heat pump

[junkyardwarrior]

30x40x10 fully insulated. R19 walls and sprayed ceiling, open truss.

Live in the mid south. Summers are always upper 90's and into the low 100's for 2 months give or take. Winters aren't too bad. I haven't seen a 20 degree night yet this year but January and February might bring some.

Looking at putting some heat out in the shop and ditch the propane torpedo because of the fumes, CO, and water vapor. I thought about a heat pump unit. I don't want it 70 in the shop in the dead of winter. 60 would be PLENTY. In the summer, if it's 80-85 out there, that's way better than 105-110. I keep it at 80 in the house in the hot months anyway. I don't have nat gas available out at the shop or I'd just get a gas furnace and A/C unit combo. How do you think a heat pump would work? 2.5 ton be sufficient? I am finding several used units on local craigslist, and could get one pretty cheap.

 

[LS6 Tommy]

I wouldn't go used, but that's just me.

Tommy

 

[JBudd2]

I got a mini split online. 24k but with 2 indoor heads for the 2 rooms. It was 9 degrees this morning and the shop was 55 inside. Cost about $2500 but there were cheaper ones.

 

[matt_i]

I would look at a "mobile home unit" which is a large HVAC unit designed to sit outside, has 2 large round ducts, one for intake, one for output. Heat pump with optional backup electric. IIRC 100% efficient down to 50F ambient, and then linear dropoff in efficiency to 0F where it will not be able to transfer any heat from outdoors....I bought it online, pickup at truck terminal, and oinstalled in my house (which had same setup previously but AC only). No charging, its precharged, just wire it up and connect the ductwork.

There are also wall mount units, with similar features, Bard is one such manufacturer.

 

[slice]

I have same size. I live 20 miles from Galveston. I have a 4 ton two speed heat pump. Summer's. 100 out I can get it down to 68. Winter. What ever I want. Point. 2.5 may not be enough. Farther north your btu rating for heating are more important than cooling. Also let me say summer time my humidity is 48 % in shop. comfy.

 

[BADSIX]

I got a mini split online. 24k but with 2 indoor heads for the 2 rooms. It was 9 degrees this morning and the shop was 55 inside. Cost about $2500 but there were cheaper ones.

this I just installed 2 of these in a 3000sq ft. home i'm remodeling, 1 upstairs 1 down stairs. they work great. I believe these are about as economical to use as it gets, unless you have free fire wood for a wood stove. my heat bill for Nov. with temps in the mid 40s to mid 50s and the thermostats set at 68 was 40.00. that's with no insulation on 1 wall up stairs and single pain windows still in 75% of the house. also running power tools work lights and in and out the door all the time.
Jay D.

 

[theoldwizard1]

How thick is that foam on the ceiling ? For your heat load, I would suggest 4-6".


The modern min-split heat pump are super efficient and do not need a gas hook up. Admittedly, they are not cheap, but depending on how many hours per year it gets used, it should pay back pretty quick compared to a used residential furnace-A/C.

For a shop your size, you really should have 2 air handlers. Even then you are going to need some good fans.

 

[OccupantRJ]

I would look at a "mobile home unit" which is a large HVAC unit designed to sit outside, has 2 large round ducts, one for intake, one for output. Heat pump with optional backup electric. IIRC 100% efficient down to 50F ambient, and then linear dropoff in efficiency to 0F where it will not be able to transfer any heat from outdoors....I bought it online, pickup at truck terminal, and oinstalled in my house (which had same setup previously but AC only). No charging, its precharged, just wire it up and connect the ductwork.

There are also wall mount units, with similar features, Bard is one such manufacturer.

Otherwise known as a package unit. I have a 2.5 ton package heat pump on my 34x36 shop and really like it so far. I ran my ductwork in the attic and have outlets in the ceiling.

 

[mjoekingz28]

Is a heat pump the same as an outside AC unit?

I looked at the store and they looked the same.

Here is what I have: an indoor gas furnace with fan. It heats the house without the use of the outside unit. In hot weater, when AC is on, both the inside and outside units are powered on.


Just wondering if they are different or am I just hearing different terminology.

 

[crabjoe]

A heat pump is basically a AC with a reversing valve... There's a bit more to it, but it's a AC that runs in reverse.

AC works by removing heating from the house to the outside. When in heating mode (Heat pump), it takes the heat from the outside air and puts it in our home, garage, or whatever building.

 

[CrashTestDummy]

Like Tommy, I wouldn't go used, either. You never know it's repair history, and the new ones are getting pretty efficient.

If you live anywhere where it freezes, you'll want a heat strip in the unit. Heat pumps don't do so well as the outside temp approaches freezing.

