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mini split life expectancy
- Thread starter 72puma
- Start date
pseudorealityx
Well-known member
I would expect with proper install, general maintenance, and starting with one of the good commercial level brands, you can easily expect 15-20 years out of one. It being in heat vs. cooling shouldn't have much effect.
how long will these things last in wisconsin used more for heating than cooling?
i'm trying to compare to my 20 year old forced air furnace and central air system that still works fine but very inefficiant.
what's your source of fuel for heat?
If your heating bills are high, it's usually not the heater that's the problem.
Mini split heat pumps are efficient for how much heat they produce for the amount of electric they consume. Natural Gas is a whole lot cheaper than electricity.
As far as length of functionality, there's a million variables, but they are not like window units, they should last a long time.
pseudorealityx
Well-known member
what's your source of fuel for heat?
If your heating bills are high, it's usually not the heater that's the problem.
Mini split heat pumps are efficient for how much heat they produce for the amount of electric they consume. Natural Gas is a whole lot cheaper than electricity.
As far as length of functionality, there's a million variables, but they are not like window units, they should last a long time.
Cost is based almost entirely on location. You cannot make concrete statements like "natural gas is a whole lot cheaper than electricity". There are plenty of locations where that's not the case, or that any advantage in efficiency is lost due to very few hours of heating combined with the added expense of running gas to the project, or that many furnaces have **** for blowers in the larger sizes and can't even produce a half inch of external static at a nominal 400 cfm/ton.
pseudorealityx
Well-known member
The other thing to consider is air distribution. If you're deal with some nice big open floor plan, a mini-split or two is fine. If you're dealing with an older house with lots of small rooms, you can run into problems or price yourself right out of the market with multiple evaporators all over the place.
finn
Well-known member
Natural gas being cheaper than electricity is irrelevant if the nearest natural gas line is six miles from your house!
Propane, on the other hand.....
Propane, on the other hand.....
have propane forced air furnace now,but have a 10 kw solar array makeing more power than i use right now. also on time of rate use .05 cents off peak and .25 cents on peak which is 7am to 7 pm ,just about when the sun shines,so my solar array would cover my peak electric rates during the day and .05 cent electricity during nights and weekends is way cheaper than all other fuels.
thats why i am thinking mini splits with my open floor plan and super insulated house,thats if these thing will last 15 -20 years.
thats why i am thinking mini splits with my open floor plan and super insulated house,thats if these thing will last 15 -20 years.
theoldwizard1
Well-known member
Heat pumps (unless they are geo-thermal) are NOT good sources of heat in cold climates. The BEST units start dropping efficiency at about 5-10°F and pretty much stop producing heat at about -10°F. Last time I checked, WI gets their share of days/nights below 10°F !how long will these things last in wisconsin used more for heating than cooling?
i'm trying to compare to my 20 year old forced air furnace and central air system that still works fine but very inefficiant.
A mini-split is not designed to replace a central heat/cooling system. They are design to mount high or low on a wall (or possibly in the ceiling) in each room and heat/cool a few rooms. The other big win is a thermostat for each room (typically wireless).
Yes, there are units that can have multiple "air handlers" (3-4 is typical), but even on typical 1200 sq ft 3 bedroom house, you are likely to not have adequate coverage. Also running the lines to multiple rooms could be a challenge.
As for durability, if you buy a top of the line unit, expect the same life expectancy as a good central air system.
theoldwizard1
Well-known member
Excellent motivation for going to a mini-split !have propane forced air furnace now,but have a 10 kw solar array makeing more power than i use right now.
thats why i am thinking mini splits with my open floor plan and super insulated house,thats if these thing will last 15 -20 years.
Well, multiple units is a good solution ! If you have a large, open, "living area", expect to use 2 air handlers.
Check into the Mitsubishi "Hyper Heat" inverter mini-split. One of the best units on the market.
Depending on how your bedrooms, bathrooms and other rooms are laid out, you will easily need 3 more air handlers. One consideration for a bathroom is resistance heat on a timer.
With 10kw of solar, you will still be buying power, but the inverter mini-splits are the most efficient thing on the market today without going geothermal. I would still suggest some kind of propane backup, even if it leaving your current furnace in place.
