Mini split vs. electric

[deepstuff]

Hi,
I'm just getting ready to build and was set on getting a mini spit for my garage until I was told by and HVAC friend that an electric heater may better and more efficiently serve my purpose.

My garage will be about 1200 square feet. I live in Canada but do not get really cold winters (only a few days per year below -4 degrees F or -20 C. I would only be fully heating the build when in use, some evenings and weekends. Otherwise I would just be keeping it a little above freezing for most of the winter. This is especially true since my work takes me away from home for half my life.

My friend told me that mini spits do not like to maintain a inside temperature below 62F or 17C. In that case would it be more efficient for me to use electric heaters to maintain my garage at 40 or 45 degrees F, 5-8 degrees C?

 

[theoldwizard1]

Electric resistance heat is probably the MOST EXPENSIVE FOR OF HEAT YOU CAN USE ! Unless you happen to live in an area where the local PoCo gives you a special discount. The best electric heat can do is 100% efficiency. A heat pump runs at better than 100% almost all of the time.

Don't worry about inside temp. You will be fine. Make sure to buy a unit that can produce heat below -20C. Not all do. You may need some auxiliary form of heat (propane/kerosene heater) to bring the temp up quickly on cold winter nights.

 

[Fueler]

I think if you super insulate now while you have the chance you can heat the place with a candle. You will be fine with a mini split. The mini splits are ridiculously efficient. Once at set temp they are running in low gear.

There are likely other units out there but here is one touting 5 degrees heat strength. Maybe too small for your place though.
http://www.heatandcool.com/INVERTER-DUCTLESS-SPLIT-A-C-H-P-p/ksio012-h123.htm

 

[LS6 Tommy]

Hi,
I'm just getting ready to build and was set on getting a mini spit for my garage until I was told by and HVAC friend that an electric heater may better and more efficiently serve my purpose.

If by "more efficient" he meant electric heat would cost less to operate, never. If he meant it would do a better job, maybe. I've never seen a mini split with electric strip heat, so for those REALLY cold days or for bringing the temp back up when the garage has been left unoccupied, electric may actually work better.

Tommy

 

[Highbeam]

Electric resistance heat is probably the MOST EXPENSIVE FOR OF HEAT YOU CAN USE ! Unless you happen to live in an area where the local PoCo gives you a special discount. The best electric heat can do is 100% efficiency. A heat pump runs at better than 100% almost all of the time.

It's no special deal. Electric resistance heaters are cheap to buy, cheap to install, and simple to run low in any temperature condition. Some places like where I live and maybe the OP have electric resistance heat costs that are actually lower than propane or oil.

Sure when everything is working right a minisplit will deliver much more heat for the buck but the minisplit in a garage environment will certainly be more money to install, less dependable, and more likely to plug up with dust/dirt.

Your friend may be right. You can always use two forms of heat. An electric resistance heater for low level freeze protection and a more powerful heater for when you want to be out in the shop at a higher setpoint. For that, it is hard to beat a propane hanging unit heater.

Check your costs. Subzero temps are very low for any heat pump. Some minisplits are rated to provide heat at this temp though.

 

[Milton Shaw]

Check into hotel/motel PAC's (package air conditioners). Most of them come with automatic freeze protection and will come on when room temps get below 40 for instance. They are a one piece through the wall unit that does not require HVAC service man to install. They come in all different BTU configurations and all will fit the same in the wall mounting box when it come time to replace in 10-15 years. They are usually cheaper than the mini splits by a bunch and save even more installing it yourself.

 

[James-W]

In a well insulated garage, when only heated to room temperature occasionally and the rest of the time the garage is kept just freezing, I would think the money saved with the mini-split would take several years to get back the price of the unit. Keep in mind there is still a cost to heat the garage with the mini-split and the garage will only be heated (at a very low temperature) maybe 5 months out of the year. I am not against using a mini-split to heat the garage, I am just saying the cost of purchasing, installing and operating the mini-split needs to be taken into consideration before a fair price comparison can be made.

