Looking to install a mini split...

[Gearhead660]

Looking to install a mini split. Wanting to get something better than the window AC unit. Also would be nice to use for heat in spring and fall. Want to install in open living/dining/family room area. All added up, around 750 sq ft. Not so air tight old farm house so want to size it a bit larger than what a newer home would need. What size should I be looking to get? Was thinking 24,000 btu.

 

[stoveliker]

I have an 18k uniting a similar area. Works well. But my home is not drafty, has new (efficient) windows. Insulation in the walls is fair. Elsewhere very good.

How much sun comes in for you? Big difference in what you need.

 

[semipro]

I'd go at least 24k BTU. I see no problem with going larger than you think is needed. Any decent mini-split will have a variable speed compressor (i.e. inverter) and variable speed fans that overall provide a variable capacity.

Also, for cooling, that 750 sqft. is the area you'll condition unless you have an open basement access. For heating, however, if you have a 2nd level much of that heat is likely to move upstairs so that would be a further argument for oversizing.

 

[Gearhead660]

I have an 18k uniting a similar area. Works well. But my home is not drafty, has new (efficient) windows. Insulation in the walls is fair. Elsewhere very good.

How much sun comes in for you? Big difference in what you need.

When its sunny out in the winter, I get a lot of solar gain. Got newer windows and insulation, but still a bit drafty.

 

[Gearhead660]

I'd go at least 24k BTU. I see no problem with going larger than you think is needed. Any decent mini-split will have a variable speed compressor (i.e. inverter) and variable speed fans that overall provide a variable capacity.

Also, for cooling, that 750 sqft. is the area you'll condition unless you have an open basement access. For heating, however, if you have a 2nd level much of that heat is likely to move upstairs so that would be a further argument for oversizing.

Basement door is closed. No need to cool it, old creepy basement just for storage/utility.
Have an upstairs, some heat would go up.

 

[Gearhead660]

Researching them, noticing a drop in SEER rating when you get above 24K. One of the reasons I was leaning towards the 24K unit. If I could get by with the 18K, that would save a few bucks. Currently using a smaller window unit, surprisingly it does an ok job cooling the downstairs.

 

[Okla]

GearHead..... If you're looking for something better than a window AC unit, you shouldn't need more than the 18,000 BTU split system you asked about. We presently cool a pretty big portion of our home with a Mitsubishi MUZ-FE18NA (an 18,000 BTU mini split heat pump).

After reading your original post, it would seem that we're using our mini split the same way you intend to, so I'd say that a system like ours will be way more effective than the window AC units we {also} used in the past...but, then again, we don't live in WI. We life in the mountains along the Mass-NY border. I hope that this helps you out.

 

[Gearhead660]

GearHead..... If you're looking for something better than a window AC unit, you shouldn't need more than the 18,000 BTU split system you asked about. We presently cool a pretty big portion of our home with a Mitsubishi MUZ-FE18NA (an 18,000 BTU mini split heat pump).

After reading your original post, it would seem that we're using our mini split the same way you intend to, so I'd say that a system like ours will be way more effective than the window AC units we {also} used in the past...but, then again, we don't live in WI. We life in the mountains along the Mass-NY border. I hope that this helps you out.

Thanks. Was looking to see what others are using. Sounds like 18k may be enough. Dont want to go too big and have it short cycling.

 

[drewmo]

What's the volume of the area you'd like to cool/heat and how many indoor heads are you thinking? The 24K seems to be oversized for that square footage.

 

[Gearhead660]

What's the volume of the area you'd like to cool/heat and how many indoor heads are you thinking? The 24K seems to be oversized for that square footage.

Roughly 800 sq ft. But wanted to go a bit oversized as there are rooms beyond the main area and its got 2 stairwells to the upstairs.

 

[maple1]

We've got a 12k in our living room. It blows towards a doorway, just outside that is an open staircase to 2nd floor. Lots of heat goes up there when heating. So 12k seems a good size for us here. House is pretty chunked up. 1500 sqft down, 1200 up. Have another 12k in our upstairs bedroom. We might get thru a winter on just the splits if we added another 12k on the other end if floor 1 in the kitchen. But when cooling, the 2 12k's really make the whole house pretty comfy in summer. Father has a 15k in his more open place. It covers that pretty good.

 

[hockeypuck]

I do not think Mini splits are prone to short cycling like the window units. Do not discount the heat they throw during the shoulder season. We use ours more for heating than cooling (hours used) even though we bought it for cooling purposes.

 

[Gearhead660]

So, finally got to try out the heating of the mini split. Been highs in the 50s during the day, lows close to 30 at night. No issues during the day keeping house at temp. As long as night low doesn't go below 30, I won't need a fire. Got down to upper 20s last night, lost a couple degrees in the house. Impressive little unit. I like the timer. Can set it to start early in the morning to warm up house before I get out of bed.
Will cut down on wood use for sure. Would have had a fire in the insert every day this week if we didn't install this.

 

[peakbagger]

They do suffer the same issue with respect to humidity control when oversized. If you oversize them they just dont get the dampness out as well.

 

[hockeypuck]

Good point. The variable compressors can dial back the output but humidity control can suffer if it is too big. We have a sprawling ranch and we put a box fan in the hall way to the bedroom to help circulate the cold air.

 

[hockeypuck]

It cut back my wood usage by 1/2. I used to burn 3 chords, now its barely 1 1/2. The stove does not get fired up until I see a string of days with highs in the 30's and that normally does not happen until mid December.