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You are a perfect candidate for a mini-split because you already have solar and a propane backup system for when it's super cold. There are some stories online about failures and poor warranty support, but the big brands all have a 7 year warrant on the compressor now. 1 unit will do a lot for you in terms of reducing your propane bill and the outlay will be relatively minor, so in the event of a freak failure you'll likely still be ahead. I wouldn't dump 10k into multiple units or a multizone system though.
Heat pumps (unless they are geo-thermal) are NOT good sources of heat in cold climates. The BEST units start dropping efficiency at about 5-10°F and pretty much stop producing heat at about -10°F. Last time I checked, WI gets their share of days/nights below 10°F !
A mini-split is not designed to replace a central heat/cooling system. They are design to mount high or low on a wall (or possibly in the ceiling) in each room and heat/cool a few rooms. The other big win is a thermostat for each room (typically wireless).
Yes, there are units that can have multiple "air handlers" (3-4 is typical), but even on typical 1200 sq ft 3 bedroom house, you are likely to not have adequate coverage. Also running the lines to multiple rooms could be a challenge.
As for durability, if you buy a top of the line unit, expect the same life expectancy as a good central air system.
Not true anymore, mini splits are just fine for the sole source of heat in most of the lower 48. Just look at the data.
Cost is based almost entirely on location. You cannot make concrete statements like "natural gas is a whole lot cheaper than electricity". There are plenty of locations where that's not the case, or that any advantage in efficiency is lost due to very few hours of heating combined with the added expense of running gas to the project, or that many furnaces have **** for blowers in the larger sizes and can't even produce a half inch of external static at a nominal 400 cfm/ton.
Per the purpose of sheer energy production, I have never seen gas prices remotely close to electric prices. Please specify which locations. There is a lot of energy in natual gas for the dollar, and thats all my post was referring too.
pseudorealityx
Well-known member
Per the purpose of sheer energy production, I have never seen gas prices remotely close to electric prices. Please specify which locations. There is a lot of energy in natual gas for the dollar, and thats all my post was referring too.
Umm, how about the OP, who basically has 'free' electricity via solar?
Regionally, I believe based on various threads I've seen here, that some locations out west, like Utah/Nevada have inexpensive electricity vs. gas. Tennessee may also due to TVA power.
But sure... a cubic ft of gas may be able to produce more energy, but there's a host of other things that go into making these decisions.
Spending money on a gas furnace in Florida over a heat pump for instance... why bother when the temp never gets below 40 where a heat pump is easily running a COP above 3.
pseudorealityx
Well-known member
Not true anymore, mini splits are just fine for the sole source of heat in most of the lower 48. Just look at the data.
That depends on your application and how you provide distribution. Sure it 'can' work, but the cost to do a typical 4 bedroom house with separate kitchen/living/dining areas.... that gets awfully spendy with evaporator heads all over the place. Especially if your house isn't insulated very well.
For instance, the guy in the other current thread with the 8500 sq ft. house. ****** application for non-ducted mini-splits.
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That depends on your application and how you provide distribution. Sure it 'can' work, but the cost to do a typical 4 bedroom house with separate kitchen/living/dining areas.... that gets awfully spendy with evaporator heads all over the place. Especially if your house isn't insulated very well.
For instance, the guy in the other current thread with the 8500 sq ft. house. ****** application for non-ducted mini-splits.
I was refuting his claim they are not capable at lower temperatures, obviously
bacr619
Active member
Mini ductless is very efficient and can last as long as the system you currently have with proper maintenance. The big advantage is your existing system is say 3 tons to cool the whole house you will need to run at full load when you are sleeping to keep the bedrooms cool or heated. Lets say you have 2 bed rooms occupied at night you only cool of heat those two rooms. You only need to condition the rooms that are occupied. The equipment is more expensive and to be installed correctly and commissioned will be more then what you currently have. If you go that route evaluate all the qualifications of all installing contractors.
theoldwizard1
Well-known member
Heat pumps (unless they are geo-thermal) are NOT good sources of heat in cold climates. The BEST units start dropping efficiency at about 5-10°F and pretty much stop producing heat at about -10°F. Last time I checked, WI gets their share of days/nights below 10°F !
Not true anymore, mini splits are just fine for the sole source of heat in most of the lower 48. Just look at the data.