 

[deepstuff]

Check into hotel/motel PAC's (package air conditioners). Most of them come with automatic freeze protection and will come on when room temps get below 40 for instance. They are a one piece through the wall unit that does not require HVAC service man to install. They come in all different BTU configurations and all will fit the same in the wall mounting box when it come time to replace in 10-15 years. They are usually cheaper than the mini splits by a bunch and save even more installing it yourself.

Do they function as a heat pump though or do they use resistance heat?

 

[bzinsky]

Do they function as a heat pump though or do they use resistance heat?

I looked into them, from what I understand they act as a heat pump, and then below a certain temp (a relatively high temp like 25-40 degrees outside) they switch to electric resistance heat.

 

[Falcon67]

I looked into them, from what I understand they act as a heat pump, and then below a certain temp (a relatively high temp like 25-40 degrees outside) they switch to electric resistance heat.

From what I understand - more or less bottom line with heat pumps is that at some outside temp, they will operate the same as an electric space heater. So that's your choice - heat pump with strip/emergency heat option or a separate electric. You'd need to study the local climate averages and decide. If I run my 5000w shop heat here, it's about .16~.68/hr cost depending on maintenance or full blast for warm up.

We have a new heat pump on the house and in this climate, we should see way more days with it in heat pump mode than not. A string of "cold" days here would be 20s. LOL, your "not many days at -4F" would be our "Oh hell, don't go outside!"

 

[theoldwizard1]

From what I understand - more or less bottom line with heat pumps is that at some outside temp, they will operate the same as an electric space heater. So that's your choice - heat pump with strip/emergency heat option or a separate electric.

Some mini-split heat pumps do NOT have a heat strip. If it gets that cold, you need to provide your own back up heat. Typically these heat pumps can operate efficiently down to close to zero !

View media item 43975

 

[LS6 Tommy]

Check into hotel/motel PAC's (package air conditioners). Most of them come with automatic freeze protection and will come on when room temps get below 40 for instance. They are a one piece through the wall unit that does not require HVAC service man to install. They come in all different BTU configurations and all will fit the same in the wall mounting box when it come time to replace in 10-15 years. They are usually cheaper than the mini splits by a bunch and save even more installing it yourself.

10-12 years is VERY optimistic for a PTAC lifespan. There's a reason hotels, public schools and other places that use them keep 5 or 6 in stock all the time. They are not would I would ever recommend to someone I know if I wanted to stay friends...

Tommy

 

[Falcon67]

The original builder of the drag strip used PTAC units in the tower. All but two no longer work and all gave nothing but trouble over the years. The bottom floor uses a 24K BTU mini-split now that works well. The PTACs are still in the wall because who wants to patch a huge hole in a steel building.

 

[volleyball]

If there is only a demand for heat, using a mini split seems like a no brainer, like you are not using your brain.
Efficiency of operations is a half truth. It is always the total cost. How much to buy, install, use and the service life. You can thermostat the baseboards so that you use only what you need.

 

[Speedy!]

I have a PTAC 15,000 BTU in my current 3 car attached garage. Been there 4 years. I don't use it a lot, but when I've needed it it has worked fine for both heat and cooling.

A/C contractor is recommending the same unit for a detached shop I'm working on now. I am going to ask them about the split ductless unit as well though just to cover bases.

 

[Fueler]

The original builder of the drag strip used PTAC units in the tower. All but two no longer work and all gave nothing but trouble over the years. The bottom floor uses a 24K BTU mini-split now that works well. The PTACs are still in the wall because who wants to patch a huge hole in a steel building.

He should look at this as an opportunity. Patch the hole and sell an advertising sign to cover the patch!

 

[yeldogt]

What is the cost of your electric?

It is very easy to do the math using your areas "degree days" .


Heat pumps are getting better every year -- the newest inverter systems modulate depending on load -- so they are sized for heat. While the efficiencies do drop off the unit is sized so even at lowest design temp it has enough output. It's all about getting the correct unit and size.


Sometimes with cheap electric it easier to have a resistance heat for the coldest of days vs spending extra for a super low temp HP.