 

[aaron1]

I'm tempted by the mini splits since my 100 yr old house has very old ducts and no return on the second floor (for cooling efficiency/distribution.). I think to do an air handler heat pump would require a lot of duct work ($$$.). My main concern with the mini splits is the maintenance/durability. For those who have them, how arduous is the PM on them? I know the filter cleaning and that stuff is no big deal, but what bout the deep cleaning of the coils and such. I worry about having to use a bunch of cleaning solution up on a ladder and splashing all over my walls and floor, or is it not that bad?

 

[maple1]

I'm tempted by the mini splits since my 100 yr old house has very old ducts and no return on the second floor (for cooling efficiency/distribution.). I think to do an air handler heat pump would require a lot of duct work ($$$.). My main concern with the mini splits is the maintenance/durability. For those who have them, how arduous is the PM on them? I know the filter cleaning and that stuff is no big deal, but what bout the deep cleaning of the coils and such. I worry about having to use a bunch of cleaning solution up on a ladder and splashing all over my walls and floor, or is it not that bad?

I have done next to zero to mine in the 3 years we've had them. Only cleaned the filters maybe 4 times. A 10 minute job with the vacuum cleaner. Absolutely nothing else. As far as I know, deeper cleanings are more apt to be needed when they are used a lot for a/c.

 

[aaron1]

I have done next to zero to mine in the 3 years we've had them. Only cleaned the filters maybe 4 times. A 10 minute job with the vacuum cleaner. Absolutely nothing else. As far as I know, deeper cleanings are more apt to be needed when they are used a lot for a/c.

Ah, that makes sense. The AC is going to mean a lot more water and possible mold and such. Interesting you don't really need to do much for heating-only. That's really good info. So, you're pretty happy with them I guess? Are they sized pretty well?

 

[peakbagger]

If you have pets and are a smoker you will need to clean filters more often. In theory the units are supposed to be cleaned every few years which requires disassembly. There are You Tube videos on how to do it. The coil are cleaned with spray on product, any drips go into the condensate drain. If you are a smoker the blower wheel probably will need cleaning. That usually requires taking it outside and hosing it. The outdoor units can be cleaned with a spray product and a hose. Many folks totally ignore them. Mine will die one day from a design defect that is not readily repairable but I will get at least 10 years on it which is the typical expected life of HVAC equipment. Motors and compressors are sealed and they will wear out eventually.

 

[aaron1]

If you have pets and are a smoker you will need to clean filters more often. In theory the units are supposed to be cleaned every few years which requires disassembly. There are You Tube videos on how to do it. The coil are cleaned with spray on product, any drips go into the condensate drain. If you are a smoker the blower wheel probably will need cleaning. That usually requires taking it outside and hosing it. The outdoor units can be cleaned with a spray product and a hose. Many folks totally ignore them. Mine will die one day from a design defect that is not readily repairable but I will get at least 10 years on it which is the typical expected life of HVAC equipment. Motors and compressors are sealed and they will wear out eventually.

Ah, that makes sense too. Pet fur can get into everything! Fortunately, I only have non-shedding pets and don't smoke, other than the wood stove occasionally, lol. I'm starting to think I should be able to handle the PMs ok. Seems like flushing/treating the drain lines would be important when I use them for AC. Obviously an HVAC guy would have to check the compression for me if that is needed.

Mostly, I just don't want to be worrying about making a bunch of mess inside the house. A little mess is ok I guess, ha ha.

Thanks for the input

 

[peakbagger]

One thing I learned is the units are designed for universal mounting but there was a definite preference on my Mitsubishi unit. I fit mine in where it would fit but wish I had drilled the hole in the wall on the right side of the indoor unit instead of the left side. My guess is every model may be different. I kept my drain line short basically directly to the ground under the hole in the wall where the lines go, Make sure you foam and then seal that hole which is usually hidden with snap on tubing trays.

 

[aaron1]

One thing I learned is the units are designed for universal mounting but there was a definite preference on my Mitsubishi unit. I fit mine in where it would fit but wish I had drilled the hole in the wall on the right side of the indoor unit instead of the left side. My guess is every model may be different. I kept my drain line short basically directly to the ground under the hole in the wall where the lines go, Make sure you foam and then seal that hole which is usually hidden with snap on tubing trays.

Thanks, yeah I would make sure to seal up any holes. Maybe the drain lines could run out with my downspout and get away from the house, though it's probably not an obscene amount of water when in AC mode.

 

[maple1]

Ah, that makes sense. The AC is going to mean a lot more water and possible mold and such. Interesting you don't really need to do much for heating-only. That's really good info. So, you're pretty happy with them I guess? Are they sized pretty well?

Yes quite happy. We could use another one in the other end of our house. I am way lax on cleaning but the filters haven't been bad when I've done it. And we have a big dog that sheds like crazy. I think it is recommended to do once a month.

 

[Highbeam]

Yes quite happy. We could use another one in the other end of our house. I am way lax on cleaning but the filters haven't been bad when I've done it. And we have a big dog that sheds like crazy. I think it is recommended to do once a month.

I forget if you have high wall units or floor units but does dog hair get up high on the high wall units?

I'm tempted by the mini splits since my 100 yr old house has very old ducts and no return on the second floor (for cooling efficiency/distribution.). I think to do an air handler heat pump would require a lot of duct work ($$$.). My main concern with the mini splits is the maintenance/durability. For those who have them, how arduous is the PM on them? I know the filter cleaning and that stuff is no big deal, but what bout the deep cleaning of the coils and such. I worry about having to use a bunch of cleaning solution up on a ladder and splashing all over my walls and floor, or is it not that bad?

I have similar old house with no ducts. Do you think you can live with the aesthetic? If you try and put the wall head in an out of the way place for looks then do you think the heat or cold will spread well?