I have looked at the data. I stand by my statement. My numbers are just a bit conservative.
View media item 43975
Note that is a specific model from a specific manufacturer. Look at the blue line. That is the "rest of the industry".
Actually, parts of AK (near Juno) would be fine for a "hyper' heat" mini-split !
I have looked at the data. I stand by my statement. My numbers are just a bit conservative.
View media item 43975
Note that is a specific model from a specific manufacturer. Look at the blue line. That is the "rest of the industry".
Actually, parts of AK (near Juno) would be fine for a "hyper' heat" mini-split !
Terrible graph and clearly mitsu marketing material
All the big manufacturers have the same stuff.
The blue line is basically older or cheaper units that dont use dc invertors. What that doesnt show is the performance falling off a cliff right there at 17 degrees. You need backup heat.
The yellow line is mid range invertor driven models. That line keeps steadily going down. This could be the sole form of heat for most of the US.
The mitsu hyper heat graph is similar to that of a few other units, they are the newest 25+ seer models. These will be efficient on the coldest of the cold nights.
Now also keep in mind, these things start with a cop of like 3-4. You drop the efficiency 20% for those few chilly nights, your still looking at about 2x-2.5x as efficient as resistance heat.
pseudorealityx
Well-known member
Terrible graph and clearly mitsu marketing material
All the big manufacturers have the same stuff.
The blue line is basically older or cheaper units that dont use dc invertors. What that doesnt show is the performance falling off a cliff right there at 17 degrees. You need backup heat.
The yellow line is mid range invertor driven models. That line keeps steadily going down. This could be the sole form of heat for most of the US.
The mitsu hyper heat graph is similar to that of a few other units, they are the newest 25+ seer models. These will be efficient on the coldest of the cold nights.
Now also keep in mind, these things start with a cop of like 3-4. You drop the efficiency 20% for those few chilly nights, your still looking at about 2x-2.5x as efficient as resistance heat.
Your problem is that you're equating "efficiency" with "capacity". Big difference.
It also means, depending on your climate, you need to oversize your system to deal to get enough heating capacity on your design heating day. That's a bunch of extra money.
theoldwizard1
Well-known member
TRUE !Terrible graph and clearly mitsu marketing material.
Well if other manufacturers have similar capability to the Mitsubishi "Hyper Heat" they sure are not advertising it !All the big manufacturers have the same stuff.
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The mitsu hyper heat graph is similar to that of a few other units, they are the newest 25+ seer models. These will be efficient on the coldest of the cold nights.
Got and advertising/data to support your claim ?
theoldwizard1
Well-known member
You understand the systems limitation !sure we get days when we have -0 temps but we have many more days in the teen's,20's+30's when we need heat so a little auxiliary heat would not be a problem.
Your only decision is how many outdoor (compressors) unit you want (more than 1 will allow you shorter/easier installation of the line sets) and where to mount the indoor units.
I have no affiliation with Mitsubishi.
Mitsubishi M-Series Contractor Guide
pseudorealityx
Well-known member
Shorter line lengths isn't only about installation. These systems lose capacity with line length. Especially on the cooling side, and especially latent.
racer1
Well-known member
I installed LG mini's last yr. in my new house. I have radiant heat so i put them in for air cond. And also for heat in spring and fall. 3 head unit, 22 seer, dc models. I used them for awhile last winter when propane hit 6 bucks. They are awsome. They would blow out over 100 degree heat at 10 Below. Still don't know how they can do it. But they do.
theoldwizard1
Well-known member
I installed LG mini's last yr. in my new house. I have radiant heat so i put them in for air cond.
That is a great combination ! I don't know how you would balance between the 2 independent systems.
Well if other manufacturers have similar capability to the Mitsubishi "Hyper Heat" they sure are not advertising it !
Got and advertising/data to support your claim ?
That is very true, there lies the problem. I literally spent about 40 hours of my time researching units for a rehab I'm currently doing.
The manufactuers are not posting the data clearly and it is very difficult to find, and when they do you can tell some are inaccurate and most just don't provide it at all. There were a few that clearly even mixed up celcius and fahrenheit from most likely a poor japanese translation.
What I think the problem is: The manufacturers don't seem to realize how important it is. It's not easy to test these things in cold conditions. I think they need to test these things in real world conditions to actually provide the data. In order to actually test these things to well below zero, you need to send a team pretty far north. Not cheap.
