

His shop was a mess and also a fire hazard waiting for a fire to flash over his fine wood working dust and if it did the fire would have ran into the heating ducts up into the bedrooms and rest of the home.After showing the customer why his bedroom was cold and dusty and a fire hazard and it was not because of us. He did admit to installing the register into the heating ducts in september of last year right after we installed his new heater.He did not even apologize for for being so rude and demanding that I correct his problem.I removed his grills and patched the holes in the duct with sheet metal and the holes in the sheet rock and adviced him to re shock rock the holes in the sheet rock with fireproof sheet rock and had him sign my no charge service invoice.I realley live in an area that unfortunatly the biggest area of our yellow pages is for lawyers.SO as a buisness owner I realley have to dot my I'S and cross my T'S so I am not liable for frivolous lawsuits.As they say nobody like a lawyer until you need one.

the garage should always have a seperate heating source and you should never violate the sheet rock the sheet rock is there to seperate the fire from the living space.

There are fire dampers that are availble to protect you from this but normally the home heater is sized for the home as it is not sized for heating the home also.

When you have a boiler because they are normally zoned with zone valves its normally more foregiving for allowing you to steel a little heat for the garage.

When we do install a hydro air for a garage and we are concerned with the capacity of the boiler we give priority to all the other zones and lock out the garage hydro air untill the heater satisfies the thermostats in the house this way the house is always garrenteed to be at tempiture.We do this incase a garage door is left open in freezing tempitures the hydo air unit would constantly run trying to satisfy the thermostat but because the door is open it could never acomplish the task.then the rest of the house would suffer because alot of the heat is going to the garage area.with a priority lock out the rest of the house will maintain and the FREE-A-STAT will protect the heating pipes in the garage from freezing.

 

[*89x2*]

...still weighing my options - wish I could make up my MIND!!!!!!!