Good point, Cap'n. I neglected to mention that our 2nd source of heat is oil hot water. So that's our backup or primary depending on the price of pellets. But good point, it'd be nice not to worry about frozen pipes over a long weekend.
Mitsubishi Heat pump quote
- Thread starter Woodspliter
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil. -
Super Cedar firestarters 30% discount Use code Hearth2024 Click here
Good point, Cap'n. I neglected to mention that our 2nd source of heat is oil hot water. So that's our backup or primary depending on the price of pellets. But good point, it'd be nice not to worry about frozen pipes over a long weekend.
Peak I do agree to a certain degree with you. I think that they're are disposable units to a certain degree. There is some sensitive electronics inside these things. I'm installing a whole home surge protector. So unless someone crashes into a outdoor uint or lightning strikes twice I should be covered!I have totall faith in these mitsubishi's. But you never know chit does happen my opinion is that, it's is a small price to pay for pice of mind. The new FS is supposed to have a coating on the indoor units to help them stay cleaner. I agree keeping them clean is the single most important thing to keep them efficient and dependable other than proper installation.
DuaeGuttae
Minister of Fire
Spacebus, have you seen @Brian26 ‘s thread about the Midea U-Shaped air conditioners from last year? They’re basically little inverter air conditioners that install similarly to a traditional window air conditioner, but the u-shaped design keeps more of the noise outside. We ordered two through the introductory promotion last year, and there was some damage to one of the units in shipping. Midea replaced the unit in a much better packed shipping container, and we’ve really been impressed with the units.
My husband works at home now, and his office doesn’t have HVAC directly to it. It just benefits from two neighboring rooms. We didn’t need to cool those rooms during the day, though, so this unit allows him to cool his office efficiently. The other we put in our big downstairs open plan area (kitchen, dining room, family room, school/craft/garden room) where we spend all of our time. During hot but not brutal times it allows us not to use the central air in the area, though it really can’t keep up during extreme Texas heat because our area is oversized for its specs.
In our case, it allows us to air condition more efficiently than running central air units unnecessarily. In your case, of course, you would be adding air conditioning, but I wanted to point these out as a much easier and cheaper alternative to traditional mini-splits.
Just google Midea U-shaped air conditioner if you’re interested in checking them out.
SpaceBus
Minister of Fire
Unfortunately we don't have a single double hung window in the house. I do really like the idea of these Midea "U" units and would do it if we had different windows.
EbS-P
Minister of Fire
I’m getting some quotes for a mini split this week and wondered if if anyone thinks a generator transfer switch for a mini split is a good idea. I don’t have a transfer switch at my panels but have considered it.
Evan
Mini Split Disconnect with Generator Standby Plug and Switch 240v 25amp DSS25
With the DSS25 240v 25amp Disconnect switch connect directly to a generator with a standard NEMA L14-30P plug. Produced by MarketAir this product is a neccessity when power outages occur while also acting as a code required power disconnect. Indicator light with toggle switch to go between power...
www.budgetheating.com
Evan
I’m getting some quotes for a mini split this week and wondered if if anyone thinks a generator transfer switch for a mini split is a good idea. I don’t have a transfer switch at my panels but have considered it.
Mini Split Disconnect with Generator Standby Plug and Switch 240v 25amp DSS25
With the DSS25 240v 25amp Disconnect switch connect directly to a generator with a standard NEMA L14-30P plug. Produced by MarketAir this product is a neccessity when power outages occur while also acting as a code required power disconnect. Indicator light with toggle switch to go between power...www.budgetheating.com
Evan
Way easier and cheaper to just wire a plug on your mini split wires from the disconnect and plug it right into the 220 generator outlet. The wires are easy to access inside the disconnect. I installed a whole house transfer plug but had 2 plugs and wires ready to go for both my splits before I did that.
Another plus with mini splits on generators is there is zero start up stage on them.
I have a gentran box out the outside of my house and an interlock switch so I can back feed right to the panel. Simple easy and not much money
DuaeGuttae
Minister of Fire
Oops. I think maybe I’ve even mentioned them to you before. Casement windows ring a bell. I misread your wording of “portable” as “window” air conditioners.
tabner
Feeling the Heat
@Woodspliter i think you got a good deal. I had one outdoor unit (MXZ-3C30NAHZ2-U1) installed with three indoor heads (2, MSZ-GL06NA-U1, and 1, MSZ-GL15NA-U1). I paid 11,800 (after the rebates) for the whole system installed with the 12 year warranty (and 3 year labor warranty).
Only complaint so far is I should have sprung for the branch box and had all the lines run off a box in the attic. Instead the whole back of my house is covered in line hide. But that's my fault.
Does anybody know if my model is the -5 or -13? It's supposed to be hyper heat, but i didn't realize there were two temp mins.
Only complaint so far is I should have sprung for the branch box and had all the lines run off a box in the attic. Instead the whole back of my house is covered in line hide. But that's my fault.
Does anybody know if my model is the -5 or -13? It's supposed to be hyper heat, but i didn't realize there were two temp mins.
Yeah tanner, when I talked to the first installer about a 36k multi zone he said the branch box was like 1500 bucks plus labor and need to run a 8awg wire for another circuit, I quickly decided against that. I love The fact of the 3 singles other than cluttering up the exterior of the house in witch they won't be visible for the road but the extra Efficiency and being able to run them independently of each other nevermind the fact that they're more cost effective was the deciding factor .