What I figured out is there is pretty much 3 categories of heat pumps, and they all have similar low temp performance. Most of them have terrible data, personally I'm not relying on anything that doesn't have data to back it up, but I'm about 99% sure they will perform from everything I've learned.
Non-invertor heatpumps (older and cheaper tech)- Nobody has performance data for temps lower than 17 degrees. Frankly because they aren't capable of it.
DC inverter, like 15-20 seer range for the AC - Allmost all of the manufacturers have data down to 5 degrees for these things, and while they are not incredibly efficient at that temp, they still operate. If they kept testing them at lower temps, unlike the non-inverter units, they wouldn't just cease to function. The btu/external temp performance is more like a steadily decreasing line, instead of a cliff. This is important for a climate like where I'm at in the Philadelphia region. If there ever is a record low temp, like 0, I know these things will still operate even though there's no proven data for it. It may not keep the house comfortable that 1 day, but they won't create no-heat situation.
Then we have the ultra high seer, 25-28 range, inverter driven heat pumps. I've concluded that there is some different tier of hardware in them regardless of manufacturer, similar to the difference between inverter and non-inverter models. Not sure what it is, but it's a big step up from the other units in low temp performance. I would bet money that all of them function at very similar performance and have very similar hardware to mitsu-hyper heat. They are like a whole different category.
Mitsu hyper-heat does the best marketing by far and seemingly is the only manufacturer to understand why this data is important. I found solid data from only two other manufactuers, both of which I searched diligently for. It's much easier to find now than it was about 6 months ago. Fujitsu and LG. I went with LG because it was the cheapest of the 3, and I went to the manufacturer provided training course on the unit, and spoke with actual people who engineered the product. They basically said the data is very conservative, and I believed them. The data is still impressive too.
Here's a government study comparing the Fujitsu and Mitsu hyper heat, these are only 12k btu models. The government study is likely more accurate than the conservative estimates from the manufacturers.
http://www.nrel.gov/docs/fy11osti/52175.pdf
The Fujitsu was pumping out around 13k btus at -10 degrees!
Here is info for the LG units, art cool premier line. These are the ones I went with because they were the cheapest that actually had proven data on them.
http://www.lg-dfs.com/art-cool-premier.aspx
Click on engineering manuals...
The 12k btu model is conservatively rated at 9kbtus at -13 degrees.
Also, I'd like as many people as possible to read this post, a lot of hard work went into finding this. You can see that even at -10 degrees these things still have a COP of 2, which means they are 2x as efficient as electric resistance heat. These new air-source heat pumps are the future. The hardware is relatively cheap, they solve a lot of installation problems that can come with duct work and plumbing. Best of all, they are without question the most efficient way to provide AC. The heating performance is amazingly pretty close to the btu/$ of natural gas, (assuming your natural gas and electric is about average in pricing)
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theoldwizard1
Well-known member
The manufactuers are not posting the data clearly and it is very difficult to find, ...
Well, the the marketing genius at Mitsubishi who invented the term "Hyper Heat" really earned his paycheck !
Well, the the marketing genius at Mitsubishi who invented the term "Hyper Heat" really earned his paycheck !
Well the hyper heat actually refers to a setting that allows it to heat a room quickly since mini-splits are known to gradually heat an area. There not like a boiler that provide 3 times as much output as necessary for a period of time then shut down. In reality it just puts the fan speed on high and the compressor on high.
But yes, mitsu figured it out, and it's why almost everybody knows about them and nobody knows about these other units.
Also, something interesting I found, after all this searching for cold weather units, I went to the canadian LG site and this unit was right on the front page (a few months ago atleast). Apparently they think it's only important to canadians. The US site promotes the picture frame style indoor unit, I guess they think we're more shallow lol.
BTW, the cassettes and the picture frame indoor units destroy the efficiency ratings, nobody should use those unless there is some odd reason why you have to.
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pseudorealityx
Well-known member
Well the hyper heat actually refers to a setting that allows it to heat a room quickly since mini-splits are known to gradually heat an area. There not like a boiler that provide 3 times as much output as necessary for a period of time then shut down. In reality it just puts the fan speed on high and the compressor on high.