 

[manwithtools]

Heat pumps also usually have a "emergency" heat source - most commonly resistive electric heat for the times the heat pump looses it's ability to provide heat in the "reverse AC mode". That's somewhere around 40 degrees F outside temperature. Below that point you need another source of heat.

 

[CrashTestDummy]

Not all come with that strip, though, so be sure to ask. I'd bet that package units, or splits would, but a standard HVAC configuration with a separate condensing unit and air handler, the heat strip is usually an extra piece.

 

[Dick in Wisconsin]

Do you have a well? Access to lots of water? Consider a used ground water heat pump. Most economical way to air condition. Sounds like your needs are more A/C than heat.

 

[theoldwizard1]

Otherwise known as a package unit.

Package units are notoriously loud and INEFFICIENT !

 

[theoldwizard1]

Not all come with that strip, though, so be sure to ask. I'd bet that package units, or splits would, but a standard HVAC configuration with a separate condensing unit and air handler, the heat strip is usually an extra piece.

Most mini-splits do NOT have the capability to add a resistance heat strip. Better mini-splits will make heat down at 100% efficiency down to near 0F.

View media item 43975

 

[theoldwizard1]

Is a heat pump the same as an outside AC unit?

I looked at the store and they looked the same.

The outside piece (compressor) of a mini-splt heat pump does look very similar to a traditional AC unit. It has extra valves/pipe so it can run "backward" and generate heat. The compressor is designed to be extremely efficient.

The bif win is the air handler mounts on the with the pipe running directly through the wall to the compressor. Short piping also helps with the efficiency.

 

[Jinks]

Depending on the amount you're willing to spend either a wall mount heat pump, or a mini-split heat pump will do what you want. I had the wall mount heat pump in my last place & it would control the temp both summer & winter well enough to make me happy. The only real drawback was the noise. Back then I just accepted it as necessary, but now I have a mini-split, & would never go back. The things are scary quiet, & the Mitisubishi inverter units are amazingly efficient. The one mistake I made was paying to have it installed to preserve the warranty. I could have done a better job myself & saved enough to replace the unit a couple of times if I had an unfixable problem.

 

[Highbeam]

Most mini-splits do NOT have the capability to add a resistance heat strip. Better mini-splits will make heat down at 100% efficiency down to near 0F.

View media item 43975

Not 100% efficiency at 0F but 100% capacity. They are capable of making the same btu. We don't know how the efficiency changes but even straight electric is 100% efficient.

 

[theoldwizard1]

Not 100% efficiency at 0F but 100% capacity. They are capable of making the same btu. We don't know how the efficiency changes but even straight electric is 100% efficient.

Point well made !

 

[OccupantRJ]

Package units are notoriously loud and INEFFICIENT !

Sound wise, it is barely noticeable while in the shop, and besides it was 6 months old and FREE. I can live with that.

 

[jonjon1]

http://www.amazon.com/dp/B006X1AZOQ/?tag=atomicindus08-20

super easy install, you can find them locally for short money, they work, and they are commercial quality, you wont touch these things for a few decades... ALL IN 1 UNIT, heat and cool...

you can put electric heater in this in 20 minutes..

takes up no inside space

just duct it through the wall, put it on a foam pad, run 220 to it, and some 18 gauge thermostat wire, you literally need $80 of sheet metal (thats if you have someone make you the boots), a $50 pad, $50 of registers, a $50 thermostat, and the wire...

 

[OccupantRJ]

My free Goodman 2.5 ton.

 

[jonjon1]

My free Goodman 2.5 ton.

VERY nice...


In reply to them being loud and inefficient..

Compared to what? I have installed many, they are no louder than a regular outside a/c unit, and inefficient? The affordable ones are 14 seer, they are plenty efficient, I ran 3 of them to cool and heat an 8000 sq ft building a few years back, it was on par with any other heating system I could have installed, BUT much less to install it...


For a garage, package units should be a no brianer, unless you are going with radiant for comfort issues, package units are the way to go.... I would take one over a radiant floor all day, I know guys say "but the floor is warm" sure it is, but I have lifts and can NOT remember the last time I laid on the floor for a long period of time (I dropped an oring today and scurried around a little, wasnt down there long enough to know if it was cold or warm, lol)...

I get the entire "the heat is under 8 feet" and "it only heats to 105 degrees". BUT, its super expensive to install (I should know, lol), it needs a good amount of service, you have WATER to deal with, you do not get AC out of it, the lifespan is limited, it can be a service horror show if there is an in floor failure (again, ask me how I know, and I use thermal imaging cams to find the failures, some guys dont even have that, just a jack hammer and saw, lol), they have to be done at the time of builidng, very hard to retro fit, etc etc etc...

So package units are a nice option to heat and cool a garage, dont write them off until you played with them a bit..