Where these units really shine are being able to heat and cool just one room or area. Below is a good example. I have 3 independent single zone 12k units. With my wife working from home the last year she setup her office right under our downstairs unit and she loves it. No need to keep the entire house at 70 when she's just working in 1 room. I know other people getting huge bills keeping their entire house at 70 when its just 1 person in 1 room working from home.
![[Hearth.com] Mitsubishi Heat pump quote](https://www.hearth.com/talk/data/attachments/275/275875-22355683cf7bc630007db4bb9653c1bf.jpg?hash=wh6TdeiSRm "[Hearth.com] Mitsubishi Heat pump quote")
SpaceBus
Minister of Fire
How much more efficient would three separate mini splits be compared to one larger one with three zones?
They are usually much more efficient when you compare SEER and HSPF numbers. The main issue with them is they are usually way oversized.
Single zone units have a much lower turn down ratio. A 12k single unit can modulate from lets say 1200-12000 btus. A 36k btu Mitsubishi multi split will usually have a range of like 9k-36k btu. Those higher minimum speeds are often too much for the actual load. The multi splits have losses as they are pumping refrigerant to each head even if they aren't on.
Here is a good example. You have 3 rooms each with their own 12k units. In the summer a room might only need 1500 btu/hr of cooling. The single zone units can throttle down that low. The lower the load the greater the efficiency with mini splits.
Lets say you have a 36k btu multi split with a 12k head in each room. Since the minimum cooling output is 9k if your ran just one head you are oversized by 6 times. Running all 3 your still oversized by 2.
A 36k multisplit might draw lets say 1000 watts at minimum speed supplying 9k. A single zone can supply 1500 btus and only use like 100-150 watts each. The multisplit is using like 3 times the power and is ridiculously oversized.
On another forum there are endless posts about people getting massive electric bills with these multi's. Maine knows this is an issue and that is why they are only giving out the incentive to single zone units. Its now widely recommended on most green building forums to install multiple single zones.
You also get redundancy. It would take all 3 of my single zones to break for me to lose heat. On a multi split all your units go down. Its also easier to repair a single zone if there is a leak. A single zone has 2 refrigerant lines and 4 flare fittings. A 3 unit multisplit has 6 refrigerant lines and 12 flares between condenser and inside units. They are challenging to get installed leak free as there are so many connections thar can leak and the unit goes down. Much easier to trace a leak on a single zone.
Last edited:
The units that operate in very cold temperatures are typically much less efficient overall, perhaps by a factor of 1.5. If you already have something else as backup heat (besides your woodstove), then I think it would make the most sense to install a unit that operates at higher outdoor temperatures and just switch to the other backup heat source as needed below that temperature.
EbS-P
Minister of Fire
I just got a quote of $4000 not including electrical work for a single 15k BTU unit MUZ-FH15na
MSZ-FH15NA
another outfit wanted $6700 for 27k btu unit for the same space. Install can’t get much simpler. I think I’m going to look at a Blaze King insert and skip the mini split or DIY it.
Seems like you are getting a good deal but prices down here near the beach can be steep any time you need quality tradesman work.
Evan
MSZ-FH15NA
another outfit wanted $6700 for 27k btu unit for the same space. Install can’t get much simpler. I think I’m going to look at a Blaze King insert and skip the mini split or DIY it.
Seems like you are getting a good deal but prices down here near the beach can be steep any time you need quality tradesman work.
Evan
SpaceBus
Minister of Fire
This is the issue I have living in "Vacationland", especially on the coast. As a result I don't really hire many things out. So far the only thing I couldn't do myself was secure and install a new utility pole and some emergency plumbing work. Even if you could afford to hire any tradesmen, they are always booked out working for vacationers or landlords. The DIY looks like a better deal even if I can't get the rebates.
maple1
Minister of Fire
I am not following. Units rated for colder temps should be more efficient? Isn't that why they can rate for lower temps - increased efficiency?
Hyperheat and similar units are rated for efficient operation, e.g., a COP of 2.5 or 3, at lower temperatures, e.g., -5 degrees F. But hyperheat-type units may have a COP of only 3 at 40 degrees or so. A unit incapable of operating or generating heat at -5 degrees F may provide COPs of 4 or 5 at 40 degrees F.
This is very true. If you don't plan on operating the unit at extremely low temperatures its better to get a non hyper heat version.
What is the cop comparison of let's say the fs 9k btu and the rating of the equivalent non hyper heat?
It's been a while since I've done these calculations, but basically you have to find the manual that includes the performance characteristics at different operating temperatures (this isn't widely available - will take some internet sleuthing), and then do your own COP calculation (output/input). Usually, they have output in BTUs and input in Watts, so you have to watts to watt hours and then convert BTUs to watt hours at 3414 BTU/kWh.
Up here in NY state I think a COP of only 3 at 40 degrees is just fine. Really how much heat do you need to generate at 40 degrees. Its been around 30 to 50 degrees this last week and I see almost no change in my electric usage using my -15 degree 24K multi heat pump compared to previous week using propane boiler for heat.
Similar threads