This is incorrect.
1) Hyper-heat is Mitsu's ability to provide 100% of it's heat down to an outside ambient temperature of 5 degrees, like your earlier graph shows. The 'normal' Mitsu product line (P series and M series) do not have that capability.
2) They are heat pumps. When the call for heating comes, the compressor kicks on, and it spits out as much heat as it can until your return air temp starts getting close to your set point. Then it will start to throttle back.
But yes, mitsu figured it out, and it's why almost everybody knows about them and nobody knows about these other units.
WHAT OTHER UNITS? LG? Sanyo? Fujistu? Daiken?
Also, something interesting I found, after all this searching for cold weather units, I went to the canadian LG site and this unit was right on the front page (a few months ago atleast). Apparently they think it's only important to canadians. The US site promotes the picture frame style indoor unit, I guess they think we're more shallow lol.
I see 0-64 as the temperature range on the LG units. And there's no mention of what the unit's heating capacity is *AT* 0 degrees. Likely, it's ~50% of the rated capacity, which is always given at 47 degrees.
BTW, the cassettes and the picture frame indoor units destroy the efficiency ratings, nobody should use those unless there is some odd reason why you have to.
All the other styles have their various uses. The cassettes definitely lag behind the normal wall mounts, but you can get them at 20 SEER or higher.
Your problem is that you're equating "efficiency" with "capacity". Big difference.
It also means, depending on your climate, you need to oversize your system to deal to get enough heating capacity on your design heating day. That's a bunch of extra money.
This gets overlooked very often, in my climate you will normally need just about twice the btus for heating that you need for cooling.
pseudorealityx
Well-known member
This gets overlooked very often, in my climate you will normally need just about twice the btus for heating that you need for cooling.
Yes. And the converse is true for hot climates. And even more confused when you realize that all HVAC cooling equipment is typically rated at 95 degrees outside, but if you've got 115 degrees in Phoenix, you're losing an extra ~20-25% of that rated capacity.
This is incorrect.
1) Hyper-heat is Mitsu's ability to provide 100% of it's heat down to an outside ambient temperature of 5 degrees, like your earlier graph shows. The 'normal' Mitsu product line (P series and M series) do not have that capability.
2) They are heat pumps. When the call for heating comes, the compressor kicks on, and it spits out as much heat as it can until your return air temp starts getting close to your set point. Then it will start to throttle back.
WHAT OTHER UNITS? LG? Sanyo? Fujistu? Daiken?
I see 0-64 as the temperature range on the LG units. And there's no mention of what the unit's heating capacity is *AT* 0 degrees. Likely, it's ~50% of the rated capacity, which is always given at 47 degrees.
All the other styles have their various uses. The cassettes definitely lag behind the normal wall mounts, but you can get them at 20 SEER or higher.
1)I could have been wrong about that, but what is 100% of it's heat? They are totally variable in heat output. Did you read anything from the links I posted?
2)LG and Fujitsu, I also posted that in my big post, please read it all
You also did not read the document from LG I posted, it says clear as day in the document of the heating performance down to -13 degrees.
Also what is 50% of capacity? There is no capacity!
Also as stated earlier, the LG puts out a conservative estimate of 9k btu's at -13 degrees, that is a far cry from your estimate at 0.
Please refrain from disagreeing with me until you read my entire post, and the data provided. It's all there.
I still think the mitsu units have a high heat button for "hyper heat" to be honest, don't feel like looking it up though.
pseudorealityx
Well-known member
1)I could have been wrong about that, but what is 100% of it's heat? They are totally variable in heat output. Did you read anything from the links I posted?
100% of it's heat is what it can produce. Look at page 8 of your first PDF. The blue sloped line is the capacity based on the outside air temperature.
2)LG and Fujitsu, I also posted that in my big post, please read it all
You also did not read the document from LG I posted, it says clear as day in the document of the heating performance down to -13 degrees.
Ugh... I looked up the 9k BTU model. The submittal gives a heating capacity of 11,000 BTU. However, if you read the print below, that's taken at 47 degree outside temp. As that temperature lowers, so does the heating capacity.
Also what is 50% of capacity? There is no capacity!