 

[finn]

VERY nice...


In reply to them being loud and inefficient..

Compared to what? I have installed many, they are no louder than a regular outside a/c unit, and inefficient? The affordable ones are 14 seer, they are plenty efficient, I ran 3 of them to cool and heat an 8000 sq ft building a few years back, it was on par with any other heating system I could have installed, BUT much less to install it...


For a garage, package units should be a no brianer, unless you are going with radiant for comfort issues, package units are the way to go.... I would take one over a radiant floor all day, I know guys say "but the floor is warm" sure it is, but I have lifts and can NOT remember the last time I laid on the floor for a long period of time (I dropped an oring today and scurried around a little, wasnt down there long enough to know if it was cold or warm, lol)...

I get the entire "the heat is under 8 feet" and "it only heats to 105 degrees". BUT, its super expensive to install (I should know, lol), it needs a good amount of service, you have WATER to deal with, you do not get AC out of it, the lifespan is limited, it can be a service horror show if there is an in floor failure (again, ask me how I know, and I use thermal imaging cams to find the failures, some guys dont even have that, just a jack hammer and saw, lol), they have to be done at the time of builidng, very hard to retro fit, etc etc etc...

So package units are a nice option to heat and cool a garage, dont write them off until you played with them a bit..

Not so friendly to the pocketbook when your power company charges $.21/kwh, though

 

[jonjon1]

Not so friendly to the pocketbook when your power company charges $.21/kwh, though

Doesnt matter, they dont charge you more per kwh depending on what equipment you use...

So when using a 14 seer package unit vs say a 21 seer mini split even at .21 its still only $150 a year in savings, that will be eaten up in initial costs, service, etc...

Real world comparisons, for the same money you can get a dual fuel package unit with a gas burner built in, use the heatpump in the shoulder months and the gas when its cold, you will save money initial all the way through the end, when the package unit goes 30 years with out a service issue and you are on your 3rd mini split...

 

[mjoekingz28]

junkyardwarrior,

Are those jet(torpedo) kerosene burners all toxic? Do they burn your eyes, give sniffles, headaches or bother you? I like them, but have never owned one......are they mainly for screened porches or otherwise outdoor spaces?

In a mildly ventilated shop environment, do you experience nausea from the fumes? I take it kerosene does not burn as cleanly as natural gas?

 

[mjoekingz28]

.....speaking of heat pumps....are they the same as a outside AC unit? In the summer my outside unit is on to blow cold air, but in the winter, only e inside unit is on- the outside unit does not activate for heating purposes.


I ask, because I was at the hardware store and looked at what looked exactly (to me) like an outside AC unit, but was labeled 'heat pump'....

 

[theoldwizard1]

I ask, because I was at the hardware store and looked at what looked exactly (to me) like an outside AC unit, but was labeled 'heat pump'....

They look identical on the outside. There are a lot of extra valves and pipes on the inside to effective make the AC unit run "backward" (i.e. cool the outside).

 

[manwithtools]

Doesnt matter, they dont charge you more per kwh depending on what equipment you use...

So when using a 14 seer package unit vs say a 21 seer mini split even at .21 its still only $150 a year in savings, that will be eaten up in initial costs, service, etc...

Real world comparisons, for the same money you can get a dual fuel package unit with a gas burner built in, use the heatpump in the shoulder months and the gas when its cold, you will save money initial all the way through the end, when the package unit goes 30 years with out a service issue and you are on your 3rd mini split...

If you want us to believe that you have gone 30 years without a service issue on any HVAC unit, you really do need to provide the bourbon you are drinking

Besides you should have it serviced regularly to make sure you are getting optimum performance.

If it DID go 30 years than you started throwing your money away at year 15. Newer technology results in energy/money savings; there is no way around that. What the payback time is may be debatable, but there is a payback window.

Then comes the initial install costs for ducts, gas (natural or LP) if they don't already exist in sufficient supply or origin. It could be a 3 to one ratio for a dual fuel package unit install if its from scratch vs. a min-split - particularly if you pay a pro for the install. Now the payback is skewed significantly in the direction of the mini-split.

 

[PWC Repair]

Original posters username is "junkyardwarrior". I'm going to go out on a limb here and guess he's not springing for new OR a mini-split. That being said a 2.5ton might do what you want it to BUT in the used market you could get a 3 or 4 ton for the same money. I'm betting 3 ton would be about right. Call your local HVAC guys, many of them will save nice used systems to re-sell if somebody has upgraded. Then run a simple trunk duct down the middle of the shop with 90* saddle takeoffs to direct the airflow. This is a slow time of the year for a lot of HVAC guys, they might cut you a great deal on a whole install......I'm thinking $1400 or less for used.