Capacity in a refrigeration cycle is dependent on the delta T involved. A heat pump is pulling heat out of the outside air. It's harder to pull heat out of 0 degree air than it is 47 degree air. Therefore, the capacity is lower.
Also as stated earlier, the LG puts out a conservative estimate of 9k btu's at -13 degrees, that is a far cry from your estimate at 0.
Please refrain from disagreeing with me until you read my entire post, and the data provided. It's all there.
I still think the mitsu units have a high heat button for "hyper heat" to be honest, don't feel like looking it up though.
Suit yourself if you think you're correct.
You also did not read the document from LG I posted, it says clear as day in the document of the heating performance down to -13 degrees.
Also as stated earlier, the LG puts out a conservative estimate of 9k btu's at -13 degrees, that is a far cry from your estimate at 0.
Please refrain from disagreeing with me until you read my entire post, and the data provided. It's all there.
.
Reading the LG engineering manual it looks like the heating capacity of a LAN120HYV/LAU120HYV at -12 db/ -13 wb is 5.77 kBTU/hour with a 68 indoor temp.
Is there a different model # for a unit that provides better low temp preformance?
Reading the LG engineering manual it looks like the heating capacity of a LAN120HYV/LAU120HYV at -12 db/ -13 wb is 5.77 kBTU/hour with a 68 indoor temp.
Is there a different model # for a unit that provides better low temp preformance?
I decided to take a look at what you're talking about, heating capacity tables clearly gives that performance.
Another mini split mystery, why'd you have to do this to me lol
If you look at page 11, it says clear as day it's capable of 9520 btu's at that same temp.
So I read the fine print, the heating tables you were looking at exclude the heat provided by the evaporator fan. That appears to be the reason for the differential. My first thought was, those sneaky bastards snuck in some resistance heat calling it "evaporator power consumption" That's 3750 btu's extra!. That's 1100 watts of resistance heat added to what is supposedly a air source heat pump. Then I went back to the capacity tables, which just happens to include total power consumption. This thing is consuming only 510 watts when it's -13 out. Which means it couldn't possibly providing 1100 watts of resistance heat.
Either there is something in there I missed, don't understand, or the data is wrong. So frustrating....
100% of it's heat is what it can produce. Look at page 8 of your first PDF. The blue sloped line is the capacity based on the outside air temperature.
Ugh... I looked up the 9k BTU model. The submittal gives a heating capacity of 11,000 BTU. However, if you read the print below, that's taken at 47 degree outside temp. As that temperature lowers, so does the heating capacity.
Capacity in a refrigeration cycle is dependent on the delta T involved. A heat pump is pulling heat out of the outside air. It's harder to pull heat out of 0 degree air than it is 47 degree air. Therefore, the capacity is lower.
Suit yourself if you think you're correct.
Go back to page 11 and read it all, don't just skim it and come back here just to tell me I'm wrong.
Just to give you cliff notes of what you overlooked, yes it says capacity 11k btus, but then it also says
Heating Capacity (Min/Rated/Max) (Btu/h) 1,023~11,000~20,472
and
Maximum Heating Capacity (Btu/h)
Outdoor 17 °F (WB)/Indoor 70 °F (DB) 11,935 (109%)
Outdoor 5°F (WB)/Indoor 70 °F (DB) 11,220 (102%)
Outdoor -13 °F (WB)/Indoor 70 °F (DB) 7,920 (72%)
how on earth does it produce 102% of capacity at 5 degrees, when capacity according to you is
Ugh... I looked up the 9k BTU model. The submittal gives a heating capacity of 11,000 BTU. However, if you read the print below, that's taken at 47 degree outside temp. As that temperature lowers, so does the heating capacity.
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I think they will last a long time as long as the cleaning is done on a regularly scheduled basis. As I said in a post recently, the cleaning of the evaporators is the Achilles Heel of the mini-split brand. That said, I wouldn't be without them in my home. IN the foothills of the Sierra in N CA last winter my highest electric bill for the well, lights, and mini-splits was $85. Shoulder season it drops to $30-40. This summer was smoking and my highest bill running the cooling constantly was, again $85.
They work well at low temps, depending upon model. My heating favorite however remains the Rinnai Energysaver gas Direct Vent. I've had them in my house, basement and garage since '91. Incredibly durable, great technology and nothing heats like the Energysaver and their maintenance requirement is about nil. Due to a remodel at the house I lost clearance on the vent outside and reinstalled it on another wall. I took the unit out onto the bench and blew it out with air and reinstalled. That is after 5 yrs of operation. I may use my mini-split for heat. I will always use my Rinnai. In fairness, I must point out that I was Rinnai's Manuf Rep in the New England area from '91-'11 and still consult with them. They are outstanding, They are not cheap and you get your money's worth! With the mini-split and Rinnai I have the best "net to the space" combination.
They work well at low temps, depending upon model. My heating favorite however remains the Rinnai Energysaver gas Direct Vent. I've had them in my house, basement and garage since '91. Incredibly durable, great technology and nothing heats like the Energysaver and their maintenance requirement is about nil. Due to a remodel at the house I lost clearance on the vent outside and reinstalled it on another wall. I took the unit out onto the bench and blew it out with air and reinstalled. That is after 5 yrs of operation. I may use my mini-split for heat. I will always use my Rinnai. In fairness, I must point out that I was Rinnai's Manuf Rep in the New England area from '91-'11 and still consult with them. They are outstanding, They are not cheap and you get your money's worth! With the mini-split and Rinnai I have the best "net to the space" combination.
pseudorealityx
Well-known member
Go back to page 11 and read it all, don't just skim it and come back here just to tell me I'm wrong.
Just to give you cliff notes of what you overlooked, yes it says capacity 11k btus, but then it also says
Heating Capacity (Min/Rated/Max) (Btu/h) 1,023~11,000~20,472
and
Maximum Heating Capacity (Btu/h)
Outdoor 17 °F (WB)/Indoor 70 °F (DB) 11,935 (109%)
Outdoor 5°F (WB)/Indoor 70 °F (DB) 11,220 (102%)
Outdoor -13 °F (WB)/Indoor 70 °F (DB) 7,920 (72%)
how on earth does it produce 102% of capacity at 5 degrees, when capacity according to you is
Ugh... stop looking at the general data an look at page 27, where the actual performance data is.
HVAC units have 'rated' capacities. They are rated at very specific points, so that all rated capacities can be compared directly to one another.
Now, some of these new mini-splits, with the 'high heat' (whatever term they use to market that) option, basically allow the system to over spin the compressor vs. 'normal' operation. When in heating mode, this creates additional heat above and beyond what you would get out of the straight refrigeration cycle.
1) That is why most of them have heating capacities higher than their cooling capacities. It's all the same equipment, just in reverse.
2) That is how they're able to heat down to very low temperatures, where as a normal split system or packaged heat pump cannot.
3) That is your missing BTU load in your previous post.
Evaporator fan heat is a real thing... but NOT in a mini-split. They don't have the static to build heat.
Another useful thing for most is to look at pages 28 and 29. *THIS* is why mini-splits aren't great for a lot of spaces. They just don't have enough throw to do much. These things are great for small room applications, but the limitations quickly appear.
Pseudo, I have to disagree on the communicating space call. I've been selling modulating equipment since '91. The thing, both with the Rinnai's and the mini-splits is that they are designed to do two things. One, satisfy the comfort demand and two, do it at the lowest possible input. They want to continue to run. If they overshoot, run at to high an input, they have to shut down, just like a single stage piece of equipment. It is why "how low" a piece of modulating equipment goes is more important to your comfort than how high it will go. Extended run times allow circulation within spaces. Basic physics, heat goes to cold. All that said, every space has a personality and proper selection & placement of equipment are essential.
Cutting registers hi and low from room to room works when air is not circulating to your satisfaction. Put a straw in a glass of water, put your finger over the straw and you can lift the water. Remove your finger and the water flows. Air works pretty much the same way. In some cases where problems with air flow occur, Tjernlund's Airshares work well to help out. I've been able to do multi room applications in large projects with the Airshares and registers using both mini-splits and Rinnai's.
Cutting registers hi and low from room to room works when air is not circulating to your satisfaction. Put a straw in a glass of water, put your finger over the straw and you can lift the water. Remove your finger and the water flows. Air works pretty much the same way. In some cases where problems with air flow occur, Tjernlund's Airshares work well to help out. I've been able to do multi room applications in large projects with the Airshares and registers using both mini-splits and Rinnai's.